Proper Parallel Battery Bank Creation, Fuses, Charging?

[Totem]

I read some interesting articles that I have never considered before today on solar charging systems.

Apparently larger systems are higher voltage (i.e. 24, 36, or 48.) and this is not so much because of gains in efficiency, but safety.

For me I have some home brew systems that would make any backwoods redneck proud... but are they dangerous?

I have some batteries that i built from a bunch Genesis bricks that I rewired in parallel. I put equal aged and as close voltage batteries into the housing as i could. There are 10 of them, 7AH each and their voltages range from 12 to 12.6 resting. Not great I know... but they are improving with the desulphator.

In any event I have all 10 wired into a screw down panel that then sends out two 2 gauge wires for hookup to the rigs inverter.

My concern here on this battery bank is that they are not balanced in charging with one single charger attached to said 2 gauge wires. so it may be a fire hazard to the toy home... i'm going in the interim to play with it and discharge it a couple times at similar load.

Also in my cabin in Northern Michigan, I have 3 deep cycle batteries of same rating each one year older than the other.... now I am worried about the same problem; the solar charge controller is directly hooked to the bank. There is a fuse to the charge controller and a fuse to the inverter... but what about between the batteries themselves. multiple batteries generate high amps/current/capacity at the same voltage. should one battery fail/short all of the other will rush it. Should I be putting 150 amp fuses in between those deep cycle batteries in between their interconnecting wires?

I suppose I could do the same in the small bank of 10 UPS battery bank I made... the fuse being sized according to the connecting wire. Thoughts?

[Totem]

So again, what the article I read stated was that either series, or series parallel of no more than 2-4 per string should be used. if parallel must be used they should be inline fused.

It also said something about connecting the charger from opposite ends of the string, which in my 10 battery bank case would be impossible since they all route to the same posts...

weird. I know cars/rvs/trucks have always had 2 batteries in parallel for years.. a fusible link was sometimes used to connect them. maybe that's what i should use in between deep cycles?

[WME]

That much parallel is never good. About the best you can do is charge them separately until they are as close as possible. After a while of use do the same recharge cycle. This will keep them as close as possible.

The best way to charge multi batteries is in series.

[Totem]

what about 3 group 24 deep cycle marine/rv batteries? is this also bad?

[zero]

I read some interesting articles that I have never considered before today on solar charging systems.

Apparently larger systems are higher voltage (i.e. 24, 36, or 48.) and this is not so much because of gains in efficiency, but safety.

Solar arrays are often hooked up with high voltage to keep wire sizes small. I've never read any claims that it's done for safety (that I regard as legitimate). I worked on a solar array this past summer that is wired for over 400 volts DC. With grid-tie systems that do not have batteries - 600 volts is not usual.

When you wire something off-grid and have a battery bank - 12, 24, or 48 volts is more common because most charge-controllers only come with those charge options.

I don't share your concern with parallel hook-ups in regard to safety. For optimum battery life, yes. I also do not know of any cars or trucks with any sort of fusible links between paralleled batteries. I know none of my Ford or Chevy diesels have any such thing. Neither do any of the John Deere or Caterpillar tractors I've worked on that have dual 12 volt batteries in parallel.

That being said, I've never had the need to have more then four pairs of batteries paralleled. Three is often the recommended limit for best battery life. My cabin in the New York Adirondacks has 1000 watts in solar panels, one 12 volt Outback controller/charger, and battery bank with 8 six-volt batteries. Four pairs of 6 volt batteries - each pair in series and then each set paralleled to make 12 volts. I.e. four parallel hookups. On its 9th year so so those Deka GC2 batteries are long past their average life. So at least in my case, "optimum life" was not shortened. My Trace/Xantrex inverter-charger has an "equalize" charge function to combat the possibility of batteries having cells not of equal voltage. I never used it though. I have no grid power to run it and never had a big enough fuel-powered genset to do it either.

[Totem]

This is what I was hoping someone would say, as I have only had my 3rd battery in the bank at the cabin a couple months. I didn't plan on hooking up more than 3 in parallel in our system, because the wiz bang desulphator instructions said not more than 3 batteries in parallel would it support.
So, should I also not fear 10 small ups batteries in parallel? Minder charger at 2 amp and other Charger is a float with 500 mA.
I have had the 10 batt bank hooked up for couple days on float after having individually charged each battery and selecting its closest mates voltage-wise from a batch of 60 that were refurbished.

I'm trying to run each battery through a 4 week session on a wiz bang also in both my toy home bank as well as cabin banks as an experiment. I fried one wiz bang and they sent me another free which was nice.

[Totem]

Www.wizbangplus.com , some say snake oil on them but so far I have observable success reviving totally dead batteries of less than 1 volt...

[WME]

Your 10 battery pack is safe, but won't offer optimum discharge amp hours or battery life.

[Maineah]

I have used 7 amp batteries in UPS systems at 96 volts in 3 banks of 8 for phone system backup. They had a 120 volt output at 23 amps.

[Totem]

So Maineah, were they parallel or series.. most of the UPS/phone batts like this I have seen were in quick trays in series.

But to JDEs point, my dodge, upon inspection did not have fusible link in it after all when i checked. I think the 3 group 24s in parallel are ok, but I probably need to make sure I move the charge discharge cables to the ends of the chain for better balancing instead of having them off of the battery on the end.

in my 10 battery setup this is impossible, so meh, I will just leave it be and run it as is. and inspect it in a year. In just the last 2 days it has gone from 12 to 12.39 at rest after sitting with the wizbang on a float. I am thinking in 3 weeks time it will be in the 13's. In my mind those 10 batts are stting there and the lowest one of them is getting the flow of charge/60v pulse and when it gains to be higher than that of the next in line lowest it will start to pulse that one. In fact I would think if left on the float long enough they bank should balancde out fairly well since they were all fairly close to begin with.

Thanks for the input fellas. In my next solar setup I think I am going to move to 48volt so that I can do 2 4 battery series parallel banks.I will series the 12 volt solar panels at that point to raise up the voltage and get a new charge controller (48v).

For now, my inverter is 12 volt and was very cheap. I am in 12volt parallel world solely because its cheap to get g24 "deep cycle" batteries, 12 volt gear etc while I learn, but the system is getting more and more used by everyone as people get comfortable with the 12 volt inverter in the toy and cabin. I do plan to upgrade.

[zero]

Thanks for the input fellas. In my next solar setup I think I am going to move to 48volt so that I can do 2 4 battery series parallel banks.I will series the 12 volt solar panels at that point to raise up the voltage and get a new charge controller (48v).

For now, my inverter is 12 volt and was very cheap. I am in 12volt parallel world solely because its cheap to get g24 "deep cycle" batteries, 12 volt gear etc while I learn, but the system is getting more and more used by everyone as people get comfortable with the 12 volt inverter in the toy and cabin. I do plan to upgrade.

My farm in New York is going to be sold on May 1, this spring. House and barn are on grid-tie solar with a 48 volt battery bank. I have a brand new Iota 48 volt battery charger. Never used. If you get feeling a need for it, I'll sell it to you for half-price. I had it just in case some disaster ever happened when the grid was down for over week, and the sun did not shine. If that 48 volt battery bank got discharged - I felt a need to have some emergency way of charging the batteries. So I bought this new 48 volt charger. If I had needed it - I would of plugged in to my PTO powered generator (run by a farm tractor). That tractor, generator, and battery charger are up here in Michigan now. Note that if you are going to have a 48 volt battery bank, you need some sort of plan for battery charging when normal modes fail. 48 volt chargers are not exactly "common." The charger I have also has the optional IQ4 adapter to make it "over-charge" battery banks.

Battery charging has been a major issue with off-grid solar users for years. What to do when the sun does not shine? Main issue is that most portable generators cannot run conventional battery chargers very well. So that means you either need a high-end generator, or . . a special non-conventional battery charger that will work with poor quality AC from a portable generator. For 12 volt systems - some of the best chargers are home-made from auto-alternators, 5 horse gas engines, and a special regulators added. Many large inverters made for solar use have built in battery chargers. Some will work with portable generators and some will not. For example, the Trace/Xantrex DR series of inverter-chargers will NOT work when hooked to a conventional (non-inverter) portable AC generator. The Trace Xantrex XW series will but costs a lot more.

By the way, one thing I forgot to mention. One other gain with high voltage solar panel wiring. If the solar array DC voltage is as high or higher then the AC voltage needed from the inverter - the big step-up transformers in the inverter can be eliminated. I.e. - send 300-400 volts DC into an inverter to make 120 or 240 volts AC and things get much simpler.

[Maineah]

My neighbor is totally off grid and lives in another state. They come up weekends the house is lit entirely with high end led's but other that that every thing else is conventional, fridge, furnace, TV and G4 control of the entire system from away. Two arrays of solar panels one two hundred feet from the house (it's tough to find sun light in the woods) that is a high voltage system the other array is on the house roof also high voltage. Last year we put up an 1800 watt wind turbine at 85'. That still was not enough to keep the batteries up to where they needed to be during the dark northern winters so a generator was added it auto starts when the battery bank voltage drops below a certain point. It is nothing special just a propane powered house generator with enough wattage to overcome the inductive instead of resistive loads it will work fine.

[zero]

That still was not enough to keep the batteries up to where they needed to be during the dark northern winters so a generator was added it auto starts when the battery bank voltage drops below a certain point. It is nothing special just a propane powered house generator with enough wattage to overcome the inductive instead of resistive loads it will work fine.

Yes it IS something special. It is a generator designed to power household appliances and I assume is not a portable "jobsite" type generator. Backup generators made to hard-wire to households are known to make near-perfect power, as compared to portable generators that often, do not. That's why I used the adjective "portable" in my post.

[Totem]

I really am seeing why i went 12 volt in the first place after all of these comments soaking into my thoughts for a few days;

I have an old schumacher set to 2 amp thats in our generator circuit that charges the battery banks when they die at night in the cabin.

Its far from perfect but i had it lying around and added it to the tapestry of evil I call my cabins "off grid" setup. Originally we started the hunting cabin using only generators; the harbor freight lunchbox ones. As the system expanded and I changed the well from hand pump to small electric jet pump (900 watt draw) I found I could run everything pretty darned well with the following (hunting Cabin setup):

• solar charge MPPT controller from ebay $10 won auction 12 volt 10 amp
• harbor freight panels (full system did not use charge controller or lights) 3 at 15 watts per and had sale and coupon ($120 in 2005)
• additional 160 watt panel from ebay auction $200
• each year i replace my group 24 deep cycle in the RV and put old in cabin 3 of them at $85 per ish - $255
• HF inverter 2500 watt spike 2000 continuous on sale with coupon $79
• one set of gold cart battery cables from ebay $15
• 12 volt LED SMD panels from china $24
• 1/3 hp jet well pump ebay $70
• wiz bang desulfator $25

SO far I only have $798 total in the shacks electric and water system of which we usually can go 2-3 days with before firing up a generator. Historically we burn 3 gallons of gas per day when we didnt have the system, gas was fairly pricy at over $3.5 for past 3 years.

I spend at least 15 days there per year and have had it 2 years.I estimate its saved me $250 so far in gas, and several trips to get gas when i dont wish to.

So in 6 more years the system will have paid itself off; yielding a total of 8.5 years running to get to payoff. From what I have read thats about standard to pretty good.

Maybe I will just stay on 12 volt. Also when we do run a genny now, we charge the batteries while supplying power to run everything and store the excess power which buys us another 2 days or so making the times we do run genny much less and more economical.

[zero]

So in 6 more years the system will have paid itself off; yielding a total of 8.5 years running to get to payoff. From what I have read thats about standard to pretty good.

Maybe I will just stay on 12 volt.

Sticking with 12 volts makes many things much easier. I only used 48 volts at my place in central New York because of distance problems. No sun where the house is. So I built a new barn on the side of the mountain to mount the panels on and distance of the DC wiring was an issue. The higher the voltage, the smaller the wires and be and the easier it is to make long runs.

My cabin in the Adirondacks is all 12 volt. It's in a low sun area. I mounted four 120 watt panels on the roof to catch morning to noon sun. Mounted another four 120 watt panels on the front wall to get early to late afternoon sun. Have an Outback MX80 controller-charger. Two inverters. One mod-wave and one sine-wave. NAPA Deka GC2 batteries (same as Trojan T-105s). I was forced to install a sine-wave inverter to pass electrical inspection. The cheaper mod-wave inverter like Harbor Freight sells will not run hard-wired smoke alarms and makes GFCI outlets buzz badly.

My Xantrex DR2414 inverter/charger has an on-board 120 amp battery charger. When hooked to a 7000 watt Homelite portable generator it can make no more then 25 amps. Huge difference between grid-power when it makes the 120 amps easily. I later got an old 17 KW backup generator made by Fairbanks Morse. Slow running at 1800 RPM and has a 140 cubic inch Continental four-cylinder, water-cooled gas engine. It runs my Xantrex 120 amp charger with NO issues.

What are you using for a refrigerator? I've got a Sundanzer 12 volt DC all-electric chest-refrigerator and love it. It is TRULY amazing. A single battery and a single 120 watt solar panel can run it. it is an incredibly efficient refrigerator.

If you start hard-wiring your cabin, look for the old-style wall switches that "snap." The modern soft or silent wall switches do not work well with DC power.

If you ever need to use AC type breaker panels - Square D type QO is one of the few easily available that is DC rated. Home Depot stocks it.

I spent 11 years slowly building that cabin whenever our family had time to camp there. Just finished it last year and now it is for sale since we are all done with New York forever. I'm not sure I have enough energy to build another here in Michigan but I'd love to have one in the eastern U.P. We might wind up stripping all the solar stuff out of the NY cabin and take it here to Michigan. All depends on who buys it. Lot of city people want grid power only.

[Maineah]

Yes it IS something special. It is a generator designed to power household appliances and I assume is not a portable "jobsite" type generator. Backup generators made to hard-wire to households are known to make near-perfect power, as compared to portable generators that often, do not. That's why I used the adjective "portable" in my post.

I run my house on a Honda "construction generator" computers, TV, lights water pump, etc. and charge the batteries in the RV. If your 7K generator does not cut it you got problems 120 amps at 12 volts is not a lot of current at 120 volts.

[zero]

I run my house on a Honda "construction generator" computers, TV, lights water pump, etc. and charge the batteries in the RV. If your 7K generator does not cut it you got problems 120 amps at 12 volts is not a lot of current at 120 volts.

Nope, the problems I mentioned were certainly not specific to me. In fact, many owners manuals for off-grid inverters and battery chargers warned about the problem. I notice you make no mention of the make and model of your battery charger, nor do you mention it's charge rate on grid power versus generator power. Seems to me you just want to "stir the pot" without using any real facts.

Note I never said that ALL portable generators make poor power, did I? I also did not say anything like ALL battery chargers have the problem.

The problem I mentioned was and still is well know with people who work in the off-grid solar industry. In fact, many dealers used to publish lists of generators known to perform well as well as lists of those known NOT to. Same with battery chargers. Many dealers also sold line-conditioners and step-up transformers to make problem generators work better with battery chargers.

To some degree this is "old news" that you apparently have never been privy too. It's "old" because most inverter-chargers now come with "bad generator" resistant chargers that are much more high-tech then the old chargers were.

The most common issue was low voltage. Grid power at our homes called "120 volts" is actually 170 volts that dips up and down to make the Hertz wave. Many portable generators only peak at 150 volts instead of 170 volts. Many battery chargers only work by clipping the 150-170 volt peaks and thus the problem.

And again, note my use of the word "many" when preceding "portable generators." I have NEVER said they all do it.

I ran tests on several portable gensets last year. Most made bad power if conventional. All but one inverter portable generator made good power.

The ones I tested included four Homelites 2500 to 7000 watt, three Colemans 750 watt to 8000 watt, one Champion 3200 watt, two Subarus, two Baldors, one KingKraft, one Yamaha, etc. Inverter models I tested were Coleman 700 watt, Honeywell 2000 watt, and a ETQ. All worked well except the ETQ. Chargers used on the test were a Marquette 80 amp shop charger, two Schumachers (6 amp and 20 amps), Makita and Ryobi 18 volt screwgun chargers, and several cell-phone chargers. Also an Iota 12 volt, 45 amp charger that is more sophisticated then the others and often sold for off-gridding.

[Totem]

Hmm I would love a 12 volt chest fridge. Right now we use ice/coolers and an older propane rv fridge that runs off a standard grill tank.
I hate coolers they get food mooshy. The older rv fridge works ok but takes 3 days to get cold well and by then we are leaving.
I almost pulled the trigger on a large 12 volt chest fridge from Costco on sale for $68 but it was too big to fit in e300 trunk.

Agree 100% on 12 volt stuff being cheaper and easier aside from 2 gauge cable. Thankfully in Michigan there are no rules on grandfathered structures especially ones that don't exist.. "Officially". I know the step up from 12 to 110 is less efficient but I gotta say that inverter from HF never ceases to amaze me. It even runs electric chainsaw and cut through hickory!

One other idea I had I got from a YouTube blog a guy does on amateur solar.. He spent $5000 on a nice electric golf cart and solar panel and charge. His cart is 48v, same as the charge controller and the carts roof sports a 205 watt panel for regeneration. He had huge Trojan batteries in the cart also (4) and a 48v 3000 watt inverter under the seat with built in outlets in front and back of the cart. He would drive the cart up to his cabin where a cable waited for him to hook up and the golf cart also ran the cabin and connected the cabin's extra 6 panels back to the cart. His cart HF electric chainsaw and firewood bed in the back. I love that concept, that the cart IS the battery bank and portable generator.

[zero]

Thankfully in Michigan there are no rules on grandfathered structures especially ones that don't exist.. "Officially". I know the step up from 12 to 110 is less efficient but I gotta say that inverter from HF never ceases to amaze me. It even runs electric chainsaw and cut through hickory!

I built half my cabin with a $99 Harbor Freight 2000 watt mod-wave inverter. It never failed and I still have it. The older ones had thermal fans that only ran if overheated which is a nice feature inside an RV. The newer HF units have el-cheapo fans that run constantly. The fan noise drives me nuts when inside an RV.

The only problem I had with it was starting a small air compressor I used to run my nail-gun. The first year I had the HF inverter it started the compressor fine. Then the compressor starting having issues getting started and the inverter alarm would trip. I did not know if the inverter had gotten weaker or the compressor was having issues. I then switched to a Ramsond Sunray sine-wave inverter rated at a lesser 1500 watts and IT runs the compressor fine. So I assume the inverter got weaker but cannot prove it. It's rated 2000 watts continuous and 4000 watts surge. The sine-wave Ramsond is rated 1500 watts continuous and 3000 watts surge. My old Harbor Freight inverter is inside an RV now running a TV, DVD player, etc.

We used a Dometic three-way refrigerator for years at our cabin - on propane. It's a 1973 and still works fine. I just got sick of screwing around with propane and lighting it every time we came up. I got my Sundanzer for $799 when on sale. They are well over $1000 now. It is truly amazing how little they run on. Almost defies reason. Made by the same company that used to make Dometic. I guess having 6" of insulation helps a lot.

[Totem]

yah their 2000 4000 (4 outlet) watt unit I returned... fan ran constant and it wouldn't power up my freezer when i load tested it.

Funny, the 2000 2500 one that they had for past few years DID fire up the freezer, as well as pumps motors, dehumidifiers etc. That one is the one that runs my chainsaw and one of the few they sold that had a 5 star rating.... It was discontinued and its fan only comes on if it gets hot; and is nice and quiet. I guess they stopped selling that one because it was too awesome. I wish I had bought 2 of them.

[zero]

I wish I'd bought more back when they were $99 (11 years ago).

I've only had a few real bad inverters. Especially some big Vector/Black&Decker 5000 watt units.

You'd think now-a-days inverters would all pretty much work the same but they don't. Lots of variations (within the classes of mod-waves and sine-wave models. Some wipe out all AM radio reception within 50-75 feet. Some power battery chargers better then others.

I've got a somewhat expensive "true sine wave" inverter I was forced to buy just to pass electrical inspection. Neither my Xantrex nor my Harbor Freight mod-wave inverters could power hard-wired AC smoke alarms at all. And both made GFCI outlets buzz like crazy. So to correct the problem and JUST to pass inspection, I had to get the Ransond Sunray sine-wave inverter. It does the job of powering smoke-alarms and GFCIs fine. But ????

I was getting pissed when charging my 18 volt screw gun batteries (Makita and Ryobi). Using the "true sine wave" inverter a dead battery took more then twice the time to charge as compared when hooked to a cheap mod-wave inverter like my Harbor Freight unit. And when hooked to true grid-power it charged faster then with any inverter I had there. So, hard to figure. Certainly no good way to know before you buy.

I will say this. Many people have had issues running refrigerators off of inverters. Even small ones. I got talking to several guys with mobile food-service rigs (hot dog vendors mostly). This was when I wanted to put a cheap AC Walmart-type refrigerator in one of my RVs and run it all the time with an inverter. Every person I spoke with who got things working well was using a cheap AIMs 1250 watt mod-wave inverter. So that's what I did. I used it for years running a refrigerator and it never skipped a beat. I'm not saying there aren't plenty of others that would work as well. Just saying I know, for sure, the AIMs does the job.

The AIMs 1250 is rated for 3500 watts surge which is pretty impressive. The "el-cheapo" model with a fan that runs all the time and no digital readout is $99. The more pricey version with a thermally controlled fan and digital read-out is $129. Oddly the cheaper one has a 3500 watt surge rating and the more pricey one only a 3100 watt surge rating (which is still high).

[Totem]

Yeah I am not a fan of running a fridge on a 12 volt inverter at all. I would much rather get a 12 volt fridge for that application.

I know my inverter will easily run any fridge/freezer but its the starting watt load that is the issue; the same problem for air compressors and air conditioners.

The initial load that hits the inverter to kick the compressor or air compressor will trip alarm on many units and also suck the juice out of the capacity of a bank really quick.

My answer to the air compressor problem was to lessen the compressor down to an oiless 6 gallon pancake unit (1/3 hp). the inverter has no trouble firing that thing up and I just ended up connecting it to a 15 gallon pig tank that runs 120 psi; it then can run mostly anything i need. When I used to smoke cigaretttes I would just go outside for a smoke and a beer or two and come back and it would be ready but man is that thing crazy loud.

[Maineah]

Nope, the problems I mentioned were certainly not specific to me. In fact, many owners manuals for off-grid inverters and battery chargers warned about the problem. I notice you make no mention of the make and model of your battery charger, nor do you mention it's charge rate on grid power versus generator power. Seems to me you just want to "stir the pot" without using any real facts.

Note I never said that ALL portable generators make poor power, did I? I also did not say anything like ALL battery chargers have the problem.

The problem I mentioned was and still is well know with people who work in the off-grid solar industry. In fact, many dealers used to publish lists of generators known to perform well as well as lists of those known NOT to. Same with battery chargers. Many dealers also sold line-conditioners and step-up transformers to make problem generators work better with battery chargers.

To some degree this is "old news" that you apparently have never been privy too. It's "old" because most inverter-chargers now come with "bad generator" resistant chargers that are much more high-tech then the old chargers were.

The most common issue was low voltage. Grid power at our homes called "120 volts" is actually 170 volts that dips up and down to make the Hertz wave. Many portable generators only peak at 150 volts instead of 170 volts. Many battery chargers only work by clipping the 150-170 volt peaks and thus the problem.

And again, note my use of the word "many" when preceding "portable generators." I have NEVER said they all do it.

I ran tests on several portable gensets last year. Most made bad power if conventional. All but one inverter portable generator made good power.

The ones I tested included four Homelites 2500 to 7000 watt, three Colemans 750 watt to 8000 watt, one Champion 3200 watt, two Subarus, two Baldors, one KingKraft, one Yamaha, etc. Inverter models I tested were Coleman 700 watt, Honeywell 2000 watt, and a ETQ. All worked well except the ETQ. Chargers used on the test were a Marquette 80 amp shop charger, two Schumachers (6 amp and 20 amps), Makita and Ryobi 18 volt screwgun chargers, and several cell-phone chargers. Also an Iota 12 volt, 45 amp charger that is more sophisticated then the others and often sold for off-gridding.

If a generator is not making 170 volts peak it’s not making 120 volts either if it can’t it is under sized when the peak voltage drops to 150 volts the generator is only making 106.5 volts and the frequency drops also. Generators are rated in watts they are tested against resistance load. There is a big difference between resistive and inductive loads. Lights are resistive battery chargers are inductive. Power factors or apparent power is expressed in volt amps the power being used by the charger to charge the batteries is greater than the power need to provide power for resistive loads at the same wattage output. Battery chargers have a power factor of .6 so if the output of the charger is at 1500 watts charge rate consider the power factor of .6 (1500 divided by .6) your generator is now having to make 2500 watts not 1500 just to keep up to the 1500 watt charge rate. It is very easy to over load a generator charging batteries at a high amp rate. You seem to like figures how about sharing your extensive generator testing with real figures things like voltages RMS and peak, watts, volt amps, RPM, frequency and power factors. By the way I am no stranger to generators our little generator at work that was part of my responsibilities before I retired was a 16 cylinder 2,200 HP 480 volt triple phase generator making 2,000 amps per leg the Siemens transfer switch was in my office it stood 7 1/2’ tall. Bottom line if the generator is sized to the inductive load it should have no problems charging batteries this is why my little 1500 watt generator will charge my camper batteries at 35 amps because the demand is less than 900 watts.

[zero]

If a generator is not making 170 volts peak it’s not making 120 volts either if it can’t it is under sized

Hey, think what you want. I find the "undersized" claim a bit silly. I've tested many generator and charger combos. Note - ACTUAL testing and not sitting around talking the subject to death.

I've been working with off-grid solar for over 30 years and have witnessed the generator problem MANY times. The same problem I refer to has been written about ad nauseum and gets mention in many electronic owner's manuals. Hey, maybe some of these companies should of called you instead of addressing the problems?

When a battery charger that runs on less then 100 watts cannot work properly when plugged into a 2000-3000 watt generator - I'd be hard-pressed to call the generator "undersized."

10 years ago many solar equipment dealers/installers for off-grid were compiling lists of generators, charges, and AC household appliances that had known issues and work-around. New England Solar is one. Run by a couple of electrical engineers. I'll tell them you say they are wrong next time I talk with them. http://www.newenglandsolar.com/ Another good place is Backwoods Solar in Idaho. http://www.backwoodssolar.com/

Many off-grid dealers are doing poorly now due to all the tax-payer supported State and Federal solar incentive programs for Grid-tie. It's kind of a shame.

In the world of RVers, if using a generator to charge any battery - how many actually check and time their chargers to see if they work the same as when plugged into the grid? I bet not many. I also assume that even if a cell phone takes twice as long to charge, it often doesn't matter to the owner as long as it DOES charge.

Fixes offered years back for bad generator-charger combos included step-up transformers, line conditioners, etc. Also with some generators - just increasing the RPM by 200-400 RPM made a nice difference. Doing that upsets the 60 Hertz Cycle but with a lot of stuff -the Hertz is a non-issue. I'm listening to my 50 Hertz Canadian radio right now and it's plugged into a USA 60 Hertz outlet. Works fine.

In the solar-industry - advanced electronic battery chargers now are almost the "standard" and have eliminated most of the charge issues. Pricey though. Iota chargers were one of the first. Then the Xantrex "True Charge." It will work off an input of 90-265 volts AC and 47 to 63 Hertz.

[Maineah]

We have several solar installers here in Maine (by the way here in Maine they have to have a Masters license with solar ticket to pull a permit) so info is not hard to get. My neighbor and his wife (the ones with around 20KW worth of solar) are both electrical engineers at M.I.T. so they are pretty up to date about this sort of thing also. Try as I will with google I was unable to find much to say about generators and battery charging problems but I’m sure you have hundreds of reports you would be glad to share as long as they are not from 10 years ago. Generators have not changed the chargers have. Trying to charge a cell phone battery with a generator is a waste of time and money unless there are other loads a light bulb is all that is needed once that is on line it will charge properly. You telling people they can’t charge their camper batteries with a generator is not helpful it does work with generator from the finest to the cheapest and I am not alone in this assertion all though I am only but one among 10’s of thousands that use generator with great success to keep all of their batteries charged and their lights on in their RV’s. Not only do I keep track of my generator voltage I also have on board battery voltage meters so I know what the charge rate is. Volts RMS output divided by .707 will give you peak voltage otherwise you will need a scope. What are the figures from all of your tests? Photos and methodology please.

[zero]

We have several solar installers here in Maine (by the way here in Maine they have to have a Masters license with solar ticket to pull a permit) so info is not hard to get. My neighbor and his wife (the ones with around 20KW worth of solar) are both electrical engineers at M.I.T. so they are pretty up to date about this sort of thing also.

My brother was an engineer from MIT and damn near spent his entire adult life there . In fact, he's buried in a pauper's grave in Cambridge. He had lots of high-powered smarts and is published all over the world. He was an absolute idiot when it came to the real world and practical applications. I got the bad opportunity meet over 20 of his "MIT" buddies at his funeral. Maybe 5 out of those 20 could apply their intellect to something real and useful. Also, getting a New England "Masters" license requires zero knowledge about what I've been speaking about. And you have friends with a photo-voltaic system? Yeah, and that proves what?? Tell me about the charger and generator systems they've experimented with and maybe it would be relevant here IF they do not have a grid-tie system with no battery bank. Seems you are hell-bent to disprove something that exists in reality. Why? Seems futile to me. But hey, got for it if it.

[Totem]

Most of my generators come with a 12 volt charger for car/marine/deep cycle lead acid applications... thats the funny looking plug that has angled plug teeth with two wires (red and black) that are terminated with alligator clips. I am assuming its putting out 14 volt though I never checked it; perhaps I should...

Anyone ever use that wire for charging camper batts?

[zero]

Most of my generators come with a 12 volt charger for car/marine/deep cycle lead acid applications... thats the funny looking plug that has angled plug teeth with two wires (red and black) that are terminated with alligator clips. I am assuming its putting out 14 volt though I never checked it; perhaps I should...

Anyone ever use that wire for charging camper batts?

I tried using the 12 volt outlet on several of my portable generators. For the most part, they were pretty useless. I've got a dozen small portable generators and any with a 12 volt DC port are only rated 8 to 15 amps. All mine will trip a breaker and shut off if a large 80% charged battery is hooked to the outlet. In fact, the only portable generator I have here that has a 12 volt port that works fairly well (for battery charging) is my Coleman Pulse 1850. Rated 14 volts @ 15 amps. If hooked to a large battery or bank in need of charge -it will surge to 15 amps, then quit when the breaker trips, then come on again, then trip, etc. I assume it would not last long if used for charging batteries in a state of deep discharge.

Battery charging can be a big deal to people living off grid. Now that high-tech electronic battery chargers are more common (then 10-20 years ago) - many small portable generators work well when these pricey AC chargers are plugged into them. Besides that, there are now a lot more small portable generators available that make AC power much better then some of the older ones did. All depends on what you have.

Many off-grid inverters come with built-in battery chargers made for use with an AC input. The newer ones mostly all now come with high-tech electronic chargers, purposely done because of all the past problems with small generators not working well with conventional chargers.

The only portable generators I've had that worked well for bulk-battery charging were DC units, not AC. I have an 8 horse Subaru gas/LP generator that was special made for the telecom industry for charging remote 12, 24, or 26 volt battery banks. It can charge at a rate of 15 volts @ 100 amps. Special made by Pow'r-Guard. Others I've seen were home-made with lawn-mower engines hooked to automotive alternators. Those require special home-built voltage regulators to do the job right.

[Totem]

100 amp charge rate... that would mean minimum 400 Ah bank or more; lest they boil.

[zero]

100 amp charge rate... that would mean minimum 400 Ah bank or more; lest they boil.

My Xantrex inverter/charger has a 120 amp charger BUT it can be used on just one battery if wanted. No "boil" problem. However, batteries in banks are supposed to get "boiled" once awhile. Usually at 16 volts. It's called the "equalization" mode.

The inverter/charger has many settings. How many batteries, what size, what type, temperature, etc.

Inverter/chargers are often very complex. This Xantrex is considered "simple" now adays and the manual is over 300 pages.

The new Outback system that runs my house and barn is complex to the point that I can barely figure out anything on it. 10.000 watts in twin stacked inverters, two MX80 charge-controllers, and a computer-controlled hub (worst part of it).

More then I figured most people care to see - but here are a few sections from my Xantrex DR2412 manual. Lots of good info. Charger is four-stage with "equalization" being used manually.

[Maineah]

My brother was an engineer from MIT and damn near spent his entire adult life there . In fact, he's buried in a pauper's grave in Cambridge. He had lots of high-powered smarts and is published all over the world. He was an absolute idiot when it came to the real world and practical applications. I got the bad opportunity meet over 20 of his "MIT" buddies at his funeral. Maybe 5 out of those 20 could apply their intellect to something real and useful. Also, getting a New England "Masters" license requires zero knowledge about what I've been speaking about. And you have friends with a photo-voltaic system? Yeah, and that proves what?? Tell me about the charger and generator systems they've experimented with and maybe it would be relevant here IF they do not have a grid-tie system with no battery bank. Seems you are hell-bent to disprove something that exists in reality. Why? Seems futile to me. But hey, got for it if it.

Can't have a grid tie without power lines and so far they have yet to perfect a wireless system. Outback and Trogan ring a bell? Yes a Maine masters does indeed involve knowledge of generators and how they work including all the math, it ain't easy to get a Maine license. Seem to have little use for engineers don't you.

[zero]

Can't have a grid tie without power lines and so far they have yet to perfect a wireless system. Outback and Trogan ring a bell? Yes a Maine masters does indeed involve knowledge of generators and how they work including all the math, it ain't easy to get a Maine license. Seem to have little use for engineers don't you.

I get along fine with engineers who can apply theory to real world things and do something with their hands. I just don't bow to someone's alleged expertise just because they have a degree or three. I just had a long discussion with a new electrical engineering grad who was convinced the Electron Theory is no longer theory but proven fact. He also had never heard of the Hole Theory. Makes me wonder what the heck some of these schools are teaching their students now-adays.

Of course Trojan and Outback "ring a bell." Outback is a company created by a bunch of guys who left Xantrex. I have Xantrex and Outback equipment running my systems. And Trojan? Yeah - those are the batteries that many State solar-incentive programs will not allow to be used because the Trojan warranty is too short. Especially the "quasi-deep-cycle" T-105 gold-cart batteries. One of the reasons why Outback started selling their own batteries. Also why many systems done with State-incentive money use Canadian Rolls-Surette batteries. And again - getting a Master's License in Maine has absolutely nothing to do with someone having knowledge of what small generators have problems with certain battery chargers.

[zero]

We have several solar installers here in Maine (by the way here in Maine they have to have a Masters license with solar ticket to pull a permit)

Master's License to wire on your own property, i.e. a single-family residence? I don't believe the state of Maine has gotten that ridiculous, yet. Even New York does not require a license when a homeowner does his/her own work. Nor does Michigan, where I am now.

I just looked up what I'd need to do electrical work in my own house or on my own property in Rockland, Maine. No license required.

Where, in Maine state law - is there something written to the contrary?

I only chose Rockland beause it's one of the few places I'm familiar with in Maine. Rockland, Demariscotta, and Steuben by Mt. Desert.

[Totem]

In Michigan, I believe all that's necessary is approval of power company and inspection. If a contractor is chosen they must be licensed to do the work. That's where the real fun begins; because of how arcane they have written the laws they make it so that power company must approve at their own discretion and they baked in a rule that says once the project is started it only gets x number of days to complete... So all the power company has to do is stall or refuse to approve or inspect etc and you are shut down.

I am unaware of anyone in Michigan other than big businesses and casinos that have legal licensed grid tie setups; doesn't mean they don't exist in domestic homes but I have lived here for the greater half of my life and I have never encountered a home with a grid tie setup here in this state. I believe the laws are purposely setup to prevent it.

[zero]

In Michigan, I believe all that's necessary is approval of power company and inspection. If a contractor is chosen they must be licensed to do the work. That's where the real fun begins; because of how arcane they have written the laws they make it so that power company must approve at their own discretion and they baked in a rule that says once the project is started it only gets x number of days to complete... So all the power company has to do is stall or refuse to approve or inspect etc and you are shut down.

I am unaware of anyone in Michigan other than big businesses and casinos that have legal licensed grid tie setups; doesn't mean they don't exist in domestic homes but I have lived here for the greater half of my life and I have never encountered a home with a grid tie setup here in this state. I believe the laws are purposely setup to prevent it.

People a few miles down the road from my place in Hawks have solar grid-tie (northern Michigan). Not far from where the double murder of two Posen farmers just occurred (big deal for this rural area). I suspect solar grid-tie is not common in Michigan because the state never had any huge cash incentive programs to pay for most of it. New York, New Jersey, and California, yes. it;s a liberal thing and sorry for those on these forums who get mad when that word is mentioned in a technical discussion. States with big incentive programs force the power companies to attach extra fees to everyone's monthly bill to pay for the few that opt for solar grid-tie. My system in New York had a total price tag of over $40,000. I paid, out of pocket, about $5600 as I recall. The rest was "free" if you don't consider all the fees and taxes near everyone had to pay to get me my solar setup.

The main requirement anywhere in the USA is that your local power company allows grid-tie. Most are forced to but a few are exempt. In my area of Michigan, power comes from Presque Isle Electric & Gas. They DO allow grid-tie but basically steal any excess power you make if not used within a year. Same for New York and Maine. In New York, self-install of grid-tie means you lose any chance for State incentive money. What BS ! In New Jersey, self-install does NOT disqualify a homeowner.

The plain fact of the matter is this. Even if you live in a State that allows you to install solar for 10 cents on the dollar - chances are it will never pay for itself at today's price of grid-power. If you live in a state with NO incentive money like Michigan -there is NO chance of even coming close to breaking even. So why would anyone bother? #1 if you are misinformed. #2 Just to make a green statement. #3 You want to live somewhere where grid power is not available. Or #4 - my situation. You already have the equipment and just moved to Michigan.

Off grid it totally different. The equipment is MUCH cheaper. A 3000 watt grid-tie certified inverter is near $2000. An off-grid 3000 watt inverter can be had for $250. Solar panels to qualify for State incentive programs must be certified. Off-grid not (much cheaper). Same with most all the equipment. Of course the down-side to off-grid is there's no way to save excess power and "save for later."

By the way, where incentives are available, money given to businesses is usually MUCH more then a private owner can get.