Proper Parallel Battery Bank Creation, Fuses, Charging?

[zero]

Here's what a solar grid-tie power-bill looks like. I just got it in today's mail for our place in New York. Shows as a negative KWh number. Actually there seems to be something wrong with our house or barn, but since we're 800 miles away - I can't check. Something is using near 80 KWh per month yet the house is empty. We did leave the oil-furnace on but it's set at 40 degrees. Did the same last winter and did not see the same electric use.

[Totem]

So, another question entered my mind. I have a solid state battery isolator and a 10 battery parallel bank of 7ah batteries for a total of 70 amp hours capacity. The SLA batteries i am using in the bank are to be 1/10 the AH of the bank total max current charged or less.

At home I charge them on 1/2 an amp to 2 amps usually in that bank with good results.

What would be a good way to tell how much current the alternator is pushing to the half of the isolator that the more fragile battery bank sits on?

The goal would be to limit max current to 7 amps of charge or less.

I thought about resistors inline with the charging wires; but not sure of the effect or needed resistor size (27 ohm ?).

another option would be to get another inverter that runs a 120v smart charger to charge the other bank and inverter but seems silly.

thoughts?>

[Maineah]

The least resistance is going to get the better part of the charge. The alternator charge rate is based on voltage not current. The alternator will only put out max current if the field (the rotating part) is presented with max voltage by by passing the regulator. So if your batteries have the proper charge voltage the current will be low. The alternator only looks at the truck battery voltage when you have a solid state isolator in line this is another reason I prefer the relay type.

[zero]

What would be a good way to tell how much current the alternator is pushing to the half of the isolator that the more fragile battery bank sits on?

The goal would be to limit max current to 7 amps of charge or less.

Easy way to know how much current is going through that one circuit is to just stick an ammeter in series there. That will end any guessing.

If you want to ensure that charge rate can never exceed 7 amps - just stick a self-setting circuit-breaker in series there.

[zero]

Totem - you likely have this info already about temperature compensation for battery charging. If not - digital ink is cheap.

[Totem]

JDE agreed and thanks; I was just thinking about WME said that he used fuses to regulate current. Not a bad idea, cept that you might be eating fuses alot. Your idea is push to reset. Only other thing I would need is an idiot light letting me know the breaker tripped; i bet they have them like that. will start searching.

Maineah, your point is true enough but misses that batteries may often be drained low from use and the alternator will throw everything it can at them like they are a deep cycle marine or truck battery. Its the lack of control in that current that I fear would destroy this particular type of battery.

After further research i was also reminded of those battery boosters they sell at auto stores; many come with a cigarette lighter socket recharger... some guys opened them up in a youtube and low and behold it just was a parallel circuit; but on 15 feet of 14 gauge low amp fused wire... my guess is that was their low cost way of regulating the current. In my case I was wanting to hook up my newly built pack where the old deep cycle marine battery used to go.

The VRLA/SLA 7 AH batteries I have 10 in parallel they do have some advantages

• can be deep discharged if promptly charged
• 70 AH in small 40 lbs form factor
• they were free
• I have 700 of them
• can be replaced if go bad.
• are fireproof
• do not gas nearly as much and are approved for indoor use
• 20 hour ah capacity rating instead of 100 like marine/rv batteries (makes battery planning easy&

As mentioned i "nuked" a few in experiments to see what would happen; i hooked up 6 of them in parallel to 7 amps and 1 melted and cracked open bulging extremely hot. It was the "hotspots" on the negative plate caused by over current thermal runaway. The one that melted was no good anyway but i purposely put it in parallel to see what it would do. It took all of the charge from the others and melted. the other batteries seemed ok in that test just the one melted. the one that sat on top of it i took out also because it was super heated and is most likely failed also now only taking a charge to 12v flat. ; its also in the "recycle" pile (old batteries to be melted down into bullets.)

By my calculations a fully charged bank of 10 7AH should run a small 400 watt inverter for a while (approx 10 hours?) with total draw being consumed at 80-90 watts ish.

[zero]

The VRLA/SLA 7 AH batteries I have 10 in parallel they do have some advantages

I've had short-life spans with my SLA batteries. I have three portable Duracell 600 powerpack-inverters. Each has a 26 amp-hour SLA battery. All three went bad in three years. But - they went bad slowly. No sudden failures. Just got so that once charged - they go dead on their own faster and faster. Got so that after being fully charged - they'd go dead in a few days. That's when I finally spent the bucks and replaced them all with new "wheel-chair" batteries. First new batteries failed withing two months and were obviously defective. Made in Viet Nam of all places ! Never thought I'd see the day when I'd be buying a product made in 'Nam, Second set I got under warranty were Panasonic from Japan and so far, have been fine. Been almost two years now.

By the way - perhaps a bit off your topic - but the older Duracell Powerpack 600s are kind of amazing devices. 26 lbs. Has enough 120 volt AC power to plug in a 19" LCD TV and DVD player and watch a full 2-3 hours of movies no problem. My wife has plugged her laptop into it while I was cutting wood and run it over half a day (while homeschooling our kid in the woods). It will jump-start a car or truck with a dead battery MUCH better then using long jumper cables hooked to another truck. For somebody who does not have any AC power in their camper when camping or traveling - these things are fantastic. Charge up pretty quick just plugged into the cigarette lighter port or 12 volt power-port. The older ones like in these photos have 26 amp-hour SLA batteries. The newest ones have been changed and now only have 18 amp-hour AGM batteries.

[Maineah]

Totem it is highly unlikely that your alternator will ever output max amps. If your 7 amps are all wired together your still under the output of the 65 amp alternator any way if your getting 70 amps out then it will take 70 amp in. It is common practice to charge hand held public service radios with a LED in line to limit current I would like to see the utube thing the little charging circuits are too easy and cheap to build no need to waste wire to attenuate the current output . The 7 amps are used in emergency lighting and most small UPS's very common batteries and generally changed out every two years good or bad. You are kind of asking for trouble with 10 batteries series of unknown date or quality.

[Totem]

who said they were unknown date/quality? I know exactly their dates and quality. I have also rigorously reconditioned\tested them.

"generally changed out every 2 years" Not sure I agree with that. more like 3-5 years. In our case they were installed in 2012 and only ran 2 years they should have a least a year or so left and even still, not all of them go bad all at once. I took several that were straight up dead and they are running solid now with resting voltage of 13.6; very excellent after setting on the wizbang for a month. Time and effort are all it takes to recondition batteries. most folks dont wish to put time or effort into much these days but for me, these batteries are fun and since they are the fire retardant ones less risky.

[zero]

Time and effort are all it takes to recondition batteries. most folks dont wish to put time or effort into much these days but for me, these batteries are fun and since they are the fire retardant ones less risky.

You cannot "recondition" just any battery. They all wear out and when the plates are expended - there's nothing you are going to do to "bring it back to life."

You can,however, save certain batteries that were given up due to sulphation. I've reclaimed many and at times, gotten years of use out of them.

Now if this was year 1925 - plates and cells were replaceble inside an auto or tractor battery case. No more. At least not in standard stuff like we usually see.

The longest lasting FLA batteries on the market are used in the telecom industry and are 2 volt, single-cell. They are often hooked in serie and used in 48 volt systems. Known to last over 20 years.

The old Delco "light plants" that powered many rural homes and farms in the 30s also used 2 volt batteries often wired for either 32 volts or 110 volts. I have one here. Those batteries came in glass jars and you could buy parts to "renew" them.

On the subject of longevity - I think the longest lasting SLA batteries I've ever had were in those big Harbor Freight flashlights they no longer sell. I still have on I got 10 years ago and it still holds a charge. The new ones from Harbor Freight no longer have those same SLA batteries in them though.

[zero]

I've got a Delco 32 volt "Home-Light" system here from 1923. A few things I find interesting or at least ironic. #1 is Delco says to NOT use gasoline with ethanol and looks at us now ! #2 - Delco reminds owners to "equalize" their battery bank on the 1st of every month. Look at the one photo and you can see it on the overhead. How many people today even know what an "equalize" charge is? Back then people were expected to know more about their own stuff and did not just "throw things away" on a whim.

[Totem]

You cannot "recondition" just any battery. They all wear out and when the plates are expended - there's nothing you are going to do to "bring it back to life."

Well, I can try and in fact succeed on some. Not all of them mind you but many of them have come back to life. Generally I have been taking the ones that have some voltage in them and separated them from the ones that are 1 volt or less. Next I took those and I add some distill water to them after cracking them open and popping off the rubber caps. next I put them on a 30v 1 amp power supply for an hour; this raises them up fast. next i hit them in a group of 6 parallel on the battery minder for 1 day. the cream of the crop will go straight to float charger; those that are under 12 will get the wizbang and another float charger. eventually when they get to 13.xx volts I put them in like (within .05 volts likeness) group and a wizbang and let them sit on float for 2 days on 2 days off for 4 weeks.

anything thats over 12 volt going through this program pops out with a resting charge of 13.xx-15 volts believe it or not.

I currently have 20 of them out of 60 bricks of 10 that "graduated" to this point. And yes, they all pass a load test of 2 incandescent automotive bulbs for 1 hour individually.

Now, during this process I run into some that sizzle, get hot or even bubble out electrolyte...any that exhibit these signs get put in the "trash" bin to become bullets.

So you see JDE, I can recondition many batteries, not ANY batteries but some and when I have hundreds of them to play with why not?

--back to the process, so once they are "good" I wire 10 of them back into their brick case in parallel. I then put a wizbang on the brick along with a float charger at 1/2 amp and let it set for 3 more weeks 2 on 2 off, while monitoring the brick for heat. no heat or issues, test the brick it will rest 15 volts for 2-3 days then com down and settle to 13.6 ish. 10 of them in parallel are VERY strong; have great endurance; much better than a Marine deep cycle believe it or not, in my testing.

So far I have two bricks. I will take some pictures methinks and show a built our brick when my voltmeters come in (I bought some white LED mounted volt meters for the bricks.) As to ammeters, I thought about adding one onto the brick, but when I saw the required power shunt and sawing of the shunt, calibrating etc I lost interest in that. Nope 2 wire voltmeter is good enough.

[Totem]

Was thinking about investing in a Fluke FLIR add on to my iphone also; this allows your iphone to see heat as if it were Arnold Schwarzenegger's old pal the predator. I figure that would let me see wheres waldo on individual battery health as well as heating/cooling leaks in my home and RV...

[zero]

I wasn't "looking down" on your practice of recovering older or discarded batteries. I used to do it all the time. When I worked at a John Deere dealership - we had piles of "condemned" batteries that were replaced under warranty. I took many home and some recovered after being desulphated and worked well for years.

As to your cell phone working as a heat detector?? I don't know. Two of my sort-of pricey RMS multi-meters have a infrared heat-detector function. I can point to something 30 feet away and get the temp. Fun to use but I know it is not accurate. Seems to get "fooled" by certain colors.

That being said, the versatility of modern phones/devices is pretty amazing. Yesterday I was trying to scan some photo negatives from the 1930s and 1940s. Neither of my flat-bed scanners would do a decent scan. Then - I found a guy on-line that put a "flashlight" app into is Droid-Mini. That's what I have. And he used it to scan negatives. So I tried it and it worked GREAT. It's the app that makes my whole screen light up. It turn it on, lay it on a negative and then scan in a flat-bed scanner. Results are pretty amazing. I know, "off topic." Maybe I'll get arrrested now.

[Totem]

I'll post bail if you do. I was only agreeing with you not taking offense. I readily permit all posters to post anything they feel, even the ones on Ignore. I am adult enough that if I don't like someones input I can hit the "iggy" button and go about my day. For all I know, Rad Wolfe could be in here belching flames about me again. I will never know, because he earned iggy purgatory...

(when he calms down enough to post in a respectful manner, and not try to tell me what i do or think or assume to know my history I may remove iggy.)

My grandpa used to tell me to never write checks my booty cant cash; needless to say I never write checks and my waist is 38"...my derriere ain't small.

You're a stand up guy in my book.

as to the FLIR, its a case that goes over the Iphone; the phone interfaces with it. It simply uses the phones computer as the brain to control the case. It provides same functionality as a full on FLIR just $2800 cheaper and at $250 who wouldn't want one? Nice right?

[WME]

I fly RC model airplanes, some of my larger ones are electric. The motors are in the 3-4 hp range The batteries are large and $$$ Li-ion. This is one of the tools I use to manage the battery packs.

Voltage and resting voltage is OK but actual AH under a controlled discharge is the real ticket.

http://www.westmountainradio.com/cba.php

[Totem]

Yes, the C Rate of a battery is very important. Marine "deep cycle" batteries are sort of misleading. While they work ok, they are meant for deep discharging at non constant "burst" intervals, like starting an outboard or pulsing some thrust to a trolling motor. A real deep discharge/deep cycle battery is more inclined to have a better C-Rate and take a constant current discharge (such as golf cart batteries or batteries intended to power long runs on inverters) This is one of the nice things about SLA batteries, they know those will be powering an APC/UPS which is a glorified inverter. I think the SLAs will perform much better than the marine wally world group 24.

[zero]

Yes, the C Rate of a battery is very important. Marine "deep cycle" batteries are sort of misleading.

"Marine battery" has no specific meaning. It can be a cranking battery, a deep-cycle battery or a compromise "hybrid." The type 24, 27, and 29s that Walmart sells for electric trolling motor use are the ones NOT designed for cranking. Exide used to make them for Walmart and I had several go bad in 2 years. The new ones are made by Johnson Controls. I have three -and two are on their fourth year. So far, no problems.

The title of "deep cycle" battery is also a relative term. Many people in the business of storage batteries do NOT consider Trojan T-105 golf cart batteries as true deep cycle batteries. More a "light duty" deep-cycle battery. All depends on context. For me - any battery sold as "deep cycle" that includes it's cycle life projection is a "true' enough deep-cycle for me. Trojan and Rolls gives that info for all their batteries. Walmart certainly does not - but Johnson Controls will if you call up their tech department (I have).

[zero]

On the subject of type 24 "marine" batteries.

Here are six different versions and they vary a LOT.

24M7 weighs 45 lbs., 52 amp-hour rating

24M6 weighs 40 lbs., 50 amp-hour rating
24M5 weighs 35.5 lbs., 37.5 amp-hour rating
24M4 weighs 32 lbs., 29.1 amp-hour rating
DP24 weighs 42 lbs., 50 amp-hour rating
DC24 weighs 45 lbs., 54.1 amp-hour rating

Also included the life-cycle chart for Trojan T-105s. Not allowed in NY for solar-grid tie if incentive money is used.

[Maineah]

who said they were unknown date/quality? I know exactly their dates and quality. I have also rigorously reconditioned\tested them.

"generally changed out every 2 years" Not sure I agree with that. more like 3-5 years. In our case they were installed in 2012 and only ran 2 years they should have a least a year or so left and even still, not all of them go bad all at once. I took several that were straight up dead and they are running solid now with resting voltage of 13.6; very excellent after setting on the wizbang for a month. Time and effort are all it takes to recondition batteries. most folks don't wish to put time or effort into much these days but for me, these batteries are fun and since they are the fire retardant ones less risky.

Well it is common practice to change out batteries use in emergency systems every two years we got a lot of good batteries that way but we also know the systems would work when needed. I still have a 35 amp gel cell from a fire alarm system after 6 years I use for my radios. Now here is my point with a small battery bank and lots of batteries one bad apple spoils the entire barrel and then you’ll have to find out where it is in the chain.A standing voltage in a battery is not a good indicator of battery health with out a load. What I have found with UPS batteries is they look fine with a volt meter but crash with a load. I know they are free but a group 31 or maybe a pair of 27’s would be my choice and have twice the amp hours.

[Totem]

twice the amp hours but at what rating? 100 ? if the goal is to power an inverter and blower motor for a while or pumps etc I would think golf cart batteries (deep discharge) would be better than the 24 or 27 group marines although those are definitely cheaper. You may be right in that these SLAs may not be the best bank but I do like their C rate. if need be that bank could run an electric saw or microwave etc for a bit (in theory). if a battery gets a short yeah it will bring down the rest of them but when we are talking parallel i like to think of the bank of batteries as cells themselves.

[zero]

I would think golf cart batteries (deep discharge) would be better than the 24 or 27 group marines although those are definitely cheaper.

Trojan T-105s are certainly more durable then any type 24s or 27s as far as how many deep-discharge life-cycles then can endure. But they cost more. Just like there are many heavy-duty deep-cycle batteries that are much more durable then Trojan T-105s, but they ALSO cost more. I checked on the long-term price back when T-105s cost $50 each and Exide type 27s cost $80 each. At that time, the Trojans gave the most battery for the buck, for the long-term. I don't think so now. A Johnson Controls type 27 deep-cycle at Walmart is $82. A Trojan T-105 is $150 plus shipping since no one near me sells them. When all done, a Trojan costs me around twice as much and with luck - it might last twice as long as the Walmart type 27 battery. The Walmart battery basically costs the same as far as use you get out of it. It also has the advantage of being 12 volt so just one can be used, and also it can be used in other types of equipment when not used in the RV. Some of my type 27s get used in tractors during the winter and back in RVs in the camping-travel season.

I assume you know this but not all Trojan T-105s are the same. The lighter-duty versions are T-105s and sell $140-$150. The T-105REs are $160-$170 and weigh 5 lbs. more. NAPA sells equivalents made by Deka that are every bit as good as the Trojans, are cheaper, and no shipping charges. NAPA # 8146 is the equivalent of the Trojan T-105RE and costs $123. NAPA # 8144 is the equivalent of the Trojan T-105 and costs $110.

The heavier T-105RE is projected to withstand being completely discharged 800 times before it's worn out. Or - discharged down to 50% 1600 times before it's worn out. The Walmart type # 27 is supposed to survive 50% discharges 1100 times before it's worn out.

The Rolls-Surette batteries have been the standard for years in battery banks but they too are getting very pricey. The Rolls equivalent to the Trojan T-105RE is the S-290. It has a 7 year warranty, often lasts over 10 years but sells for $300.

[Maineah]

twice the amp hours but at what rating? 100 ? if the goal is to power an inverter and blower motor for a while or pumps etc I would think golf cart batteries (deep discharge) would be better than the 24 or 27 group marines although those are definitely cheaper. You may be right in that these SLAs may not be the best bank but I do like their C rate. if need be that bank could run an electric saw or microwave etc for a bit (in theory). if a battery gets a short yeah it will bring down the rest of them but when we are talking parallel i like to think of the bank of batteries as cells themselves.

It is fine to think of them as cells but look at it this way you now have 60 cells to worry about! I have gone 5 days in my camper with two 80 amp series batteries with out a recharge running pretty much every thing. The only problem with T105 is size and the fact you need two. I had a 100 amp Trojan battery that lasted 12 years I liked is so much I keep it when I sold the trailer it was in.

[zero]

The golf-cart version of the Trojan T-105 has a predicted life-span of 7-8 years if allowed to get old before cycled to death.

The battery-bank version - the Trojan T-105RE around the same but with a 5 year warranty instead of just two years like the other.

My Deka GC2 equivalents are on their 9th year which is pretty good. Only used one month a year though and hooked to off-grid solar. Cost me $48 each when I got them new at NAPA. Now over $100 each.

[Totem]

yeah they do seem to be gouging on battery prices these days; especially on deep cycle now that solar and wind has come down so much. Heck I saw in a catalog the other week, these small rotary generators that look like little torpedos; you just throw them in a decently moving stream and they produce electricity to charge banks. Now that I thought was awesome; stream fed would be more reliable than wind or sun... still not totally reliable as they may get clogged or dry up but still very interesting...

[zero]

yeah they do seem to be gouging on battery prices these days; especially on deep cycle now that solar and wind has come down so much. Heck I saw in a catalog the other week, these small rotary generators that look like little torpedos; you just throw them in a decently moving stream and they produce electricity to charge banks. Now that I thought was awesome; stream fed would be more reliable than wind or sun... still not totally reliable as they may get clogged or dry up but still very interesting...

One big problem with many streams. If they run fast enough to power a turbine-generator, they are also likely government controlled. I own the first water-powered mill site in Worcester, NY and my deeded rights to the water go back to 1795. Regardless, I am still not allowed to use the water energy for anything. NY Department of Environmental Conservation won't let me do a thing with it - except pay the taxes. Techinally I own the land under the water but not the flowing water itself. My wife ran a water-powered mill for years that also had some water-driven electric turbines. But - that 1800s mill was built by diverting part of the creek into a pond. When they want power, they open the dam and drain the pond. Once empty, no power for quite awhile. It was built in the mid 1800s and by law - is "grandfathered" in.

That all said, there's a water-powered mill for sale right now here in northern Michigan. $175,000. I have no idea if anyone is allowed to harness that water power anymore.

[Totem]

got a link to that mill?

[zero]

http://www.houseworthrealty.com/GristMill/

I was told by my wife the listing expired and they dropped the price down to $175K. She got that from some of her friends at SPOOM. (Society for the Preservation Of Old Mills).

We went there around 5 years ago. Nice property. House probably too nice for my tastes.