Ctek D250S Dual Battery Charger

[steeve]

Anyone use ctek dual battery charger?

[Derek up North]

Which one did you have in mind?

http://www.ctek.com/au/en/chargers/12v

[Maineah]

Being from the land down under they are most likely 220 volt. Maybe if they have US distributors they will be 120 volt. Tried to find a US price with out too much luck. For $35 you could buy two battery maintainers most any where or by pass the isolator and charge both with one.

[Derek up North]

http://www.techbatterysolutions.com/CTEK-D250S-Dual-Battery-Charger-p/c008.htm

[steeve]

Sorry for my english, i am french, i from Quebec canada

Ctek d250s, It's a dc to dc battery charger. 5 steps battery charger 20 Amps with mppt controller for solar charge, have vsr (voltage sensitive relay) to isolate the truck battery and have a sensor for monitoring battery temperature. If you need more amps to charge more battery combine with Ctek Smart Pass. Last year i bought a wiinnebago warrior 1991 and it have no generator. I want to use this space for put 2 T105 trojan batteries with 145 watts solar panel. What do you think about this set up?

By the way it' an interesting forum.

[Derek up North]

I've no problem understanding your English. It's the 'Electrical Speak' I have trouble understanding! I hate electrics!!

[WME]

Will it work, yes. Will it do what you want, maybe.

So the big question is " What do you want to power with 2 T105s?"

[steeve]

running blower suburban furnace spring and autumn, pot of coffee, microwave, television. video game for my son and lap top. 225 amps 50% 112amps.Maybe is more amps than i need. Do you think a bci group: 31 130 amps is enough?

[Maineah]

A good converter/charger at 55 amps is about $100 cheaper has 3 stage charging and will charge two batteries. It would replace the less than stellar stock one. Your solar panel will take forever to charge two discharged T105's max output is only 12 amps at high noon any thing other than noon it's output goes down hill fast. A controller for your solar panel would be less than $30.

[Maineah]

running blower suburban furnace spring and autumn, pot of coffee, microwave, television. video game for my son and lap top. 225 amps 50% 112amps.Maybe is more amps than i need. Do you think a bci group: 31 130 amps is enough?

What did you have in mind for an inverter? Coffee pot and microwave use lot of amps the T105 will handle it for awhile but they will have to be recharged the worst part of going solar and big batteries is cost and effectiveness. Frankly you would be better off with a good replacement converter/charge, a 2,000 watt generator and maybe a group 31 battery. The generator would give you all the power you need for the gadgets and a group 31 would power the TV, games and furnace till you restarted the generator.

[steeve]

For the inverter i will buy samlex ssw 1500 watts and xantrex 15 amps automatic transfer switch. I bought a wf-9800 series 55 amps to replace magnatek/parallax converter at best converter.com. This summer, I go for 4 weeks in vacation and lot of week-end too. Some days, on boondocking and some days not. I think if i have a good dc to dc battery charger and solar panel. i can put 60 to 80 amps in my battery when i drive 4-6 hours.

[WME]

30 min of coffee pot and microwave will use more power than your 165w solar panel will produce in 1 day.

A T-105 flooded cell can be safely charged at 10% of capacity, an AGM battery can be charged at 33% of capacity.

So t-105 flooded batteries can be charged at 20 Amps, a GOOD controller would let you use around 300w of solar. That much solar would recharge your batteries in about 4 hours after 30 min of coffee pot and microwave, the rest of the day would charge back the balance of your 12v use. Then you would be always charged with out running the engine.

[Maineah]

For the inverter i will buy samlex ssw 1500 watts and xantrex 15 amps automatic transfer switch. I bought a wf-9800 series 55 amps to replace magnatek/parallax converter at best converter.com. This summer, I go for 4 weeks in vacation and lot of week-end too. Some days, on boondocking and some days not. I think if i have a good dc to dc battery charger and solar panel. i can put 60 to 80 amps in my battery when i drive 4-6 hours.

Driving will help; cutting your loads will help more. Driving will give you a max of 30 amp charge rate unless you change the wiring size. There is a huge reserve of energy in a 20# propane tank far more than you can store in 10 batteries. A micro wave is convenient but an energy hog. Any kind of resistance heating uses lot of power (coffee pot/toaster). I have a trailer I use when I go to the Gaspe’ I have been 5 days without a recharge on two 80 amp batteries. I reduced the lighting loads from 26 amps to 3.08 and that’s with all 15 LED’s on so it’s usually more like ¼ of and amp for the lights. I have an accumulator on the water pump to reduce the run time and startups. I cook with propane and boil water. I am not a big TV watcher but I do watch the news with a LCD TV. And run my ham gear. If I had to run the furnace I would buy a generator, charge the batteries every other day and sleep quiet. It all sounds nice but keeping batteries charged is a big issue, cloudy days with solar panels and your left to charge the batteries with a 130+HP generator (the truck). Solar is cool big batteries are nice but unless you are willing to spend lots of money you’ll never be able to keep them charged for any length of time unless you use power wisely games and TV’s would be ok but the big loads will kill you. I don’t mean to discourage you but the numbers are just not there. We’ll say 70 amps driving that’s only 30% of you battery capacity with two T105’s. Add up all of your loads and think about replacing that with external power an 800 watt microwave will draw 67 amps from your battery while it’s running provided it’s 100% efficient transfer of power. Or 6 hours of direct noon day sun with your solar panel.

[Boots]

Hi Steve,

From my understanding of battery charging, you should not charge any battery at a rate greater than 10% of your battery's rating. So say you have a battery rated at 100 Ah (20hr rating) you should select a charger which is set to charge at 10 amps constant (and the Cteks are a good multistage charger with tightly controlled amperages) - another factor which is very important is battery temperature. So chargers / controllers have a temperature sensor which is attached to the battery case. If for some reason you are charging at a rate higher than the recommended charging rate (say 25 amps) the battery's temperature will rise and can cause battery damage, including shortening the life of the battery / loss of warranty.

Todays modern solar panels have (in the bright sunlight) an output of 19volts DC which is then modulated by a controller down to the recommended volts (see 4 stage chargers) and this is how you never have to worry about solar DC voltage output for the most part. For more here is a basic explanation: http:\www.freesunpower\chargecontrollers.php and here is a YouTube video with a good over of a MPPT controller. Look up Morningstar TriStar MPPT 60 amp unit. This may not be the exact model for your RV system but it is information.

Another source is Altestore.com / look up Morningstar. Not this unit can handle up to 36 volts (three 12 volt solar panels in series)

Brian

[zero]

I kind of got lost in some of the directions this all went. I'll just add a few comments.

First - very little has changed with solar panel "real world" output in 20 years. No matter what panel you get, or what controller - the end result for what you're doing with wind up pretty much the same. You're going to get 1.5 to 2 amps @ 14 volts per square foot of panel IF pointed for the best solarization. In plain English - about 1/3 an amp per hour, per square foot for a 24 hour day. There are many claims out there - especially with MPPT controllers and "shade tolerant" solar panels. Much means little in your kind of low-voltage application. When you wire solar panels for 400 volts DC - it DOES make a difference.

Second - mention was made of charge current being limited to 30 amps from the alternator in front to the house batteries in back? No reason to live with that limit. Very easy to run 15 feet of #2 AWG copper cable with a 100 amp breaker on each end. Then you can use all the capability of the alternator to charge the back and/or help run the inverter. Sticking with the factory setup of a 15 foot piece of 10 gauge wire front to back seems silly to me.

Third - I agree with your choice of a pair of T-105s or a generic equivalent like Deka GC2s. Where I live in the Northeast - the Dekas are easier to get, cheaper, and last every bit as long at the Trojan T-105s. Most NAPA store can get the Dekas with no shipping charges. I have a cabin that's on it's 8 th year with a 1200 watts of solar and a bank of 8 Deka GC2s. 8 years is pretty amazing.

There is one factor I did not see mentioned here (maybe I missed it). When powering high-amp-draw 120 VAC appliances through an inverter - it's not just about the batteries amp-hour ratings. It's also about their voltage dip when hit with a load. Most inverters automatically shut down if incoming DC voltage drops below 10.5 volts -even if for just a microsecond. Some batteries even when rated high in amp-hours dip too low to use well with an inverter. NOTE I am NOT talking about voltage drop via the cables. I'm talking about the drop inside the battery. Some battery makers test for this and post the specs - but most do not. Outback is one of the few that give that type of data. I tested two T-105s hooked to three different inverters. Two 2000 watt mod-wave and one 3000 watt so-called "true sine wave." I'm talking continous rating and not surge. The latter worked the best with a microwave. But even so - IF you have a microwave that surges at a 14 amp draw @ 120 VAC - two Trojan T-105 often dip to 10.5 volts and trip the inverter. off. This might differ with various microwaves - but even some small 700 watt microwaves will draw 1600-1700 watts in surges. That is . . unless you get something like a Panasonic "inverter" microwave that does NOT pulse and has NO surges at all. Just a stead draw.

One of my RVs has a pair of T-105s and a conventional 1200 watt microwave. Hooked to a Rasmond 3000 watt sine-wave inverter. I can run up to 80% heat and do fine. If I run full heat - the inverter will trip UNLESS I start the engine. Even with just the engine idling - that extra current from the alternator is all it takes to run the microwave at the full heat range.

I use a marine Guest 2611A 10 amp dual battery charger in my Toyota when it's parked and not being used. Keeps front and back batteries fully charged and isolated. It is NOT a battery to battery charger. Uses an AC input. I also have a voltage sensor that trips the isolation relay with the cranking battery getting priority. I found one slight problem with that. When used with a "maintenance" battery charger that keeps ALL the batteries charged at 13.5 volts or higher -that sensor-module gets locked on all the time and that isolation relay is on all the time. Simple fix was to install a relay cut-out switch.

[zero]

I got looking at the specs on the Ctek D250S DC to DC charger. Problem is - I cannot find hardly any specs on the company Website. At least where I'm looking they give very little info. No manual or spec sheet in .pdf. They rate it as having a max 20 amp charge rate which I'd regard as too small.

I've worked with DC to DC chargers but the ones I've worked with were made by ProMarine and come in 40 amp or 130 amp charge models. Some people choose them when the cranking batteries need a totally different charge profile then the "house' batteries. With Trojan T-105s - one charge profile for all the batteries will work fine.

Not giving advice here. Just an opinion. If I was running a couple of hundred watts of solar in an RV, I'd do this. Have the cranking batteries separated from the house batteries with a simple, low-draw, continuous-rated relay. I'd have at least #2 AWG copper cable running from under the hood to the back house batteries. This will enable 60 amps @ 14 volts of charge current to the back if wanted. Many Toyota RVs come wired with 10 gauge wire that only allows a 15 amp charge to the back @ 14 volts (with over 3% voltage loss). 10 gauge cannot carry a 30 amp charge that far and maintain 14 volts (over 6% voltage loss).

The relay can be triggered by a simple switch, or the IGN circuit, or a voltage-sensing relay. I've also seen a few RVs with timers that give a few minutes priority to the cranking batteries before connecting to the back.

Adding solar should not need anything "extra" to add to the system. Just a controller with the output hooked to the house batteries. I can't name a bad controller since I've never had one fail yet. My house and run on twin Outback controllers. My cabin runs on a Morning Star controller. My RVs have ASC controlllers. ASC controllers are used all over the place in off-grid installs and subsequently - are often found for sale cheap. I bought a dozen of them 8 years ago for $15 each and not a single one has failed yet. Mine have battery temp sensors (that I do not use) and are rated 12 amps each. I use one per panel (up to 150 watts). Controllers can get pricey when the input does not match the output - e.g. when you've got 400 volts DC going in and want 12 volts DC coming out. But with an RV - with 12 volts in and 12 volts out - they are cheap, durable units (yes, more like 16-19 volts in and 14 volts out to be exact).

[zero]

This is the marine Guest dual charger I have on three different RVs. I love them. I've seen many on big boats and was impressed with their durability. You mount it on-board and hard-wire it to the cranking and house batteries. Note -this is for when the RV is parked and in storage. Not meant to take the place of the converter. You install it in addition to the converter. My RVs spend a lot more time parked then being used. These maintainers do a great job. My 88 Mini-Cruiser still has the original 30 amp converter, along with this unit.

As I mentioned earlier - one slight glitch. IF you have an automatic voltage sensing battery isolator -hooking this maintainer will trigger it "on" all the time. My fix was to just wire in an "on-off" switch for the isolation relay. When in storage and this Guest is plugged in - I just turn off the switch.

[Maineah]

Google "combiners". Most marine stuff is excellent equipment using stainless parts and better quality control it's a little different than a MH their lives depend on being able to start engines and have reliable communications.