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Old 02-15-2016, 01:31 PM   #1
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1967 17' Caravel
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How many batteries required ?Help!

We are putting together the inside of our '67 Caravel and we discovered a weight and balance question. This is not a restoration but a complete remodel inside. The sink, stove top, refer, water pump and tankless hot water heater are all on the street side. On the curb side we have a shower and toilet. The water tank and grey water are under the floor, either side of the axle. We bought 2- 6v Life Cycle batteries and they weigh about 125 lbs each. The only place to put them is on the street side, but then we end up having more weight on the street side than the curb. Question is, do we need to have 250#of batteries. Everything is LED and we are adding solar to the roof. Open to all suggestions
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Old 02-15-2016, 01:46 PM   #2
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Why not just get a single deep cycle 12 volt battery? This is what I am using:
http://www.amazon.com/gp/product/B00...rch_detailpage
It weighs 75 lbs.
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Old 02-17-2016, 04:41 PM   #3
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Thanks for the tip
What else do you run with the one battery? Do you have solar what about an inverter?
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Old 02-17-2016, 06:20 PM   #4
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Go to AGM battery - stay with 2x 6v. Thus you can use smaller/lighter battery for the same amp usage - deeper discharge/more capacity per size/weight. Also you can put AGM's anywhere without venting - under bed, etc. thus more flexible.
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Old 02-18-2016, 08:39 AM   #5
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No solar. 600 watt sine wave inverter runs everything except A/C. Can top up battery with 2000 watt genny. AGM battery is mounted under the bed (no venting required).
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Old 02-18-2016, 10:45 AM   #6
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I understand that the way to establish battery capacity is to match it with solar capacity. So your answer is likely to establish the solar power you can install. Then install enough battery capacity to allow the solar to deliver the designed solar output. If you have smaller battery capacity, it chokes the solar output. Now, this may be incorrect if the solar is not directly connected to the battery bank, but that is how our AS dealer described the install.

So, you need to give this all considerable investigation. A long conversation with a solar expert coupled with an inventory of your projected power usage is likely a good step.

As far as the battery location, they ought to fit on the tongue, or at least one will, and the other could go in the Street side location. Would plan for enough room in the street side location to go Li-ion in the future. Some day they are going to be less expensive and the only way to go.

And since I have little understanding of this solar business and just repeat what I read and hear, I'd appreciate you explaining it all when you get it figured out.

Travel safe when you get it together. It's going to make a lot of smiles as you make the miles. Pat
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Old 02-18-2016, 11:06 AM   #7
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Thanks to everyone. So tell me if I'm getting this correct. I have 2, 6v AGM Life Line batteries that weigh 125#s each and they are huge, 14 x 6 x 10 inches each. It's OK to mount them on either side or fore and aft and run a cable between them and then to the inverter?
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Old 02-18-2016, 03:53 PM   #8
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As you're considering batteries, you should start by determining your usage. Will you be boon docking off "shore power" for extended periods of time? You must look at your batteries as a "battery bank"--how many amps are they rated for at 12 v? For example, we have four Lifeline 6v 220 amp batteries. When each pair is properly wired together to make tow 12 volt batteries, their capacity is still only 220amps, but when we then wire the two "12 volt batteries" together we end up with a battery bank of 440 amps. Lifeline recommends never discharging their batteries below 50% capacity, so effectively we have 220 usable amps. This is a good balance with a Blue Sky MPPT solar charger and about 270 watts of panels on the roof. We long ago converted to LED's, and run laptop and cellphone chargers, stereo (no TV). And the refrigerator (yes, even on propane), furnace (big drain when fan is running), ceiling fans and all other appliances have varying sized draws. Even your inverter has a draw, and it loses power in conversion.

You need to calculate your probable battery usage in amps daily.
We sometimes boondock for a couple of weeks at a time. If the sun is shining, and it's near June 21, the sun angle is good and we're fully charged by 11 am. But if it's late winter, and it's foggy or overcast, it might take all day or we might not reach full charge.

Now on to placement and weight. Batteries should be installed near your charger/inverter/solar charger so as not to lose voltage through wires. You can compensate with very heavy gauge wire, but this is expensive, and for long distances, adds a lot of expense and weight. We have one pair of batteries just forward of the cabin on the tongue, and the other pair very close, just inside the cabin (on the service side) and very close to the converter/inverer/solar charger. But our batteries weigh about 70 lbs each for a whopping total of 280 lbs! And our already tongue heavy trailer, with that extra weight on the service side, has led to front left tire blowouts (although we've recently upgraded to 16's and Michelins.) So our ultimate solution will be to switch out the 440amp glass mat battery bank for a 300 amp lithium bank. Because lithiums can be discharged by 85% instead of the 50% of the glass mats, we'll actually have a net gain (255 instead of 220 amps) from the SMALLER, MUCH LIGHTER lithium batteries--instead of 280 lbs, they weigh 84 lbs! Downsides? Expensive, and current technology is not chargeable below 32 degrees ambient temp (inside the coach) without destroying them (so you have to disconnect them if you're going to be absent during freezing temps.)

If you can afford the lithiums, this might be a good solution for you--because they are smaller and much lighter for the same usable amperage, you could replace your Lifelines and save some weight AND be able to keep it all physically together and close to the converter/inverter/solar charger.

To summaraize--(1) estimate your amperage needs (2) know that you need your batteries near your converter/charger/inverter/solar charger (3) consider lithiums for their lighter weight and smaller size. If you're sating with your (excellent) Lifelines for many good reasons, you're going to need to locate them together and close to the other equipment. You'll have to compensate in other ways if that weights you incorrectly. Ideally, any significant weight gains should be over the axles, but sometimes the ideal is not possible!

Have fun!
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Old 02-19-2016, 06:23 AM   #9
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12 Volt Wheelchair AGM Batteries

I installed four 12 volt AGM wheelchair batteries in my Airstream and so far I am very pleased. These are deep-cycle and rated at 35 amp hours each. Unlike wet-cell deep-cycle marine batteries that provide cranking amps, these are sealed, lighter and smaller. They charge faster and discharge slower. You don't need cranking amps to run LED lamps, fans and chargers. I connected them in parallel (+ to + and - to -) to maintain 12 volts. I charge them with a roof-mounted PV solar panel. I can last two weeks off grid with this setup.
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Old 02-19-2016, 05:07 PM   #10
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Thank you for all your answers...but maybe I misled some. I have 2 AGM 6v batteries that weigh 125#'s each. I think I paid about $800 for the pair. Being extremely aware of weight and balance I would like to put them on the curb side but I only have room for one. Putting both under the sink next to the refridge on the street side is going offset the balance of the trailer. Putting both on the on the tongue will cause yet another set of issues.
Can I put one on the curb side in the closet and one under the bed in the back. It's a lot of cable and how does this effect the over performance of the batteries?
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Old 02-19-2016, 06:11 PM   #11
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Ideally the batteries should be as close together as possible. Probably separated by no more than a couple of feet. Even then you'll need thick heavy gauge wire.
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Old 02-19-2016, 06:16 PM   #12
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Quote:
Originally Posted by vanster View Post
Thank you for all your answers...but maybe I misled some. I have 2 AGM 6v batteries that weigh 125#'s each. I think I paid about $800 for the pair. Being extremely aware of weight and balance I would like to put them on the curb side but I only have room for one. Putting both under the sink next to the refridge on the street side is going offset the balance of the trailer. Putting both on the on the tongue will cause yet another set of issues.
Can I put one on the curb side in the closet and one under the bed in the back. It's a lot of cable and how does this effect the over performance of the batteries?
Vanster,

If you have Lifeline AGM batteries, then I don't think that you have your descriptions correct. If you have a pair of GPL-6CT Lifeline AGM batteries @ 6VDC, then they measure approx. 7 x 10.5 x 13 and weigh 90 lbs, rated at 300 amp/hours.. if you have a pair of GPL-L16 batteries, they measure 7 x 12 x 16, weigh 120 lbs and are rated at 400 amp/hours @ 6VDC.

Seems that you are combining weights/dimensions of these two types. Either way, I would think that you have a pair of the GPL-6CT batteries @300 amp/hours and 90 lbs, as the L-16s are very rare!!!

You can split these batteries, but you will need massive cables, depending on their distance from each other and you will reach a practical limit for excessive distance that will create measurable 9and unwanted) voltage drop.

How far apart are you planning to place them?
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Old 02-20-2016, 07:53 PM   #13
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Lewster
You are correct, the batteries are the GPL- 6GT. For some reason I thought they were 125# each. I weighed them and one is 88.1 and the other is 89.4#
This makes things a bit easier as now I will have 284#'s on the street side and about
197# on the curb side and I can still leave the two batteries together on the street side. Not perfect but I think it will be OK.
Are you going to the Vintage Trailer Academy this coming June?
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Old 02-20-2016, 08:11 PM   #14
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