Dual Batteries

[GaryH]

Hey now, it looks like we bought a 2007 17'er last week! We put a deposit on it & close the deal in mid April (the owners away 'till then). Can't wait until then to plan some mods. So, my first one i want to try is putting in a dual battery system. I'm thinking of putting them under the rear drivers side bench seat. Is there enough room for 2 - group 27 batteries there? Floor strong enough? Ventilation adequate? I had thought about leaving them outside on the tongue, but they are better off away from the cold & vibration. How does the wiring pass by this area? Eventually, i'd like to be able to have a solar system, but this will work for now. We usually go off into the bush for 1-2 weeks at a time & are very frugal with our power (although i might have to break down & get a genset). Anyway, thanks for your input, Gary

[gbaglo]

That area is rather full. It contains electrical ( breaker box etc. ) your hot water tank and heater and the only somewhat vacant space is where your AC power coils up. On the passenger side, you could have a problem with ventilation.
Just go ahead and get that gen set. You have my permission.

baglo

[escape artist]

Hi: GaryH... Our 5.0's battery is in a sealed box under the left side of the dinette...thats if you are facing the rear of the trailer. There is a vent on the back of the trailer and a hose connecting it to the box. If the batteries are inside the trailer then a sealed box and vent are necessary.
escape artist N.S. of Lake Erie

[PGDriver]

Hi Gary & congratulations on your purchase.
If your going to dual batteries I'd put in 2 6volt ones
you will get more amp hours out of them.
Just a thought......

[mosquitodirk]

Congrats and welcome to the Escape club....

I've done 3 things to extend battery life, replaced the 12v with tow 6v, replaced most of the lights with LED bulbs, and added a hand pump to go with the sink. Seems the biggest draws on the battery are the pump and the lights - so using them less will help.

My aim is to get two weeks of life out of the batteries. (Reace figures 3 times the length battery life with the 2 6v batteries vs the 12v battery).

The two 6V are going in the back under what is now the bed - Reace added a vent to the outside (same as what's in the 5.0).

[GaryH]

I'd love to go with 2 6V batteries. However, i already have an extra 12 V Deep Cycle plus the one that's with the trailer. So, i'll just use these until it's time to replace them. How does the hand pump work? Where did you get the led bulbs & are they as bright? My eyes are always begging for brighter-brighter Thanks for the replies. Cheers, Gary

[mosquitodirk]

Hey Gary,

I got the bulbs from Reace - my guess is other RV places might carry them as well. Haven't tried the handpump yet - I pick up the trailer this week. I'll report back after the weekend. As for bright bright - not so much. The LED bulbs are bright enough for cards, and for reading if you don't need it super bright. I find that I use a little book light anyhow (saving batteries even more).

Cheers,
Dirk

[Hokie Escape]

Originally Posted by GaryH

I'd love to go with 2 6V batteries. However, i already have an extra 12 V Deep Cycle plus the one that's with the trailer. So, i'll just use these until it's time to replace them. How does the hand pump work? Where did you get the led bulbs & are they as bright? My eyes are always begging for brighter-brighter Thanks for the replies. Cheers, Gary

Hi Gary,
I replaced all the lights in my old Casita with LED's. Let me include a reply from the Casita Forum that answers your question"
"I ordered one Warm White (92 lumens) and one Cool White (120 lumens) "bulb" (actually bulb base connected to printed circuit board with LEDs on it) from SuperBrightLeds.com and tried them out in the camper. The Cool White really puts out the light, but it's too harsh. So I ordered all Warm White "bulbs" for the camper and put two Cool White ones on the outside lights. As you can see by the pics on my website, the interior is lit up beautifully at night with LEDs. When turning on the factory incandescent bulbs in the camper, with just two lights on the battery voltage dropped 1/10 volt, another light would drop it another 10th, etc. With all 7 interior lights on, the voltage would drop almost immediately half a volt, and in a few minutes it would drop a full volt. With the LEDs I can turn all the lights on, inside and out, (a total of 10 lights) and the voltage doesn't drop at all. NOw I can stay up half the night with all the lights on and still have enough battery power to run the furnace all night. See my latest mod on the my website and click on "Led Lighting." You can click on the pictures to enlarge them and you can download them.

http://web.me.com/dr.pepper007/Site/...sita_Mods.html "

I found the same problem. The Cool White was brighter, but too harsh (or something like that, it's hard to put your finger on it), but the Warm White was very soothing, though not as bright. As you can see, you can have lots of them on, and not use too much power. So, you could put a double light over the spot where you like to read. I used the same source (SuperBrightLeds.com ), and they were nice to work with. They also have bulbs that are colored, like bug lights, for outside. Since I haven't picked up HokieEscape yet, I don't know which incandlescent bulb is used in the Escape, so I can't tell which one to order. Let you know in a few weeks however : - )
The link to the Casita Forum that's dealing with this subject is: http://www.casitaclub.com/forums/ind...howtopic=11953

[cheryls]

Hi - That first link above didn't work for me, but I think I found the right page here:

http://web.me.com/dr.pepper007/Site/...ghting.html#14

They do look bright alright!!

[PGDriver]

Just ran across these LED lights, price seems good and you can just plug them in....
http://www.v-leds.com/Shop/Control/P...id/0/SFV/32481

[GaryH]

Good info to know, thanks

[wpski]

Hi all

Can any one tell me if 2 12 volt deep cycle batteries in parallel wouldnt provide more amp hours than two 6 volt in series thanks walt.

Walt

[ronstew]

Walt,

At a first approximation, each kilogram of battery will have a fixed amount of stored energy. Energy (in joules) is amps times volts times number of seconds. (The voltage varies as the battery discharges, but we will ignore that.) Say you have a twelve-volt battery with 112 A*hr. Since there are 3600 seconds in an hour, the battery stores 4.8 megajoules. A six-volt battery storing the same amount of energy (because it has the same mass) will deliver 224 A*hr at 6 V.

Note, though, that when you put batteries in series, the number of amp-hours for the two batteries cannot be added together, because each amp that passes through the first battery also passes through the second. If you put them in parallel, you can add the amp-hours. So putting two 6-V in series gives you 224 amp-hours at 12 V, and so does putting two 12-V in parallel.

Now, all of this depends on the statement that the mass/energy ratio is constant for a particular type of battery. I checked Crown Battery's web site and found three representative batteries:

Part number

Voltage

Amp-hours[br](20-hour discharge)

Mass

Energy stored

Energy per kilogram

CR-235

6 V

235 A*hr

29.9 kg

5.1 MJ

170 kJ/kg

27DC36

12 V

115 A*hr

26.7 kg

5.0 MJ

190 kJ/kg

31DC36

12 V

140 A*hr

30.3 kg

6.0 MJ

200 kJ/kg

So, in this case, two 30-kg 12-V batteries in parallel should will give you a bit more energy than two 6-V batteries in series. You might want to look at the prices of the particular batteries.

But, as we discussed in a different thread, if your 12-V batteries are not perfectly matched, you will wear them out faster. They are not designed to be wired in parallel.

[thoer]

Ron,

This is really good information - thanks for sharing that.

Eric

[thoer]

Does anyone know if it is ok to use a 12v smart charger across both 6v batteries? I have one of these: http://www.amazon.com/gp/product/B00...ss_T15_product
and am hoping that it will work ok across the dual 6v.

Eric

[PGDriver]

Hi Eric

It will work fine, mine are on my work bench right now
and I put the charger on them once every month or two.