I have an A122BH and we love going camping with it. When we are dry camping the single battery after about 3 days begins to lose "ummph". Has anyone hooked another same "deep discharge" battery in parallel and been fine for five days or so? We're pretty good a power management (LED lights for instance) and thermostat set at 50 deg during the night to keep the heater motor from running too much.
On this first experience of multiple days of camping I backed my Honda Pilot and hooked up the wire harness and idled the car for about an hour to get some charge back in the battery. Is that ok to do?
We put a second 12v battery on our Roo. Went 4+ days with no issue - just being careful on what we used. May have been able to go longer, but our fridge has a cooling fan that was running almost constantly that week. The key is you need 2 batteries of the exact same type and age to work most efficiently.
There is lots of info and opnion here and on other sites on 6V batteries vs 12V, multiple batteries, permanent or portable solar panels of many sizes, and generators for dry camping.
If your rig is fairly new, see if the dealer has another matching battery. It will be your cheapest and quickest way to double your capacity. Just make sure you have a diagram of how to correctly connect them. The dealer will probably also make you up a pair of wires for the connections for a few extra bucks.
As for using the tow vehicle in a pinch, I think many of us have done that in a pinch. Works good when you don't have any other power source.
Several of us have put dual batteries in our aframes, and they do extend your camping range well. 5 days on a full charge is routine for me with my dual Group 31 batteries. They're not pure deep cycle batteries, they're sort of combo batteries--thicker plates than standard car batteries, but not built like true deep cycle batts either. For me, cost was the issue that got me to buy the hybrid type. I figured if I have to replace them every X years anyway, then the hybrids would work OK for me.
+1 on the need to have exactly matching type, capacity, and age batteries in a dual setup.
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It's never too late to have a happy childhood!
Lee, WU0V, and Courtenay, N0ZDT
2011 Rockwood A128
2000 Silverado 1500 pickup
60W solar system
2000W inverter generator
Several of us have put dual batteries in our aframes, and they do extend your camping range well. 5 days on a full charge is routine for me with my dual Group 31 batteries. They're not pure deep cycle batteries, they're sort of combo batteries--thicker plates than standard car batteries, but not built like true deep cycle batts either. For me, cost was the issue that got me to buy the hybrid type. I figured if I have to replace them every X years anyway, then the hybrids would work OK for me.
+1 on the need to have exactly matching type, capacity, and age batteries in a dual setup.
Thanks, HamGuy! It's all brand new so I'll pick up another Interstate like the one I have. What is Group 31?
Also what kind of battery box?
Group 31 is a size category. They're larger than the Group 24 batteries typically put on our aftrames. They're also heavier; mine are 60# each. Group 27 batteries are the size between. I think the 24s and 27s will both fit the same battery box, just pick up another one like you have and rig up some kind of mount for it. The Group 31 is too big for that box, so I had to buy two boxes in addition to the batteries and the new mounting system.
I bought 3 36" perforated angle irons from Home Depot to make the battery box rack, which sits on top of the tongue in the same location as the original box, it just sits across both arms of the frame there. One of the angle irons was cut to make the cross pieces; the other two were cut just long enough to accommodate the two batteries in their boxes. It's a rectangle that is bolted to the "A" part of the frame with self-tapping screws. I sprayed it black and it looks like it was always there.
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It's never too late to have a happy childhood!
Lee, WU0V, and Courtenay, N0ZDT
2011 Rockwood A128
2000 Silverado 1500 pickup
60W solar system
2000W inverter generator
I found that two 6V golf cart batteries (deep cycle) fit perfectly in the standard battery tray area with no modification needed - except that there's no room for battery boxes if there even are boxes for batteries that tall. I see no need for battery boxes other than for hiding the obvious. Although I could have drilled some holes and used standard battery holddowns, I use giant sized zip ties do that job.
Now is also the time of year that Costco and other stores clear out their deep cycle batteries.
I have 2 group 27. THe group 24 battery case had to be changed out as it was too small. Also could not use the mounting frame for the group 27 either, had to make new frame. I use my battery one at a time. I add a switch on each. Only been out 2 day at a time. and 1 battery is doing fine for that.
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Steve and Adele
2017 RB-195
2005 Toyota 4runner 4x4
I have 2 group 27. THe group 24 battery case had to be changed out as it was too small. Also could not use the mounting frame for the group 27 either, had to make new frame. I use my battery one at a time. I add a switch on each. Only been out 2 day at a time. and 1 battery is doing fine for that.
Do you use a voltage meter to tell when to switch? If so what reading "triggers"the switch to the fully charged one. I have two group 24's, and they're 82lbs combined on the tongue.
I have 2 group 27. THe group 24 battery case had to be changed out as it was too small. Also could not use the mounting frame for the group 27 either, had to make new frame. I use my battery one at a time. I add a switch on each. Only been out 2 day at a time. and 1 battery is doing fine for that.
You do know that you get less total capacity with the batteries separate than linked together???
I upgraded my crappy Group 27 for a nice AGM Group 31 Deep Cycle. Last night I ran the furnace most of the night (probably kicked on a dozen times for about 10 minutes each) and my voltage was still 12.5 this morning, even after I recharged my kindle and phone overnight as well (I installed 12v USB plugs). Coupled with LED bulb replacements, a cut-off switch for the radio (so it doesn't phantom drain) and my power use is pretty minimal minimal unless I intend it (really the only phantom draw left is the CO/Propane detector in the power station).
I definitely recommend the replacement/upgrade to a Group 31. If you can fit two of them (I can't due to space and tongue-weight limits) you can do it either with two Group 31s in parallel, or a pair of 6volts in serial to equal 12v. Both work and there are pluses and minuses to both.
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2012 Lincoln MKX
2013 Rockwood A122BH A-Frame
You do know that you get less total capacity with the batteries separate than linked together???
The advantage of separate batteries is that one can be removed and taken someplace for charging with minimal effort. It is great for dry campers staying in one place for a while.
The advantage of separate batteries is that one can be removed and taken someplace for charging with minimal effort. It is great for dry campers staying in one place for a while.
Yes, I am sure there are many reasons to run batteries separately, and that is a good one and it would be a good reason to have 2-12volts in parallel instead of 2-6 volt in series.
It is also true that you get somewhat reduced capacity because of Peukart's law and so in a situation where you really need all the amphours you can get, you may want to hook the batteries together.
Yes, I am sure there are many reasons to run batteries separately, and that is a good one and it would be a good reason to have 2-12volts in parallel instead of 2-6 volt in series.
It is also true that you get somewhat reduced capacity because of Peukart's law and so in a situation where you really need all the amphours you can get, you may want to hook the batteries together.
Just some ideas to consider.
Here is a great article on the Peukart Effect.
Since amp draw determines total available capacity, (more amps; less capacity), sharing the amp draw across more batteries will result in a SIGNIFICANT improvement in battery life under load.
Remember using 2 6 volt batteries double the voltage and not the capacity, so the amps out of both are the same and the effect is felt equally on both batteries.
With 2 12 volt batteries you double the capacity and halve the amp draw on each battery.
So using the graph below with a 100 AH "stack" of "notional" batteries (2 100 AH 6 volt batteries or 2 12 volt 50 AH batteries), examine the capacity loss across the stack for a 30 amp continuous draw.
In the 6 volt scenario, your 100 AH stack will have its total available capacity reduced to 54 AH.
In the 12 volt scenario, the 100 AH stack (since the 30 amp draw is shared between the 2 12 volt batteries with each matched battery contributing 15 amps) will only be reduced to 68 AH.
Obviously, if the 12 volt batteries are not matched internally, they will have dissimilar amperage flows and the capacity will be reduced from the optimum 50% share. Matched means similar manufacturer, size, capacity, charge discharge cycles, and age.
If one (the lower internal resistance) is contributing 75% (22.5 amps) and one (the higher internal resistance) is "loafing" at 25% (7.5 amps), the effect will have a serious degradation on overall battery "stack" life, as the higher voltage (loafing) battery will start trying to charge (equalize with) the lower voltage (harder working) battery.
This "self charging"/reduced capacity effect with non-matched batteries does not happen with 2 six volt batteries. The older 6 volt one will just die even though the other is still "good" resulting in the entire stack dropping offline.
This is why changing out the entire stack (rather than just one) is critical in multi-battery installations in order to keep things in balance whether 6 or 12 volt.
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
I've got to wonder, in a boondocking situation, how often the current draw is much over 5 amps. If you want your batteries to last, I wouldn't think it would not be high current for very long and not very often.
I've got to wonder, in a boondocking situation, how often the current draw is much over 5 amps. If you want your batteries to last, I wouldn't think it would not be high current for very long and not very often.
Yep. What kills batteries are inverters, furnace, and incandescent lights.
Pretty much in that order.
a 2 921 bulb fixture draws 2.3 amps
a 400 watt inverter powering a 200 watt appliance draws 17 amps
Cut from another post:
LPG detector draws .2 amps Single dual bulb light (198 bulbs) 2.3 amps Single dual bulb light (LED panels) .1 amps Light fixture over dining table (4 198 bulbs) 4.5 amps Single reading light over bed (1 198 bulb) .8 amps Recessed Halogen lighting, living room (6 lights) 8.4 amps Full on
2.1 amps Fully dimmed
Recessed Halogen lighting, over sink (1 light) 1.4 amps Full on
.4 amps Fully dimmed
Recessed Halogen lighting, over couch (3 lights) 4 amps Full on
1.2 amps Fully Dimmed
Refrigerator 1.2 amps
Furnace (Suburban SF35) 7 amps Water Pump (Shurflo Smart Sensor 5.7) 11.9 amps running, 12.6 max
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Lou & Freya the wonder dog
2008 GMC Sierra 3000HD Allison Duramax
2019 Flagstaff 8529FL
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