Hello all,Per my other posts, we started getting heavier into boondocking this year. As such, I quickly noticed the importance of good batteries. We always bring a portable inverter set but when we are deep in the woods we really prefer to use it as little as possible. This past weekend the nights got down to upper 30's and apparently the furnace fan eats a lot of battery because it was dead by morning. Currently we have the battery that came on our camper 2 years ago which is a single deep cycle. I have read many threads about batteries including 6v vs 12v, Optima / high end battery, etc etc. My question, specific to boondocking is bang for the buck. I'm not interested in spending $700 on batteries at this point. So would I be better off buying 2 12V batteries from Wal mart (or wherever)to replace my single, or a single "high end" battery such as Optima or similar? Or, is the 6v difference so big that it makes it worth it? My guess for next year is we will boondocks 5 or 6 weekends total (2 or 3 nights each time). With that said, what would you do keeping cost in mind? Not trying to find the literal cheapest way, rather I'm looking for "bang for the buck". Thanks!

You have to see your power needs first. Longest trip , what else are you using in addtion to the heater. What do you use the inverter for? They really are inefficient. Once you do that you can see what type of batteries you need. Many like the golf cart batteries instead of 2 12 v ones. Tbh, i really dont boondock much. You can also get solar to recharge the battery while your off grid.

A pair of 6V GOLF cart batteries will give you much more stored power and they can be discharged safely to a lower level. They are big and heavy tho so make sure you have room for a pair. I think optimas are designed for starting vehicles and aren't suited for your use. But the battery experts will speak up. The high end would a pair of Lithium or Silicon batteries and they cost a LOT more. Trojan golf cart GC2 batteries are somewhat better than Walmart/Costco but can be harder to find and pricey.

Hi,Yes, the furnace fan really goes through power fast.I doubt that your present battery is a true deep cycle battery. More likely, it is a cross between an automotive (starting) battery and a deep cycle battery.What I would do would be to:- Install two (or four) deep cycle (golf cart) batteries in series (or series/parallel if you got four).- I would also get a catalytic heater such as the Olympian Wave Heater and not bother with the RV furnace at all (keep in mind that this is a non vented heater so you should have an open window at night ... I use a cracked window and fully open vent).- Look for other places that power is "wasted" such as incandescent light bulbs (replace with LED/s).- Install solar panel(s) to keep the battery charged.(note that not all of these items need to be done at once. Do one at a time if needed .... keeping in mind the planned end result so you don't have to tear out anything later)With such a system, it is very likely that your trailer would never need to be plugged in (leaving today for 10 days of cool weather camping and won't be plugging in at all). However, putting together a system like this isn't cheap.A lower cost/simple alternative (not the cheapest either, but one that works well for many folks), would be to purchase a quality (and quiet) generator (~$1000) and just recharge your battery as needed. Perhaps a combination of a generator, LED lights (if not already installed) and a good catalytic heater (~$300) would be the best solution for your needs????????An even lower cost alternative would be to use your truck to recharge the battery (and/or have a second battery that you swap out). Perhaps the least expensive alternative would be to forego the heater and just wear more clothes.No doubt you will get plenty of other great suggestions. Have fun camping.

When you say "portable inverter set" are you talking about a "portable inverter generator" that burns gasoline to generate 120vAC power or an inverter that takes 12v battery power and converts it to 120vAC power. Results in a totally different answer to your question but it sounds like you are talking about a generator.If it's a generator, a couple 6v deep cycle batteries and then run the generator in the afternoon for an hour or two to recharge them, should allow you near unlimited time away from shore power and should be plenty to run the furnace overnight. Just plug in the normal shore power cord and your onboard charger will take care of charging the batteries (don't use the 12v outlet on the generator, it's very low amperage (7-10amps vs 40-60amps) and it's unregulated). For 5-6 weekends per year, I wouldn't mess around with a solar system. If it's an inverter, you really need to consider what you are using it for. 120vAC items tend to use a lot of power and a battery bank to support it will be pretty big if you are using a lot of power.PS: Inverter Generators are a generator type that generates DC power and using a built in Inverter converts it to AC power. A traditional generator develops AC power as it's native output but requires the engine to run at a speed that corresponds to 60hz AC power. A couple of big advantages to inverter generators, they typically use high quality inverters that generate much cleaner AC power compared to old style generators and second, unlike old style generators, they can throttle back when loads are light to reduce fuel consumption and noise. The old style try to maintain an exact engine RPM that corresponds to 60hz...typically either 1800 or 3600rpm. Even with little demand, it takes more fuel to keep the RPM up, it makes a lot of noise running so fast and when you add a heavy load, the RPM sags resulting in poor quality power which can damage sensitive electronics.

Two 6 volt golf cart batteries is a good start. Optima is an AGM battery so no maintenance but because of their spiral cell construction will be less amp/hours than a traditional flat plate battery.

Battery questions for boondocking | Good Sam Community

Boon_Docker
Explorer III
Dec 24, 2020
We boondock in the mountains (very cold at night and in morning) and use the furnace in the evening for a couple hours and in the morning for an hour. Our 200 watts of solar does just fine with our 24 foot trailer.
pnichols
Explorer II
Dec 24, 2020
FWIW, I consider our 25K BTU motorhome furnace typical. As such, it draws around 6 to 7 amps per hour when it's running. However, it of course doesn't run full time at all.

If it runs about 1/3 of the time, it only depletes amp hours out of the coach batteries at a rate of one third of 6 to 7 amps per hour. That would amount to only 2 to 2 1/3 amps per hour of battery amp hours depletion.

Most dual battery RV setups in good condition, and kept fairly well charged every 2-3 days, should do quite well keeping the coach warm in anything but extreme low temps if ... the RV isn't a large one and if you block off sections not occupied during nights.

Our motorhome is small, and it's furnace keeps us comfortable with 230 AH of battery capacity that powers everything else, including two CPAP machines every night.
ppine
Explorer II
Dec 22, 2020
Running the furnace for more than a few minutes in the morning or evening uses a lot of power. This time of year 200 watts is not going to keep up.
SJ-Chris
Explorer II
Dec 22, 2020
Two 12v Deepcycle lead acid batteries (~$100x2) plus 200w of solar (Amazon: ~$280) and you will probably be able to boondock comfortably 95% of the time with nothing else. If you are running the furnace at night, it will suck a lot of those AmpHours. If the batteries get low, you've got the generator (or alternator) to charge them back up again along with the solar. If over several trips you notice the solar not keeping up, add another 100w panel (simple at that point) for another $100 to give you 50% more solar charging power.

Good luck!
Chris
time2roll
Nomad
Dec 22, 2020
kfp673 wrote:
Thanks again all. Quick question on charging 6V batteries. If I go with 2 and wire them in series, does the charger built into the trailer still charge both as it would a 12V battery when plugged into shore power? Also, when using a standard charger (not the built in camper charger) how do you properly charge them together? Do you put your charger clamps on the same terminal as the RV would, 1 batteries + and the other batteries - with the jumper from + to - still attached? Thanks!
Once you connect them in series you have one twelve volt battery. Do not connect anything to the battery to battery jumper and all works fine.
riah
Explorer
Dec 22, 2020
A few thousand?
We DIYd 400 watts of solar panels and MPPT controller for less than $1K!
So even if one chose a lifepo4 battery it’s still under $2K!
But I agree that it depends on how long you expect to use it and the payback time to determine if it’s worth investing in!
(For us, personally, I wish we had installed it sooner!)

valhalla360 wrote:
pianotuna wrote:
Valhalla360,

A solar system is the nearest thing to a free lunch anyone is likely to see. My 2005 panels continue to produce their rated output.

So someone came by and installed a free solar system? Where do I sign up?

I've had solar systems before. They have their place but it's silly to drop a few thousand for a system that will only provide benefit 5-6 weekends per year when the OP has a perfectly functional generator.

A little trickle charging system would be much cheaper but won't negate the need for a generator on those 5-6 weekends per year.
SteveAE
Explorer
Nov 28, 2020
kfp673,

A note of caution regarding your built in charger.
If it is located any distance at all from the batteries, you may have a substantial voltage drop between it and the battery bank due to undersized wiring in the RV. You can determine this drop by measuring the voltage at the charger and then measuring the voltage at the battery bank. The difference is the voltage drop. If more than a couple tenths of a volt, it is probably too much and your batteries won't get a full charge. Either change the location of the charger and use large wires, or use an external charger.
lane_hog
Explorer II
Nov 24, 2020
Two 6V's will get you more amp hours and last longer, but the point about one failing and taking out the entire system is a good one.

Our 130W of solar with two 12V's has worked for us over the last 15 years, but I only need 3-4 days at a time without shore power, and at least one of the generators are always with us just in case. We don't do as much winter camping as we used to, so if we need heat for a couple days, it's either propane and a lot of battery draw, or we run the generator and electric space heaters.

BTW, as for sunk costs and the generators... Last night our house lost power in freezing temps, and those sunk cost generators gave us a lifeline for the six hours that it took the power company to fix things. One powered up the coach with space heaters, and the other was hooked up to our sump pumps and selfishly, the DVR to record my football games. I was in the process of splicing into the furnace wiring (house breaker off) just in case the power wasn't coming back until morning.
pnichols
Explorer II
Nov 21, 2020
For drycamping heat, we use two 12V, 115 AH, deep cycle AGM batteries wired in parallel to power the built-in propane furnace. We do not sleep in the cold, so sometimes the propane furnace has to cycle ON/OFF all night at around 65 degrees, just like the furnace in our home does. I don't "believe in" using the little screw-on 1 lb. propane bottles or using flexible propane hoses to fuel propane heaters sitting inside the coach whether we're awake or sleeping. I don't like leaks, especially propane ones that can result from the propane passing through temporary connections or non-rigid connections.

In extreme high temperatures for long periods, instead of moving to another area to camp we keep the coach cool with the larger of our two quiet generators powering the rooftop air conditioner. For short extreme high temperature times, we can keep the entire coach cool by idling the V10 and using the cab A/C.

We're not full-timers, so permanent rooftop solar for day after day long term battery charging is not worth the investment in money, or the holes in our one piece roof, or the panel-cleaning time. If we added solar, it would be via about a 200 watt portable panel so as to provide the flexibility of being able to charge the batteries while camping in the shade. Currently, we top up the batteries every 2-3 days with one of the generators, or by very quietly idling the V10 an hour or two here and there.
pianotuna
Nomad III
Nov 19, 2020
kfp673 wrote:
Thanks again all. Quick question on charging 6V batteries. If I go with 2 and wire them in series, does the charger built into the trailer still charge both as it would a 12V battery when plugged into shore power? Also, when using a standard charger (not the built in camper charger) how do you properly charge them together? Do you put your charger clamps on the same terminal as the RV would, 1 batteries + and the other batteries - with the jumper from + to - still attached? Thanks!

Yes the converter will charge the twin six volt batteries.

Yes put the charging clips on the same terminals as the converter uses.

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