Battery questions for boondocking

[kfp673]

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!

[Boon_Docker]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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.

[Sjm9911]

If your boondocking, a lot dont use the 6 volt batteries. They use 2 12 volts instead. And seperate them , that way if one goes bad you can salvage something of your trip. 3 days , one larger battery should be good, depending on temp. Get the mr buddy heater for colder temps or solar to top off the batteries for the campers heater. If you want to run anything other then heat and the basics you need more power, as in the geny.

[kfp673]

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!

[pianotuna]

pnichols wrote:

pianotuna wrote:
Time to roll I did five years of part time without a generator. Once I was full time, I had to be a power pole princess, or upgrade the solar, or get a generator. I made a HUGE mistake and got a generator.

Don, how did/do you - worst case - thumb you nose at the weather and camping location in complete comfort with no generator? :h

My battery bank was 875 amp-hours.

I have 256 watts of solar, so every trip started with battery bank at 100% state of charge.

I added a 2nd charging path from the chassis battery with #8 wire to the house batteries.

I changed the lights I used regularly to led.

I carry 3 fans, small, medium and a large box fan.

I ran out of water before I ran out of power.

I could trip for a week before having issues with power--but never ran out.

In a pinch, I would run the V-10 when using the microwave.

I used a hot plate for cooking.

When I had access to 15 amp power, I used double conversion to power just the converter and ran the rest of the RV off a 2500 watt Cobra inverter that was rated to run motors.

I added two auxiliary shore power cords so if there were multiple outlets on separate circuits I could run the water heater on one, a heater on another, and the rest of the RV on the OEM 30 amp.

[Gjac]

OP said: 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". With what the OP said I don't understand the solar recommendations. 2 6 v CG batteries from Sam's Club or Batteries plus will be less than $200 and will easily last 2 or 3 nights, a buddy heater or similar if you camp in cold weather would eliminate the need for the propane furnace which uses a lot of electricity. My Sam's Club batteries are 13 years old now and I can still go a week with no genset use and batteries would be at 50% SOC. I always run out of water before battery power. So best "bang for the buck" would be 2 6v GC batteries. Just check regularly fully charge after dry camping, equalize several times a year and they will last you a long time and be much cheaper in the long run than Li, Gel etc. Remember a lot of people on here have more energy requirements or fulltime but for the average part time boondocker 2 6v GC batteries will be more that adequate for your needs.