Forum Discussion

TURNKEY's avatar
TURNKEY
Explorer
Oct 26, 2012

Deep cycle or starter battery charging issues

I recenty moved from a class B to a small fiver. My old van had one deep cycle battery and I installed an isolator. This set up was good for several nights of light usage before I had to run the van to charge the battery. My new trailer seems to use a LOT more power. Granted, it has an electronic start fridge, rather than a constant pilot light as well as the furnace and a propane monitor(the old van was a 1982)I still think I should get more than 3 nights of use off a battery charge. We used very little light, no water heater, no fantastic fan and only 2 or 3 cycles on the furnace per day.

We dry camp 90% of the time and I intend to purchase a generator for now and solar when we retire in a couple of years.

I beleive we will have to charge fairly often, maybe daily.....but I don't want to be one of THOSE GENERATOR A##()&Les! who need to run their generator for hours at a time disturbing everyone's peace and quiet. I'm looking for a max 1 hour charge time.

I have a smart battery charger that will charge at 2, or 10-20 amps as well as an onboard IOTA convertor that has a 750 watt input @120 v that will put out 45 A at 12v. My local dealer sez the convertor really will only charge at 5 amps or so. He also sez deep cycle batteries should be charged very slowly for best effect.

Is my best bet to install a starter battery rather than a deep cycle on the trailer and charge it heavily and quickly? I recognize the best set up is to go with solar but can't justify the cost yet.

Thanks all for your anticipated input.

Turnkey

59 Replies

Show More
  • TURNKEY's avatar
    TURNKEY
    Explorer
    Oct 26, 2012
    Thanks for all the great info.
    I'm still trying to drill down to a better understanding with regards to MY :?specific desires....if they are acheivable.
    On our first, and latest, trip with the new rig I figured my old deep cycle (and yes iit WAS a marine/starter battery) pooched so I got the ONLY deep cycle in the small town I was in to replace it. This is a new group 27 885 CCA marine/starter deepcycle.
    This with a full charge only lasted a couple nights. My problem with accepting this is the years of performance experience with my old Class B that would let me dry camp for as much as a week between charges in conditions much the same as we had this fall with the fiver, namely 3-4 hours of lights, 1-2 furnace cycles in the morning, very little water pump usage per day. I can't see how the bigger fridge (running on propane) with electronic control (the old fridge did not use any 12 volt power at all) and a propane detector could make that much difference.
    Also I'm concerned with the charge rate I can use to charge the batteries. The greater the charge amps the less time to recharge BUT I was told deep cycle batteries are best charged slowly.
    I gather from the above posts that if I have more batteries given a set amount of useage they will each draw down less and therefore can be charged to full capacity faster, BUT if I use the same charger in both situations, given it has a set output, won't the resulting charge time be the same?????

    Thank everyone for the help.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Oct 26, 2012
    Try to avoid spending way too much money on a too small whiz-bang super genius charger. For one discharged group 24 RV battery 40 amps is plenty but too many "smart" chargers are too stupid to understand "time is money" when it comes to being connected to a generator. When they should be hammering out 14.8 volts for the last half hour of charge, they decide to kick back and take life easy.

    Get recommendations here from folks who have chargers connected to gen sets and then pay attention por favor to the fact that many gensets develop bad power. Like running a car on 69 octane fuel. A 400 horsepower turbocharged air foil special may deliver 90 horsepower. I believe the inverter generators are better at this but being I do not own one, I must not delve too deeply here. Perhaps actual users can deliver "hands on" advice"

    You want speed? Two 40 amp chargers for 2 RV batteries. I don't blame you. I had at one time 400 amps recharging so I did not have to put up with a "quiet" diesel genset for long.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Oct 26, 2012
    Standard design consideration now days is ONE NIGHT from the battery bank, if you are getting 3 you are doing very well indeed.

    Want more time between recharges.. Add more battery. Try to get DEEP CYCLE batteries (Trolling or golf car batteries) not marine/deep cycle (Which are really starting batteries)

    The best bang for your buck is usually pairs of GC-2 Golf car batteries, NOTE that when compared to 12 volt DEEP CYCLE there is no advantage to this type save for cost. But they are DEEP CYCLE, they are low cost (But high maintenance) and they do work. But only in pairs (in series) Treat each pair exactly as though it were a single 12 volt battery,, Save you can remove them one at a time when it comes time to do so (Some folks can not pick up an 8-D 12 volt.. I can, but I do not care to).
  • DryCamper11's avatar
    DryCamper11
    Explorer
    Oct 26, 2012
    mena661 wrote:
    What's ridiculous about it? There are tons of people here with 4 6V's in their 5ers.

    I'm with mena661 on this. I have four 6Vs in my small class A. As you add capacity, you increase the rate at which you can recharge and decrease the frequency that you need to recharge. Both of those let you minimize generator runtime, which the OP said was important. That's why I went to four 6Vs from two. It minimized gen runtime for me and had the advantage of reducing fuel usage, as I was charging at a higher average rate while the gen was running.
  • mena661's avatar
    mena661
    Explorer
    Oct 26, 2012
    If you're boondocking that much I would concur with getting 6V's. I would also switch out your most used lights with LEDs. I switched all of the interior lights in my old 5er to LEDs. Went from 350W total draw to 87W (all lights on).

    RJsfishin wrote:
    4 6v golf batteries in a small 5'er is rediculous !
    LOL! What's ridiculous about it? There are tons of people here with 4 6V's in their 5ers. I had the same 740 amp hour bank in my old 5er that I do now in my MH. It all depends on how you want to camp.
  • ksg5000's avatar
    ksg5000
    Explorer
    Oct 26, 2012
    TURNKEY wrote:
    I still think I should get more than 3 nights of use off a battery charge. Turnkey


    My experience would argue that 3 is pretty good if your using a type 24 battery - when it gets colder you won't even get that - consider buying bigger battery +/or more batteries.
  • RJsfishin's avatar
    RJsfishin
    Explorer
    Oct 26, 2012
    Your power useage is not out of line at all.

    If your converter only charges 5 amps, JUNK IT !

    IOTA and charge wizard are not compatable.

    4 6v golf batteries in a small 5'er is rediculous !

    2 6 or 12v deep cycle batts will do you just fine, but you will need a 35-45 3 stage converter, and a little generator running 1-2 hrs a day, depending on your needs. But if you run that forced air heater, along w/ the other needs, figure on charging 2 hrs a day.....w/ a good 3 stage converter/charger.
  • donn0128's avatar
    donn0128
    Explorer II
    Oct 26, 2012
    Your best bet right now is to change to 6 volt golf cart batteries and a lot of them. Find a place to install at least 4 golf cart batteries. This joule give you at least 4 or 5 days of use with no furnace. Last year we camped for 4 days in cool weather. Meaning cloudy, one rain showers and the furnace on a lot. Using only my solar panels I was able to go the whole four days and only use the generator once the last day for a couple of hours. And YES your fifth wheel is a power hog compared to older RV's. everything takes power now days from the refer to the smoke detector to the gas sniffer. Heck I can remember back in the old days you could leave your car sit for months go out and hit the starter and it would crank. Try that today with the newer cars. All those computers take energy to keep running.
  • beemerphile1's avatar
    beemerphile1
    Explorer
    Oct 26, 2012
    Stay with a deep cycle. Problem is that you probably don't have one now. Most dealers install a combination starter/deep group 24 marine battery which isn't a deep cycle battery.

    The furnace most likely is your heaviest load. If you run heat all night a group 24 battery will last one night. You probably have an LP detector and possibly a CO detector that is a constant draw. With the refrigerator you might have a drain of 1 amp per hour or more.

    The typical group 24 combo battery has 80 amps. Just the basics are likely draining 24 amps per day without running lights, fan, or furnace.

    The answer is to have more batteries and charge once per day for a couple hours. You don't want to regularly drain the battery more than 50%. Many of us use 6 volt golf car batteries because they give more amps per dollar.

    Use the IOTA, it is a good charger especially if you have the charge wizard.

    I see you have been a member of the forum for a long time. These subjects are discussed regularly. I suggest you spend some time on here and do a lot of reading. The wealth of knowledge on this forum is amazing.

    Read all three pages of this;
    http://www.marxrv.com/12volt/12volt.htm

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,291 PostsLatest Activity: Jul 29, 2025