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trvsdad1's avatar
trvsdad1
Explorer
Oct 22, 2013

Battery Charging Question!

Calling all you brainiac's. I have a charging, well actually a couple of battery charging questions for you to tackle. In my Alpenlite I have two deep cycle batteries. I can charge them in the following ways,1. with camper power switch off and unplugged from shore power source they charge through the F350 alternator while truck engine is running (power switch in camper must be off). 2. Plugged into shore power source with camper power on or off they charge.This leads me to believe that my "inverter" is on all the time whether the camper power switch is on or off. 3.Start my generator, it charges the batteries whether the camper power switch is on or off, (again I'm thinking my inverter is not off with camper power switch). We ran the batteries down at the Grand Canyon this past weekend. Had to start truck to juice them up enough start generator. Was the generator charging the batteries through the inverter or directly? (I may have answered my own question, because the generator puts out AC current to run a/c, microwave, can't charge 12 volts batteries with 120volts). So does my inverter always draw some level of current regardless of camper power switch being on or off? I've been thinking that off meant off, but please set me straight. Second question, how long should I run the generator to charge the batteries back up to full charge. Campground rules limited me to two hours in the morning and two in the evening. I don't think that's nearly enough, please set me straight. As a foot note I do have a solar panel to maintain a full charge but "DOES NOT" charge a depleted battery, only maintains a full charge. Thanks for reading and for your answers!
Truck Campers
  • TCcruzn's avatar
    TCcruzn
    Explorer
    Oct 22, 2013
    It sounds like you are waiting too long to recharge your batteries with the genny/shore power. You should not let the batteries get below a 50% charge. The converter you have is a 3 stage converter so you are good there. I would consider 2 upgrades:
    1) Add a Trimetric. Single best upgrade if you boondock at all. It will tell you the state of your batteries at all times.
    2) Add more solar. 2 batteries, 200w solar is a good target.
  • time2roll's avatar
    time2roll
    Nomad
    Oct 22, 2013
    Can't speak for the switch but yes the generator or utility power drives the converter to charge the battery. Yes it always draws some 120v power when available. More power with low battery, less power with full charged battery.

    Two hours is plenty with a good multistate converter that I suspect you do not have. Post the converter or power distribution model# for best suggestions.

    Solar will charge a low battery but depending on wattage it may take an extended time and need long sunny days. If you put 200w panel up there it should charge quite well.


    On edit:
    PD9245 is actually a very good charging converter. But verify you are getting 14.4 volts on the battery terminals when you expect fast charging.
  • trvsdad1's avatar
    trvsdad1
    Explorer
    Oct 22, 2013
    Ok, I dug out my "camper file". You are both correct, it is called a Converter. I have an INTELI POWER 9200, mdl. pd9245,output 13.6vdc, 45 amps. it is in a 2006 Camper. It will put out 14.4 volts for 4 hours on a depleted battery then drops voltage to 13.6 volts for 3-36 hours storage mode 13.2 volts (saves water loss) from 33 hours to 52.5 hours then bumps back up to 14.4 every 21 hours for 15 minutes. Owners manual graph shows a boost to 90% charge after 8 hours with a battery that was at 10.5 volts, full charge after 11 hours. So I guess I need to camp where I can run the generator longer so we don't deplete the batteries so much. So I'm ok and figured it out myself (lazy me), but its always nice to chat with you guys. Thanks again, trvsdad
  • Crazy_Ray's avatar
    Crazy_Ray
    Explorer
    Oct 22, 2013
    I think you mean Converter NOT Inverter. Look it up and let us know. JMO
  • KD4UPL's avatar
    KD4UPL
    Explorer
    Oct 22, 2013
    I suspect you don't have an inverter. They change 12v battery power to 120v AC. What you're probably thinking of is a converter which is the RV industry's term for a battery charger. Apparently yours is wired so the battery disconnect does not disconnect the converter, only the loads.
    Your generator is likely charging thru your converter. Depending on what model of converter you have it may only put out a measly 10 amps for battery charging.
    How long do you need to run it? Depends on battery size, charger size, wiring in between, battery condition, other loads that may be on while charging, etc.
    If you run your battery(s) way down it will likely take many hours to recharge them from the generator with your stock set up. A converter upgrade is likely in order if you need to charge this way very often.

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