charging // batteries - Event Date: 08 Mar 2021

+1 to podwerks. It wouldn’t hurt anything to bypass the on board charger and use a separate charger but there’s no reason to. You can also just leave your solar charger connected, shouldn’t be a problem.

 Another question I have is if you have two small generators operating in tandem together , say one that peaks at 1200 watts and another at 2500 watts what kind of wattage are you supplying to the rpod. I am wondering if I put two small generators together if it will supply enough power to run  the 15k air conditioner on the rpod? I have purchased the smaller generator to start off with knowing that it is inadequate to run the air conditioner but it has the the plug ins to run another in Parallel.

All battery chargers including the built in one will transition to a low current float or “trickle” charge mode if left supplying the batteries long enough for them to near full charge. That is because lead acid batteries won’t get fully charged at high current, they need that finishing charge at low current to reach 100% state of charge. So it wouldn’t matter if you connect your generator directly to the rpod or not.

To avoid running the generator for long periods just shut it down once the charge rate begins to tapers off. You won’t get to 100% charge that way but the batteries will tolerate it for up to several weeks of use. Most of us don’t boondock that long anyway so as long as you can plug in to grid power overnight within that time frame you will be fine. If you can’t do that then either leave your generator on for several more hours once in awhile or get a solar kit.

Re paralleling two generators yes that works and can run your a/c but the two genies have to be from the same manufacturer and specifically designed for parallel operation. If you just connect the output of two generators together you will be lucky if you only trip their circuit breakers.

Some of your questions suggest to me that it might be good to review the differences between various electrical power sources. Generators and the grid in North America provide 120V (or higher voltages) 60 cycle AC (alternating current). The voltage and current are cycling back and forth 60 times a second so you don’t notice it. But if you connect two such power sources together and they aren’t first synchronized all kinds of bad things can happen. So the compatible generators have electronics which allow them to talk to each other and be synchronized before they run in parallel.

Batteries are DC (direct current, no cycling) devices so you have to have a battery charger that converts the 120Vac to the proper dc voltage for your battery. Since the rpod system is nominal 12 volts you need a charger that produces around 14V to get them charged fully. Solar is also dc so you can connect that directly if you have the right solar module, but you should have a charge controller for that too so you don’t overcharge the batteries on sunny days.

Finally, if you want to run AC appliances from your batteries without a noisy generator then you need a device called an inverter which takes the 12vdc from your batteries and “inverts” it 60 times a second while stepping it up to 120V. But if you go that route don’t try to get an inverter large enough to run big loads like your a/c and microwave, you don’t have a big enough battery for that.

Hope that helps and if you already know all that stuff my apology in advance.

One other thing, rather than getting two generators that run in parallel you can run your air conditioner on a single smaller generator if you install a device called an Easystart in the a/c itself. That is because the startup of the air conditioner compressor uses a huge amount of power for a short period. The Easystart reduces that load dramatically, so you can start and run a 13.5k btu/hr Dometic a/c on a single smaller generator. I do it frequently on my Honda 2kw. You can’t run anything else significant at the same time though, if you need to do that then you do need to get a second (or single larger) generator.

Yeah the 1200 watt genny will not operate the a/c, it takes around 1700 watts running, not counting startup. Min would be something like a Honda 2.2kw plus an Easystart.

Some folks here have put in battery monitors. Those work by measuring current in and out of the battery and using that information to calculate amp hours. It knows when the battery was last at full charge by its voltage and then clocks amp hours out so it can display battery state if charge as a percent of rated capacity. That is handy information but not essential, you can get a rough idea of SOC by measuring battery voltage.

My recommendation is if you do get one select one that uses a current shunt (calibrated resistor) to measure amps. You install that inline to the battery in the negative leg. There are some out that use a Hall effect donut that you slip the battery conductor through, which is a slightly easier install. The drawback is that Hall effect donuts are subject to drift so not as accurate.