charging // batteries
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URL: http://www.rpod-owners.com/forum_posts.asp?TID=14441
Printed Date: 14 May 2025 at 7:47pm
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Topic: charging // batteries
Posted By: Hunter
Subject: charging // batteries
Date Posted: 08 Mar 2021 at 1:43pm
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I have a small generator I would like to charge my two Paralel batteries when camping wo power. I have an rpod196 2021 and it has a manual cutoff switch on the outside for the batteries. Rather than plug the generator in to the whole system I would like to go directly to the batteries to speed up the charging process. I suspect their would be a slow triclle charge from the ropod vs going directly to the batteries? I also have solar on board. Would I hurt anything if I turn off the battery like to the rpod and charge the batteries with a charger. I guess I would need to attach the charger to the pos on one battery and to the neg on the other battery? Anyone have any suggestions here? Thanks Hunter
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Replies:
Posted By: podwerkz
Date Posted: 08 Mar 2021 at 4:19pm
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Nope...just turn on the main battery switch and plug the generator into the r-pod shore power connection and be done with it. There are a couple of unusual situations and reasons to do as you suggest, but in all normal situations, use the factory supplied 120v to 12v converter to charge the batteries, using your generator for a power source. Your solar charge controller should be hooked up to the batteries directly, if so, the battery switch can be in either position when using solar input as a charging source.
------------- r･pod 171 gone but not forgotten! |
Posted By: offgrid
Date Posted: 08 Mar 2021 at 5:45pm
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+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. ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: Hunter
Date Posted: 08 Mar 2021 at 8:35pm
| Thanks for getting back to me. The reason I was thinking of going to the batteries directly was because I read somewhere, I thought, that the on board converter supplied a trickle charge and I would have to leave the generator going on for much longer to get a charge. If this is not the case then you are right it would be much easier to just hook up to the rpod. The generator noise is not something I or other campers want to listen to any more than is necessary. This is my first time with the forum and I can see it will be very helpful. Thanks to you both again. Also if I do go to the battery directly how do I hook it up with two batteries in parallel? |
Posted By: Hunter
Date Posted: 08 Mar 2021 at 8:48pm
| 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. |
Posted By: podwerkz
Date Posted: 08 Mar 2021 at 8:49pm
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You can plug into the small generator and it should have enough power to charge not only the house batteries but also if you have laptops and/or smartphones, cameras, cordless tools, etc, that is the time to plug them in and let your genset charge multiple items during that cycle... If it is a small portable inverter generator, say, 1000-2000 watts or so, then it should be quiet enough that it wont bother anyone during the daytime, unless they are parked really close to you. I've never used a parallel kit so I dont know the particulars with that....maybe someone else will chime in.
------------- r･pod 171 gone but not forgotten! |
Posted By: offgrid
Date Posted: 09 Mar 2021 at 2:12am
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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. ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: Hunter
Date Posted: 12 Mar 2021 at 7:42am
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Thanks for the info and the time given! I think that the easystart makes allot of sense!! Particularly if you want to keep the weight down with your generator. I suspect I will still need to eventually purchase a larger generator to run in parallel with the one i Have as it peaks at 1200 watts.
Another question is has anyone worked with a battery monitor beyond what is supplied by rpod? |
Posted By: offgrid
Date Posted: 12 Mar 2021 at 8:17am
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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. ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: StephenH
Date Posted: 12 Mar 2021 at 8:23am
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Peaking at 1200 watts, even paralleled, will be unlikely to work successfully with the AC. You would need to parallel something with a peak of 2000 or a larger single generator. Even then, an EasyStart would likely be helpful. The 1200 watt peak is more like about 900 running watts. That would be good for charging the battery, powering lights, the television, and possibly the refrigerator, but not much beyond that. ------------- StephenH Happy is the man that findeth wisdom,... http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
Posted By: Hunter
Date Posted: 12 Mar 2021 at 10:20am
| Yes I did not think the little guy (westinghouse 1200i) would have enough power but was wondering if paralleled with the westinghouse igen 2500 there would be enough power? How does the parallel thing work if you were to combine these two what kind of watts would you end up with? This is very helpful being able to use the forum!! I am very new to all this as you might have guessed. |
Posted By: offgrid
Date Posted: 12 Mar 2021 at 10:38am
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Does the manufacturer claim those two generators can parallel with each other? If so then the output under continuous load should be roughly the sum of the two. Probably not the case for startup due to slight differences in response time between the two sizes, but that’s speculation on my part. ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: StephenH
Date Posted: 12 Mar 2021 at 10:59am
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+1 The manufacturer's web site is the best source of information on capability. ------------- StephenH Happy is the man that findeth wisdom,... http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
Posted By: Hunter
Date Posted: 13 Mar 2021 at 7:18am
| I see you are a fellow cpap user and nc neighbor . I used to have a poptop camper and would take a large marine battery with me and use an inverter to run the power for the cpap minus the heating part. Used to get about four nights. I am about to head out for a camping trip (South Mountain State Park) w/o hookup and wonder how fast the battery will draw down using the rpod onboard inverter. Also it looks like we are also going to need to use the propane furnace with fan and wondering the same here. Thanks Hunter |
Posted By: StephenH
Date Posted: 13 Mar 2021 at 2:36pm
The CPAP machine I have is the Philips Respironics Dream Station. It runs on 12V. When traveling, I use a 12V plug-in and not the 120V power block. I also turn off the humidifier to reduce the power needed. I can run a number of nights. If you do not have a convenient 12V outlet handy, you could do as I did and install one. The cords are rather pricy. I bought one for the Dream Station, not knowing that the one I had from my previous machine would fit. I'm not sure where I put that spare cord though. I ordered it from Amazon. It isn't cheap, but it saves having to go though the 120V power block and an inverter. If you are in the Raleigh area, perhaps we can get together and discuss this. We live in Wake Forest, northeast of Raleigh.
------------- StephenH Happy is the man that findeth wisdom,... http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
Posted By: Hunter
Date Posted: 13 Mar 2021 at 5:41pm
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Thanks for your response. Does your cpap have a 110 plug and a 12 volt connection on the back. I have this on the back of my resmed escape 2,and old and heavy dog. I have never tried the dc plug on the back for fear of blowing the thing up. Guess its time to try. I have a small portable lithium battery that has a 10 volt dc outlet. wish me luck. I will send you and email if i am heading your way. With the covid thing my travelling has been very light in the last year. Thanks again for the consult .
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Posted By: StephenH
Date Posted: 13 Mar 2021 at 7:18pm
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If the output of the Lithium battery is 10V, then likely that won't work. If it is 10A, that is a different matter. It has to be 12V. I think you would be satisfied using the 12V power if it has a connection. Mine just has the jack for the cannon plug. Whether that canon plug comes from the 120V power block or the 12V power cord does not matter. It works the same both ways. I did a search and found this: https://www.amazon.com/KFD-Charger-Adapter-R360-760-Machines/dp/B07P7KPW31/ - https://www.amazon.com/KFD-Charger-Adapter-R360-760-Machines/dp/B07P7KPW31/ You would need to verify, but it looks like it would work for your machine. It turns out that your machine actually uses 24V instead of the 12V mine uses.
------------- StephenH Happy is the man that findeth wisdom,... http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
Posted By: Hunter
Date Posted: 14 Mar 2021 at 7:50am
| Wow . Thanks for looking into this! I need to find out what the output of the cigarette lighter connection is on my portable battery but this just might work with it. it is only a 200w unit so I am not sure if it has the power? How much loss is there when you go through the inverter vs directly to 12 v in efficiency? Thank very much. I can always order the unit from amazon and send it back if it does not work. One of the many benefits of Amazon. |
Posted By: offgrid
Date Posted: 14 Mar 2021 at 8:10am
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Those little inverters are typically around 75-80% efficiency. But it it’s not a sine wave inverter (most of the cheap ones aren’t) then it will probably reduce the efficiency of the cpap as well. The would overheat it and could damage it long term. If the cpap manufacturer provides a 12V input then you are much better off doing it that way. ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: StephenH
Date Posted: 14 Mar 2021 at 8:45am
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+1 on Offgrid's remark. It is always more efficient to go direct rather than through an inverter. Given the age of your machine, you might consult your doctor about ordering a new one. If so, then look into the Dream Station. The DreamWear masks are comfortable as well. I use the Dreamwear model number 1138410 which uses a nasal cushion. I do have to use a chin restraint (ResMed 16015) to keep my mouth shut. I have a high, narrow bridge on my nose, so the full-face masks cause me significant pain from the pressure. The nasal cushion does not have that problem. If you do get a new one, then see if it can be a 12V model. That will be better for travel. ------------- StephenH Happy is the man that findeth wisdom,... http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
Posted By: Dirt Sifter
Date Posted: 14 Mar 2021 at 11:33am
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I love this forum. So much good information put out in an understandable manner by guys who like sharing.  ------------- Greg n Deb 2020 195 HRE '07 Tundra 5.7L., '17 Tacoma 3.5L. Both with tow packages 1 Puggle, 1 Chihuahua support staff |