How to keep batteries charged while dry-camping

[Ron Dittmer]

Originally Posted by DbleDutch

Did you replace the batteries as a matched set or simply add a second battery? If the later your original could still be the culprit with a weak or failed cell. I have always heard "keep battery sets identical for size (amps) and age" for best results.

I replace my batteries in unison, going the extra step to make sure their production dates match. Still both my pairs of 12V wet acid batteries were serious under-performers compared to my 6V AGM. I will never go back to 12V again.

I have no first-hand experience with wet acid 6V batteries. Maybe there is a compromise in there somewhere. I did NOT consider them due to the limited access to my battery compartment for checking fluid levels. I had to ditch the slide out battery tray to make room for taller 6V batteries. CLICK HERE to see the project.

[Sbrownstein]

to answer the op's question...NO, you cannot connect a 120 volt feed to the generator output terminals when it is not running. You will need a transfer switch or something to keep the non-running generator from seeing 120 volts from your portable.

it does seem that something is wrong with your converter section, however. You should get significant amperage from the converter, enough to recharge a good two battery bank in a few hours. check the output of the converter and...if possible...the charge current that it is supplying. you will never get to a 'full charge' but will get to maybe 85%.

[Mark_K5LXP]

Originally Posted by Legolas

How exactly do the portable solar panels work, ie how do you connect them to your rv so that the batteries get charged.

There are cheap easy and expensive hard answers. Just how far do you want to go?

Cheap and easy is to buy a panel, put it somewhere sunny and connect it to any 12V spigot on your RV that is fed from the house battery. I've done this countless times camping with a variety of vehicles. Not the most efficient or effective use of the panel but trivially easy to do. My RV has a 12V lighter plug by the outside radio so I just plug in there and it's done. The battery gets whatever warm fuzzy from the panel there is and something is better than nothing.

Expensive and hard is to come up with a charge controller that can accommodate an array of portable panels and whatever fixed ones you have on the RV that will both maximize power transfer and also manage the charge cycles. You'll have enough panel capacity to bring your batteries up within one solar day, and enough battery to go 2 or 3 days without much solar input because even in a solar friendly place like here in New Mexico, it only takes one cloud to bring everything to a halt. Factor additional panels to augment capacity in the event you won't be going outside every half hour or so to reorient the panels towards the sun to keep them at peak output. Review the solar insolation tables for your area and factor that into the panel ratings. "Sunny Florida" is pretty good but there are way more cloudy days and humid atmosphere to go through than here in the high desert.

Knowing just how much panel you need no matter which way you go or anywhere inbetween depends entirely on your anticipated power requirement. You can go with what you know empirically from past outings or decide on a hard limit and design to that. The good news about solar is that it scales pretty easily, you can start with a given capacity then if it comes up short you can add more panels.

Practically speaking I find that unless you live off grid for weeks or months at a time, solar is a really expensive, time consuming and unreliable source of power that's just not worth the trouble. When I go camping the last thing I want to do is unpack and set up a bunch of stuff every time. Just about anything else is more cost effective and convenient. There are those that are willing to ante up to put up a bunch of panels, fancy controllers and spendy batteries, and work it successfully. All to not run a small inexpensive generator an hour or two a day. Just comes down to what hill you want to die on. There are turnkey portable panel products out there that cost a crazy amount of money or you can hit the solar power websites and design your own system from components. Either way you'll be investing your resources and energy into something you really have to want to have to make it worth it. So my recommendation to you if you don't have much solar and battery experience is to start with something small, say a couple of panels and a controller, then use it for a few outings to get a feel for what you'd be in for to scale it up to whatever level you might ultimately want or need.

Mark B.
Albuquerque, NM

[DbleDutch]

Originally Posted by Legolas

I am totally in the dark here-forgive the pun, but the portable option seems doable to me. However not knowing anything about them my question is - How exactly do the portable solar panels work, ie how do you connect them to your rv so that the batteries get charged.

Do a search on Amazon for "folding RV solar panels". I chose the AcoPower 105w set that comes with a simple but efficient controller. They come with battery clips but I cut them off and installed the heavy gauge battery connector plug same as Battery Tender connector. The connector is permanently connected to the battery bank and long enough to drop out of the bottom of the open bottom of my class C battery enclosure. Plug the panel and controller in and set the panels in the sun- done.

The AcoPower panels I have are about 7# and fold to the size of a thin briefcase. The panels do not have the heavy acrylic/glass protective cover, so could be damaged, but pack up so easily when weather or hazards are present I put them away.

[JayMartin]

I was just looking at my notes from when I had the truck camper with a single battery.
I used a Honda EU2000i generator and a Black and Decker Smart Charger. I found I could stop the BD Smart Charger when amps got down to 3.7A. After that it was drastically diminishing returns.
I also have a note about 5A per 110Ah, but it has been too long for me to even know what that means.
Jay

[Rockwood27]

Not all batteries are created equal. Smaller pairs of batteries will only supply about 100 amp-hours (50 A-H useable) to over 200 A-H (100 A-H useable). A good set of 6 volt golf cart batteries (GC2) will give you 200 - 235 A-H. You need to add up your power usage (energy audit) and install enough batteries to meet the demand between recharging cycles.

I'm not understanding the issue with using the portable generator. Why don't you just plug the RV power cord directly into the generator. Problem solved?

Are you sure you can't mount a couple of 100W solar panels on the roof? I have plenty of room on my 20.5 foot long by 6.5 foot wide Class B.

[Budhumph]

To: Dble Dutch/Mark_K5LXP/Ron Dittmer/avfordguy/Legolas/Sbrownstein/Jay Martin/ Rockwood27

My apologies to one and all for the delay in responding to your responses and thoughtful advice. My computer has been inop until just now. Sorry. Budhumph
I concur with basically all that has been written. After reviewing all comments and giving more thought to my situation, I have arrived at the following plan: Being almost 85 years old, I foresee only snowbird dry camping a couple of more winters, so it doesn't seem good sense to installing an expensive, unwieldy solar system. Instead, I plan to use my little quiet Honda portable 1800 watt generator during required times while not using the on-board generator, to keep my batteries charged. (I was obviously having a brain fart thinking that I needed to attach it to the output leads from the on-board generator, rather than to simply plug it into my shore power cord.) I have replaced my light bulbs with LED, and have added a second 12 volt battery....I plan to make-do with these relatively new 12 volt ones rather than convert to the more efficient 6 volt ones. As recommended, I am going to install a new multi-stage charge converter and get a battery monitor, and will test to ensure that both batteries are okay. I believe that these actions should basically solve my problem. Thanks again to one and all for your responses and sound advice!!! Budhumph

[Mtn. Lion]

If you are willing to run your Honda, just do that. I run a Yamaha generator with a 40' cord. It runs about 8 hours every day. It is quiet. Gas usage is about 4 gallons for 7 days. About $12.00 per week @ $3.00 a gal.. Compare that price with solar j/k Solar is all the rave.

[Phil G.]

Originally Posted by diginomad

If you are willing to run your Honda, just do that. I run a Yamaha generator with a 40' cord. It runs about 8 hours every day. It is quiet. Gas usage is about 4 gallons for 7 days. About $12.00 per week @ $3.00 a gal.. Compare that price with solar j/k Solar is all the rave.

Well ... solar may be all the rave if, and only if ... 1) you don't mind having even more holes in a roof that has to remain leak-free year after year in a sun that slowly ruins all sealants, and 2) you don't mind having to somehow work around solar panels whenever up on the roof resealing must-have openings or eventually having to repair broken or damaged equipment on the roof.

[WorldCat25]

Maybe someone addressed this. Why connect a generator to a charger to the batteries.

Don't you just plug in the RV to the generator like when you're hooked up to shore power? Does the rv have a charger capablilty?

[ajsfla]

Originally Posted by Budhumph

Johninsd: The roof would be nice for solar panels but I don't have the room due to vents, etc., so I'd have to ground-m
For All: I'm still looking for an answer as to whether it is electrically okay to hook my small portable Honda generator directly onto the on-board generator output leads, or whether I need to isolate the on-board generator from my portable generator/output lead connection. Thanks again to all..Gordy

Why not plug the Honda gen set into your shore power cable that would be the best way I think

[Busskipper]

Originally Posted by Budhumph

I have a 28' Thor Chateau. During last February's month-long snowbird dry-camping trip to Key West, I was not able to keep my battery charged for any significant length of time. My on-board generator provided power when in use but it was not practical to continuously run this noisy, gas-guzzler, and without this generator running, the battery would quickly run down so much that sometimes I couldn't again re-start the generator. Since then I have added a second battery, in parallel, and have replaced my bulbs with LED, but this won't solve the basic problem.

I am now looking for a solution to keep my batteries charged during extended dry-camping trips in the future. One option is to purchase a 200 watt suitcase solar panel system, that I would have to ground-mount, but this is rather expensive and is unwieldy. I am wondering if perhaps I might attach my quiet, fuel-efficient little 1800 watt Honda portable generator to the output leads of my big noisy on-board generator, and run it during low-electrical use periods to power my low-draw lights and such, as well as to keep my batteries charged.

If this is feasible, could I alligator-clip my portable generator directly onto the on-board generator output leads, without first disconnecting and isolating the on-board generator? Or would I need to install a junction box so as to isolate the on-board generator from the attachment of my portable generator to the output leads?

Is there a better solution to keep my batteries charged during extended dry-camping trips? All advice and suggestions will be appreciated. Thanks, Gordy, US Navy Retired

Think the easiest solution would be to start the Generator - 1,800 watt - and just plug into it run it for a couple hours in the am and then again in the pm. No need to mess with clips - as it should be just like plugging in at a campsite.

KISS - works in this case - Might want to add a locked cable to the Generator as those 1800 watt Honda's often grow Legs

On one of those weeks in the backcountry you might figure out how to Mount the Solar so as to have it become EASY.

JMHO,

[Ron Dittmer]

A small Honda generator is a great idea. I just have trouble with the idea of carrying a second generator.

[Phil G.]

Originally Posted by Ron Dittmer

A small Honda generator is a great idea. I just have trouble with the idea of carrying a second generator.

Ron, of course you and I have along with us a pretty good means for bulk charging our RV's coach batteries - just idle our V10 engines and let the Ford alternator dump a lot of current into the coach batteries for about an hour.

I do this quite often for initial bulk charging because it's so convenient and super quiet to do so anytime anywhere ... even though in my case I also have two generators on board.