The new-to-us coach has 4 12-volt house batteries in parallel. Our uses for it will include boondocking for weeks at a time in spring and fall in the mountains. It has a couple of solar panels (100 watts total), but I don’t know how far those will go in replacing the relatively small amount of battery power we will use without shore power.The inverter will charge at 100 amps, but the genset takes a half-gallon of propane per hour. Aside from charging batteries, we would not often need to run the genset. And running the genset will shorten our stay due to the limited amount of propane aboard.I have a little Yamaha ef1000is generator which will run for many hours on a small amount of gasoline. I just bought a Black & Decker VEC1093DBD 4/10/20/40 amp automatic charger to use with the little Yamaha to provide extra charging for the batteries, rather than running the big propane genset if the solar cannot keep up.Question: Does it matter where in the parallel circuits I attach the portable charger cables? I find that the existing cables are routed as follows: Red to battery 1, then battery 2, then cables from 2 to both batteries 3 and 4. Black to battery 4, then 3, then 2, then 1. The closest terminals to hook the clamps for the portable chargers are on batteries 2 and 3. Batteries 1 and 4 are in the back of the drawer.In order to treat the batteries kindly in recharging, can I attach my charger clamps at batteries 2 and 3, in the front half of the drawer, or should I bother to reach to the back to charge at the same terminals the built-in charger uses, on batteries 1 and 4?Thanks,Wayne

Wayne, balanced batteries become more and more important as amperage increases. You can get away with murder at 40 amps yet have big problems powering a huge load with a huge inverter. Place the positive charger lead on one battery positive and the negative on any other battery negative and call it quits.Much more important is to insure terminals, posts and the copper wire inside the cables is in excellent condition and shiny bright. The area where copper wire strands are crimped inside a battery lug are hidden from inspection and can cause a lot of problems.

That little 900w continuous genset may be hard pressed to power the b&d 1093. BFL would know, seeing as he has one.Generally you should balance the wiring. Both the load (out) and charge (in) must be wired to (the same) opposite poles of the bank.http://www.altwindpower.com/battery-series-parallel.php4th diagram down.You may be able to move wiring around to put the two terminals needed more within reach? You may also want to consider hooking up the 1093 with terminal lug rings, instead of clamps, for a more semi-permanent (one time) installation.

You can put the 1093's clamps on any pos and neg post you can get at. In fact you can put the pos clamp on a pos post and the the neg clamp on the rig's frame like it says to do :) You can leave the solar on while you are charging with the 1093.You can probably rearrange the battery links so your most "balanced" pos and neg are up front.If you get a Trimetric then its shunt neg will go to the neg battery post and you will need to connect the 1093's clamp to the outer end of the shunt for the Trimetric to show what the 1093 is doing along with the solar neg and the rig's negs.You can solve a lot of that by balancing the batteries and run a set of wires from the proper posts to a pos bus and the shunt as the neg bus. One guy with a four battery tray like that put two holes in the "roof" of the compartment where the tray is and ran the wires up through the holes to the busses. That way he didn't have to worry about getting the tray all the way out anymore.BTW the little gen will run the 1093 but won't have much left over to run anything else at the same time until amps have tapered down quite a bit from the initial 40 amps.Also the 40 amps will take a long time to recharge four batts from 50-90%SOC maybe 6 hours. My 100 amp charger can do that in under three hours but needs a bigger gen of course. Its the old story, noisy big gen for a short time or quiet small gen for a long time (unless you have a big Honda which is quiet and fast)

Thanks for the quick replies.Yes, I thought I recalled a need for balancing the charging, but then I found the current wiring to be a bit different than expected.Before buying the 1093, I looked up the user manual and found that the draw is 785 watts continuous, and I knew that the ef1000is had a rating of 900 watts continuous. Closer than I would have preferred, but I figured it would power the charger. I also assumed that I could dial the charger up only to 20 amps if necessary to hold down the draw from the little genset.Wayne

2*100W portable solar tilted South in January in, say, Charleston WV, will collect on the average 40 AH a day. More on a sunny day, less on cloudy. It is possible to live off 40 AH if you don't use 120V devices other than TV couple of hours, and rarely run a furnace. In any event, it will help shorten the generator time.

Charging 4 12-volt house batteries with portable charger

51 Replies

mena661
Explorer
Oct 24, 2014
JiminDenver wrote:

This is my point. Even without the list it seems like the same things are suggested before the OP usually knows what they need.
True, I tend to gloss over that part. :)

It would give the people looking a chance at making a better choice.
I agree. It would help greatly. I don't know if I do pros/cons myself but I'll make an effort to do that in the future.
JiminDenver
Explorer II
Oct 24, 2014
mena661 wrote:
Honestly, we could easily tell people to buy a list of stuff and it would work well for them. BUT, they wouldn't learn anything and the personalization would not be there. They'd have to use it as is for the most part.

This is my point. Even without the list it seems like the same things are suggested before the OP usually knows what they need. Sometimes finding that out is hard because if a person knows what they need, finding the solution isn't all that hard. That takes effort on their part and after owning a personal services and home management service for 29 years, I can tell that people think I can read their minds. So I have nothing but respect for those here that take the time to help and figure out what someone really needs.

One thing I'd like to see is not just the up side of a suggestion or description of a system, but some discussion of the downsides in the same post. That way if someone does point out a downside it isn't seen as an attack. It's no hair off my back if while I say how wonderful having 720w of solar tracking is to include that I can't wait to get at least some of it mounted and not deal with the storing and handling of three huge panels. That while my affordable generator is dependable, that it is too noisy to use around others. The Eco-worthy that is a nice controller IF it fits your needs should have it's limitations noted. It would give the people looking a chance at making a better choice.
mena661
Explorer
Oct 24, 2014
Honestly, we could easily tell people to buy a list of stuff and it would work well for them. BUT, they wouldn't learn anything and the personalization would not be there. They'd have to use it as is for the most part.
NinerBikes
Explorer
Oct 24, 2014
JiminDenver wrote:
Ahhh for the good old days when rigs only used power if you turned on a switch. No blower on the furnace, no pump on the water. no control boards and you lit the pilot yourself. On the downside, those furnaces took forever to warm up the rig. It was a pain to go out and relight the pilots when they blew out. My brother and I took turns with a bike pump on the water system so the old folk could take a nice hot shower. Then they tossed our butts in the lake with a bar of ivory. (it floats)

Our rigs biggest issue was we never intended to go back to boondocking. We had roughed it for decades and were going to see how the other half did it. One trip in campgrounds and we found out we couldn't stand being crammed into a tiny spot with noisy neighbors. So we were stuck with a rig that couldn't go more than a few days without life support.

Had i done what was recommended back then, I would have mounted the two extremely mismatched panels and confused the heck out of the recommended controller of the day, the Rogue 30a. Even Mark at Rogue didn't mention the problem with mismatched panels, I figured it out in my yard testing.

AGM was and still is the best thing since sliced bread and back then I had a line on four Lifeline AGM 8-Ds. They would be toast by now as my controllers, converter and home chargers wouldn't do well with them.

I would have a very expensive generator that would never get used. Oh wait, the solar system would be messed up and the AGMs dieing, so maybe I would need it after all. ;)

Being able to test different panels has been a blessing. Try to tell someone about the results and they will read the hype off of a web site and tell you are wrong. They will never know the difference because they buy one type of panel and that's it. If a mono panel takes a nose dive, well it's cloudy stupid. what did you expect.

Niner, I wouldn't pick on you, well no more than anyone else I suppose. lol I think that anyone here that has worked out their systems to meet their needs is doing pretty well. I would never tell another that they were wrong considering my set up is about as far from recommended as you can get. Too much solar for the banks, batteries that are being used for things they were not intended for. My generator, inverters and controllers are all cheapies. It's amazing we haven't blown up and lit the forest on fire. lol

All I am saying is wouldn't it be easier to have a sticky labeled "Taking your rig off grid? You need...." and then list every high dollar, most recommended equipment that full timers need because they depend on it in all conditions.

Isn't it wonderful that we all take different wonderful bumpy roads, and chose different forks in the road to take when dry camping? There is no one way to skin a cat. Options, options, options.
JiminDenver
Explorer II
Oct 24, 2014
jrnymn7 wrote:
Yes, I had read your screwy 31 thread... rather enlightening for sure.

that would be a understatement.
JiminDenver
Explorer II
Oct 24, 2014
Ahhh for the good old days when rigs only used power if you turned on a switch. No blower on the furnace, no pump on the water. no control boards and you lit the pilot yourself. On the downside, those furnaces took forever to warm up the rig. It was a pain to go out and relight the pilots when they blew out. My brother and I took turns with a bike pump on the water system so the old folk could take a nice hot shower. Then they tossed our butts in the lake with a bar of ivory. (it floats)

Our rigs biggest issue was we never intended to go back to boondocking. We had roughed it for decades and were going to see how the other half did it. One trip in campgrounds and we found out we couldn't stand being crammed into a tiny spot with noisy neighbors. So we were stuck with a rig that couldn't go more than a few days without life support.

Had i done what was recommended back then, I would have mounted the two extremely mismatched panels and confused the heck out of the recommended controller of the day, the Rogue 30a. Even Mark at Rogue didn't mention the problem with mismatched panels, I figured it out in my yard testing.

AGM was and still is the best thing since sliced bread and back then I had a line on four Lifeline AGM 8-Ds. They would be toast by now as my controllers, converter and home chargers wouldn't do well with them.

I would have a very expensive generator that would never get used. Oh wait, the solar system would be messed up and the AGMs dieing, so maybe I would need it after all. ;)

Being able to test different panels has been a blessing. Try to tell someone about the results and they will read the hype off of a web site and tell you are wrong. They will never know the difference because they buy one type of panel and that's it. If a mono panel takes a nose dive, well it's cloudy stupid. what did you expect.

Niner, I wouldn't pick on you, well no more than anyone else I suppose. lol I think that anyone here that has worked out their systems to meet their needs is doing pretty well. I would never tell another that they were wrong considering my set up is about as far from recommended as you can get. Too much solar for the banks, batteries that are being used for things they were not intended for. My generator, inverters and controllers are all cheapies. It's amazing we haven't blown up and lit the forest on fire. lol

All I am saying is wouldn't it be easier to have a sticky labeled "Taking your rig off grid? You need...." and then list every high dollar, most recommended equipment that full timers need because they depend on it in all conditions.
jrnymn7
Explorer
Oct 24, 2014
Yes, I had read your screwy 31 thread... rather enlightening for sure.
NinerBikes
Explorer
Oct 24, 2014
JiminDenver wrote:
Even better is the person that wants to dry camp for a weekend ending up with a pair of 6v's, a 2000w generator, solar, a new converter, LEDs, a portable propane heater and NOW..... low power TV too. lol

I am glad people buy the stuff though. What is interesting is seeing what is hype and what is real with all the high dollar gear. Sometimes the small usable advantage is so over hyped and there is always a downside beside the extra cost. With some batteries it isn't just their cost but the cost of the controller/converter needed to keep them up.

I have a year or two left on my banks, I hope you guys find the holy grail soon.

Who, me? :)
NinerBikes
Explorer
Oct 24, 2014
jrnymn7 wrote:
Thanks Niner, but I realized I was just being too lazy to click on BFL's link and read the old thread... my bad. I repented, cleared my post, and did some interesting reading.

Nice explanation though, thanks.

I EQ'd a pair of 6's last week, and posted the results in my pm4b-75 thread. Should be the last post.

"Screwy 31" is another benchmark must read on trials and tribulations of batteries, and getting a free education at someone else's expense, as we all wise up to the reality that sometimes, when recharging, a little bit higher Voltage with modest amperage is King to healthy battery life.
Snowman9000
Explorer
Oct 24, 2014
JiminDenver wrote:
Even better is the person that wants to dry camp for a weekend ending up with a pair of 6v's, a 2000w generator, solar, a new converter, LEDs, a portable propane heater and NOW..... low power TV too. lol

I am glad people buy the stuff though. What is interesting is seeing what is hype and what is real with all the high dollar gear. Sometimes the small usable advantage is so over hyped and there is always a downside beside the extra cost. With some batteries it isn't just their cost but the cost of the controller/converter needed to keep them up.

I have a year or two left on my banks, I hope you guys find the holy grail soon.

Good post, putting it into perspective, Jim.

OTOH, the RV 12v system as delivered is usually pretty poor for off grid use, so you have to do something. Lower power draws and more batteries are beneficial 100% of the time, unlike solar, gensets, and stronger chargers.