Will Charging my Chassis Battery charge my Coach Batteries?

[ManWonder]

I am considering getting a foldable solar panel to keep my 2 batteries charged in my coach. My thought was to connect the charger directly to one of my coach batteries. But then I got to wondering would connecting to my chassis battery also charge the house batteries?

[mkguitar]

on most models the batteries are isolated- for instance my 06 PW has a surepower isolator under the hood-( it's a 8 x 4" blue metal box with cooling fins and heavy cables attached).

some of the solar kits are not regulated and may over charge a battery, boiling out the electrolyte.- check yours

you can use a jumper cable to connect the 2 batteries when trickle charging- but you better remember to remove it! ( mine is a small yellow wire with alligator clips...I tie the ignition key to it so I don;t forget)

IF one of your batteries has an internal fault it can drag down the other batteries- so make sure they are in good shape.


if you are worried about batteries discharging while stored over the winter, you could disconnect the battery with a connector or switch on the negative pole.

if you are in a frigid climate, remove batteries and store on the bench where it isn;t as cold


my van is a GM with a side post battery- I used a disconnect like this:
https://www.amazon.com/Side-Battery-...P175G9PPD7MQFD






Mike

[booster]

Your 2004 would have an isolator, not a separator, so it will not charge the starting battery at the same time, as it is one way only. The engine will charge both batteries, but the shore power or solar won't.

As was mentioned, you could use a jumper wire to make it happen, but it is a PITA to do all the time and not forget it and melt it.

It would be better to use an either/or switch and do the coach or starting battery separately. Depending on the size of the panels and the time of year, you may not have enough power to adequately do both at the same time.

[ManWonder]

My situation is that we hope to use the RT 190P on occasional outings during the cold months here in northern Virginia. Where we keep it parked is too far away from the house to run an extension cord. My thinking was that I could avoid the weekly drives to keep the batteries charged by installing a portable solar panel (and controller) and connecting it to my coach batteries. Then the thought occurred to me that maybe if I connected the solar panel to my engine's battery the coach batteries would also get topped off. But I reckon that's not the case, correct?

[booster]

Not unless you either replace the isolator with a low draw separator, or jump out the isolator while parked only. You would also have to make sure the solar is able to keep up with whatever draw you have on the batteries, as Roadtreks usually don't have complete shutoff of the batteries, and the shore charger usually takes a little. If you do also connect to the starting battery, you will have to allow for the losses of the Chevy parts of the van also. In the winter, 100 watts should be enough if you have it aimed well and keep the snow off it, and it isn't in the shade.

[mkguitar]

I'd wire up plugs to charge the batteries- such as the deltran battery tender uses - these plugs are available at any motorcycle or autoparts store
( 3A version of deltran onsale at costco right now BTW ).

with easy to access plugs you can swap the panel every week of so from chassis to coach

Chev- my chev 3500 used 1.4 amps when sitting when I first got it...the things which stay on are doorlocks, alarm, power mirror, speedo cluster and radio.

by pulling each of my fuses and cleaning the contact legs, I reduced this draw by 1/2. it now draws 700mA when sitting.

even so, I don;t need alarm, doorlocks or radio memory, I disconnect the battery when parked behind our gate.

cleaning the fuses is a fun task- I also have fuses under the driver's seat ( much cleaner)...to make it easy- with battery disconnected i did all the reds, all the blues, all the greens- makes for less label reading of who goes where.

clean the legs with a fine file, scotchbrite or emerypaper- I found the file quickest- and then add a little dielectric grease.

these are the fuses out of one of my bikes- after about 4 years use in a dry climate, before and after:






mike

[booster]

I am surprised an 06 Chevy pulled that much to the van itself, even at 1/2. Our 07 is substantially less that that at about .04 amps. It was, however, very difficult to determine what the actual parasitic was because it varied like crazy. Open a door and timers ran for up to 20 minutes some times, turn the key on and off, another batch of higher amps for quite a while. Even pulling a fuse and putting it back in was enough to mess up the basic parasitic, because automatic stuff would run or reinitiate for a long periods. I finally wound up just checking one thing at a time, and let it sit an hour before doing the next one. During the testing, different stuff would run at the 1.5 amps you saw, but would eventually stop. We couldn't figure out why the van be fine for a over a month sometimes, and other times be near dead in two weeks, and it all was due to if we were going in and out of it a lot, or not.

[BBQ]

Originally Posted by ManWonder

My situation is that we hope to use the RT 190P on occasional outings during the cold months here in northern Virginia. Where we keep it parked is too far away from the house to run an extension cord. My thinking was that I could avoid the weekly drives to keep the batteries charged by installing a portable solar panel (and controller) and connecting it to my coach batteries. Then the thought occurred to me that maybe if I connected the solar panel to my engine's battery the coach batteries would also get topped off. But I reckon that's not the case, correct?

Assuming your coach batteries are deep cycle batteries,
they should hold their charge for months, even in cold weather.

Your chassis battery will need topping up more than the coach battery.

[ManWonder]

Originally Posted by BBQ

Assuming your coach batteries are deep cycle batteries,
they should hold their charge for months, even in cold weather.

Your chassis battery will need topping up more than the coach battery.

So then I should be more concerned with the engine battery...? Well, if so, that's kind of a relief. I was under the impression the coach deep cycle batteries needed to be protected from getting drained even with the switch turned to off. But if I can go weeks between charging then I may be good to go just keeping the engine battery trickle charged.

[booster]

Originally Posted by ManWonder

So then I should be more concerned with the engine battery...? Well, if so, that's kind of a relief. I was under the impression the coach deep cycle batteries needed to be protected from getting drained even with the switch turned to off. But if I can go weeks between charging then I may be good to go just keeping the engine battery trickle charged.

With a caveat. The AGMs need to be full when stored as the freezing point drops fairly quickly with state of charge. If you have wet cells, you do have to keep up with adding water if on continuous charge, although most starting batteries these days are low water use design.

You can't go by idiot light state of charge indicators and would need a good voltmeter or battery monitor.

[ManWonder]

i appreciate all the sage advice. I plan to both add a solar charger and monitor the batteries with a volt meter and charge as needed. They are wet cells and so checking the levels will be necessary as well but not a big chore really. Thanks to all.

[JohnnyFry]

It would be possible to make a second small isolator to install at the output from the solar panel to each battery. Essentially 2 diodes with sufficient capacity for the Solar current (say 40 amp rating) fed to each battery positive. You could also use a regular isolator block.
The downside here is that the solar output would be subject to the normal 750mV drop across the diodes. Not having done this, I would experiment first but you should be able to keep the batteries up with this kind of arrangement. You would probably need to bypass it for normal crusing use.

[DCHitt]

Just as an aside.... As part of the security system newer vehicles have a "Key Fob" that can be detected by the vehicle. When the "Key Fob" is "in the area" it fires up some of the computers and the battery current will go up.

I was warned not to just hang the keys next to my van in the garage because it would run down the battery.....