Outside of Quartzsite boondocking for the last month. Very happy with the solar but have one last question i thought id throw out to the group.I can hear that Aux Start relay kicking in. Im thinking about installing a switch next to the solenoid so that I can disable it. Is it necessary having the solar charging the chassis batteries? Not really sure how much parasite load i have on the chassis batteries. Not really sure if haveing them connected on a daily basis is good or not. I could flip the switch on once a week or so to keep them topped off. I was also thinking about setting it up so that the charge controller would dosconnect that solenoid when its harvesting solar. Driving down the road the panels are charging the house batteries. The alternator could just charge the chassis batteries.Thoughts?

Try it and gain insight into how much the chassis batteries discharge. It's certainly not necessary for solar to charge the chassis batteries.When driving I want the alternator to charge both banks and hence I don't think about having enough sun to charge the house batteries. But your alternator and solar should both charge together. Also wondering if you can add some sound deading material to reduce the clicking.

I recommend to leave it work as designed.

I have never heard of a solar charge controller that engaged the Aux Start relay in order to charge the chassis battery. I suppose that would be OK, but could also be a problem if you have AGM House batteries and a standard wet cell battery for the chassis. Each type requires a different charge and float voltage. My BlueSky 3000i solar charge controller has a separate output of up to two amps just for maintenance of the chassis start battery so there is no need to engage the Aux relay. As others have stated, its really not necessary to charge the chassis battery.

EdSome of the higher end charge controllers have one or more aux. ports that can easily be setup to do a varity of tasks. I could setup my Midnight Solar charge controller to send +12vdc out the aux1 port when it starts charging the batteries at a set voltage. All you need is a relay that would simply disconnect the feed to that solenoid.I wish I had a clampon 12v meter to see what that solenoid draws. Sure does get hot!Running 4 flooded 6 volt on the house side.

That's not the aux startThat is the biderctional Charge relay it does the same thing on shore power and generator, Once the house batteries reach a set voltage the charge relay connects the chassis batteries so as to maintain thenI would leave it as is, unless you are having problems with low power on the house batteriesYou are not going to over charge the chassis/engine batteries,

My solar and the chassis batteries | Good Sam Community

57 Replies

mchero
Explorer
Nov 03, 2016
I understand the fleetwood B.I.R.D. and such. I just call it the Aux start because of the Aux Start switch on the dash. Had a 93 PADP B4 the 07 Discovery. been all over the charging systems between the two.

Can someone point me to the BIRD documentation I'd like to see the specs on it.

Also, if someone has a 12v clamp on meter that could tell me what that fat solenoid draws? I'll go out & see what solenoid I have. Mine is on the back wall, not buried behind the BCC.

Trombetta 114-1211-020

While on solar I can her that bugger cycling in the AM hrs, stays steady on during mid day
CA_Traveler
Explorer III
Nov 03, 2016
Some solenoid controllers will activate the solenoid when the house battery is charging and the chassis battery needs charging. The BIRD D2 is one and it's actually bidirectional. Independent of solar.
MrWizard
Moderator
Nov 03, 2016
That's not the aux start
That is the biderctional Charge relay it does the same thing on shore power and generator,
Once the house batteries reach a set voltage the charge relay connects the chassis batteries so as to maintain then

I would leave it as is, unless you are having problems with low power on the house batteries
You are not going to over charge the chassis/engine batteries,
mchero
Explorer
Nov 03, 2016
Ed
Some of the higher end charge controllers have one or more aux. ports that can easily be setup to do a varity of tasks.
I could setup my Midnight Solar charge controller to send +12vdc out the aux1 port when it starts charging the batteries at a set voltage. All you need is a relay that would simply disconnect the feed to that solenoid.
I wish I had a clampon 12v meter to see what that solenoid draws. Sure does get hot!
Running 4 flooded 6 volt on the house side.
Ed_Gee
Explorer II
Nov 03, 2016
I have never heard of a solar charge controller that engaged the Aux Start relay in order to charge the chassis battery. I suppose that would be OK, but could also be a problem if you have AGM House batteries and a standard wet cell battery for the chassis. Each type requires a different charge and float voltage. My BlueSky 3000i solar charge controller has a separate output of up to two amps just for maintenance of the chassis start battery so there is no need to engage the Aux relay. As others have stated, its really not necessary to charge the chassis battery.
time2roll
Nomad
Nov 03, 2016
I recommend to leave it work as designed.
CA_Traveler
Explorer III
Nov 03, 2016
Try it and gain insight into how much the chassis batteries discharge.

It's certainly not necessary for solar to charge the chassis batteries.

When driving I want the alternator to charge both banks and hence I don't think about having enough sun to charge the house batteries. But your alternator and solar should both charge together.

Also wondering if you can add some sound deading material to reduce the clicking.

Forum Discussion

My solar and the chassis batteries

57 Replies

About Technical Issues

Related Content

chassis battery charge ?

Chassis batteries not charging

Chassis battery

Another solar question.

Solar charge to chassis battery