Solar and Engine Charging

CDACamper · 10-25-2020, 09:08 PM

My van has an MPPT solar charge controller hooked up the house battery and the house battery is also connected to the engine alternator (stock SMB set up with Sure Power 1602 islolator). Is it ok to start the engine when the solar system is connected and charging via the MPPT or does this backfeed the MPPT and cause problems/overload/short?

1der · 10-26-2020, 12:26 AM

no problems, this is the normal connectivity of a house battery, solar and vehicle alternator.

rizzabove · 10-26-2020, 09:01 AM

I have a question regarding the similar part of my electrical system. I have the “Victron dc/dc 30 isolated“ charger. it’s charging my house battery from my starter battery. It does not allow my solar power to charger my starter battery because of the isolator. My question is... can I hook up my solar input on the starter battery side of the dc/dc charger and have the solar power charge my starter battery then run though the dc/dc Charger to my house battery? Or do I just want to replace my dc/dc Charger with the non isolated version?

boywonder · 10-26-2020, 09:49 AM

Quote:

Originally Posted by rizzabove

I have a question regarding the similar part of my electrical system. I have the “Victron dc/dc 30 isolated“ charger. it’s charging my house battery from my starter battery. It does not allow my solar power to charger my starter battery because of the isolator. My question is... can I hook up my solar input on the starter battery side of the dc/dc charger and have the solar power charge my starter battery then run though the dc/dc Charger to my house battery? Or do I just want to replace my dc/dc Charger with the non isolated version?

Is the Victron a battery separator? Can you provide the model #? Some battery separators are bi-directional (allows solar connected to one battery to charge both) others are uni-directional they will only allow current to flow in one direction. In that case you could connect solar to starting battery and if solar controller voltage is high enough with the sun out then the separator will close also charging house battery(s).

rizzabove · 10-26-2020, 10:24 AM

It’s the “Orion-Tr Smart 12/12-30 isolated”

It has an “engine shut off” detection that disconnects the battery’s when the van is off. I have disabled that to see if it will stay on and allow solar power to charge the starter battery.
It also has a input voltage rating of 8/17v. Does that kill my idea of putting the solar to the starter side. My solar controller is putting out up to 44v.

boywonder · 10-26-2020, 10:58 AM

Quote:

Originally Posted by rizzabove

My solar controller is putting out up to 44v.

Well...I hope it's not putting out more than about 14.4 volts or so.....anything above that tends to boil batteries. What make and model is your solar controller?

boywonder · 10-26-2020, 11:26 AM

Ok..here is a link to the Victron specs in case Scalf77 shows up..he'll need it

..

https://www.victronenergy.com/upload...50-400W-EN.pdf

This is a very sweet battery separator that acts as a smart 3 stage charger for your house battery while your engine is running. It's bluetooth-able to your phone and very configurable.

Reading the specs I don't see anything about it being bi-directional i.e. allowing the house connected solar to be able to also charge your starting battery. It also appears that you can't use the house battery to start the van in the event that you kill the starting battery....but being a smart charger overrides the above limitations in my booklet.....

So presently you have your solar connected to your house battery?

I think you can move the solar to your starting battery and get the Victron to charge the house battery...it's certainly worth a try..can't see any downside...not going to harm anything..unless your solar controller is putting out 44V..which it shouldn't be....

rizzabove · 10-26-2020, 12:18 PM

You’re correct about the volts out of the solar controller. I was seeing the volts out of my panels are 44v. The mppt controller is putting out 14v. I think the answer to my problem is to connect the solar controller to the starter side of the dc/dc charger. Thanks Wonder!

ctb · 10-26-2020, 01:31 PM

Boywonder, you are one SMART person! Yet ANOTHER member I pay attention to no matter what the post! Thanks for ALL your input o all subjects important!

Ps If I am to understand, If I have three 165W panels (wasn't using rooftop at time, using two unattached to van/I put them angled to sun and run a cable to side receptor) hooked up and its showing 15v+ peak on my Zamp control unit...I can see the voltage fluctuate as the sun goes from full to cloudy etc...am I overcharging/boiling my batteries?

boywonder · 10-26-2020, 04:28 PM

Quote:

Originally Posted by ctb

Ps If I am to understand, If I have three 165W panels (wasn't using rooftop at time, using two unattached to van/I put them angled to sun and run a cable to side receptor) hooked up and its showing 15v+ peak on my Zamp control unit...I can see the voltage fluctuate as the sun goes from full to cloudy etc...am I overcharging/boiling my batteries?

If the solar controller output is over 15V then yes...but I suspect that the voltage you are seeing is the panel voltage going in to the controller, which varies up to 17V or so for RV type panels.