Need the solar/power pros to weigh in

luthj

Engineer In Residence
Just to confirm, the only cable connected to the battery side of the shunt, is the battery. The chargers and loads are all connected to the opposite side, correct?
 

TantoTrailers

Well-known member
Just to confirm, the only cable connected to the battery side of the shunt, is the battery. The chargers and loads are all connected to the opposite side, correct?
Yessir! 1 connection on the battery end of the shunt and 3 connections on the Load/Charger side (Fuse box, IP67 charger, Renogy Rover MPPT). Once I get the DC/DC converter I will have 1 more connection on the Load/Charger side but I will be testing that out using the existing Rover cabling since that is easily hijacked with the PowerPoles I used at the Rover. Once tested it will get permanent install and then this thing will be DONE!
 

Alloy

Well-known member
Yessir! 1 connection on the battery end of the shunt and 3 connections on the Load/Charger side (Fuse box, IP67 charger, Renogy Rover MPPT). Once I get the DC/DC converter I will have 1 more connection on the Load/Charger side but I will be testing that out using the existing Rover cabling since that is easily hijacked with the PowerPoles I used at the Rover. Once tested it will get permanent install and then this thing will be DONE!
Ground wire on the shunt also?
 

TantoTrailers

Well-known member
Ground wire on the shunt also?
So about that, my entire system is self contained and I have pretty much 0 steel to ground to. The frame under the camper body is aluminum, separated by 3/4" plywood all around, and everything wiring wise is isolated from the trailer light wiring (for now until I get the DC/DC converter).
 
  • Like
Reactions: DRP

Alloy

Well-known member
So about that, my entire system is self contained and I have pretty much 0 steel to ground to. The frame under the camper body is aluminum, separated by 3/4" plywood all around, and everything wiring wise is isolated from the trailer light wiring (for now until I get the DC/DC converter).
I always run a grounding wire just because it doesn't hurt to do so.

What kind of amperage are you running through the battery leads?
 

TantoTrailers

Well-known member
With everything at full blast and fridge running I think I peaked at maybe 8 or 9A but that stuff never runs that way...I only did that for testing. I will be giving it a full on test next week when I return from a work trip using the BMV, but I don't think I will ever exceed 10A. Everything is 12v, no inverter.
 
  • Like
Reactions: DRP

luthj

Engineer In Residence
If you do have a ground, wire it to the load side of the shunt. In some applications the ground/chassis connection carries current, and needs to run through the shunt to keep the meter accurate.

You do not generally need to bond the ground/chassis to negative, especially if you don't have an inverter.
 

Recommended books for Overlanding

Long Way Round: Chasing Shadows Across the World
by Ewan McGregor, Charley Boorman
From $10.99
Cycling the Great Divide: From Canada to Mexico on North ...
by Michael McCoy, venture Cycling Association
From $9.99

Alloy

Well-known member
I always run a grounding wire just because it doesn't hurt to do so.

What kind of amperage are you running through the battery leads?
The wire is not necessary.

I do it becsue I've seen allot of crazy things and I never know what will be done in the future.
 

Buddha.

Lurker
OK bear with me here...
What happens if I take a 12v to 36v 10 amp voltage booster, mount it under the hood next to my truck's battery, run 10 gauge positive and negative back to the trailer and feed those wires into the solar controller I plan to buy? It looks like I'd only get 1 volt of drop in a 50' run. I could switch the input to the charge controller from the solar panels or the truck as needed, if that's necessary.
Does this eliminate the need for a expensive 12v to 12v charger? It would save me a couple hundred dollars.
 

Attachments

Last edited:

Buddha.

Lurker
What is a good desktop/benchtop battery charger for Lead/Acid batteries that would not break the bank.
I use one I bought from sears years ago. Was about $50. It has 2 amp, 12 amp, or 75 amp options. It's always worked. I've heard some of the new chargers are too smart for their own good, whatever that means.
 

luthj

Engineer In Residence
Using a DC-DC through your solar MPPT controller works fine. In some cases you may need to change how your MPPT sweeps/searches. That won't be an issue if the DC-DC output is the same or greater than the solar controllers max.
 

dwh

Tail-End Charlie
I've heard some of the new chargers are too smart for their own good, whatever that means.
What it normally means is that the "smart charger" can detect a reverse polarity hookup. But to do it, requires the battery have some voltage. My Stanley smart chargers need the battery to have at least two volts to do the reverse polarity check. Other chargers need higher voltage to do it. Most won't enter charge mode if they can't do the reverse polarity test.
 

Buddha.

Lurker
Using a DC-DC through your solar MPPT controller works fine. In some cases you may need to change how your MPPT sweeps/searches. That won't be an issue if the DC-DC output is the same or greater than the solar controllers max.
It looks like this DC-DC charger is 100w greater than the controller's max. Would these two would work together without issue? Do I have to disconnect the panels when the truck is charging or vice versa disconnect the truck when the panels are charging?
ebay.pngcharge controler.png

MPPT100-30.png
 

Attachments

Top