Solar Charging

[MTMan]

I'm thinking about installing a solar panel on top of my topper and I have a Renogy 50A Solar MPPT controller and lithium battery to run some camp gear.
https://www.renogy.com/learning-cen...e=1&gbraid=0AAAAADrlcl7JhhL7fPNVWltVCCdyyjk1J
I'm wondering if I need to run battery cables to the starting battery as I'll have the lithium battery and controller in the bed or is there some way to tie into the trailer connector. Anyone done something like this?

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[Buyer2021]

I'm wondering if I need to run battery cables to the starting battery as I'll have the lithium battery and controller in the bed or is there some way to tie into the trailer connector. Anyone done something like this?

What you're doing is no different than installing a solar / lithium system on an RV trailer, it just happens to be mounted in the truck.

As with an RV system, the need for charging from the truck depends on the output of your solar panel, the battery capacity, and your 'camp gear' loads.

In the case of my trailer system, just for example, my panel array / battery / loads are 'matched' and I have no provisions for charging the trailer's lithium battery from my truck at all - the solar panels alone keep the battery charged just fine.

If you decide you need charging from the truck to keep the lithium battery 'happy', an appropriately sized DC-DC charger between the truck connection and the lithium battery may be in order. That charger would

• provide an appropriate lithium charging profile (different from your truck's AGM charging profile)
• ensure no 'reverse current flow' when the lithium battery is stronger than your truck battery (it acts as a one-way isolator)

Just for your consideration, Have Fun!

 

[Davexxxx]

Two different approaches to the same thing.

 

[moonlanderadventures]

I thought I read somewhere you can route the D+ ignition cable to the 7 pin and "activate" it by pressing the brake pedal, otherwise you are going to have to route it to the starter battery. The whole point of the D+ ignition is so that the Renogy unit only pulls power while the engine is running and doesn't kill your starter battery. It is also important to make sure you have overvoltage protection (like a 60A in-line fuse). Heat is the enemy and you want good airflow, so you want it away from like the turbocharger, so engine bay is likely not the best place. You can easily sacrifice a bit of voltage drop for longevity. Just be sure to consult the manual on what the proper gauge wiring is as well (probably likely to be 4 or 6). I heard that if solar is producing any power at all, the alternator charging is limited to 25 amps. It also acts as a battery maintainer if the SOC of your house battery is full, or it detects ample solar charging, not sure on the threshold.

 

[MTMan]

Yeah, the Renogy basically does it all. I was just curious about the charge lead from it if it can connect somehow to the trailer connector without having to run a battery cable lead all the way back to the starting battery but it looks like this is the best way.

 

[MTMan]

Anyone run battery cables from the starter battery to the back of the truck?

 

[MTMan]

One thing the Renogy charger has is an extra lead if you have a smart alternator. I’m assuming all of these trucks have smart alternators.

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