Solar addition questions

[Climbermac]

Greetings expo/solar hive-mind, I'm a long time reader and find I post very rarely as I am always amazed at how easily I find the answers out there in these forums before I get to posting! I don't seem to have found all I need on this occasion so here goes.

First off, the full setup is an 05 GX470 with dual batteries (AGM Northstar 27F and 35) in the engine-bay on a BlueSea ML-ACR that has worked very well for several years. Essentially all auxiliary loads are either on the s-pod, powered by the Aux battery or on a secondary fuse panel (BS ST Block) in the rear wired with 6ga (fused accordingly). The only major accessory exceptions are the winch and ARB dual compressor powered off the 27F starter battery to offer a bit more juice on such high draw items (the winch also has a disk combine switch for when I've been REALLY stupid). I tow a Boreas XT trailer with a new pair of 100ah SLA/AGM Mighty Max batteries and a 100w panel supplementing a Progressive Dynamics charge controller etc... In general the trailer side works very well and the whole setup has been serving me on a wide range of trips.

Lately I have been re-working the back of the GX and re-structuring my storage, also taking the chance to sort out gremlins and ticks that have bugged me for many miles. I am dropping in a new larger fridge (85L!) and in preparing for it I decided to try to sort out power consumption/generation in the truck. I snagged a 110w panel am building into the roof rack to help support the Aux battery against the draw of the fridge in camp. To that end:

• The cleanest wiring of this new panel is to run to the rear of the truck, put the charge controller in the rear and tap into the 6ga leads feeding the fuse panel. From what I've read, given the distance from the battery, I should use a PWM and NOT a MPPT...is the the right logic?
• The path for the wires down into the rear is funky and I'd like good, flexible conductor, like welding cable. I've been planning on 10ga (though that is overkill for 110w) is PV conductor what I should use? I'll run it in a high quality braided sleeve but the 10ga PV I have seen is NOT very flexible. Should I run less than 10ga even with the leads on the panel being 10ga?
• I'm imagining that I will want change how I run the ML-ACR and keep it off more than I used to, to allow the Solar to keep better tabs on the Aux battery. I recognize that a DC-DC would be a better option if I were building new but given that I have this whole rig already wired, running and happy, I'm less inclined to tear it all out unless there is a major issue with the setup.

Advice and input are greatly appreciated. I don't run any major draw appliances or an inverter (yet). The trailer sees far more of the camp use I just want the truck to be able to sustain itself on longer sits in camp with a big 85L fridge drawing on the batteries.

Cheers!

-mac

 

[Peter_n_Margaret]

In my experience, an MPPT will always give a better result than a PWM controller. And I would always choose one that was user configurable (such as Victron) in order to provide the precise charge parameters as recommended by the battery manufacturer.
With either it is important that the controller is as close as possible to the battery. Voltage drop between the solar panel and the controller is much less important than any error generated between the controller and the battery.
Cheers,
Peter
OKA196 motorhome

 

[SBDuller]

I prefer Marine Grade cable for any truck wiring.

 

[rayra]

any multi-stranded wire ought to do for a vehicle install, especially a 'fixed' bit of infrastructure wiring. I went both extreme and cheap on my main cabling due to my desire for rear winching ability. So my main runs to the rear of the vehicle became 1/0 cable, both pos and neg runs, and that gets costly in the lengths I was running. And I went ahead and ran each in their own PVC flex conduit along the outer top of the vehicle frame and crossing under the cargo floor, using junction box bulkhead connectors for a sealed connection up thru the floor. It took me years to get around to the final front and rear power cable extensions and Anderson plug connections at both front grill and rear bumper to facilitate a winch. Literally just finished that this month. But the intervening years that 'trunk cable' facilitated all sorts of other power connections, inverters, rooftop solar etc.
The 'cheap part was using residential / commercial THNN cable. Not very flexible at all, but I always considered it 'infrastructure', install once. So the struggles to deal with its rigidity and eliminating twisting forces in connector lugs were a one time thing. Some of the other extensions and short runs requiring greater flexibility were accomplished with fine strand welding cable. As in the recent additions of the grill / bumper runs and re-cabling of the winch power pigtail.

eta one of these days soon I'll do some proper diagrams and illustration pics. My stuff is scattered across different topics and my build topic. Would like to put it all in one topic / posting.