Solar Questions and Troubleshooting

[Doods]

Hello. We recently pulled the icebox and put in a 12V fridge (Dometic NRX60T). We have notice significant draw from our battery, which is not surprising but the battery does not seem to be charging even after driving the truck for an hour or more. Everything but the fridge is ATC installed components on our 2020 Bobcat. I am traveling so I don't have access to all my shop tools to fully check things well but all fuses look good. Any ideas on what else I can do to troubleshoot? I am tempted to upgrade the controller.

Also, I am thinking about adding a second, portable panel. I know FWCs can come with an extra SAE plug at the rear. I am wanting to put one in so we can have a portable panel to aim. Has anyone done this? Is it just as simple as adding a splitter before the controller to run in parallel? I feel I may be overthinking this one.

Thank you!

 

[Vic Harder]

Yes, you can simply put another in parallel, if the controller can handle it. Which controller do you have?

As to why your battery is not charging, are you expecting it to charge from solar or from the alternator while driving? That does work, just want to be clear on what you have and are asking about.

 

[Doods]

Hi Vic. Thanks for the reply. It is the Renogy rs232. A little more investigating and searching the right terms, I think the battery isolator is preventing the alternator from charging if the camper battery is too drawn down. I think I may still upgrade the controller to a Victron and put in a smart shunt (I see you recommend that often on here) just so I can get more info and track power.

 

[pvstoy]

Those battery separators are designed to protect the truck battery and charge it first. Change it out with a better one and problems go away.

 

[Wandering Sagebrush]

If your portable solar panel has an onboard controller, you’ll probably want to wire the auxiliary charging port to the battery (with fuse), not to the existing controller.

 

[Doods]

Thanks, pvstoy. Do you have a recommendation for a good isolator. I like the idea of having one since we tend to boondocks for a few days at a time.

Sagebrush, I have been looking at panel the specifically do not have the built in controller. Is there a specific advantage to a panel that has one?

 

[Wandering Sagebrush]

Thanks, pvstoy. Do you have a recommendation for a good isolator. I like the idea of having one since we tend to boondocks for a few days at a time.

Sagebrush, I have been looking at panel the specifically do not have the built in controller. Is there a specific advantage to a panel that has one?

Only that you have regulated charging when used on other batteries. Reduced risk of damaging a battery with overcharging is my understanding.

 

[Vic Harder]

The Blue Sea line of isolators are good. I used to use a Model 7622 (with the remote) before I ditched it for a DCDC charger.

I looked up your solar controller - https://www.renogy.com/template/fil...QSrylFOpHRoXGYbva4MYqqpGdWlfCPBqPGZ5jc9jiqrVF

It can likely only handle a single small panel. (50V and 10A max) It might be good to look at a Victron 100/30 or similar MPPT solar controller.

 

[Doods]

Thanks, Vic. It seems like a full overall is what I need to do. I am reading up on DCDC chargers now. Is there any downside besides cost over an isolator? I am thinking Victron for everything too.

 

[Vic Harder]

The only downside is that your solar can no longer charge your truck battery as well as the camper battery once the DCDC is in place. Once you decide how much battery you need, then you can size the solar array and all the Victron components to size. Ideally, you want to be able to provide 25-50% of the AH capacity of your batteries (say 200AH) in charging capacity. That means 50A - 100A of charging. My Victron DCDC can only do 30A and it takes a bit too long to recharge. Same with my 330W solar panel, I get 25-30A max out of it too (on a good day). My thinking is that I'd like to be able to fully recharge in one day if I have been out and about and draining the batteries.

For example, we were just camping in Wells Gray Park in BC, deep in the trees. Battery lasted us until the last day, with just 15% left. We drove 8 hours and I was fully recharged. 4 hours would be nicer, given how we usually camp/relocate.