Is it OK to connect solar MPPT controller to mains battery charger?

[Dukester52]

Hmmm...

Hey guys

A professional marine electrician not-so-recently fit some solar panels and an MPPT controller for us. I’d intended to install everything myself, so had the parts and had specced out the install after much research. However since I was having other electrical work done it seemed ideal to ask him to install the system.

He’d admitted he hadn’t fit the 10a fuse, promised to remedy but never did, so I wanted to fit one... So checked the battery terminals and couldn’t see a connection. Tracing the cable from the MPPT controller it seems he’s connected it to the mains battery charger - at least that’s where the cables run (I may be wrong but I’ve retraced the cable a dozen times). I haven’t opened the charger to check the internals. It’s a Cristec CPS2 charger.

Does this sound like a valid thing to do?

I’m more than a little concerned, so advice really appreciated!

Thanks in advance

Al

 

[RichardS]

I connected my small panel and cheap controller directly onto the outputs from the mains battery charger to avoid having the install more new wiring and it worked fine for several years. I now have a more powerful MPPT controller and have connected that directly to the house battery bus-bar. However, the small panel for the engine batteries is still connected to the battery charger.

Richard

 

[Dukester52]

Thanks Richard, that really helps to put my mind at rest. I really was getting quite concerned!

Thanks again

Al

 

[alan]

Electrically the mains battery charger is (?) connected directly to the batteries - at least mine is! So, connecting the MPPT controller to the output of the mains charger is electrically the same as connecting it to the batteries, and you save on some bits of wiring. As you have already said the wire going to the MPPT controller should be protected with a suitable fuse.
I do not see anything wrong with this.

Alan.

 

[temptress]

Electrically the mains battery charger is (?) connected directly to the batteries - at least mine is! So, connecting the MPPT controller to the output of the mains charger is electrically the same as connecting it to the batteries, and you save on some bits of wiring. As you have already said the wire going to the MPPT controller should be protected with a suitable fuse.
I do not see anything wrong with this.

Alan.

Agree, that's how our pannels are connected after the mppt...

 

[gregcope]

My MPPT regulators connect to the negative bus bar and Battery connection of the 1-2-1 switch.

This has many advantages;

1. No need to run complex wire runs to batteries
2. Cheaper
3. Benefits from large cables, which reduces voltage drop

So reusing wiring has lots of positives!

 

[Dukester52]

Thanks everyone, much appreciated!