MPPT charge controller in my L200

[123hotchef]

Ok someone here will be clued up on this I am sure.

I just purchased a 3rd battery for my L200 and plan on getting a solar panel for the roof.

Any way I already have a sensing split charge relay to charge my 2nd battery.

If I fit a mppt controller and solar panel would this work along side the alternator and be smart and not charge the batteries when I am driving?

I would probably be better with a DC-DC charged too I am sure.

 

[Chippie]

Essentially you have two controllers…the primary one being the alternator, whose output varies with the load attached to it while driving….your 2nd battery being charged via the scr.
if you add a 2nd controller,the mppt unit, I’d connect it to the 3rd battery which would be in parallel with the second and have them connected so that when the engine isn’t running, the 2 batts are charging..( assuming it’s sunny..)
The Mppt unit won’t deliver any charge if it’s output is lower than the alternator.. If the engine is off the scr will be disconnected anyway from the alternator….…
So either all 3 batts are charging while the engine runs, or the 2 secondary batts charge when it’s sunny

Hope this makes sense…?

One further thing…you didn’t want the mppt unit charging the L200’s battery?

 

[123hotchef]

Essentially you have two controllers…the primary one being the alternator, whose output varies with the load attached to it while driving….your 2nd battery being charged via the scr.
if you add a 2nd controller,the mppt unit, I’d connect it to the 3rd battery which would be in parallel with the second and have them connected so that when the engine isn’t running, the 2 batts are charging..( assuming it’s sunny..)
The Mppt unit won’t deliver any charge if it’s output is lower than the alternator.. If the engine is off the scr will be disconnected anyway from the alternator….…
So either all 3 batts are charging while the engine runs, or the 2 secondary batts charge when it’s sunny

Hope this makes sense…?

One further thing…you didn’t want the mppt unit charging the L200’s battery?

That makes perfect sense thank you. That is how I had planned to do it before asking on face ache... No I don't need the mppt to charge the main starting battery really. Because I installed a switch and relay so that I can jump start myself from the 2nd battery I currently heve in the tub.

 

[hotponyshoes]

You can get charge controllers with 2 outputs (for 2 batteries/banks)
You can set the output 50/50 or prioritise one over the other, ie 95% going to the l200 battery until it is full or vice versa.
Probably redundant though if you already have the ability to manually connect them..

 

[123hotchef]

You can get charge controllers with 2 outputs (for 2 batteries/banks)
You can set the output 50/50 or prioritise one over the other, ie 95% going to the l200 battery until it is full or vice versa.
Probably redundant though if you already have the ability to manually connect them..

I have seen those. Yes not needed here I think.

 

[bert]

I have one of those on my boat. 1 supply for the leisure battery and the 2nd 1amp only supply to a starter battery when leisure batteries are full

Doesn't cause any issues with the engines running

 

[finyuk2005]

the split charge relay will charge your starter battery using the solar panels if the lesure batteries reach 13.3v, or some vsr's are 13.7ish,
they work both ways,
so really, it doesnt matter where you connect the mppt up, but i suppose you would want the lesure batteries to charge up first

 

[Barking Mat]

You've got 3 batteries, how many outputs on your charge splitter.

You're starter battery will only need minimal top up, it's your domestic / service batteries which need charging.

On our boat splitters, the input to the the splitter goes direct to the domestic / service batts, the starter is secondary.

 

[123hotchef]

I will install a bus bar in the tub when I install the MPPT and the 3rd battery.
That way the solar will go to the 2 batteries in the tub.
I installed 2 relays when I installed the 2nd battery with a switch so that I could jump myself in the event of a flat main battery.

 

[123hotchef]

What is the consensus on circuit breakers and fuses?

I know as close to the battery as possible for fuses.
Does the solar pannel need a breaker before the MPPT and after the MPPT

 

[James1979]

What is the consensus on circuit breakers and fuses?

I know as close to the battery as possible for fuses.
Does the solar pannel need a breaker before the MPPT and after the MPPT

Definitely one before. I read up on this when I did the first camper build.

The theory at the time was that if you put an input into the controller with no output it would kill it.

Things may have moved on but that was advice from almost every source about 2014/15

The other reason is that if you have two wires from the panel in the sun they’ll be live. An isolator will avoid that.

 

[123hotchef]

Just be researching, it will be easier and neater to get a little C/U with DC breakers then.