Maybe a silly question regarding multiple Solar charge controllers and shading.

[jcoop0001]

I have a 42' motorhome with lots of open roof space for solar. Somewhere I read or saw a youtube video talking about a strategy of using several smaller charge controllers verses one large one for the following reason. Say you have 2 panels connected to 1 small victron charge controller. Say you have 3 more identical set ups.

The thought is if some of the panels are shaded and some are in full sun the panels that are shaded will not drag down the ones that are in full sun. Does this make any sense or BS?

Magna 3000w inverter
610 ah LifeP04 batteries
Victron smart shunt
Victron charge controllers
Victron lynx and distribution.

Thanks John

 

[justinm001]

Yes absolutely but more mppts mean more money and more wiring. You do need 5-7+ more voltage than your battery system

 

[Checkthisout]

I have a 42' motorhome with lots of open roof space for solar. Somewhere I read or saw a youtube video talking about a strategy of using several smaller charge controllers verses one large one for the following reason. Say you have 2 panels connected to 1 small victron charge controller. Say you have 3 more identical set ups.

The thought is if some of the panels are shaded and some are in full sun the panels that are shaded will not drag down the ones that are in full sun. Does this make any sense or BS?

Magna 3000w inverter
610 ah LifeP04 batteries
Victron smart shunt
Victron charge controllers
Victron lynx and distribution.

Thanks John

Just parralell all the panels. No need for multiple controllers.

 

[0truck0]

You can parallel into one big controller.
Yes, the reasoning is sound for multiple ones also. No issues feeding multiple controllers into one battery/bank.

I did this. I have 3 by 200 watt 24 volt systems feeding into the trailer (24 volt panels to 12 volt batt). The reason is I kept adding panels and the first controller was not high amp enough to take another 200 watts, so I just put in another controller, and same when I put in another 200 watts again. Also, the wiring was more happy with new wires instead of all going down the same one pair of wires had I parallel'd all of the panels.

I do have 3 redundant systems at least. Money for a couple extra controllers was not a concern.

 

[efficientPV]

I have extreme shade and run multiple strings in parallel. I used to run three controllers because I had strings of multiple voltages. Multiple controllers work well when batteries are really dead and the controllers all are working in bulk charge. Otherwise, I would have two which would two not producing anything. I went to just one controller. In the world of nothing but bad solar ideas, it isn't the worst idea to run multiple controllers. You are mostly just adding another parasite on the battery.

 

[justinm001]

I have extreme shade and run multiple strings in parallel. I used to run three controllers because I had strings of multiple voltages. Multiple controllers work well when batteries are really dead and the controllers all are working in bulk charge. Otherwise, I would have two which would two not producing anything. I went to just one controller. In the world of nothing but bad solar ideas, it isn't the worst idea to run multiple controllers. You are mostly just adding another parasite on the battery.

Isn't the parasitic load for like Victron mppts only around 10ma? Having separate mppts should increase performance in basically any conditions even if it's just a couple watts it should be way more than the draw.

Im sure someone with multiple identical strings can chime in that all their mppts aren't always identical. I have 3 in parallel then 5s3p. My 3 parallel mppt gets better performance per panel.

 

[efficientPV]

One will take over and the others will think they are in float. There are controllers designed to be in parallel with one decision maker.

 

[justinm001]

One will take over and the others will think they are in float. There are controllers designed to be in parallel with one decision maker.

Yeah I'd only suggest Victron smartsolar mpptswith a smartshunt. If you're looking to maximize performance then buy the best. Smartsolar mppts have bt and would use the shunts voltage and communicate with each other over vesmart Bluetooth... I think. They also all have vedirect and connect to the cerbogx which definitely controls them. And if you have a battery with a BMS that communicates with cerbogx then the battery controls the charging.

Without a system. You also risk overcharging if you have a ton of solar but small batteries.

Idk about the cheaper bluesolar mppts I'd assume they can be parallel too.

 

[DPC]

What to do with an old solar system that both small and inefficiently run on a PWM controller?

Is there a way to bridge two systems together one old one new and share loads?