Upgrading from 12v to 48v system, and mixing panel wattages, can this work?

[drithus]

Hello All!

New Member, glad to find this awesome forum.

Ok, going to try and lay this out coherently.

My current solar system (installed on my travel trailer) consists of the following:
5x 100watt Mono Panels connected to a 40amp charge controller
3x 300watt Mono Panels connected to a 60amp charge controller
8x 230ah 6volt Duracell golf cart batteries configured for 12volts
2000 watt inverter charger

We spend most of the winter down here in AZ for months on end. I want to add more solar panels to my system. Due to lack of roof space, my plan is to ground deploy the additional panels. Found a good deal on some 370watt Mono panels and plan to pick up at least 2 of those, but would like to add 4 of them.

Through dumb luck, I have the opportunity to take ownership of a brand new 48v inverter/charge controller/charger combo from renogy: https://www.renogy.com/48v-3500w-solar-inverter-charger/
3500w inverter, can handle 4400 watts of solar, max pv input voltage of 150v (145v recommended), max PV input current 50a

What I want to do is use all of my solar panels i currently have, plus the addition 4 panels and use the 48 volt controller. With a max potential of 2,880watts. I understand i'll need a 48v to 12v converter for my 12v loads. Then i can get rid of the smaller charge controllers.

My main question is there a way that i can wire this crazy mis-matched bunch of solar panels to work together on this new charger controller/inverter/beast? What's the most efficient way to hook those up? Maybe I have to ditch a couple of the small panels?

Please let me know your thoughts. Thanks you!

 

[RStone13]

Hello All!

New Member, glad to find this awesome forum.

Ok, going to try and lay this out coherently.

My current solar system (installed on my travel trailer) consists of the following:
5x 100watt Mono Panels connected to a 40amp charge controller
3x 300watt Mono Panels connected to a 60amp charge controller
8x 230ah 6volt Duracell golf cart batteries configured for 12volts
2000 watt inverter charger

We spend most of the winter down here in AZ for months on end. I want to add more solar panels to my system. Due to lack of roof space, my plan is to ground deploy the additional panels. Found a good deal on some 370watt Mono panels and plan to pick up at least 2 of those, but would like to add 4 of them.

Through dumb luck, I have the opportunity to take ownership of a brand new 48v inverter/charge controller/charger combo from renogy: https://www.renogy.com/48v-3500w-solar-inverter-charger/
3500w inverter, can handle 4400 watts of solar, max pv input voltage of 150v (145v recommended), max PV input current 50a

What I want to do is use all of my solar panels i currently have, plus the addition 4 panels and use the 48 volt controller. With a max potential of 2,880watts. I understand i'll need a 48v to 12v converter for my 12v loads. Then i can get rid of the smaller charge controllers.

My main question is there a way that i can wire this crazy mis-matched bunch of solar panels to work together on this new charger controller/inverter/beast? What's the most efficient way to hook those up? Maybe I have to ditch a couple of the small panels?

Please let me know your thoughts. Thanks you!

remember if it's a 48v controller, the battery bank must also be 48v

 

[colemab]

remember if it's a 48v controller, the battery bank must also be 48v

Most MPPT controllers can take a higher voltage (say 48) and step it down to a lower (say 12/24/36 v) but NOT the inverse. So they don't have to be the same but the array voltage has to be higher than the battery bank voltage.

 

[Supervstech]

I would arrange what you have on a separate controller, and the new to the new controller.
Keep panel types on their own controller.

 

[drithus]

Thanks for the replies everyone. I thought i'd post an update.

Rstone13 - yes I organized my 8x 6v duracells to 48v configuration.

So here is what i ended up doing:
5x 100w Panels all in series = 93v/5.38a
3x 300w Panels all in series = 96.6v/9.32a
3x 370w Panels all in series = 117v/9.49a
If my math is right, connecting these all in parallel should give me 93v/24.19a = 2,250watt (of 2,510w installed).

So i've been running this way for a week or so, all connected to the Renogy 3500w solar inverter charger and have been getting good results. Peaked at 2,180w the other day and 2,300w "edge of the cloud".

So much cooler in my passthrough storage vs the two charge controllers and 12v inverter.

 

[colemab]

Be aware that your diodes have voltage limitations and you don't want to exceed them. So when you start running more than 2 strings, you'll want to make sure you have a fuse/breaker and diode at the end of each string. That is what is in most combiner boxes on larger systems but I've seen them inline (MC4 connectors) before.

 

[drithus]

Be aware that your diodes have voltage limitations and you don't want to exceed them. So when you start running more than 2 strings, you'll want to make sure you have a fuse/breaker and diode at the end of each string. That is what is in most combiner boxes on larger systems but I've seen them inline (MC4 connectors) before.

I did install a midnight combiner box and breakers for each string.