Can I parallel a 150/100 and a 250/100 smart solar MPPT or do they need to be the same input voltage? Thanks
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Justin Cook for the following reason: The question is answered, right answer was accepted
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Mixing MPPTs
@johnp It's 2 x controllers for 2 separate strings - 150/100 will have 3S5P and the 250/100 will have 4S4P, both to the one battery bank
That's a better question. GIGO.
Yes, you can have 2 different arrays with 2 seperate mppt's, with each mppt having different input voltages (within the mppt's input limits) charging the same battery bank.
Do make sure the mppt's battery settings are the same.
Since you mention the input voltage, i assume you want to feed both MPPTs from the same PV string?
I skimmed over the manual for the 250/100, i have not seen that this would be explicitly forbidden.
But i also cant imagine that a config like this would offer a good efficiency. Im imagining both MPPTs hunting for the maximum powerpoint, each influencing the other, and thus not reaching a stable state. Or they let the magic smoke out.
On the battery side, you can use mutliple MPPTs in parallel, the model of MPPT does not matter, so you can use a 150/100 and a 250/100 on the same battery
You cannot share PV, this is EXPRESSLY unsupported. The docs show how units can be paralleled. In no way is there an example that shows shared arrays, and no vendor will create documentation based on detailing everything you should not be doing.
I have lost track of how many similar questions have been answered with this guidance, all available via a simple search.
If you aren't sure, rather don't imply that it could be done.
Each MPPT needs its own string, they can be completely different to any other string on other MPPT's, they just need sufficient voltage to start the charger and to keep it running.
The whole point of multiple MPPT's is to cater for different array sizes, shading etc.
The implication that it might be possible comes from me knowing that it might be possible. Ive used two 100/20 in parallel on a fixed 72VDC input voltage. Why did i do that? Because the DC/DC converter that done this job blew up and all i had at hand were the two 100/20s. The part that im unsure about is the mixing of dissimilar MPPTs and the use on real a PV string.
MPPTs are DC/DC buck converters with additional things like input/output voltage and current measurment and the software that we all love. DC/DC converters have been used in parallel configs for decades. Just like in the old days, i used two pwer resistors to ensure equal load sharing.
This however does not mean that this should be a permanent solution, or a solution period. Its not what the manufacturer intended, most likely you will void warranty. Its not energy efficient. It might not work at all when hooked up to a real PV power source. So im totally with you in that regard, dont do that, get a matching MPPT for each string.
As for expressely unsupported, i mean its all there to implement active load balancing on a hardware level, so all it needs is software changes. Just imagine creating a VE.smart network and letting two units run in parallel, with one taking over master control over the charge parameters. Maybe not for MPPTs, but why not for Orions? Also theres loads of things described in the manuals that are clearly stated should not be done, so why not exclude input paralleling as well if its so bad.
But anyway, the question of OP wasnt even going in that direction.
Thanks for the replies. It's 2 x controllers for 2 separate strings - 150/100 will have 3S5P and the 250/100 will have 4S4P, both to the one battery bank.
