question

afinhert avatar image
afinhert asked

100/50 vs 150/35

Hello

I can’t decide between these two MPPT units,

150/35 or 100/50

Currently I have two 12v 165ah batteries in parallel,

and two 100w Renogy monos wired in series.


My concern is in the future when I purchase more panels and batteries for my system (my battery bank will always be 12v), which controller will be a better bet, leaving me with the most options? Having a 150v max input is definitely a great benefit, but does that benefit in series voltage trump the loss of 15 output amps (when compared to the 100/50)? What is the benefit of 50amps vs 35amps?


Please someone help me understand

According to Victron charts the 150/35 is a step above the 100/50...but I don’t understand why as they seem to be the same basically in as much as power.

MPPT Controllers
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2 Answers
JohnC avatar image
JohnC answered ·

Hi A. For your 12V, let's use 14V for the calcs as it's a 'sort of average' V in full production..

35A x 14V = 490W

50A x 14V = 700W

That's roughly the most you can expect from the panels, even if you add more than that - possible, subject to other limitations,

Depends on your expansion plans, but if you were to double your existing panels then the /50 might suit better. The /35 can handle 48V batts, but if you're absolutely certain you'll never go there then the /50 is a no-brainer.

Take care that additional panels are matched at least in specs, and be especially wary of adding in more parallel batt strings - can cause nightmares well before bedtime.. :)

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wkirby avatar image
wkirby answered ·

A higher charge current is especially beneficial on a 12V system.

50A is a nominal charge power of (12V X 50A = 600W) whereas the 35A controller gives you a nominal charge power of 420W

The 100/50 limit's your series PV strings to 2S, but you can then add another set of 2S panels in parallel with these.

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