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dutchy0198 avatar image
dutchy0198 asked

Victron MPPT 100/20

Hi all sorry if this has been asked a thousand times, below are the only specifications i can find on my solar panels (2x 150W in parallel) equaling:

Mono-Crystalline 300W
Max Power Voltage 18V
Max Power Current 16.6A
Open Circuit Voltage 21.24V
Short Circuit Current 18.34A
Module Efficiency 18.3%
Tolerance Wattage 0-10W


Will the 100/20 Victron Mppt charger be ok for my camping application to keep a 100ah battery topped up only really being drained by a fridge?

I keep seeing concerns about vbat +5v? its a bit over my head, is this an issue i will face with the selected controller?

Thanks in advance community.

MPPT Controllers
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2 Answers
JohnC avatar image
JohnC answered ·

Hi Dutchy.

Presumably a 12V batt. The 100/20 is the right choice, but I'm not sure what you've done there with the panel specs (doubled up on W and A?). Maybe a 'packaged' 300W of 2x 150W units? Fair enough.

The '+5V' thing may impinge you in low light, where panel specs go out the window. May or may not be a worry, just try and see. If it won't fire up in poor light (and you need it to), you could consider rewiring the panels in series.

A lot of these panels were really made to match up with cheapo pwm cc's. The better mppt's prefer a higher Voc to extract the most from their capabilities in poor light. I'm not suggesting you go pwm though, your choice is good..




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dutchy0198 answered ·

Thanks for your reply John! this has eased my mind a bit, i think missing out on a bit of early and late solar production wont hurt me too much, and as you pointed out (probably with the help of this forum) i could probably re-wire in series if its not working good enough.

Maybe a 'packaged' 300W of 2x 150W units? Yes mate this is correct bought as a 300w solar package with one of those infamous cheapo blue pwm's on it. The pwm may work fine i just dont want to have to worry about overcharging the battery etc because its not "smart" enough to reduce amps and voltages as the battery reaches its full SoC.

I was thinking of putting short leads (10 AWG) on both the MPPT and PWM with Anderson plugs and some Anderson plugs also in the circuit near my Aux battery so i can switch to either unit in a matter of mins if the situation requires.

Cheers Dutchy

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JohnC avatar image JohnC ♦ commented ·

Both types don't read 'SOC' as such, just V's. The 'Smart' designation of the Victron (that model) refers to it's bluetooth/phone monitoring and programming capabilities. Which are impressive and comprehensive.

If you do 'switch-em-out', even just to test, try to remember to hook the batt(s) up first, before the panels. Some kit may reset it's target V's otherwise, that's all.

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dutchy0198 avatar image dutchy0198 JohnC ♦ commented ·

Ok thank you, a good point to remember.

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