question

danracing avatar image
danracing asked

MPPT 150 35 solar charger not working

Hi i cant seem to figure out what has gone wrong with the system it was working for 3 weeks now nothing

Any ideas i feel its a setting problem

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MPPT Controllers
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3 Answers
matt1309 avatar image
matt1309 answered ·

Hi @danracing

Did anything change recently, ie any firmware updated or setting changes?

The charge controller say it's in float mode. ie keeping your battery at the float voltage set within the MPPT (or set in inverter VeConfig settings if using ESS). If the battery is already at the float voltage no power will flow into the battery. If that makes sense?


ie MPPT is outputting 26.98v but battery if battery is already 26.98v then the current wont flow. My guess is therefore an issue with float setting being incorrect. Or the battery is full and the SoC of 30% is incorrect?

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danracing avatar image danracing commented ·
Hi Matt

thank you so much for reaching out with an answer.

nothing has changed software wise and I've been through all the settings and everything looks great

The battery level is definitely reading differently to the battery monitor and screen and the batteries are absolutely at 35 percent.

I found a youtube video where this was happening to someone else and the only fix was to take away power from the controller and let it reset itself.

then worked perfect

this guy said it was happening all the time.

im about to try this and see what happens



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marekp avatar image
marekp answered ·

@danracing

Measure the battery voltage on the MPPT battery terminal and on the battery.

If there is a difference it means you have a voltage drop on the wire between MPPT and battery.

It can be a result of bad contact or bad fuse (if you have one).

I had a similar problem and bad fuse was at fault. It had higher resistance.

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danracing avatar image danracing commented ·
thanks ill trace this line and look for the fuse


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astrayan avatar image
astrayan answered ·

My MPPTs can be tricked to go into float real easy. So I was glad when they recently allowed a setting for the number of hours you can spend on absoption. I have OPzV gel batteries and set the float at 13.95, anyway. For solar applications, it doesn't matter with lead acid if you set the float a bit high, because the sun goes anyway. If you have a battery on a charger 24/7, then it matters. Victron also provides a "Tail" current, but this is better turned off, unless it's a dedicated pumping application.

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astrayan avatar image astrayan commented ·
...and the other reason this can happen is a street light. The controller does not have a wake up absorption time of 2-3 hours.
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