question

iris123 avatar image
iris123 asked

Difficulty with MPPT100/30 + 305W solar

Hi there,

I got a Victron 305W Solar panel and smart solar MPPT 100/30 installed by a mechanic in my van but I feel like it's not working appropriately.

The Mppt is connected directly to the batteries (2x100Amp in series) (positive on first battery, negative on second). Theres a fuse breaker between mppt and batteries.

My problem is that the app always shows float, no matter how much I've used my fridge, lights etc. It also shows immediately whatever voltage I put in the battery settings. So If I change the battery voltage to 14.0 it just jumps to it without ever entering "bulk" mode. Lastly my wall voltmeter (I know it's not fully accurate) keeps dropping during the day and night.

Not sure if it's important but I also have a split charge relay to charge the batteries while running the engine. So when I drive for a while and stop my wall voltmeter shows 12.8V while the victron app doesn't show a higher voltage. When the engine is running the app is jumping all over the place showing battery voltages between 4 and 15 and going between float, bulk and absorption.

I would really appreciate any help.

Thank you in advance.

20210516-070741.jpg

20210516-070529.jpgscreenshot-20210516-070815.jpg

MPPT SmartSolar
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

2 Answers
klim8skeptic avatar image
klim8skeptic answered ·

The circuit breaker next to the mppt appears to be off. This appears to be the breaker between the mppt and your battery.

A couple of other things of note,

No breaker/fuse between the battery and inverter..

Battery wiring needs to be optimized for parallel charging..

Wiring Unlimited is a useful read for new ppl to solar.


Edit.. A better photo of the front of the mppt, showing cables and breaker would be nice plz.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

iris123 avatar image
iris123 answered ·

Thank you so much.... I just presumed that the breaker is set correctly as it was like this since getting it from the mechanics. Sooo, yes it was off and once I switched it, as if by magic, everything worked. Super stupid of me, so I'm very very greatful.

I didn't do any of the electrics. Thanks for the note on the breaker between battery and inverter, I will get that sorted (using a similar one as the one for the mppt would work would it?).

Thanks so much again and apologies for my stupidity!


2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.