question

zeph avatar image
zeph asked

SMARTSOLAR 75/15 + AGM 80AH +120w solar panel

Hello all,

I got a problem or missundertand with my new victron MPPT, yesterday i install on my campervan, and it charge 60wh (from 6PM to night). So today I look on victron connect it was charging at 30w and after i start my campervan it was still charging the battery show 14V, so I start my fridge to see if charge still it was ok. After I Stop my van no more charge 0w. My car charge the battery when driving. and the MMPT is directly on battery is it the good connection?

Now the blue led is blinking every 3 seconds. no error message, i have jumpe out for battery life algo.

Should I have battery at 100% for first connection ?

Have you any idea ??, my charger in van for battery is Schreiber 15A, with 220V and alternator input. And I got a battery coupler with 50A fuse going to battery

MPPT Controllers
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10 Answers
Justin Cook avatar image
Justin Cook answered ·

It sounds as if your battery is full, so your MPPT isn't charging it. The blinking "bulk" (blue LED) light is the MPPT waking up, checking voltage at battery and PV, and going back to sleep.

You do not need 100% battery when you first connect the MPPT, and yes the MPPT should be wired directly to the battery (properly fused, of course); it sounds like your MPPT was charging the battery, then you drove for a while and the alternator also charged the battery and between the two charge sources your battery was fully charged and the MPPT effectively went to sleep. If you still have good sunlight, an easy way to test this is to put a decent load on the battery; as your battery voltage comes down, the MPPT should wake back up and start charging until the battery doesn't take any more, then it will go back to sleep and start blinking the bulk LED again.

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zeph avatar image
zeph answered ·

Thx what do you mean whan you write :MPPT should be wired directly to the battery (properly fused, of course).

I just wired + and - as MPPT 75/15 should protect with is fuse.

And I have my fridge connected which take descent load . What i do not understand that is my campervan control panel tell me battery is 50% charged and it do not start charge. ANd victron connect show me 11,9v but do not start charge , so i decide to put on 220V, for night as i drive before night I was a 13,1 v and with night on 220v my fridge on, on morning i should be fully charged and will reset MPPT by disconnecting and reconnecting to see if change anything in the day. I will also made test my battery as it not a new one

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swede avatar image
swede answered ·


Can you provide a screen-dump like this when you have sun-light? Maybe also a photo of your connection.


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zeph avatar image
zeph answered ·

Here is screenshot


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zeph avatar image
zeph answered ·

Some news , as i a ma technician after all, but not electricity one and do not find any electric technician which can have a look at my installation I decide to put every thing down and make fresh install.

I test my solar , in open mod and get 21v. So i wire all without electricity. Put only the battery on mppt , and i hope this work and it's work. So I put everything on battery and it work.Next step , I will drive and see if it was the alternator which put MPPT in default, or if my cable which come from solar panel, was not really well clamp in MPPT .


Screenshot of today, with cloud



Solar panel with cover

Charging, cover removed






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zeph avatar image
zeph answered ·

So when I come back in the van. Battery come back to off and no chargingonly from 11.5 to 11.9 ... I try to put mppt out off energy for 20 minutes but it do not come back to charging. I m disappointed may be a faulty one?

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zeph avatar image
zeph answered ·

I made another test keep to fresh install got 22v from my panel but when everything wired no charge. What strange is that I got something on solar panel. 0.1v with no panel wired?



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crythis avatar image
crythis answered ·

I have the same problem. The constant Vorlage is set to be around 27V ( i do have a 24v system) but still the mppt decides that 25 v ist enough and doesnt charge, suppressing the voltage from the solar module which should have by far a higher voltage at relateable weather conditions. Only triggering cell balancing starts charging again as far as i found out.

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zeph avatar image zeph commented ·

Thx for your help, but in y case i test triggering too but stay off

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zeph avatar image
zeph answered ·

As i m still searching , should i put a fuse between the battery and the mppt some say yes, some say MPPT allready protect.


So don't know if i should or not . Actually not.


When I search and found some picture of install, there is no fuse or there is.


If i Look a scheme from victron there is fuse between Solar Panel and MPPT on -/+ but as I got a 75/15 and 120w solar which Fuse 2x20A?

And on the + from MPPT input to battery + i have to add a fuse 20A too.


Am I right or not, every one tell it's plug and play, but as I understand it's not i add to protect on solar input and battery in/out too?


So the 20A fuse in victron is only for himself or is it a redundant one?

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zeph avatar image
zeph answered ·

So after several test and explanation I decide to start from scratch so first off all I change my battery for a new one Varta lfd90.

I put fuse on solar panel + and -.

I put fuse on + battery and start .


Since yesterday it seems to be good. So i start my fridge to see if everything working.


It seems to be good at time tell you more in 2-3 day of testing.


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