question

james09 avatar image

Generator and 30A Victron Charger

Hi

We have a 12v / 415AH off grid setup with solar (1KW + Victron MPPT 150/50). We are not getting enough sun (barely any actually). So we are running a small 2KW generator for about 10 hours with a Victron 30Amp charger from time to time to try and fully charge the batteries. However for some reason we never seem to be getting the charge up to 13v (or even above our 70% / 12.3v level). You can see from the data when we run the charge (5 July, 12 July, 19 July) the min voltage is stepping up but it's not getting to where it should be (running 10 hours at 30amps should give us 300 amps which should be well north of 12v. We are not running the power on the charging days so we cant figure out what's going on. Any ideas?

Generatorchargervoltage
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2 Answers
JohnC avatar image
JohnC answered ·

Hi James. Those are bad figures. With one/both of your chargers presumed serviceable, I'd first go looking for a failed battery. You likely have a number in parallel configuration.

After some charge that may manifest itself in hot battery(s), but doesn't necessarily indicate the faulty one(s). Touch them, yep that simple. Isolate them from each other, leave stand for a while, and test them for V.

Try that first and come back.

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james09 avatar image
james09 answered ·

Thanks JohnC... Do you think maybe our charger is too small (30/420 =7.14%?)?

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As a backup, it should probably be ok. I think you have a more serious issue. 30A added in to at least some pv production should be plenty. Both chargers together..

If your batts aren't too depleted, I'd expect charge V with that added 30A to exceed 13V within minutes, and rise to Absorb level pretty smartly too.

Frankly, I'd be in panic mode if my own system showed those V figures. If both chargers running together are showing normal 'Bulk' status and you're confident of them, then look to the batts. A bad-un can bring down the whole circus. If it's that, just remove it from your system and run with less batts.

If you need your system up and running at all times (you've said its offgrid), you can cycle through your battery removals. i.e. remove one battery, let that one sit then check voltage, whilst leaving the rest in. If that one battery is good, wire it back then then remove the one. This way you can keep the system up while prodding at it.

Edit: Above is assuming you're using 12V batteries. If you're using 6V batteries, may need to give the sequencing a bit more though to avoid imbalance.