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peterbennett9 avatar image
peterbennett9 asked

Will using an MPPT with a DC to DC pass too much current to my battery

  • Hi guys i have added a Victron 15a MPPT solar controller wired to 155w of solar panels that can produce 8a on a good day, i also added a 12/12 18a DC to DC charger to charge my battery off the alternator in my campervan.

I have a 75ah Bosch sealed lead acid leisure battery

My question is this, since the dc to dc’s dont have VE networking, will the mppt and dc dc produce too much current for my battery during a bulk phase? Or will they self regulate via V?

So I know wether i need to isolate the solar panels while driving


Thank you

smart solar set-up help
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wkirby avatar image
wkirby answered ·

Generally 0.2C is a good rule of thumb. So, for a 75Ah battery, that would be ~15A maximum for the bulk stage. Then self regulation by the absorption Voltage will reduce the current at whatever your absorb Voltage is set to. So maybe best to disconnect or disable the MPPT while driving.
Like I said 0.2C is a rule of thumb, so if you want to be sure you could contact your battery's manufacturer or consult the datasheet.

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peterbennett9 avatar image peterbennett9 commented ·
ok thank you, the van has a habitation cut off when driving anyway so this means I can leave it as is
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