question

martin avatar image

Tail current setting when using multiple MPPTs

I'm running three BlueSolar MPPT 100/50 chargers in parallel. I've noticed that even though absorption and float voltage are set correctly, the batteries seem to be overcharging - there is excessive bubbling and they need topping up frequently. Also, the MPPTs often aren't in the same charging state. They are connected to a CCGX and shared voltage sensing is enabled.

I'm wondering whether the tail current will have to be adjusted when using more than one MPPT as it's 2A per charger from my understanding. Should the threshold perhaps be higher so that the absorption phase ends earlier?

MPPT - Solar Charge ControllerCCGX Color Control
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1 Answer
JohnC avatar image
JohnC answered ·

Hi Martin. Your tail current is unlikely to be your issue. More likely just V on your batts if it's charging excessively.

With a GX perhaps you're set up to see your V graphs. Check with a multimeter just in case there's some V anomaly.

If that's ok, maybe you could post a screenshot of V over a day? Picture/thousand words thing..

Or just drop your target (absorb) V to reach your 'bubble' target?

An onsite batt man (not the pointy-eared guy) could probably diagnose this within minutes. Tough from here..


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