Hi everyone. I've got a snag on one of our installations. There are 3 24V battery banks A200 of 12x2V cells 225Ah total capacity each bank. Each is charged using Phoenix 24/16 charger using default factory settings.
During a recent inspection, we depleted each bank to around 23.5V and then charged them back up again. Each Phoenix charger failed after between 6-7 hours. There is a solid red fail LED illuminated but nothing else.
For the main bank, we swapped in another phoenix and exactly the same problem after 6-7 hours. A skylla-TG 24/50 was then installed instead and set to 16A charge current. This failed after 10 hours with a flashing bulk, steady fail LEDs. This indicates bulk protection mode has kicked in (there is conflicting info in the manuals, one of them says it will swap straight to float, but another manual says it will fail with LED code as above).
So I'm thinking we need to increase the charging current to at least 25A for a c/10 rate. I manually set it to 40A just to get the batteries recharged and this worked fine.
My question is. Is this what is causing the Phoenix 16A chargers to fail also? I looked at the manual and also in google. There is no mention of this series having bulk protection mode. Also, if there is bulk protection mode does it default to 6-7 hours? We had exactly the same issue last year on another site, with both phoenix chargers failing after 6-7 hours but just gave up and swapped them for skyllas which have been fine. I can't believe that all our phoenix chargers are faulty though. This does not happen in float mode with already charged batteries, only after bulk mode has been on for 6-7 hours (best I can do from telemetry indications). The ambient temperature is around 10-15 degrees C and there is around 2 feet spacing around each charger. They do not get hot and the fans are working. The batteries are 2 years old. On the other site, they were 3 years old. Fitting a skylla removes the issue (at both sites).
Just to be clear. These are the Phoenix chargers, not the inverter/ multiplus units.