I'm wondering if my charge controller & BMS are arguing...
Setup: I've got 8xCATL300AH in a 24v pack, temps are 5deg-40deg all year round, i'm happy to run them very conservatively for longevity. Victron Smart 100/50 for the charge controller
BMS settings as per SteveS' work (https://diysolarforum.com/resources/general-lifepo4-lfp-voltage-to-soc-charts-tables-12-24-48v.109/), which i'm basing everything around & want to stick to those. So i configured my BMS - which hits overvolt & flicks the Charge Controller from bulk into absorbtion. But i'm not sure if i need to change my Charge Controller lower than default - so that it is "in sync" and both the BMS & charge controller decide to go to absorption & stay there around the same voltage.
I'm thinking the devices need some alignment - if the absorption is pushing the cells/pack to overvolt then its just flicking on/off instead of holding it at the right level & dropping current. So my Charge Controller absorption voltage needs to be *just* below the voltage which triggers a cell or pack overvolt? That way it'll stay in absorption & push the most current without racing past the overvolt & resetting.
Make-a-sense?
By setting the CC absorption below the triggering overvolt i can see solid amps going into the battery pack without triggering overvolt, stopping & starting again.. Before it was triggering overvolt, pausing, then starting again & triggering overvolt... pausing... over & over again.
BMS Settings
Charge Controller Settings (Victron Smart Solar)
Setup: I've got 8xCATL300AH in a 24v pack, temps are 5deg-40deg all year round, i'm happy to run them very conservatively for longevity. Victron Smart 100/50 for the charge controller
BMS settings as per SteveS' work (https://diysolarforum.com/resources/general-lifepo4-lfp-voltage-to-soc-charts-tables-12-24-48v.109/), which i'm basing everything around & want to stick to those. So i configured my BMS - which hits overvolt & flicks the Charge Controller from bulk into absorbtion. But i'm not sure if i need to change my Charge Controller lower than default - so that it is "in sync" and both the BMS & charge controller decide to go to absorption & stay there around the same voltage.
I'm thinking the devices need some alignment - if the absorption is pushing the cells/pack to overvolt then its just flicking on/off instead of holding it at the right level & dropping current. So my Charge Controller absorption voltage needs to be *just* below the voltage which triggers a cell or pack overvolt? That way it'll stay in absorption & push the most current without racing past the overvolt & resetting.
Make-a-sense?
By setting the CC absorption below the triggering overvolt i can see solid amps going into the battery pack without triggering overvolt, stopping & starting again.. Before it was triggering overvolt, pausing, then starting again & triggering overvolt... pausing... over & over again.
BMS Settings
- Cell overvolt: 3.45v
- Overvolt release: 3.35v
- Pack overvolt: 27.6
- Overvolt release: 26.8v
Charge Controller Settings (Victron Smart Solar)
- Absorption 27.1v
- Float 26.8v