Hybrid grid-tie / off-grid system: Victron

stephendv

Re: Hybrid grid-tie / off-grid system: Victron

AceNZ wrote: »

I'm running daily absorbs at the moment, but once I get the charging profile figured out, the usual configuration is to only run bulk (and float if it finishes bulk), and then absorb once every 14 days or so.

At the moment, I'm trying to make sure that when it does do an absorb, that it gets as close to 100% SOC as possible.

With that type of charging regime, you could go with a higher end-of-bulk voltage to ensure that you get the batteries adequately charged between absorbs, and also to get some mixing going with higher voltages.
The sunny island does something like this, although they throw in short absorb's at higher than normal absorb V every now and then. In a nutshell, they do:
- If SoC has not dipped below 75%, then go straight to float, skip bulk and absorb.
- If SoC is below 75% or a threshold number of days has passed without doing bulk, then do a bulk and short (1-2 hours) absorb at 2.55 Vpc
- Every X days do a full and proper absorb to bring the batts to 100% SoC.