We would like to replace our old AGM batteries (600 Ah) with modern LiFePo batteries in our garden house (6panels, 1.2kWp power, Phoenix 24/3000 and a MPPT 100/50 BlueSolar). Can anyone share their experience / recommendations here? Thanks a lot
asked
Phoenix 24/3000 - Erfahrungswerte Batterie-Erneuerung LiFePo
Advice given actually requires knowledge of what you expect to achieve.
You have some loads? That you are powering from batteries?? And you need to charge those batteries via solar???
Thank you -
We want to run the same loads on the system as before, no expansions planned, and yes, the battery is to be charged by the approx. 1.4kWp solar array (6 solar panels) with the MPPT, so we need to find a good balance between a reasonable capacity and proper sizing to keep the panels from spending the day charging a possibly over sized battery. Have read a rule of thumb, when replacing lead-acid batteries with LiFePo, you can get away with 50% of the capacity of the lead-acid batteries, if you do not change anything in the requirements. May be we simply go with a Victron LiFePo? Any thoughts?
Time spent charging, assuming you start the new system with a fully charged battery pack, is dependant on discharge amount, not battery size.
Lead acid/AGM is usually sized for max discharge of 50%. This is to optimise battery life.
With lithium, usable range is about 70-80% of battery size, max discharge of about 80%. Lithium will charge quicker, as charge rate doesn't drop off as quickly, also charge efficiency is higher.
Can't help much more, you're going to have to work out total load/daily consumption and guess at illumination. Also remember that if you're in an area with cold winters, lithium might stop working.
Thank you for your hints. Winter doesn´t bother us, because we are in Greece with this installation, nevertheless we installed a temperature sensor monitoring the temperature in the cabin. We tend to go with a 24V LiFePo from Victron, this should match our situation best (5x50Ah Superpack)
