May 29, 20224 yr Good morning Iv got a small solar setup with a 30a charge controller, 300w 24v panel open circuit voltage is 44v, 4 100ah gel batteries connected in series parallel to make in theory 24v and 200ah or 4800wh, victron bmv702 connected directly to the battery bank, and an 800w victron inverter, all linked as close as possible to each other. While monitoring iv got TV running off the system and router for internet with no solar input (at night) I'm drawing between 100w and 150w. With this load I seem to be getting to 22v after only 4 hours. That's only 600wh and the inverter shuts off from low SoC. The batteries are new. Can anyone give me advice why calculations and real world are so far off?
May 29, 20224 yr What setting have you used for bulk and float charge and what kind of charger if any from grid? Are you sure the batteries still have 100Ah capacity? Bear in mind if in Gauteng your panel might only be providing 225W this time of the year during the peak hours. Less before 11h and after 14h30. This is far less than what you are using. While drawing 150W during the day plus the about 20W the inverter is using to operate it does not leave a lot of power for charging 4 x 100Ah batteries. Edited May 29, 20224 yr by Scorp007
May 31, 20224 yr Author I don't have anything connected to the grid for charging. So purely solar the load during the day is just the router and inverter. If I check the victron bmv702 with the shunt it says in drawing On average with no input about 52w during the day. Constant draw it says it's going to 100% SoC
May 31, 20224 yr 4 hours ago, Machine458 said: I don't have anything connected to the grid for charging. So purely solar the load during the day is just the router and inverter. If I check the victron bmv702 with the shunt it says in drawing On average with no input about 52w during the day. Constant draw it says it's going to 100% SoC So it is now clear you have a good setup for charging. With batteries at 100% and only getting 4 hours one can only think the batteries do charge full but they have lost capacity. Remember when calculating the power used to include the 52W self use of the inverter if it is not part of the 100-150W. I would have each of the batteries tested. 2 at a time while it is running on the other 2 and charged from PV.
June 1, 20224 yr Author I think my problem is is it's getting through the bulk charge but not float charging 100% so my reading of full charge isn't actually full because as iv been using less the putting in its getting better. I need more panels so I reach float charge earlier in the day my charge controller is still putting in 2-3 amps to the battery at 2pm so if I can charge quicker I can hopefully get the battery full quicker and flowy for longer then maintenance charge in the afternoon instead of still trying to charge the batteries
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