if both are exactly the same cell and just their surface is different, obviously the cell with the larger surface area will stay cooler
how hot a cell gets is determined by its internal resistance, current health and surface area
The TP4056 stops to charge, when the battery is only taking 55mA of charge at 4.2v. Meaning the lower the cell voltage after charging, the lower the capacity of the cell overall.
Depending on the capacity, I'll go down to 4.1v in 30 days.
Heaters can often be fixed, however i dont know if its...
Thats quiet a deal when you get them for free.
However as they are already used since 3 years, they probably wont have much life in them left. As by the manual, the service life is only 4 years if the battery is being kept at 20°c, after that it only has 80% capcity left which is falling...
Lead batteries should be charged at 0.2c, most door openers have a battery with 5-10Ah, so the charger itself should already be limited to 1-2A.
And i also doubt, that he is going with a 4s1p config and even if, the charging current should still be fine, discharge however might not.
just use a buck converter to change the charging voltage
i'd go for 4s charging the batteries up to 15v (3.75v), that should still be within the limits of the door opener circuit and keep the batteries at a happy charging state, so they dont degrade as fast.
1. Yes, if one gets shaded, the whole string will loose its power, Voltage might stay high, but ampers will go down significantly. You probably need a higher Solar Voltage than your battery voltage, so putting 3 in series is the best option there.
2. Go on Aliexpress and search for DALY Smart...
Probably deleted, cant find any information on that topic besides beeing mentioned in other threads.
My solution to hot Sanyo cells is, to charge them until they get warm, let them sit for 2 days, charge them again.
Nearly all my cells Sanyo cells still work just fine.
Don't know why they...