Hi everybody, could someone confirm the value of tail current to 0,1% of floaded lead acid battery bank capacity A/h ? After long reserch on this blog and others, i find this value, i drop the 1 amp tail current setting to 0.3 amp (0,1% of my 300 A/h bank) and finally i see a good increase of SOC without any heat or gas, with absorbing time into the parameter limit and a good increase in capacity that i didn't had before. Just to know if the value can be correct. Thanks.
The recommended tail current varies depending on the exact type of battery and make, but its normally in the range of 1.0% to 2.0% of battery bank capacity (not 0.1%, that's too low and likely can't ever be achieved).
So for a 100Ah battery, about 1A to 2A.
PS. Some manufacturers recommended less than 1% for AGM type batteries.
Thanks Mark, my battery bank is 2 x 150Ah normal truck starter battery, setting 14.5v bulk and absorbtion, but with tail current set to 1A the absorbtion time was too short and i realize a SOC of only 80%, working with load alweys between 80 to 50%, once set the tail value to 0.3A , the absorbtion time take longher (how have to be to top up the last 20% SOC) but still into the paramiter of absorbtion time by the charge controller algoritm, and finally i see my battery cherged....so for my point of wiew is correct...could be because i am in Malaysia where folk say the battery factory fill with low % of acid mix due to the temperature range at 30 degree celsius average? Thanks for your time.
If you are using a battery monitor to track SOC% you should be setting it to synchronise to 100% SOC when the tail current is slightly above the MPPT tail current.
Tail current at the absorption voltage is the best indicator that the battery is at 100% SOC.
Judging by your comments, I think your battery monitor might be getting out of sync and/or your batteries may be on their way out.
Because i don't trust in battery monitor and i am still studying the Phukert law, i use the old hydrometer sistem, take it 1 hour after charge end, and at morning before charge start all compensated by temperature, battery bank 1 year old...and with 1A tail current set, i never see 100% (80% max), now with tail set to 0.3A after 3 days i start to see 95%....
