I've an old lead acid battery with the following specs:
- 12V, 7.2Ah
- Valve regulated
- Sealed lead-acid type
I've no idea about batteries prior. This battery has been in the attic so far and I would like to use it now. But, it is almost dead. I tried to recharge by applying 12V to it for one hour. But that doesn't seem to work. So, how can I recharge the battery or how to find out whether the battery is dead?
Best Answer
Ouch. My best guess is that your battery is toast.
Lead-Acid batteries suffer from several damaging chemical processes if they are allowed to remain discharged for long periods of time. One of the real problems is something called "Sulfation". You can use Google to search out that term and also look at the many attempts to build de-sulfation devices. Wikipedia has a good description of the problem: Wikipedia
In general, I have good results with Lead-Acid batteries so long as they are kept charged. We build our own chargers: Equalize voltage is 15.0Vdc and float voltage is 13.5Vdc. The battery is charged with constant current until the current drops below the current limit value, then the charger drops into float mode. There are better 3-stage chargers available now but we have had great success with those chargers - some of that gear is more than 20 years old and the users routinely get 5 to 7 years of battery life.