Battery reconditioning - 12V SLA


2019-09-27 8:23 pm
So I have a Yamaha Jog 3KJ 1997 50cc Scooter ive been playing around with and the battery has dramatically decreased in performance. I have charged it before and refilled the cells a bit, but a lot of the water has leaked out as the battery is mounted sideways. I am going to double up the seals with a old latex glove to maybe add more of a sealing to it, to prevent it from loosing all the electrolyte again.

I have read the thread about the mains desulphator, but i was too lazy to build one because i had to jet the bike and sort a few things in the shed and the battery had to be in the bike by Monday, that day being Saturday.

I just wanted it working away asap.
So thought ill use my power supply that goes up to 32V 5A. Just left it there for almost 24h now at 32V @ 200mA. Battery voltage kinda goes up and down but its at about 15V. I am going to keep cranking it. When i lower the voltage to 15 it only draws about 300mV. Ill keep cranking it with volts. Stick it back in bike later and check it again on friday and post results.

It definetaly has some hope i got a few more battaries i can play with but might be worth boosting the voltage up from my lab power supply, maybe a transformer? if knows what sort of transformer or circuit that could boost that 30V output to +/- 150VDC.

Lead acid batteries need to be kept 100% charged all the time. You can almost think of the thing having a limited life based on the number of hours it is sitting discharged. So all those people who like to run something and then put it away for the winter discharged, they are a big disappointment. These batteries also self discharge over the course of a few months. So they always need to be on an appropriate float charger when not in use to maximize life. They work great in a car you use several times a week.
Once a lead-acid battery starts to sulfate its on a steep downwards slope, and nothing will restore original capacity. You have to charge every month, and not store unless fully charged, they are a right pain (except as a vehicle battery for a regularly used vehicle).

I'd suggest thinking about better battery chemistries - LiFePO4 have much better behaviour, MUCH longer life (1000's of charge cycles), and can be stored for long periods. They don't leak sulfuric acid either...
Sealed lead-acid batteries (GEL, AGM, etc.) are not really sealed, there is a safety valve for each cell. These batteries are supposed to work at any position. However, some electrolyte evaporates and finds its way out through safety valve with time due to heat and pressure during charging, apart from sulfation due to extreme discharging, and there is no way to check or refill the electrolyte without degrading the mechanism in some way. These SLA batteries are no longer designed to be reconditioned by the user, as opposed to flooded cell lead-acid batteries. So recommendation is to move the problem back to the industry, find a point where batteries are taken for recycling, give it, and buy a new one, surely in the range of $20.

BTW: A check of charging circuit to ensure it is not doing overvoltage is also recommended.
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