I have an underwater strobe light which is no longer holding charge and wish to change the batteries. It is fitted with 6 off 1.2v 2200mAh tagged batteries giving a 7.2V supply.
Having opened the battery pack I can see couple of the batteries have started to weep. The other problem is the printed circuit switch has corrosion on its tracks. What is the best way to clean this corrosion of the board and its corresponding rotating connector.
Any recommendations for procedures to follow when changing the batteries.
Battery corrosion can be dealt with by wiping with vinegar, cleaning the vinegar off with water, then isopropyl alcohol to dry it all up. In the absence of a fibreglass pen or Garryflex block, you can use the ink end of an eraser (do they even do those two-coloured ones these days?).
Nothing special to do when changing th cells as lon as you use tagged ones. Give the tags a rub with emory paper or garry block to break the oxide befor soldering and don't overheat them.
After you have cleaned the contacts lubricate them with a smear of vaselene. DON'T use the divers favorite, silicon grease, any arcing will turn it into silicon dioxide (glass) and ruin the contacts.
Faber Castell still make fibreglass erasor pens which I used to used many moons ago when I was a draftsman on a drawing board. Used to use them for modifying ink drawings. Still remember getting itchy hands after brushing the broken fibres with my hand.
I would think that a change of battery chemistry might be prudent? Cadmium is on the ‘naughty list’ and just two lithium cells would suffice (with a decent battery management system – which would likely be at the cell level). Nickel metal hydride might also be an alternative.
If you have a fast charger, please make sure the cells you select are capable of accepting that maximum charge rate.
A few years ago I replaced a couple of duff cells in a Skill battery pack (with Maplin cells of the same capacity, and claimed charge rate).
Everything worked fine for several recharges.
One day I pressed the Fast Charge button and wandered downstairs to make a brew.
A little while later there was an exceedingly loud bang from the bedroom.
One of the new cells had expanded and blown the end out. The insides followed leaving a spring like Zeberdee.
The adjacent cell was blown straight through the plastic case, and made a sizeable dent in the bedroom ceiling.