i got roped into doing the hedge trimming for my next door neighbours. He had cordless trimmers, i started the job only to find they died after 2 or 3 minutes use (that's the trimmers not my neighbours
). Having paid 90 quid for the trimmers and only used once or twice a year and now only 3 years old, would one expect batteries to be duff? Me, being kind hearted said i would sort it out. Though It did not take long for my knowledge to falter. i know they were charged prior to being packed away and stored in house. i know they were recharged before use. I know the voltage is showing 20.2 volts, i opened the pack to find 5 off 3.6 vdc lith iron battery cells, i measured each one all 4.0vdc or alittle over. the electronic monitoring pcb inside did smell a little when sniffed up close but i decided that it was not bad and i did not see any burnt damaged components, well obvious ones anyway.
Rant, This has happened to this chap several times and these battery packs really annoy me because the cells could be ok but the control could be duff , but most people dont have any idea and throw away repairable expensive stuff!
what can be done? on the cheap, my thoughts; use a 12v car battery and connect direct to trimmers, though it is 18vdc Li iron bat, although probably work, the motor looks so feeble and the current draw would i suspect burn the motor out.
Next, thought to get a transformer, but the cost ? well the battery pack looks to be rated 1amp/hr but each cell is 2400mA printed on them. so you are looking at big transformer, big diodes for rectifier, big money?
i thought a bout upgrading the cells but then the control pack would be affected.
Please, any good ideas or help, how many trimmers does my neighbour have to buy?