Charging rechargeable batteries

[ericmark]

I have an older but similar charger. It expects batteries to be flat when inserted and runs for a set time after which it switches off.

In the main the output of the charger is not enough to damage batteries.

I had one of these

got it from a radio rally and these Delta V chargers nearly always charge each cell individually. But do cost around £20.

However I have some old faulty cells and one destroyed the charger. It did last a couple of years first and it did do a good job but these also have a safety system built in to stop damage when a cell is inserted the wrong way around. This safety system also means it will not charge cells which have been over discharged. So you still need one like yours to charge up cells which have been over discharged.

In theroy we should stop using a cell when the volts drop below 1.1 volts but in practice we often will use a cell until the appliance stops working which is likely well below 1.1 volt per cell.

So although in theroy using a Delta V charger is the answer in practice it's not really worth the hassle and you just accept the cells will not last as long and with Delta V.

For me I was using with a flash gun which stopped running well before the battery became over discharged so the Delta V worked well giving me six sets of batteries but for my wife who leaves batteries in items until completely flat it often refused to charge the batteries until they had been in a cheap charger for a few minutes first.

For most people the charger you have is good enough. Some want maximum output and maximum life from their batteries and for them it is worth the money for a delta V charger.

 

[B91]

That's a helpful post - thanks. In the end I left the four cells in the charger until it switched itself off after 15 hours. They did get quite hot to the touch after a while though so I was a bit concerned about safety, but needlessly it seems. I don't have the means to test the voltage, only a cheap multimeter with 1.5v and 9v settings. All the cells were halfway between good and bad but there is enough in them to run my BP monitor. We'll see for how long

I know nothing about this sort of thing but wondered if the heat may be because the charger - as I read it anyway - splits 2.8v between two cells so each 1.2V cell is being pumped up at 1.4V. Or is that complete nonsense?