On Thursday, March 12, 2015 at 10:18:55 AM UTC, Another John wrote:
In article ,
Martin Brown wrote:

Your least worst option now is to charge it for a couple of hours with a
dumb as a rock simple lead acid battery charger to see if you can get
any charge to stick (ie. enough to start the mower). If it won't hold
charge for at least a week you are stuck with replacing it.

Ideally an initial charge rate of C/10 to C/5 but keep an eye on it.

Smart chargers will sense battery parameters and do a safety cutout if
the battery has gone high impedance or has one cell reverse polarised.
The lifetime of the SLA has been compromised - possibly to zero.

surely to zero

Thanks Martin ... yerrrsss: my charger is "dumb as a rock": just has
lights (no dials or meters), and very little in the way of controls (in
fact just one switch: 6V or 12V?!)

if it has a 'charged' light then its not entirely dumb

I regretted buying it as soon as I got it, but it cost about 35 quid and
was reluctant to spend more, especially as I myself know almost nothing
about electrics/electronics.

A used dumb charger is worth nearer £3.50

I'll see what happens next time I go across and give it another charge.
I'll report back, as I really do appreciate the help you've all supplied.

If you want to try and overcome sulpahtion you need to hit it with much higher voltage. But realistically, scrap it and get a new battery.


NT