Advice on charging lawn mower battery?

Any comments on this scenario please chaps?

I went to the place where I do the garden, put the lawn mower battery on my charger, then went off to do other stuff for an hour or two.

Funny thing: when I connected the charger, it stuttered about a bit showing "charging" (orange light in this case) then "fully charged (green).

Since the mower's been idle all winter, I knew the battery couldn't

*really* be charged; it wouldn't even cough when I tried the starter before connecting the charger. And so I left it at green, thinking it would "sort itself out" -- I was in a hurry to get started on my other tasks.

After an hour I came back: light on green; disconnected charger; tried the engine: it coughed, then stopped; no further attempt at coughing: battery obviously dead.

I connected the charger again and this time it stayed at orange ("charging"), implying that it might get properly charged this time! Had to leave it though because the mower's not in a place where I can leave the battery charging and me not there.

Any suggestions as to what happened here? Why did (nay: could) the charger say "fully charged" when first connected?

The charger is new - a Ring RCB206 Automotive Dual Voltage Standard Charge 6, 6amp, 6 or 12 volt (used it on 12 volt for the mower).

Any thoughts appreciated! Cheers John

Reply to
Another John
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Sounds a lot like like a dead battery. What else can one say?

NT

Reply to
meow2222

Assuming the charger is ok, it sounds like the battery has gone high impedance, so not taking a charge. A high current discharge test is the best way to check if it's knackered.

Reply to
Dave Plowman (News)

Assuming a lead acid, and no quiescent drain (unlikely on a lawn mower) there's no reason why it shouldn't retain most of its charge over winter. You did charge it before laying it up? Lead acid don't like being left in a discharged state.

Reply to
Dave Plowman (News)

Thanks a lot for the replies so far!

I hope the battery's not dead! When I tried to take it out last year (when I first started this job) it would NOT come out of the mower body, following the manual's instructions. I may have to take the mower apart to get the battery out.

I will have another go at charging next time I'm across. And No Dave, I didn't charge it last thing last autumn, mainly because (having successfully charged it when I took this job on last year) it always started first time thereafter (it takes about 90 minutes to cut the grass).

Cheers for now John

Reply to
Another John

Get yer string out.

NT

Reply to
meow2222

/Get yer string out.

NT /q

How predictably cryptic.

Jim K

Reply to
JimK

If it is a sealed lead acid battery (SLA) it is almost certainly defunct, they really dislike being left discharged for any length of time.

Reply to
Peter Parry

In message , Peter Parry writes

Charge it up. Leave it disconnected for 48 hours then check the voltage. You'll soon see if a cell has gone down.

Reply to
bert

If its sulphated it won't charge to any significant capacity. Folks used to mess around conencting such batteries to a high charging voltage, but I'm not convinced it was ever very successful. Lets hope the mower has a suitab le pulley for ye old pull start.

NT

Reply to
meow2222

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.

Reply to
Martin Brown

And (thankfully!) put it another way:

Thanks NT - Nope: no pull start on this mower. (It's a Murray, maybe

4-5 years old and a B&S engine. Must say it's not as nice as the Mountfield I used to use on another job, but it's reasonable.)

Cheers John

Reply to
Another John

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?!)

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.

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.

John

Reply to
Another John

Do you own the mower? If "yes" change the battery or get it changed. If "No" - then "Hey Boss, Sorry but the mower wont start - who has your repair account"?

Reply to
snot

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

A used dumb charger is worth nearer £3.50

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

NT

Reply to
meow2222

Putting a multimeter in series on the amps range to see what current is flowing might be informative. Or just look for the spark when you make the connection to show that there really is some output.

I find dumb as a rock ones OK provided you remember to either charge at C/10 or religiously set a timer/alarm to switch off when fully charged.

Rapidonline have a reasonable selection of SLA batteries at fairly decent prices. The official lawnmower spare will be overpriced though probably not by as much as wheelchair batteries. It does have to be pretty rugged and robust to stand up to the vibration on a lawnmower.

Reply to
Martin Brown

yes - there are ones suited to that, you'll need one, not an NP type.

NT

Reply to
meow2222

Any comments on this scenario please chaps?

Can you get your vehicle neat it?

If so hook them together with jump leads, leave the leads on with vehicle engine running for 10 mins, then start it whilst still connected. The extra oomph of the vehicle alternator charging it may help bring the battery back to life, but at least the mower will be started.

Mike

Reply to
Muddymike

or push start it. An alternator doesnt provide any extra charge voltage.

NT

Reply to
meow2222

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