Page 1 of 1

Wossat high pitched tone ?

PostPosted: 08 Jan 2019, 22:34
by RogerS
Happened to venture outside this afternoon (in the sunshine :D ) and heard this high-pitched whistle coming from ? Well..somewhere. My hearing is shot but managed to locate it coming from the log store. Gut feel told me what it was but I wasted time searching.

It's the Clarke portable car-starting-thingummy-jig....haven't charged it for months and months. It's in the same TUIT list as fire-up-the-generator/empty the petrol from the lawn mover/run dry the hedge trimer/strimmer/4000 other things to do before winter.

Zero on the meter. Nada. Zilch. Surprisingly managed to find the charging gizmo and plugged it in. Charging light came on briefly then went out.

Bob, you'd be proud of me...I sussed out instantly what was amiss...so flat the initial current was tripping something internally (charger/gizmo/whatever). So I kept flashing the charging plug in/out/in/out until there was enough charge to coax the circuitry into letting me plug it in fulltime.

Question.....because I let it run so flat, have I nadgered up the plates ? Guess proof of the pudding would be trying to use it...but then I need it to work !

Re: Wossat high pitched tone ?

PostPosted: 09 Jan 2019, 10:20
by 9fingers
Good strategy for getting it to charge but sadly very poor maintenance strategy for the device in the first place.

I'm assuming this is one of fairly bulky, heavy devices based on sealed lead acid batteries rather than the more modern LiPo based ones?

SLA batteries really do like to be charged at least every few months at constant voltage. 2.35v per cell. Their normal failure condition is to go high internal resistance. The fact that your charger seemed to be being overloaded could be quite encouraging as it would need a low internal resistance to draw enough current to trip the charger.
Assuming that the charger will now complete the process, it should drop back to a lower maintenance charge voltage of about 2.25v per cell.
I would then gently discharge it - usually these things have a torch built in - to around 1.9v per cell and then re-charge fully before asking it to give its all by starting a vehicle engine.

I have less experience with LiPo but do know their energy density is very very high but in return they do have to be treated carefully with max charge rates and minimum discharge voltage strictly adhered to. Usually they have sophisticated electronics inside to manage this as evidenced by power tools cutting off dead when the battery needs charging.

Good Luck

Bob

Re: Wossat high pitched tone ?

PostPosted: 09 Jan 2019, 13:55
by RogerS
Thanks, Bob. That's reassuring. They're SLA's. Will do as you suggest.

Re: Wossat high pitched tone ?

PostPosted: 09 Jan 2019, 14:17
by Andyp
I will bow to the more experienced around here but is it really necessary to drain petrol from a lawnmower over winter?

I have only owned one ( a Honda) for 11 and a bit years and have never drained the tank over winter. I cut about 1200 m2 once a week from about march to October.

Re: Wossat high pitched tone ?

PostPosted: 09 Jan 2019, 14:23
by RogerS
Andyp wrote:I will bow to the more experienced around here but is it really necessary to drain petrol from a lawnmower over winter?

I have only owned one ( a Honda) for 11 and a bit years and have never drained the tank over winter. I cut about 1200 m2 once a week from about march to October.


If it's a Honda and a four-stroke then I'd probably not bother because Honda engines are bloody good. It's not so much draining the tank as running the carb dry AFAIK. Much more imprtant with two-stroke though.

Re: Wossat high pitched tone ?

PostPosted: 09 Jan 2019, 14:50
by Andyp
I don't run the carb dry either. I have drained the oil and replaced once, cleaned the plug once and occasionally use the petrol oil mix. Not good news to Bob's ears.

Always starts on 1st or 2nd pull, even the kids can usually start it.

BTW when I need spares for it I go to LINGS Honda, excellent service and way cheaper than locally available here.

Re: Wossat high pitched tone ?

PostPosted: 12 Jan 2019, 15:02
by RogerS
Not good news. The charging light is supposed to go out but it's been on now since I started this thread.

Re: Wossat high pitched tone ?

PostPosted: 12 Jan 2019, 19:19
by DaveL
RogerS wrote:Not good news. The charging light is supposed to go out but it's been on now since I started this thread.
Roger,

Can you measure the voltage of the battery, as Bob suggested?
You may find that if you cycle the battery it might recover with a few cycles, but the battery will never be 100%.

Re: Wossat high pitched tone ?

PostPosted: 12 Jan 2019, 22:46
by RogerS
DaveL wrote:
RogerS wrote:Not good news. The charging light is supposed to go out but it's been on now since I started this thread.
Roger,

Can you measure the voltage of the battery, as Bob suggested?
You may find that if you cycle the battery it might recover with a few cycles, but the battery will never be 100%.


How many cells are there ?

Re: Wossat high pitched tone ?

PostPosted: 12 Jan 2019, 22:52
by 9fingers
RogerS wrote:
DaveL wrote:
RogerS wrote:Not good news. The charging light is supposed to go out but it's been on now since I started this thread.
Roger,

Can you measure the voltage of the battery, as Bob suggested?
You may find that if you cycle the battery it might recover with a few cycles, but the battery will never be 100%.


How many cells are there ?


Now lets think about this. We are miles away and you have the thing in front of you :lol:

Bob

Re: Wossat high pitched tone ?

PostPosted: 13 Jan 2019, 08:36
by RogerS
9fingers wrote:
RogerS wrote:
DaveL wrote:....
Can you measure the voltage of the battery, as Bob suggested?
You may find that if you cycle the battery it might recover with a few cycles, but the battery will never be 100%.


How many cells are there ?


Now lets think about this. We are miles away and you have the thing in front of you :lol:

Bob


Um...the SLA is sealed inside the case. If you're telling me the cells should be charged at 2.35v or 2.25v per cell then what ? Six cells ? Roughly 12v. Not sure the charger is putting out that much TBH...will measure later. Off and on-load.

Re: Wossat high pitched tone ?

PostPosted: 13 Jan 2019, 11:43
by 9fingers
I'd assumed a few screws would reveal all.
Highly likely to be 6 cells
13.6 ish on charge rapidly falling to 12.6 off charge and slowly reducing to 12 as it discharges. Cease discharge at say 11 v then recharge and repeat
Bob

Re: Wossat high pitched tone ?

PostPosted: 13 Jan 2019, 11:46
by RogerS
9fingers wrote:I'd assumed a few screws would reveal all.
Highly likely to be 6 cells
13.6 ish on charge rapidly falling to 12.6 off charge and slowly reducing to 12 as it discharges. Cease discharge at say 11 v then recharge and repeat
Bob



Thanks Bob...will report back. I'm guessing that the output croc clips will be at charger voltage when that's connected. Gives an easy monitoring point. Can't think that there would be anything complicated between charger input socket and the SLA. It is a Clarke after all :lol:

Re: Wossat high pitched tone ?

PostPosted: 24 Jan 2019, 11:58
by RogerS
Pretty sure the battery is knackered. After the red charging light has gone out, the voltage is 11.9. But turn on the wee light on the unit and the volts drop by 0.5v. High resistance internally?

Battery is a 6-FM-38 and pricing seems to be around £115-120 mark. A new unit is only £149. :eusa-think:

Some on eBay though for much less but not sure that they are suitable for car starting.

Re: Wossat high pitched tone ?

PostPosted: 24 Jan 2019, 16:22
by 9fingers
Have a look at the more modern LiPO starter packs for a lower cost complete unit.

Numerous reviews on youtube and the sort of thing you can keep in the glove box float charging ready looked after for when you might need it.

Bob

Re: Wossat high pitched tone ?

PostPosted: 24 Jan 2019, 17:37
by RogerS
Thanks for that, Bob. I'm out of touch with what's available. Do you know how they fare with a really flat car battery ?

Re: Wossat high pitched tone ?

PostPosted: 24 Jan 2019, 18:09
by 9fingers
RogerS wrote:Thanks for that, Bob. I'm out of touch with what's available. Do you know how they fare with a really flat car battery ?


I've not had to use one Roger. I got close to buying one when I had a car with very voltage critical electronics that would drop out with a low battery but ended up trading it in for someone else to teasr their hair out over.

There is the usual specmanship to be careful of especially as the A/H capacity is oft quoted with respect to 1 LIPO cell of 3.7v instead of the 3 or 4 in series used to get 12 ish volts.
There may also be some with three cells (11.1v) and 4 cells (14.8v). I did not get that far.

I would suggest doing your homework and not just getting the first one you see. They possible all come out of China but some may have a respectable badge and better quality control than others.

Caveat Emptor

Bob

Re: Wossat high pitched tone ?

PostPosted: 29 Jan 2019, 21:12
by Rod
Image

Rod

Re: Wossat high pitched tone ?

PostPosted: 29 Jan 2019, 22:14
by 9fingers
I see there are quite a range from that maker, from this one at 400 amps to the big boy offering 4000A if you happen to need to start an aircraft engine I suppose :lol:

Bob

Re: Wossat high pitched tone ?

PostPosted: 29 Jan 2019, 23:00
by RogerS
I'm sticking to 'Old School' :D