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flat battery advice please.

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Jerry atric View Drop Down
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    Posted: 31 Oct 2018 at 19:27
I have a 2 or 3 month old battery that has been completely discharged, its as flat as a witche's lady part (well it is halloween). Is there a way to resuscitate it? I have to confess, this is off the Honda 175 so its only little in Guzzi terms, there must be a wiggly amp drain on the bike, I left it with the fuse disconnected but that doesn't isolate the starter. Any advice from those in the know, very much appreciated. Thanks
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 31 Oct 2018 at 22:23
Battery charger? Then see if it holds the charge.


"Chicken nuggets don't dance on a Tuesday."
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 31 Oct 2018 at 22:23
What charger do you have?
Newer chargers like the CTEK have pulse charging which is the most likely to get it back, but try any charger on it. Chances are you might get it charged again, but it will have post some capacity. Whether that will make it unusable or not remains to be seen.

Very small capacity batteries can discharge quickly as there isn't much in there to start with, but clearly in future disconnect the battery completely if leaving it for any time. But hindsight is a wonderful thing.
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jerry atric Quote  Post ReplyReply Direct Link To This Post Posted: 31 Oct 2018 at 22:34
Thanks Brian. Its a 9 amp hour battery. I put my optimate charger on it for the morning but it shows no lights at all, ie: battery dead. I tried the car battery charger for about half an hour with no result, but thought I had better stop it incase it did more damage than good but on reflection I guess things cannot get worse. Just annoying.
Aha. I just saw a tip on youtube to connect a good battery direct to the dead one for an hour. I'll give that a go in the morning

Edited by Jerry atric - 31 Oct 2018 at 22:38
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bugsy Quote  Post ReplyReply Direct Link To This Post Posted: 31 Oct 2018 at 23:31
No lights at all with an Optimate? With a knackered battery I usually get a light for "on" and at least a desulphating light but nothing at all?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jerry atric Quote  Post ReplyReply Direct Link To This Post Posted: 01 Nov 2018 at 07:19
Sorry, I meant no battery condition light. There is the red 'on' light.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 01 Nov 2018 at 07:37
Don't connect a good battery to it, you could end up killing the good battery.

Leave your car charger on it for longer, it might just pick up, but it will take an hour or more to show anything. I'm assuming here the car charger is a 4 Amp or thereabouts, not a big starter/charger pushing out 20 Amps.
Battery conditioners like the Optimate will be useless in this sort of situation.

I have rejuvinated an AGM type bike battery which was flat by connecting my home made big charger to it which was pushing out 16 volts. But you have to check that the battery is not overheating.
But even then the battery was never as good again.


Edited by Brian UK - 01 Nov 2018 at 07:41
Brian.

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Jerry atric View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jerry atric Quote  Post ReplyReply Direct Link To This Post Posted: 01 Nov 2018 at 07:40
Oh. Thanks for that timely warning, I was just going out to do it. No it isn't a very beefy battery charger, I'll do that then
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 01 Nov 2018 at 07:45
You need more volts across the dead battery anyway than a good battery will produce. So a charger is the only possibilty really.

I have seen the "other battery" idea suggested for small lithium batteries which have gone "dead". But that's a different situation as they all contain components which prevent them beng charged in the normal way if they go below a certain voltage.
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote iansoady Quote  Post ReplyReply Direct Link To This Post Posted: 01 Nov 2018 at 10:18
I agree, leave the old-style charger on for 24 hours or so. I've had a couple of apparently dead batteries that have responded to this although they've never really recovered to full capacity. OK with a magneto and kickstart though.....
Ian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jerry atric Quote  Post ReplyReply Direct Link To This Post Posted: 01 Nov 2018 at 11:04
My mistake, Of course its not an optimate, I have an acumate. Its just a gentle charger I think as opposed to a trickle charger . Mags are great until they need fixing. Its a call from the magneto man that has prompted me to find a headlight rim for the Super Alce...He's finally started fixing it after 8 months!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote iansoady Quote  Post ReplyReply Direct Link To This Post Posted: 01 Nov 2018 at 11:57
I always use Tony Cooper who really knows his stuff and is cheaper than most. He also has a nice mini collection of bikes....
Ian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jerry atric Quote  Post ReplyReply Direct Link To This Post Posted: 01 Nov 2018 at 12:16
Paul Lydford in Shaftesbury is the best around my way. The problem is that very few places in UK will do Magneti Marelli mags which Guzzi used. From what I can gather, the opposite things spin to Lucas etc. and they are far better design than the Lucas stuff (not really surprising) and BTH.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote c13pep Quote  Post ReplyReply Direct Link To This Post Posted: 01 Nov 2018 at 14:20
The small scooter/lightweight bike batteries do die very quickly if left unused and in my experience they aren't worth trying to resuscitate as the loss in capacity renders them virtually useless unless they are ridden daily.
I have used the second battery method ie. `flashing` the jumpleads onto the dead battery while its on charge, but the spare battery needs to be a big one, (mine is 110Ah), with some good results but the original battery still loses capacity.
I fear its bite the bullet and buy a new one    

CHRIS
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Jerry atric View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jerry atric Quote  Post ReplyReply Direct Link To This Post Posted: 01 Nov 2018 at 19:04
hooray! I have a result. Had to go out this afternoon but before that I got 12.9 volts on the multimeter How long it will last, I'm not sure. I think next time I may splash out on a Yuasa for it.
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