theconrodkid
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| posted on 11/5/13 at 04:26 PM |
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more nicad woes
a few months ago i broke the charger for my impact gun,today a new one arrived,it,s a big propper jobbie one as well,put a battery on and left it for
about 8 hours,it is still flat,charger is getting warm,any ideas ?
batteries and gun are about 1 year old and only used a couple of times
who cares who wins
pass the pork pies
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HowardB
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| posted on 11/5/13 at 04:42 PM |
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well........ I used to maltreat nicd batteries, and sometimes one would find a similar situation to that you describe,... what I did was to use a
charger with a variable voltage output and keep winding up the volts until current flow occurred and then gradually turn the voltage down to keep the
current "reasonable". This is similar to using a claw hammer to undo screws, it works but isn't very kind to the battery.
Caution is required because charging nicd batteries at very high currents causes explosions!
keep safe
Howard
Fisher Fury was 2000 Zetec - now a 1600 (it Lives again  and goes zoom)
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CNHSS1
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| posted on 11/5/13 at 05:23 PM |
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ofte if nicads are flattened sufficiently and are part of a pack ie number of cells in series to make up the voltage, then you can get one or more
cells reverse polarity which stops the pack charging.
if you can get the case off (they often screw/clip together) then stick a load across the pack terminals sch as 5w bulb, and then check each cell
voltgae with a multimeter.NiCads are nominally 1.2v per cell. If one or more cells are dead or reversed, thn remove the load and 'flash'
12v from a car battery or car batery charger across the cell.i wont charge that cell, so dont put tye load on it agian or same wi happen, but it will
accept a charge. Repeat for all cells until they all show a positive reading on the meter and then stck on charge using the correct charger.
i wouldnt run the pack flat for next few cycles, just use and charge.
with nicad cells, the case is negative and the pip is positive.
nicads are very robust and can be massively abused if you follow a few rules.
they self discharge by approx 10% a week, so its always worth charging the device once a montj whether its used or not.
nimh (nickel metal hydrides) and Li-on (lithium ion) and Li-poly (lithium polymer) are different animals and have differing rules but are becoming
more common in power tools, certainly higher end models
"Racing is life, everything else, before or after, is just waiting"---Steve McQueen
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theconrodkid
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| posted on 11/5/13 at 06:49 PM |
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thanks for the replies,the battery packs are 24 volt,my volt meter says they down to about 19 before the gun just about stops turning,i can get them
up to 22 but no higher and the gun wont work at 22
ill have a go at flashing them if it stops raining morra 
who cares who wins
pass the pork pies
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theconrodkid
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| posted on 12/5/13 at 07:34 PM |
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gave the packs a flash as seen on you tube with my welder (45 volts),they seem to be charging but taking many hours and eventually they will get to
24.3 volts,put them in the gun and it runs for about 10 seconds before they go flat again,are they toast ?
who cares who wins
pass the pork pies
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blakep82
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| posted on 12/5/13 at 08:22 PM |
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Keep doing it, leave them in chargers for days, weeks, even months.
Someone was telling my their ipod wouldnt charge. Held about 5 minutes of charge at the most. He had one of those charger dock speaker things, so it
found its way in there permanantly for a few months, used just in that speaker dock, and bought another to take out. A few months later he took it out
and tried again, held a days charge.
If its holding something, you might be some way there?
Idea if ipod batteries are nicad though, so might not work the same
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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CNHSS1
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| posted on 12/5/13 at 08:31 PM |
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did you flash the pack or individual cells? if the pack as a whole, thats pointless no matter what youtube might say!
do the individual cells as per my previous post and try again.
"Racing is life, everything else, before or after, is just waiting"---Steve McQueen
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