Hi All,
I am considering re-calling a 12V Drill battery.
I?ve had a quick look, and hit a snag. I can?t figure out how to get two of the cells out of the ?turret?.
I have put a couple of pictures up on Flickr
Also, the battery is rated at 1.2AH (10 cells).
I assume I should buy 1200mAH cells to maintain the 1.2AH capacity?
TIA
Chris
Cells are sometimes very tight, the usual solution is violence. In this case, you don't need sealing at the top of the turret, I'd suggest drilling a couple of holes that would line up with the axis of each cell and using these to press them out. The cells will presumably be bridged by a conductor strip, so they will need to be pressed out together.
It may also be that they're glued in. A little heat (hairdryer?) may loosen the glue.
If there are 10 cells, that suggests NiMH - or is it old enough to be NiCd? In principle there's no reason why you couldn't go for more capacious cells, although your charger may not charge them correctly (a completely dumb charger is likely to be fine, a 'smart' charger that isn't very smart may terminate the charge too early)
Theo
They are Nicads. And I think the charger is dumb.
I wonder if I could use NiMH instead?
I think I?ve substituted those in Dect phones without any issues.
I had a similar drill battery and pushing hard on the terminals alternatively did remove the cells. The exposed metal parts are spot welded to the cells. The third terminal if there is a temperature sensor. You have nothing to fear as the battery is no longer serviceable.
Good luck and Happy New Year.
There are two sorts of nickel chargers. One supplies such a low current that it never switches off. Fast chargers all work on the delta peak principle which is that, at a constant charge current, the cell voltage drops slightly as full charge is reached.
Neither charger cares about how much capacity the cells are - big ones will take longer to charge, that's all.
However there is one gotcha. The delta peak is far larger on NiCd which means that a delta peak charger designed for NiCd may *not* stop charging on the smaller delta of NiMh cells.
In short a NiMh charger will always work with NiCd *and* NiMh, but an NiCd fast charger *may* not work with NiMh.
If the charger works, its a better bet, just dont flatten them - NiCds will take it but NiMh will not...
Happy New Year John,
I was just about to report that I had worked this out.
Cells are out.
I shall get ordering some NiCad replacements.
I didn't think you could still get them
ebay has plenty
In general, consumers aren't intended to be able to buy them, there was an exemption for power tool use which ended in 2016, they're still permitted for emergency lighting, alarm systems and medical equipment.
RS and others still sell them, I doubt they give you the spanish inquisition ..
No doubt they'll soon get round to tippexing out "Member States" ...
I certainly got some from CPC last year - for emergency lights. Otherwise it would have meant 6 new fittings.
You can, although NiMH have higher internal resistance so don't have as much 'grunt' in power tools. It's worth getting 'low self discharge' cells otherwise they self-discharge over a month or two - if you put the tool away they'll be flat next time you use it.
If you go for lithium ion it'll give the tool a new lease of life but it's more work - you can probably get 3x 18650s to fit inside the pack, although you'll need a BMS board (search ebay for '3S BMS' for whatever current rating) and a new 'dumb' 12.6v CC/CV charger, eg:
Theo
Thanks all, NiCads bought and successfully fitted and charged.
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