New cells for my drill batteries?

[Penners]

My two B&D 18v 1.7 Ah power drill batteries are now fading fast. The prices of new ones are prohibitive - two new batteries will cost me 2/3rds of the price of an equivalent drill.

It looks as though the battery pack is dismantleable by removing a few Hi-Torq screws, although I haven't tried this yet. Does anyone know whether it's possible to buy new cells and fit them into the battery packs? Would this be a high-tech job, or is it do-able by an ignorant soldering iron jockey?

If it's a straightforward job, any ideas on suppliers of cells?

 

[Flyfisher]

You may well find it cheaper to buy a whole new kit instead of just buying new batteries, especially during the Christmas season of special offers. Madness, I know, but that's what I found when my batteries died. It can be quite handy to have two (new) batteries and two drills though.

But replacing the cells is certainly possible in principle, if you can obtain suitable replacements. Since you have nothing to lose, open up the battery casing and have a look. It's possible that not all of the cells are faulty and this can sometimes be determined by measuring the voltage across each cell. If you do decide to replace/rebuild the battery it's best to obtain replacement cells with spot-welded solder tags so that you don't have to attempt soldering directly to the battery. Unless you have a big iron and can solder very quickly you'll over overheat the cell and probably damage it.

I wouldn't be surprised if someone somewhere on the web has not already posted details of how to rebuild such battery packs. I say that after spending the afternoon successfully repairing a PC LCD screen in which the backlight kept switching itself off after a few seconds, rendering the screen useless.

A quick web search revealed it to be a known problem requiring the replacement of one of four transistors and someone had kindly posted step-by-step repair instructions and photos. I found an online supplier for the transistors and ordered 10 of them at 4:30pm Thursday and, amazingly, they arrived at 10:30 the following morning - even though I had only selected the 'free' delivery option! I decided to replace all 4 transistors this afternoon and the screen is now working perfectly for a total cost of under £10.

A bit of simple DIY can often save things from landfill for surprisingly little cost.

 

[Feltwell]

What did we do before the interweb?

Today I've successfully removed, rebuilt and replaced the ignition switch of my car. In the last week I've replaced the motor on our old Dyson with a secondhand one taken from a broken Dyson on Freecycle, and managed to replace the utterly useless Windows Vista with Windows XP on my father-in-law's old laptop, with many many driver issues to overcome. I would have managed all those things without the internet in the end, but with instructions from someone who's already done it it is so much easier!!

There are plenty of sites about replacing cells Penners. I'd be interested in seeing how you get on, as I've got a perfectly good cordless circular saw which needs new, unobtainable Ni-Cd battery packs.

I stick with Ni-Mh or Li-Ion batteries now on new tools - I've got fed up with Ni-Cad's dying long before the attendant tool does. My vague plan is having splashed out on a very expensive, but utterly brilliant Makita LXT range 18v Li-Ion cordless drill and impact driver twin pack, to then buy any other cordless tools as "bare" Makita ones without charger or batteries. Ebay is a good source.

 

[Penners]

Thanks for those thoughts, chaps. I'll do a bit of poking about in Mr Google's innards and see what I can find in the way of advice.

FF - yes, I have already determined that, if repairing the batteries turns out to be a non-starter (most probably due to a technical or courage shortfall on my part) I shall buy a new drill. It's ridiculous to spend 2/3rds of the price of a new tool on a couple of batteries for an old one.

Feltwell - if I have to buy a new drill, I shall definitely opt for a Ni-Mh or Li-Ion model.

Why do such things always have to crop up at the most expensive time of year?

 

[Feltwell]

Feltwell - if I have to buy a new drill, I shall definitely opt for a Ni-Mh or Li-Ion model.

If you do, I heartily recommend the Makita kit if you can stretch to it. I thought this (which is a slightly lower spec version of what I bought a while ago - it's just missing the admittedly useful light) looked like a good deal, but a quick Ebay check says you can get them for about £120 on there.

http://www.screwfix.com/p/makita-bhp453rfx-18v-3-0ah-li-ion-cordless-combi-drill/50393

Add in a "bare" impact driver for about £80 and it's a good deal cheaper than the equivalent Makita twin pack, if you can live with only 1 battery, bearing in mind they charge in about 20 minutes - just enough for a nice cup of tea and a kit-kat. Impact drivers are brilliant, definitely one of those "Why didn't I get one before?" tools.

 

[Flyfisher]

Why do such things always have to crop up at the most expensive time of year?

Quite - and it's even worse when combined with house and car insurance renewals in January.

 

[Feltwell]

Sounds rather "too good to be true", but feedback contains quite a few "it worked" comments as well as a few "it didn't" and lots of "haven't tried it yet".

http://www.ebay.co.uk/itm/BATTERY-F...Home_Garden_PowerTools_SM&hash=item2c6158d71f

Chances are whatever his technique is, it's on t'interweb somewhere for free.

 

[Penners]

Yes, I found that thanks, Feltwell. So I googled "battery fix" and "battery rejuvenation". I found quite a bit of information about the techniques involved. To me it was rather frighteningly technical - I'm more of a "if it doesn't work, thump it" sort of guy.

 

[Feltwell]

Me too, but you've inspired me to get off my @rse and try to get my dead cordless saw going again.

I think I'll give this one a try - seems pretty simple, I've got 2 decent batteries from another tool to use and 3 dead ones for the saw so hopefully at least one of them is salvageable.

http://www.youtube.com/watch?v=1e8hHLyXAyQ

 

[MdB]

If people are looking for electrical bits (like transistors / batteries etc) then PM me and I can likely point you in a sensible direction to get them. That is if you can identify what you want. Many parts only have codes printed on them and going from that to part number can sometimes be fun...

 

[middi]

Mr P, spread the word, call in all those good deeds you have done over the decades to those loved ones of yours.

" NUDGE, NUDGE ..... WINK, WINK" ( a new makita l-ion battery drill driver would be a nice thing for a xmas present )

How could they refuse ( unless you have done no good deeds you can call upon :wink: )

Middi

 

[JohnB]

If you can't fix the battery, here's another possible option. In this book, the author shows how to replace batteries in tools, radios etc with a wood block with contacts connected to an external power supply. Or you could remove the cells from a dead battery and attach a cable to the contacts. Not as good as being cordless, but a way to keep the tool going.

 

[Flyfisher]

To me it was rather frighteningly technical - I'm more of a "if it doesn't work, thump it" sort of guy.

Funny you should say that but one of the methods of rejuvenating rechargeable batteries is precisely that - a sharp bang on the table!

One of the failure mechanisms for rechargeable batteries is for crystal 'dendrites' to form causing internal short-circuits. A sharp whack can sometimes break such crystals (or a brief burst of high current charging may fuse them) and restore the function of the battery for a while.

 

[Feltwell]

Clearly the advanced school of electrical engineering has some worth then

"It isn't working"

"Hit it wiv an'ammer"

"It still isn't working"

"Hit it wiv a bigger 'ammer"

 

[Keithj]

I've replaced a fair few over the years.

If the battery pack is dead anyway, open it up and have a look. If you replace cells, replace them all. You may have three dead ones and a load more in terminal decline or the last knockings of old age. You won't have three dead ones and the rest all in the prime of life.

The individual cells are obtainable at (fairly) sensible prices from Ebay and other sources.

There is a catch (or two):

1. Lithium-type cells have a finite life - from date of manufacture, not based on number of charges, although abusing them can reduce the life. If you find one supplier with cells far cheaper than all the rest, check the "manufactured date". If it's over 6 months or thereabouts, pass on.

2. You may find that there's a strange unidentified component in the battery pack, maybe in series with the cells. Replace it in the same place, unless you can identify what it is. Most times it's an over-temperature fuse (so don't heat it up with the soldering iron). Sometimes, it's a polarity protection diode - so put it back the same way round.

The other advice above - such as "don't solder direct to the cells" is right.

 

[Moo]

I'm about to consign my collection of cordless drills with defunct batteries to the local tip, and disinter my trusty old drill that never runs out of juice.
It has a thickish wire that comes out of the handle, with a three-pin plug on the end. Should we be too far from a socket, we use something called an 'extension cable'.

 

[Penners]

You fuddy-duddy. Where's the challenge and the sense of victory against overwhelming odds in that?

OK, maybe your drill works, but....

 

[Feltwell]

Me too, but you've inspired me to get off my @rse and try to get my dead cordless saw going again.

I think I'll give this one a try - seems pretty simple, I've got 2 decent batteries from another tool to use and 3 dead ones for the saw so hopefully at least one of them is salvageable.

http://www.youtube.com/watch?v=1e8hHLyXAyQ

Well, it took some time to get off my @rse as it turns out, but last week I did try the Youtube trick above of "shocking" my old dead 18v Ni-Cad batteries, using the 2 Li-ion batteries from my Makita kit connected in series as a power source.

It does work - all 3 dead batteries responded and definitely showed a distinct improvement, but are still far from their new performance. They are OK now once immediately charged, but lose their charge quite quickly. With the 3 batteries and 2 chargers I have, it made the saw just about useable but I got fed up swopping batteries quite quickly so when my job news arrived I treated myself to a new "bare" (i.e. no battery or charger) Makita cordless saw, to match my exisiting drill and impact driver.

This turned up today - very well made, quality tools are such a pleasure to use! This is definitely what I'd recommend to others now - splash out a decent branded drill with 2 batteries and a charger, and then gradually acquire other tools as "bare" items which makes them much more affordable. I've also noticed that the Makita LXT 18v Li-ion range is now popular enough that pattern batteries are available from 3rd party manufacturers, which makes it a lot cheaper - and with this range being so popular you should be able to get replacement batteries for many years to come. It's so frustrating to have perfectly good cordless tools with dead batteries and no way to buy new ones!

The "shocking" treatment for dead Ni-Cads is worth a try though.