Intermittent Panasonic SDS drill

[anto]

Hi all,

I have a 24v Panasonic SDS drill (EY6813) that came my way as part of a job lot of tools.
Have 2 batteries for it. One won't take a charge the other will but shows up as being fully charged very quickly.

Now, the one that holds charge does work. The drill does work. However, it seems to work for a little then slows down then back on the power again.

Any ideas?
Does it sound like a battery problem?
If I thought the drill was good I'd go for a battery but at 60quid I'd want to be fairly confident that it was not a drill problem.

Thanks on advance,
Anton

 

[The_Yellow_Ardvark]

Sounds like the batteries are dead or on their way out.

 

[hotponyshoes]

How many terminals on the battery connection?
If it's only the 2 I would hook the drill up to some other power source to test it.

 

[anto]

Four connections on the battery post.

Edit.... Only two connections in the actual drill though

 

[anto]

Rigged it up to a 24v battery charger and it was displaying similar characteristics as the battery.
Drill works but will go slow then fast. Letting off the trigger and then back on gets it going again???

Edit the brushes seem to have good life left in them.

 

[Martinb]

Give it a blow out with an airline, could just be dust from overhead drilling I Have a Bosch that does it and a blow out sorts it

 

[anto]

it a blow out with an airline, could just be dust from overhead drilling I Have a Bosch that does it and a blow out sorts it

Nothing to lose I suppose. Will give it a go

 

[anto]

Seems to be related to the switch.
If I keep the switch at about 80/90% it seems to work fine. Pull the trigger fully and it seems to want to die slightly.

 

[Martinb]

Switch will be full of dust and crud

 

[anto]

I did give it a good blow out but the actual switch seems to be a sealed unit?

 

[Martinb]

Try contact cleaner

 

[Turbo]

Sometimes you can prise open the switches enough to give them a blow through with contact cleaner followed by an airline. Not sure what Panasonic parts prices are like but see how much a new switch is before possibly wrecking the old one.

You might be able to rescue the batteries by slow charging them with a rc charger like an Imax B6 followed by a discharge, repeating until the mAh figure from the discharge no longer rises. I have used this method to recover nicad & nimh drill batteries that refused to charge on their own charger. I have been planning to do a guide on the site about this.
Sadly though you will rarely get back their full capacity & they will often quickly self discharge.

Do you have any Makita 18v LXT batteries from another tool? If so, instead of buying Panasonic 24v batteries, get one of these adaptors.

https://www.ebay.co.uk/itm/36310817...dAPrCu7KcsNuY3enW9I2|ampid:PL_CLK|clp:2334524

Then get creative and make a Panasonic to makita adapter, using the top & contacts of one of the panasonic batteries & graft on the ebay adaptor.

I have a few 24v bosch tools but no decent batteries left. I made a bosch to makita adapter & all the tools run perfectly on the 18v makita batteries with more power & a longer run time!

 

[anto]

Thanks @Turbo
I have dewalt 18v batteries but surely they would need to be 24v? No? Will the drill run off 18v correctly?

Ive seen on Youtube about zapping them with a welder? Worth a go or just dangerous?

 

[anto]

Right the "bad" battery is showing 24v on the multimeter, same as the "good" battery.
Why will the "bad" battery therefore not run the drill?

 

[hotponyshoes]

The battery needs to be able to deliver amps as well as volts so just reading OK on a meter might not mean it has enough oomph to do anything.
Try putting a bulb on the battery at the same time as the meter.and see how quick it drops voltage compared to the good one.

 

[Turbo]

Thanks @Turbo
I have dewalt 18v batteries but surely they would need to be 24v? No? Will the drill run off 18v correctly?

Ive seen on Youtube about zapping them with a welder? Worth a go or just dangerous?

Because Li-ion batteries are so energy dense an 18v li-ion will match the performance of the 24v nicad or nimh.
When my 24v nimh batteries were still fresh I was able to drill 5 or 6 16mm holes through a 6" block wall before the battery died. With the 18v Li-ion makita fitted I got to 8 holes & still had 1/2 a battery left, plus the drill had a lot more power! If you look around there's probably someone selling a dewalt universal adapter.

But you can only do this with batteries that have the voltage monitoring software built into the battery, otherwise you can drain the battery too much & brick it! The only ones I'm sure of are Makita & Dewalt, there may be others.

Forget about the zapping, 90% of the time it doesn't work & even if it does its only a temporary fix. I've been messing around with nicads & nimh batteries for a few years & the best result comes from doing a trickle charge & cycling the battery between charge & discharge. If the battery is really dead sometimes you need to give it a quick charge on a 12v car charger to get enough volts so the Imax will recognise it.

 

[Turbo]

Right the "bad" battery is showing 24v on the multimeter, same as the "good" battery.
Why will the "bad" battery therefore not run the drill?

If you open up the battery there will be 20 sub c cells inside. Number them in order, measure their voltage & record it. You'll likely discover that there will be 1 or 2 bad cells with very little voltage. They effectively stop the power flowing from the good cells. I have had some good results from charging just the bad cells using jumper wires to get them to hold a charge before then power cycling the whole battery.

If you can't get the whole battery to hold a charge often you can get away with just replacing the bad cells with good ones salvaged from a donor battery.

 

[anto]

@hotponyshoes
Right @Turbo having done what you suggested I seem to have one cell that isn't holding charge.
All the rest were approx 1.03-1.08v with the final one only being 0.2v so I will assume this is the problem one.

Where to go from here..... a cell from RS is nearly £9 + Postage. Given that a new battery is £60 and I dont have the greatest soldering/electrical skills I am debating if its worth paying it.

Can the bad cell be bypassed and allow the rest of the cells to work correctly, all be it at a lower voltage? Will this affect the drill much?

I have an old dewalt 18v ni-mh battery that is no longer used. The cells are a different size but would one of them work in place of the bad panasonic cell?

 

[anto]

Have ordered one of those dewalt battery adaptors in the event that I cant get the second battery working .

 

[Turbo]

Can the bad cell be bypassed and allow the rest of the cells to work correctly, all be it at a lower voltage?

Nope.

I have an old dewalt 18v ni-mh battery that is no longer used. The cells are a different size but would one of them work in place of the bad panasonic cell?

What do you mean different size? If you mean mAh capacity how different are they? Your existing panasonic cells will have lost some capacity over the years so you could get away with a 2.6 Ah.

I used to solder batteries but its not recommended as the heat can cause damage the battery. I spot weld them now. What you can do is save as much of the battery tab as you can on the bad cell & the donor cell and solder the tabs together. Clean up the tabs well with sandpaper & use a good flux & a hot iron to tin the tabs with solder. Then press the tabs together & heat them with the iron to join the tinned sides together. Put a slip of thick card under the tab to avoid burning the cell insulating cardboard/plastic.