• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Cordless tool battery question

Status
Not open for further replies.

mdenegre

New Member
Hello all, I am new here and have a question that I cannot find an answer to. Hoping someone here can help.

I have a few cordless power tools, mostly Dewalt 18v NiCd. I have one tool in particular, a drill, that I swear kills batteries. I am not sure if this is possible or a coincidence. I attempted to use the drill twice recently with two separate batteries that I thought were fully charged and functional. Both times the tool only worked for a few minutes then stopped. The battery would not recharge after that. Both batteries were older.

I have brand new batteries that work fine in other tools but have been reluctant to try them in the drill for fear that there is something wrong with the drill and it is somehow ruining the batteries.

Is it more likely the tool or a coincidence that both batteries died at the same time.

Is there a way to determine if the tool is ok?

Thanks for your help

Mark
 

Externet

Well-Known Member
Hi.
Many battery chargers will not start if a pack is hot or overdischarged; there is sensors that tell so.
If the drill is draining the battery, it will be the behavior you see.
Try powering the drill with alligator cables from a 12-18V source and check if there is current when should not, or if it gets warm somewhere when off.
Charging the battery from a separate power source for a short time to bring them to an acceptable level can make them to trigger the stock charger to work with that over discharged pack and restore its health.
 

alec_t

Well-Known Member
Most Helpful Member
If the older batteries are indeed NiCd, not NiMH, they exhibit 'memory effect' which may severely limit their ability to store charge.
A drill is current-hungry, so may well run for a shorter time than other tools on a similar battery.
 

Tony Stewart

Well-Known Member
Most Helpful Member
Battery packs are also sensitive thin dielectric between conductor foil and will get damaged if dropped or wear out fast if over heated, under charged for long periods.
Also long drilling sessions at high speed increase cell temps.

Batteries which charge up quickly have low capacity and high ESR Ω and will not work.
Older technology NI-CAD batteries are now going obsolete due to Cadnium disposal.They also used thermal,sensors for regulating end of charge and if they stay on and keep warm, will also accelerate wear out.

Try Hitachi with LiPo cells and smart charger when they come on sale.
 
Last edited:

mdenegre

New Member
So chances are slim that the drill is ruining the batteries, just that weaker, older batteries are not going to power the drill?
 

Tony Stewart

Well-Known Member
Most Helpful Member
Torque and battery current are proportional. DRill designs have improved a lot as well as battery technology.
So it's hard to say how it was used and how well matched the battery is to the motor and load.

But I would give up on NI-CAD in favour of LiPo, which may only support 250 full cycle recharges but more than 750 half power recharges, without memory. so lifetime Ah*cycles improves with lower depth of discharge unlike NiCad which has an absorption memory effect.

These numbers are relative to the battery quality and may be much better (or worse ) for some.
 

Dr_Doggy

Well-Known Member
this one time ,
my drill had excess load torque on it , and from what i though was a charged battery just stopped and wouldnt even try to work (it didnt slow down to a stop, it just stopped working), I put it back on the charger and it recharged at a fraction of the usual time, and it proceeded to start working again... without any problems since

electronically if i had to explain it, i would say there was surge protection on it that got triggered, then reset by charger , but this is just a guess as i am not aware of what kind of circuitry these devices have
 

Tony Stewart

Well-Known Member
Most Helpful Member
I think the mechanism is similar to a wrapped foil polyurethane capacitor.

Contaminants are quality controlled to very small values <1pp but if a microscopic sliver shunts outs the leads, it just microfuses out safely. The heat and forces from high current may have created this condition.

Protected cells or packs will have fuses.
Smarter devices will have a low voltage cut-out.
 

canadaelk

Active Member
I have to second TonyS on LIPo batteries. I have started to convert my battery driven hand tools from NiCad to LIPo.
An all but new Ridgid hand drill had 5 of the 12 D-sized NiCads bad. I am not pleased! E
 

3v0

Coop Build Coordinator
Forum Supporter
Is it more likely the tool or a coincidence that both batteries died at the same time.
To a degree Nicd batteries are getting a bad rap. This is worth reading: Note the part about not recharging Nicd's that are only partially drained and how to recondition them.
http://www.greenbatteries.com/nimh-battery-faq/#NiCd memory

It he battery packs are the same age and seen the same use/charge cycles there is a good chance they will go bad at the same time. Especially if you have not used them in a while. Heat seems to be the #1 battery killer. Fast chargers and chargers that continue to charge past full are hard on batteries. Batteries left in my 'smart' Dewalt 18V charger remain hot after charging, If it really stopped charging the batteries would cool down. So I try to pull them after the charger indicates they are full. The charger for my snap-on cordless impact does too. Using a timer with these chargers can be good. It can't cook the cells without power.

People into conspiracies might claim the crappy chargers kill the batteries, and the batteries are priced high to force us to replace the entire tool. It may not be too far from the truth.
 

tcmtech

Banned
Most Helpful Member
With my cordless tools, I have reached the point where I just rebuild the batteries with either individual cells or kits from these places rather than waste money and frustration on new batteries that I know will die just after their warranty is up. :mad:

http://gcbattery.com/

Or

http://www.all-battery.com/

Being as most anyone who uses cordless tools over the last number of years knows the overall quality and capacity Vs price of most every cordless tool battery made now outrightly sucks regardless of brand or model.
Then to add insult to injury many are now putting 4/5th sub C cells with spacer plates in their packs so that they look like they have full-size sub C cells when in fact the have smaller crappy 800- 1200 mAh that are being grossly overworked when trying to supply the 25 - 35+ amps many of the newer high powered tool motors can take at full load. So far I have found them in B&D, Ridgid, and Dewalt (come on! Harbor Freight doesn't even pull that crap with their cordless stuff.) :mad:

Last year I rebuilt 4 of my Craftsman 19.2 batteries that were originally 1400 - 1800 mAh with Tenergy 3000 mAh kits from Gulf Coast Battery for less than what new batteries cost. ;)
I've also done a few rebuilds of older tool batteries with the individual Tenergy 3000 and 3800 mAh cells from All Battery that have taken some severe abuse without problems too plus a number of rebuilds of families cordless tool batteries as well now of which all of them have shown drastic improvements in power and run time over the stock battery units on their best day.:cool:
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
I really only have one Makita cordless drill with two packs and a nice charger. Batteries stay decent and are NiCd.

One usually stays on the charger since it's a smart charger. since they are NiCd based, they self-discharge quickly.

"They" don't make it easy to take the pack apart. I have a LED calculator with an internal pack. I don't use the OEM packs for cordless phones and I get 5-7 years on the battery. I've changed some to NiMH.

NiCd's develop whiskers which can be blown out if you have access to the cells. Poorly designed chargers give bad lifetimes.
 

spec

Well-Known Member
Most Helpful Member
Is there a way to determine if the tool is ok?

Mark
Hi mdenegre,

Yes, there is a way to check if your drill is OK or faulty.

The way is to measure the current that the drill consumes when in use. If you then tell us what current you get we can tell if your drill is ok or not. We would also need to know the power rating of your drill and any other data on the drill's label. In fact it would be a help if you could give us the drill make and model number and all the information that you have about the drill, including the information on the lable.

Measuring the drill current will involve connecting an ammeter between the battery and the drill with external wires. It would also be wise to include a 40A, or so, automobile fuse

I have not looked into the practical side of this, but no doubt other ETO members can advise.

A good drill will take relatively little current off load (not drilling) but as the load increases the current will increase proportionally.

Note that the batteries on power tools have a hard time because the manufacturer's try to extract the maximum power out of the batteries at the expense of battery life.

As well as over-voltage, as has been stated, a charger may refuse to charge a battery if the battery voltage is below a certain voltage. If that is your problem we can advise how to recover from it.

spec
 
Last edited:

mdenegre

New Member
Thanks for all the input.

Spec, I will look into trying to measure the current.

I have a box of old batteries lying around I would love to try to recover. I have read about jiggling the battery in the charger or turning the charger on and off quickly and tried those with no success.

My drill is a dewalt dw988 drill driver hammer drill 18v DC, the only information on the label is performance data 0-450/min/0-1450/min/2-2000/min(RPM) 0-34,000 BPM
 

spec

Well-Known Member
Most Helpful Member
Thanks for all the input.

Spec, I will look into trying to measure the current.

I have a box of old batteries lying around I would love to try to recover. I have read about jiggling the battery in the charger or turning the charger on and off quickly and tried those with no success.

My drill is a dewalt dw988 drill driver hammer drill 18v DC, the only information on the label is performance data 0-450/min/0-1450/min/2-2000/min(RPM) 0-34,000 BPM
Thanks; that is useful information.

The way I see it, is to test your drill and then to have a way of testing your batteries.

As you no doubt know, in broad terms, there are three battery chemistries used in power tool battery packs:

(1) Nickel/Camium (NiCad)
(2) Nickel Metal Hydride (NiMH)
(3) Lithium Ion (LiIon)

LiIon cells have many advantages and are taking over most battery applications, apart from traditional applications where lead acid batteries are still predominant, automobiles for example.

In terms of charging, NiCad anf NiMH are similar, but LiIon is quite different and requires a different charger. Having said that, LiIon batteries are much simpler to charge, but LiIon batteries require relatively accurate charging and discharging voltages or they will be damaged.

With a little experience and the right equipment you should be able to make your own battery packs as has already been described by tcmtech. But one thing you cannot do with success is to mix different cell chemistries in on battery pack.

You can make a very good 3A/H (3000mA/H) 18V LiIon pack from seven new 18650 liIon cells at a total cost of around £28UK but the cells would have to be a specific type from a reliable source and not any of the many rip-off cells on the market.

Many power tool users have been interested in powering their tools from the mains. This is relatively straight forward and very-cost effective compared to buying battery packs.

spec
 
Last edited:

spec

Well-Known Member
Most Helpful Member
The DeWalt DW988 hammer drill is a solid machine. It has 400 Watts of chuck(net) power, so assuming it uses 500W of input power, the current consumption would be 500W/18V= 27A. Thus it will be heavy on battery packs.

spec
 
Last edited:

tcmtech

Banned
Most Helpful Member
My drill is a dewalt dw988 drill driver hammer drill 18v DC
It most likely uses this battery rebuild kit. 2200mAh. $47 http://gcbattery.com/dewalt-18v-dc9096-2-2ah-nicd-replacement-internals/

Or if you want to go a bit nuts, 3800 mAh $82.50 http://gcbattery.com/dewalt-xrp-battery-18v-upgraded-beast-mode-internals-tenergy-3-8ah-nimh/

Or totally over the top, 5000 mAh sub-C cells $110.70 , http://www.all-battery.com/sc5000mahhighcapacitynimhrechargeablebattery.aspx
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top