Laptop Ni-MH cells?

[Natedog]

I have a couple laptop batteries here...Toshiba 7.2 volt 4000 mah Ni-MH...(thought they were Li-Ion, but they're not) who's used these, what charger, good, bad, or?

EDIT: Haven't torn this open yet, but they look like they are about AA size cells, but a bit longer.

[clod booster]

im not sure anyone has used laptop cells but they seem like a good idea, once you get them in a pack youd need a charger that can handle 4000mah. contact christhebatteryman, hey would probably have some info.

[Natedog]

I think my chargers will already handle this...have to double check. Got the pack apart and it is made up of 6 Toshiba Nimh cells, size 4/3A. They are 2 5/8" long X almost 11/16" diameter. The pack has a thermal probe for charging in the laptop so it doesn't overcharge/overheat.

[newracer]

What charger do you have? Before you build them up for your rig I'd try discharging them to see if they will handle the load.

[Natedog]

This is the charger that I use most of the time, works great and good price, just no li-po capability:

Piranha Digital Peak Charger
LCD Screen
Angled for easy viewing, the Digital Peak Charger's custom LCD screen shows battery voltage, peak detection mV, charge time, current, capacity and more.
Exceptional peak charging value — with SIX programmable features!

* Two-line, 16-character LCD shows battery voltage, peak detection mV, charge time, current and capacity — as well as errors for improper input voltage, poor battery connections, and reverse output polarity.

* Memory stores pre-set charge parameters for up to 10 batteries.

* Automatic charge mode takes effect and charges batteries safely if specific settings are not selected.

* Compact size (5" x 3.4" x 5.5") and AC/DC input options allow convenient use at home or the track.

* Solid-state reverse polarity and short circuit protection included on input and output.

5-year warranty

Tailor operation to your specific battery types with these programmable features:
Feature Programmable Range
Battery Type NiCd, NiMH - 1-8 cells
Charge Current 0.1-5.0A
Battery Capacity 50-5000mAh
Peak Sensitivity 3-20mV
Trickle Current 0, 100, 200mA
Sounds 5

Stock Number: DTXP4005
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Works great and great price.

[newracer]

It will charge them fine. Weather or not they will handle the amp draw of your setup is another question.

[JohnRobHolmes]

They will charge as any other nimh. As newracer said, will they handle your motor? I really doubt it. They were built for capacity and not discharge rate since it is in a laptop. You might squeeze 5 amps out of them, I would be very suprised to find more than a 10 amp discharge. What motor are you gonna run?

[Chris_The_Battery_Man]

I would HIGHLY doubt that those cells are anything close to high-drain. Applications like that call for low-drain cells. This would probably result in very short runtimes, battery life, and bad overall performance.

[Natedog]

Currently I'm using a Tamiya sport tuned (black can) motor, my Integy 45T lathe motor just showed up today.

What's the best way to test their discharge? Don't really want to solder up a real nice pack if they're going to suck.

[Chris_The_Battery_Man]

Well there isn't any real easy way to test cells like that. Your best bet is to attach leads and see if they hold up. And another fyi.... theres no way 4000mah will fit into a AA cell. Click here for dimensions of many cells. That will help you better judge their size. http://www.cheapbatterypacks.com/mai...gid=loosecells

[Natedog]

Originally Posted by Natedog

...Toshiba Nimh cells, size 4/3A. They are 2 5/8" long X almost 11/16" diameter...

Chris, here's the approximate actual dimensions measured with a ruler...bigger than an AA.

[JohnRobHolmes]

I would test the cells with a motor and prop, with a wattmeter hooked in between. Throttle up and it will show very quickly how much discharge they will take. Super easy.

[Mini RC Talk]

using Lipo cells can be very dangerous if not used properly... I would some research before ever considering this!

[racerx]

The cells he's talking are nimh!

[Mini RC Talk]

sorry about that... I skimmed... checked my laptop.. then proceded to put my foot in my mouth!

But if anyone is interested here are some links for LIPO Info:
http://www.pfmdistribution.com/files...Guidelines.pdf
http://www.dynamoelectrics.com/LiPo%20Essay.aspx
http://mysite.verizon.net/kevinkel/index.html

I guess I just got excited about knowing something :-(
Maybe I can pull my foot out of my mouth over the next few days...

[Natedog]

Thanks Johnrobbholmes, have to look into a watt meter and appropriate motor and prop.

Minirctalk, laptop batteries can be Li-Ion, Ni-MH, or Li-Po...depending on the laptop. Li-pos are ok if you handle them properly, but the require alot more caution than Ni-Cd and Nimh.

[electrohacker]

Originally Posted by Mini RC Talk

using Lipo cells can be very dangerous if not used properly... I would some research before ever considering this!

most laptops have LI-ion anyway... which is diffrent and more stable than Lipoly... also Li-ion needs a special charger... but yes Li-ion can explode in a firey death ball just like Li-poly (example: dell laptops)

[newracer]

Or buy a discharger or a charger that discharges.