NiCad tool battery overheating

With some help from this and other groups, I built a cool little push stick for inline skating.

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N04/ (sign removed)

I am planning to make many improvements, including upgrading the batteries from NiCad to lithium ion.

The DeWalt XRP NiCad batteries get hot during use, should I be concerned about them rupturing or otherwise self-destructing?

I can go for lithium-ion batteries, or do other improvements if the NiCads will last for a while. Upgrading the batteries is a no-brainer improvement that can be done at any time, so I would rather put my limited resources into other experimental improvements, like building another push stick with a lighter structure.

Would lithium-ion batteries improve performance in my high current application somehow? Would they be safer?

Thanks.

Reply to
John Doe
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532210N04/ (sign removed)

yes. it can burn, burst, explode

maybe not, see exact specs

Would they be safer?

no. Lithium batteries can burn, burst, explode.

lead acid batteries can burst, explode.

limit the current maximum for safety, according to SPECIFICATIONS.

Reply to
Globemaker

High rate discharge Nicads. Li-ions cant compare. Next up is Li-Poly. I would post the question on an RC group. They commonly run batteries at their max discharge rate, or above for short periods.

Cheers

Reply to
Martin Riddle

For the record, about DeWalt lithium-ion battery protection. Thanks to the replies.

DC9180 Battery Shut Down

The DC9180 have electronics in them that are designed to shut the battery down if it gets too warm. Once this occurs, the battery will not work in any tool until it is put back into the DC9310 charger, this will then reset the electronics in the battery.

The battery is designed this way to protect the cells in the battery pack and results in a battery that will last far longer than a NICAD battery pack.

Reply to
John Doe

Have you come up with electric brakes yet?

Were you planning on marketing this as a product?

Wouldn't the legal liabilities for such a product be absurd even aside from batteries blowing up?

Reply to
Greegor

532210N04/ (sign removed)

Warm is OK, Hot is not so good. Let the batteries cool a bit before recharging.

George H.

Reply to
George Herold

Inline skates come with a brake. My Motail does not interfere with normal skating, except for having to carry 6 extra pounds.

So far, I am very busy having fun using it.

Street skating is risky, best done by someone who is unusually aware of his surroundings. I get the impression that the Roller Cycle guy ran into liability problems.

When used without propping it against my rear thigh, it is reminiscent of climbing stairs with both legs and hands as a child.

I will make sure the batteries do not blow up, that is why I asked.

Reply to
John Doe

You can improve the peak current capacity of NiCd by running them completely dead after use and delaying charging until immediately before use.

Do NOT use standard Lithium-ion cells unless you want to die in flames. You'll need LiFePO4 or special high-current LiPo. I've used

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for hobby projects. Buy the correct charger too (to again avoid the dying in flames thing).

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Reply to
Kevin McMurtrie

As a general rule of thumb, NiCd batteries can safely reach 40C without damage. During discharge, it is extremely unlikely such batteries will fail in a spectacular fashion. If fast charging and overchariging, however, they can explode.

NiMH batteries perform much like NiCd, but they provide more charge per weight.

Li-Ion batteries provide much more charge per weight, but are much less safe than Ni-based batteries.

There are also batteries known as Lithium-Polymer (LiPo), although they are actually Li-Ion-Polymer. These batteries have become very popular among RC modellers, since they provide even better charge per weight performance than Li-Ion. Also, they can deliver very large discharge currents. Some models can be safely discharged in five minutes or less, and still be only warm to the touch. You can get batteries than can be charged in 15-20 minutes, which is a great advantage for some applications. LiPo batteries have a great risk of fire. If a charged battery gets pierced (they have no metal casing) by a conductive object, they will catch fire. If you put water on the fire, you will make it burn faster. Search Youtube for "LiPo fire" to see what it's about.

There's also the LiFePo battery. This battery provides somewhat less charge density than LiPo, but is much safer. The selection of LiFePo batteries is much smaller than for LiPo, and they are more expensive.

All Lithium batteries will need a specialized charger. Do not try to charge a Li battery with a charger that is not designed for that specific type of battery.

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Reply to
Robert Roland

Panasonic has an 18 volt 3.5 amp hour nickel metal hydride battery.

Thanks.

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Reply to
John Doe

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