Battery Update and Question...

[Mandy]

How many times are you supposed to be able to recharge NiMH?

The battery that Altair talked about a few weeks ago showed up on New Scientist Monday, and claims 20000 recharges for L-ion.

http://www.newscientist.com/article.ns?id=dn7081

Thank you.

 

[Vaughn Simon]

How many times are you supposed to be able to recharge NiMH?

I don't know how amy cycles you are "supposed" to get, but I see about
two years of lifetime from an NIMH battery in daily use. This probably
translates to something between 300 and 800 cycles depending on many
factors.

The battery that Altair talked about a few weeks ago showed up on New

Scientist Monday, and claims 20000 recharges for L-ion.

Sounds great, but I will be willing to believe it when I see it.


Vaughn

 

[Gymn Bob]

Some claim 500 and some 1000 cycles. I do not think the cycles are related
to it. Leave a bank on charge for a month or two and see how it performs for
you. It's almost done and needs to be cycled to be brought back to less
than it's former self.

When you leave a NiMh or NiCad on charge or charged it builds nickle bridges
between the poles and eventually shorts itself out or drains itself off. I
have been told the US military spec for storage of niCads is to drain
completely and short of the cell for storage. This is supposed to keep the
nickle bridge from developing. Many cells bought come with a short circuit
on them and they appear to be fresh after years of storage.

A circuit given in a magazine back in the 70s suggested a h8uge mo-fo
capacitor charged to about 50VDC and placed (carefully) across the shorted
or leaking NiCad cell. This charge destroys the nickle bridge developed
across the poles. It works but doesn't last long.

How many times are you supposed to be able to recharge NiMH?

The battery that Altair talked about a few weeks ago showed up on New

Scientist Monday, and claims 20000 recharges for L-ion.

 

[Derek Broughton]

I don't know how amy cycles you are "supposed" to get, but I see
about
two years of lifetime from an NIMH battery in daily use. This probably
translates to something between 300 and 800 cycles depending on many
factors.
Scientist Monday, and claims 20000 recharges for L-ion.

Sounds great, but I will be willing to believe it when I see it.

Me too, since current L-ion batteries tend to have about the same lifetime -
2-3 years (the Lion battery in my laptop totally collapsed right at
3years).

 

[Scott Willing]

Some claim 500 and some 1000 cycles. I do not think the cycles are related
to it. Leave a bank on charge for a month or two and see how it performs for
you. It's almost done and needs to be cycled to be brought back to less
than it's former self.

When you leave a NiMh or NiCad on charge or charged it builds nickle bridges
between the poles and eventually shorts itself out or drains itself off. I
have been told the US military spec for storage of niCads is to drain
completely and short of the cell for storage. This is supposed to keep the
nickle bridge from developing. Many cells bought come with a short circuit
on them and they appear to be fresh after years of storage.

A circuit given in a magazine back in the 70s suggested a h8uge mo-fo
capacitor charged to about 50VDC and placed (carefully) across the shorted
or leaking NiCad cell. This charge destroys the nickle bridge developed
across the poles. It works but doesn't last long.

The tech support shop at my college had a NiCd rejuvenator that worked
on this principle.

Note, however, that the battery compartment was fitted with a blast
shield. Kids, if you're gonna try this at home...

-=s

 

[Scott Willing]

How many times are you supposed to be able to recharge NiMH?

The battery that Altair talked about a few weeks ago showed up on New Scientist Monday, and claims 20000 recharges for L-ion.

http://www.newscientist.com/article.ns?id=dn7081

Thank you.

Hey Mandy,

You might also try your question over at sci.chem.electrochem.battery,
and/or do an archival search on the group.

Serious batt chem freaks over there.

-=s

 

[Richard P.]

Hi Mandy,

I use six "AA" NiMH batteries in my handheld radio. I discharge them by 60% to 80% before I put
them on recharge. I recharge them about 4 or 5 times a week and got 2 years of use out of them. I
feel I got my money's worth.