[EVDL] 60ah NiMH
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good find but doing the math on the weight it's 28Wh/kg. there are lead
acids outthere at over 50Wh/kg and I believe the typical LA is around
35Wh/kg
they would have to be very cheap and or live very long to be of interest
I'm afraid. heavier than lead acid is bad
Dan
acids outthere at over 50Wh/kg and I believe the typical LA is around
35Wh/kg
they would have to be very cheap and or live very long to be of interest
I'm afraid. heavier than lead acid is bad
Dan
That's not heavier than lead acid!
Well, it depends on discharge properties. But, a "60 AH" lead acid will
produce significantly less than 60AH at high discharge due to
Peukert's. And then there's a matter of how far you're willing to
discharge your lead acid due to lifespan considerations.
Traditionally NiMH has not had problems with being deeply discharged and
do not suffer voltage sag at partial charge states which would reduce
the available power as well as limiting the usable capacity. Actually
these spec sheets say "0.2C" as their standard discharge, for all we
know it may not even be capable of high power discharges.
Anyhow, the 20 hr capacity lead-acid figure is irrelevant for EV use,
rather we need to compare the capacity in EV duty. A 60AH lead acid
might only have 30 usable AH whereas a 60AH NiMH might have pretty much
all 60AH usable. So if the lead-acid is 35Wh/kg, that's only 17.5Wh/kg
of USABLE power density, making the NiMH considerably more dense.
Danny
Well, it depends on discharge properties. But, a "60 AH" lead acid will
produce significantly less than 60AH at high discharge due to
Peukert's. And then there's a matter of how far you're willing to
discharge your lead acid due to lifespan considerations.
Traditionally NiMH has not had problems with being deeply discharged and
do not suffer voltage sag at partial charge states which would reduce
the available power as well as limiting the usable capacity. Actually
these spec sheets say "0.2C" as their standard discharge, for all we
know it may not even be capable of high power discharges.
Anyhow, the 20 hr capacity lead-acid figure is irrelevant for EV use,
rather we need to compare the capacity in EV duty. A 60AH lead acid
might only have 30 usable AH whereas a 60AH NiMH might have pretty much
all 60AH usable. So if the lead-acid is 35Wh/kg, that's only 17.5Wh/kg
of USABLE power density, making the NiMH considerably more dense.
Danny
Dan Frederiksen wrote:
>good find but doing the math on the weight it's 28Wh/kg. there are lead
>acids outthere at over 50Wh/kg and I believe the typical LA is around
>35Wh/kg
>they would have to be very cheap and or live very long to be of interest
>I'm afraid. heavier than lead acid is bad
>
>Dan
>
>Timothy Balcer wrote:
>
>
>>http://www.globalsources.com/gsol/I/NiMH-battery/p/sm/1003019930.htm
>>
>>Anyone heard of these guys?
>>
>>--T
>>
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