36 v NiCD pack

prState

Pedelecer
Jun 14, 2007
244
0
Las Vegas, Nevada
I guess I know why you wouldn't want one, but I wondered if Flecc has ever considered putting together a nicd pack? I see they have cells as large as F available.

The info I've read makes them seem ideal for heavy load max power (no cut outs).
 

flecc

Member
Oct 25, 2006
52,760
30,348
Yes they are are ideal for high loadings, since the only discharge limit is temperature. They could offload their entire charge in seconds if they could be kept cool while doing it.

What stops me making one is that the standard case is for D cells only, and NiCads at best are half modern NiMh capacities. With NiCad D cells at the same price, it would be a full price battery with less than half the range.

Less than half with half capacity? The lack of resistance to current drain means that every opportunity to drain into the motor is automatically taken, so range could be 40% or less of normal.
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Ian

Esteemed Pedelecer
Apr 1, 2007
1,333
0
Leicester LE4, UK.
The problem with Nicads is that that they contain highly toxic cadmium. There is now a European directive prohibiting the the importing of products containing hazardous materials including cadmium into member states, the only exceptions being when it can be shown no other material will do the job. There are obviously some stocks remaining in the EU but once they are exhausted NiCad batteries will become very expensive and rare.
 

kraeuterbutter

Esteemed Pedelecer
Feb 21, 2007
296
0
if you want the features Nicd give you
(fast charging, high dischargecurrents,
long lifetime, no firerisk like on (many) Lipos,
very resistante against deep-discharge,)

without some of the dissadvantages
(memory effect,
high selfdischarging compared to Lipos,
heavy for given capacity,
toxic cadmium)

there is already an alternative:
Fepo4

they combine the advantages of Nicd
without heaving there disadvantages

you get for about halve the weight the same capacity of Nicd
you can run them for 1000cycles at 10C load !
they are said to live for 10years which only Nicd are able to do so far
(NiMh rated for ~6years, Lipo/LiIon rated for ~2-4years)
you can charge them very fast (up to 10C charing !!.. filled to 95% in 5-6min with the right charging device)
and when lying around full charged you the selfdischarge is very low, so your bike can always be ready

and they are no miracle cells only spoken about in www and not seen in real world, not in use..
you can realy buy them..
i already use them for 1 year now with great success.

until now there is the original cell from A123 systems
(they will also equip the new GM VOLT with Fepo4-Cells from a123 systems)
with all the good features..

there are also some chines made cells with Fepo4-technologie..
but many are far of there claimed features... some are only rated for 2C !

at least: the technologie is here andn buyable for endusers now since about 1 year
and there are already some competitors coming...

this sounds promissing, because different cells-sizes become availabe..
iam waiting for the first tests done by a college
Advanced Battery Factory

if they inherit the features of the original A123 Fepo4 (cyclelife, easy handling, robustness,...) this cells should be suitable for electric bikes..
i think the 7500mah and the 12.000mah-cells should be worth to have a closer look

the cells are not that powerfull than the original A123 Fepo4
but 160A continouse from the 12Ah-cells should be still enough for an electric-bike ?!? ;)

1700-1800g weight for 33Volt 7500mAh-cells sound not that bad
of course: with Lipos you can get a better weight/Energy-rating, but with all the disadvantages of Lipos/LiIons
 

aaannndddyyy

Esteemed Pedelecer
Jun 7, 2007
304
9
62
Norwich Norfolk
Heinzmann still do a 36Volt 5Amp NiCad battery for there kits, I drought one second hand which was at least 4 years old, I have been using it every day for the last 5 months the batteries are still in perfect condition, still able to give there full recommended distance. I take my Heinzmann bike off road regularly going though fields, thick mud, long grass, and deep water it pulls like a train has never stalled or cut out and will charge from empty to full in less than 2 hours. I have 4 electric bikes in the house this one has become my all weather all terrain vehicle from taking the dog for a run two picking up the weekly shop.
 

flecc

Member
Oct 25, 2006
52,760
30,348
Yes, the Heinzmann battery is good, and there's never any current limiting with those NiCads, as Andy says, pulling like a train. They also have a good cell reconditioning service to bring them back up to spec and extend the life.

I think things will improve when the cells kraeuterbutter speaks of are readily available in tagged standard consumer sizes, though I suspect that the e-bike manufacturers will be using them by then anyway.

Personally I can't wait to see the back of lithium ion manganese batteries, and I'm sure NiMh will outlive them in the market place and run alongside FePO4 types for a while, until consumers are convinced of the latest type's performance and life.
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