Opinions on Nicads and NIMH.......

[recumpence]

Hey Guys,

So, with all the hullabaloo going on regarding Lithium batteries on planes and trucks (shipping), who knows of a good source of Nicad and NIMH cells? I am familiar with them both from my RC days and am fine with using them, especially for customer bikes, if Lithium gets too difficult to deal with because of the beaurocrats.

I found one source for sub-C NIMH cells for $6.95 each. It would take 80 of them for a 48 volt, 10AH pack. That is under $600 with shipping. Not too bad.

:EDIT: I just found these came Elite-5000 cells for $5.50 each.

Oh, that would be a 12 pound pack with wiring.

So, what are a few good sources for Nicad and MIMH cells you guys have found?

Matt

 

[Ypedal]

in F cell format nicad 8ah, www.ebikes.ca

Personally i will never go back, lithium is the only way to go for me.

Self discharge, limited C rate, Heat.. no thanks.

That being said, they work. I've had both nimh and Nicad, the nimh self-discharged faster and were a bit more sensitive, the nicads are proven tough and reliable with 4 years of service life and still going strong in the hands of some local customers ..

 

[recumpence]

I know what you mean. In fact, I only like Lipo (hazardous, though they are) for the energy storage and power issues as well as no self discharge problems.

NIMH can discharge a boat load of current, you just pay for it with voltage drop and heat build-up. Also, they need to be fully discharged after use to keep them ballanced and they like to be pumped FULL before use. They are strange for sure. Their life expectancy is lower than lithium too.

Anyway, I am now reconfiguring a bunch of customer packs to 240wh to avoid shipping problems......... :?

Matt

 

[fechter]

Used Toyota Prius batteries. Best Nimh out there. Check eBay and Craigslist for ones pulled from wrecked cars.

 

[cycle9]

I know what you mean. In fact, I only like Lipo (hazardous, though they are) for the energy storage and power issues as well as no self discharge problems.

NIMH can discharge a boat load of current, you just pay for it with voltage drop and heat build-up. Also, they need to be fully discharged after use to keep them ballanced and they like to be pumped FULL before use. They are strange for sure. Their life expectancy is lower than lithium too.

Anyway, I am now reconfiguring a bunch of customer packs to 240wh to avoid shipping problems......... :?

Matt

Hi Matt,
If you are reconfiguring NiMH or NiCd packs for shiping, those shouldn't be a problem. But if you are reconfiguring Lithium packs, I understand why...

Regarding the subject of this thread, we also distribute the same NiCd packs that ebikes.ca has, and they have held up well for most of our customers. However, they are sensitive to reversal, if you let the voltage go too low. So the key to long life on these packs is to have a good low voltage cutoff, and make sure to never push the pack beyond it. For customers of ours that did that, we've replaced multiple cells that died.

Morgan

 

[OneWayTraffic]

in F cell format nicad 8ah, http://www.ebikes.ca

Personally i will never go back, lithium is the only way to go for me.

Self discharge, limited C rate, Heat.. no thanks.

That being said, they work. I've had both nimh and Nicad, the nimh self-discharged faster and were a bit more sensitive, the nicads are proven tough and reliable with 4 years of service life and still going strong in the hands of some local customers ..

Self discharge isn't an issue for many though. Charge at night, ride the next day is a pretty common way to go, especially for commuting. Also for commuting, you'd want an hours range. That's good for a 1c-3c rate. Many commuters are made with economics in mind as well. That's where a 4+ year service life sounds really attractive.

 

[liveforphysics]

batteryspace.com sells some "M" sized 20ah and 26ah NiMH cells. $19/cell for the higher power 20ah cells. You could put them in a string of 36 to max input voltage on a 12s RC controller. That would be $720 in cells, and the pack could only do 60amps, and it would be bulky and heavy, but a possible solution.

I think sticking with LiPo and just making sure you ship half the pack in one box, and half in another is the best option though.

 

[recumpence]

batteryspace.com sells some "M" sized 20ah and 26ah NiMH cells. $19/cell for the higher power 20ah cells. You could put them in a string of 36 to max input voltage on a 12s RC controller. That would be $720 in cells, and the pack could only do 60amps, and it would be bulky and heavy, but a possible solution.

I think sticking with LiPo and just making sure you ship half the pack in one box, and half in another is the best option though.

Yup, for the performance minded user especially!

Matt

 

[dogman dan]

Just gonna have to make the ol ping last till this stink blows over.