Tenergy NiCad SubC's Report

[Ypedal]

Wrong.. get the meter.

 

[safe]

Wrong.. get the meter.

You want to buy one for me? :lol:

If something works then why mess with it? The bike works as predicted, so I'm content. If something unexpected started to happen then maybe I might want to investigate why there was a difference from expectation, but at this point it's been a no-brainer. What was expected "happened", so what's the point of spending more money on it?

 

[Ypedal]

I could not care less what you do on your own time with your money.

However.. i do have a problem when you post on THIS FORUM and get the " Facts " wrong.....

 

[safe]

The moment the facts of the performance of these cells changes I will notify people here. If something does go wrong (as you imagine) then you will learn of it here. So far (the last few hundred miles) things have performed without flaws.

My primary goal is to keep the cells cool and stress them as little as possible.

That's normally good advice, so I'm not sure what you are concerned about. :?

(or maybe you just don't listen?)

The cells are rated as about 8-10 "C" discharge and I use them at about 1-4 "C" discharge.

The cells are rated as 1.0 "C" charge and I use about 0.5 "C" charge.

...so I'm operating within the spec.

 

[Riles]

Safe,

I admire that you are sticking to your guns with these cells. I'm in the same boat- I want to buy meters, sensors, analyzers, etc. But there are so many things in my life that take precedence, even if its just another pair of SLA's. A true enthusiast does not need a sensor to tell him when the battery is full or when it is drained, or how "dead" the cells are in their overall lifespan. There are just so many ways to know, who is to say which is right and wrong.

I don't understand why people get so angry at you for using your money and your stuff the way you want to. I also appreciate that you post your experiences, good or bad. This thread gives a wealth of information regarding the usage of NiCads in e-bikes. Contrary to what a couple of people believe, you are not spewing incorrect facts or opinions- you are providing something so much more useful than battery theory - expereience. I would much rather see a case where somebody has experience with a battery setup instead of seeing the physics of why it should work.

Hats off to you, safe.

 

[Ypedal]

Hello Riles. I'm sorry to have to drum this down once gain, but history repeats itself unfortunately.

Safe and his 5000 + posts on this forum has spent enough time with ebikes and related parts to know better, and some of his posts are coherent and valid, however, out of the blue you get a " Gem" that completely throws this into left field.. ( again, it's a long history ) and when you are new to the forum, guys like me who get frustrated at the whole thing come out looking like the bad guy.

Safe's situation of his SLA sagging more than his Nicad, is because his sla's are worn out, still usable, but not a true reflection of what good healty SLA's do.

I could write a very long post about why this etc but i've done this many times before.. safe does not listen. he does what he pleases. it's weird.

 

[safe]

Safe's situation of his SLA sagging more than his Nicad, is because his sla's are worn out, still usable, but not a true reflection of what good healty SLA's do.

You don't follow my threads THAT closely obviously.

I'm running four new 18Ah SLA's... they have maybe a thousand on them so far. (so in a sense they are "fairly new") My older cells that got me to 3,000 miles are now off the bike. (the old 38Ah's are gone)

I found this chart and it should (hopefully) help to prove my argument about SLA's verses NiCads. The NiCads have a much flatter shape compared to the SLA's. No matter what "stabilized" voltage occurs between my two chemistries we can say that as the battery "hybrid" drains the SLA's will start as the stronger contributor and end as a lessor contributor. This has to be so because of the difference in the discharge curves. What seems to be happening is the SLA's start off strong and contribute well and then as they start to sag the NiCads contribute more and more until they finally exhaust themselves (suddenly) and you are left with really sagging SLA's at the very end.

Hats off to you, safe.

Thanks.

 

[D-Man]

Yeah man, he's got new sla's!!! :lol:

You don't need the fancy meters to measure capacity. A stop watch (located on wrist watch), multimeter to measure amps(you already have that), and light bulbs from anything automotive, spot lights, headlights, whatever. 12v pack nicads discharge down to 10 volts. I'm sure you already know this. Then stop stopwatch. Use calculator and brain to do math.

 

[safe]

You don't need the fancy meters to measure capacity.

And given the way discourse happens around here if I did use the lightbulb test then people will begin a long sequence of doubting the accuracy of my testing methods:

"Did you account for the resistance of the wires?"

"How can you be sure the lightbulb wasn't losing some energy because of the contacts of the screw?"

"You do know that lightbulbs are totally overrated... why my brother tested some and they... blah... blah... blah..."

...so I figure that I'll save myself a bunch of silly banter and just say that the cells are working. If something works you don't bother "fixing" it. 8)

All I wanted was some cheap power... and these SubC's seem to deliver that...

 

[safe]

Update:

The NiCads are fine, but I am starting to see a problem develop with a "runt" SLA cell. This cell was not very good from the beginning (always ran weak) and it was prone to excessive heating while all the others were completely cold. Others had commented that you can open up a sealed lead acid battery and fiddle with it and so I've done that and added some distilled water. At this point I'm doubtful that doing so will have fixed it. (the "runt" cell looks to be deteriorating rapidly)

So while the NiCads seem to be working out great the SLA's (these were cheap $35 ebay specials) are showing signs of troubles. I've gotten over a thousand miles with them, but there is a clearly defective cell in the mix. Which means there is still some potential argument left about the validity of the "hybrid" approach.

 

[johnws6]

How are these working out for you? Are you pulling a lot of current out of the pack and still maintaining good reliability? Do you notice the pack getting hotter charging now than it did before when the nicads were new? Just wondering, i'm not fully committed to putting 280 nicads together yet for a pack and need some re-assurance. Cheers.

 

[safe]

I ran the NiCads all summer... no problems.

My next bike will get 240 NiCad cells and no SLA. That will give me about 30 miles range at full power. Weight will be 35 lbs for 634 Wh.

NiCads are cheap... about $0.40 per Wh... but they are not as light as something like these LiPoly cells but those cost around $0.70 per Wh and they are more at risk for problems. NiCads are the most proven "old school" way to get power while also having long life.

Don't forget you have to build the solderless tubes... that's more work than many will want to do.

For a lot of people it's probably easier to just buy the LiPoly.

I just like the idea of the NiCads being very durable and idiot proof. It's a big enough investment to want to have it last a long time. For pure performance you would be better to do other things. I might alternate between the "distance pack" (NiCads) and a "racing pack" (LiPoly or other) for the speed runs. When logging a lot of regular miles the NiCads seem to hold up well.

Battery decisions are always hard.

 

[D-Man]

My next bike will get 240 NiCad cells and no SLA.

How many battery chargers for this?

 

[johnws6]

I ran the NiCads all summer... no problems.

My next bike will get 240 NiCad cells and no SLA. That will give me about 30 miles range at full power. Weight will be 35 lbs for 634 Wh.

NiCads are cheap... about $0.40 per Wh... but they are not as light as something like these LiPoly cells but those cost around $0.70 per Wh and they are more at risk for problems. NiCads are the most proven "old school" way to get power while also having long life.

Don't forget you have to build the solderless tubes... that's more work than many will want to do.

For a lot of people it's probably easier to just buy the LiPoly.

I just like the idea of the NiCads being very durable and idiot proof. It's a big enough investment to want to have it last a long time. For pure performance you would be better to do other things. I might alternate between the "distance pack" (NiCads) and a "racing pack" (LiPoly or other) for the speed runs. When logging a lot of regular miles the NiCads seem to hold up well.

Battery decisions are always hard.

Safe, i didn't bother with solderless tubes, i just soldered my cells end to end and fitted them into garolite tubes. It made for a pretty nice fit. I'll be putting the packs in some UHMW plastic to hold it all together. I don't know why nicads get knocked down as being so inferior to lipoly? It's as if running nicads at anything above 3C is suddenly taboo.

I've seen 3 ah nicad packs hit peaks over 200 amps and didn't have any immediate effects, and still run 80 amps continuously. The cells i have now being built into packs can do just that. If you search ebay well enough you can find the same sanyo n3000cr cells i have for about $ 400 per kwh.

 

[safe]

How many battery chargers for this?

I have 6 chargers at 24 volts and 1.5 amps. This means I'll have to charge in two stages. (12 sets to charge) So rather than one hour between 30 mile rides I'll need to charge for two. Either that or buy more chargers.

24 volts * 1.5 Amps * 6 chargers = 216 watts of charge power

 

[safe]

The cells i have now being built into packs can do just that. If you search ebay well enough you can find the same sanyo n3000cr cells i have for about $ 400 per kwh.

So where did you buy them and how much did you spend?

How many are you using?

 

[johnws6]

The cells i have now being built into packs can do just that. If you search ebay well enough you can find the same sanyo n3000cr cells i have for about $ 400 per kwh.

So where did you buy them and how much did you spend?

How many are you using?

I bought 300 N3000CR sanyos brand new for $320 shipped. I'm using 200 of them for now, if i can fit another 80 of them i'll use 280 total for a 40S 7P pack. You can run these at 80 amps continuous, so in a 7P pack that's right around 560 amps. More than enough power for a pocket bike.

 

[johnws6]

My avatar pic is all of the batteries BTW

 

[Bobocop]

NiCads are cheap... about $0.40 per Wh... but they are not as light as something like these LiPoly cells but those cost around $0.70 per Wh and they are more at risk for problems. NiCads are the most proven "old school" way to get power while also having long life.

Where are you finding NiCads for $0.40 a piece ?
I have been browsing around the net for a few days now looking for something for my build (cheap, but lighter then sla's) and i can't find any reasonable one for under $3 a piece.
mind you i can't afford to buy 300 of them, i want to buy a few here and there untill i have enough for a pack,
but even packs that iv'e seen go for close to $3 a cell.
So again where are you getting them for $0.40 ) (if you don't mind)

Edit: I can't find the Sanyo that johnws6 is using for less then $8.50 a cell --> http://www.onlybatterypacks.com/showitem.asp?ItemID=11521.22

 

[johnws6]

NiCads are cheap... about $0.40 per Wh... but they are not as light as something like these LiPoly cells but those cost around $0.70 per Wh and they are more at risk for problems. NiCads are the most proven "old school" way to get power while also having long life.

Where are you finding NiCads for $0.40 a piece ?
I have been browsing around the net for a few days now looking for something for my build (cheap, but lighter then sla's) and i can't find any reasonable one for under $3 a piece.
mind you i can't afford to buy 300 of them, i want to buy a few here and there untill i have enough for a pack,
but even packs that iv'e seen go for close to $3 a cell.
So again where are you getting them for $0.40 ) (if you don't mind)

Edit: I can't find the Sanyo that johnws6 is using for less then $8.50 a cell --> http://www.onlybatterypacks.com/showitem.asp?ItemID=11521.22

I forgot to mention, i ended up buying these off of ebay. I'm searching the site now and i can't find the listing for them anymore. I'll check and see if i can find the seller and let you guys know.

Edit: i found the original seller on ebay, i didn't see him listing these anymore so i emailed him to see if he still has any left.

 

[safe]

Where are you finding NiCads for $0.40 a piece ?

http://cgi.ebay.com/96-NiCd-Sub-C-2200mAh-Batteries-for-PowerTools-Flat-Top_W0QQitemZ230299007143QQihZ013QQcategoryZ40975QQtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l1262

96 cells for $124.99

96 cells * 1.2 volts * 2.2 Ah = 253.44 Wh

$124.99 / 253.44 Wh = $0.49 Wh

...it's more like 50 cents per watt hour. :?

As for price per cell that's:

$124.99 / 96 = $1.30 per cell

---------------------

Shipping adds a little, but not that much...

---------------------

https://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7639

5 Ah, 22.2 volt, $76.85

So doing the math:

5 Ah * 22.2 volt = 111Wh

$76.85 / 111Wh = $0.69 Wh

(the best deal in the LiPo area)

However, the NiCads don't need additional circuitry, so you have to add some more to the price of the LiPoly to get to a functional pack...

 

[safe]

I bought 300 N3000CR sanyos brand new for $320 shipped.

Wow! That was one awesome deal!

(about $1 per cell)

 

[johnws6]

It was an awesome deal, and at the time i only had about $350 to my name for the next week ( college student )/ until my next pay check. So i had to choose between eating or these batteries. The choice was pretty easy, i can always eat later.

The ebay seller got back to me this morning and said he had sold off the remaining lot he had. I'm a bargain shopper though, i'll let you guys know if i run across any deals.

Safe, have you done any discharge tests with those tenergy cells? Are they holding voltage well under high discharge?

 

[pwbset]

If you guys are dealing with 100s of SubCs anyway then why on earth wouldn't you just re-purpose the Sony/Konions that marty and DocBass are selling. Your price per watt/hr is going to be cheaper than those NiCads and you'll get lithium that doesn't need balancing and weighs a lot less and is a lot more environmentally friendly to boot. Just something to think about.

 

[johnws6]

If you guys are dealing with 100s of SubCs anyway then why on earth wouldn't you just re-purpose the Sony/Konions that marty and DocBass are selling. Your price per watt/hr is going to be cheaper than those NiCads and you'll get lithium that doesn't need balancing and weighs a lot less and is a lot more environmentally friendly to boot. Just something to think about.

The konions seem like they would be a little too delicate for my application. I don't care to bother with LVC systems. It worries me when i see all these defective packs in large numbers and the selling slogan still being used as reliable with a thousand cycles. Also i've looked at the graphs and it seems like if you actually do take these to 20C rates the cycle life drops pretty substantially along with the capacity. If that affects the actual discharge rate in terms of C, then i would have to plan on having quite a large pack in terms of amp hours of capacity to make sure im covered for at least 100 cycles of abusive conditions.

I could be totally wrong though.