The Low Down on Battery Types ...

[AussieJester]

I thought the quoted post below by Hyena was too good not to be posted again in the battery section-->

You know you want to!

Someone was asking me about the different ebike battery types the other day, so I'll post it here in simple terms


Hyena's guide to ebike battery technology (if they were women)

SLA

This is the fat girl at school. She ate all the pies and if you have to put her on the back of your bike you'll know all about the extra weight. She may break your frame if you're rough with her. That said she'll put out because she doesn't know when someone will show interest in her again. Expect some nasty sagging, and while she might be able to travel 20 miles at walking pace, don't expect her to go that far if you make her run. Expect her heart to give out after a year.

2-3C LiFePO4

This is common plain Jane from accounts. She'll cost you a bit more than SLA the Hutt but you won't break your back lugging her around and she won't drop dead after a year of you exercising her. She does have asthma though so while she'll whip along the flat OK don't expect her sprint off the line or blaze up steep hills.

6-10C LiFePO4

If wheezy Jane from accounts isn't performing well enough for you meet Helga. Part Barvarian, part Viking she can run just as fast as Jane but has bigger muscles to flex. Wanna get off the line quick or up that steep hill ? She'll throw you over her shoulder and carry you up. The trade off is she isn't exactly slight... mmmm, chunky

20-50C Lipo

Meet Kara Kent. She's hot with a fit athletic body but for her small size and weight her power is out of this world. She can easily lift 20x her weight, be super fast and in the RC world she can fly. Be warned, if you get on the wrong side of her she'll melt your skin off with her heat vision. She's a little higher maintenance than Helga, but isnt she worth it ?!

I hope the masses enjoy their lifepo4, I'm happy with lipo between my legs

Too funny Jay..

KiM

 

[StudEbiker]

Funny, but given my choice, the 2-3C LiFePo would be my pick.

 

[AussieJester]

Funny, but given my choice, the 2-3C LiFePo would be my pick.

haha...whats that old saying... "once you go LiPO you'll never go back"

KiM

 

[StudEbiker]

I was just speaking to the models representing the different batteries. I'm sure LiPo is the way to roll.

 

[liveforphysics]

lol.

Nano-techs are Kara Kent twins, both naked, and one carries you on your bike, and the other one turns your controller and/or motor to plasma with laser eyes.

Certainly can have a temper if not respected.
But... the performance always delivers.

Like those girls who are just a little too slutty to be enjoyed without caution, yet they never leave you bored and looking for an after-date-date (ahem, Ping ,Headways etc) to find the experience you were looking for.

 

[neptronix]

lfp: not much info exists on the nano-tech. I was wondering... do they puff/blow up/flame like regular lipo does under the same conditions? Have you not sacrificed a precious pack yet?

 

[neuraxon77]

not much info exists on the nano-tech. I was wondering... do they puff/blow up/flame like regular lipo does under the same conditions?

See this thread for smoldering nano-techs.

 

[liveforphysics]

lfp: not much info exists on the nano-tech. I was wondering... do they puff/blow up/flame like regular lipo does under the same conditions? Have you not sacrificed a precious pack yet?

Yes. You hit roughly 4.8v, they explode into flames pretty much identically to other performance LiPo.
The biggest danger of Nano-Tech's, is the tabs are massively thick and wide, and no NOT pop like a fuse in the event you short a pack. Other LiPo does not explode or get hot when you short it by mistake, because it just vaporizes the tab in a split second, which works like a fuse to stop the shorting. Nano-Tech tabs don't pop, so they actually try to dump a thousand (or whatever) amps, which obviously results in massive heating, damage, etc.

Normal LiPo is pretty safe if you just don't over charge it (and often safe for quite a bit of overcharge in the event you do), as the tabs are like a safety fuse between each cell.

Nano-Tech's traded that layer of safety in favor of gaining the ultimate high-current low-resistance design needed to handle the absurd current levels the cells are able to provide.


If you screw-up and short something with a nano-tech pack, it's going to vaporize whatever the highest resistance part of the circuit happens to be, and in a split second. I've had them blow/vaporize a dean's-ultra connector's prongs clear out of the socket, and the remains of the socket was just a soot covered mess of nylon, and it blistered my thumb and forefinger in a number of places. Of course this was no fault of the pack for me quickly plugging together leads in the wrong configuration

When working with them, view them not as a battery (something with limited current saturation and lots of resistance), and view them more like a magical constant-voltage source that will hold that voltage across whatever resistance you happen to lay across it, so V=IR, so as that resistance approaches zero, they are going to try to make current approach infinity. People don't realize the implications of what 0.8mOhm/cell really means.
0.0008ohms of resistance is effectively pretty similar to not having resistance, which is similar to not having a limit to the current you ask it to deliver.

 

[texaspyro]

Heck, even a 1P A123 pack will vaporize stuff in a short circuit millisecond. I just about fried my Chinese DMM when I put the wrong leads onto a 7S1P pack. The meter was set to 20A... POW! I thought that I had picked up the leads to the meter set on volts... nope! Wound up vaporizing a fat etch in the meter. The fuse just sat there and watched. It's still good

 

[Hyena]

My summary may be a little biased towards lipo, but for good reason

It sounds to me that dealing with nano techs should be treated with much the same caution as live house mains AC.

 

[Solcar]

I'd think about adding a fusible link in line with a nano-tech pack.

 

[texaspyro]

Mommy, battery lady number 3... she hurt me... she hurt be bad

 

[Ypedal]

*wipes coffee from keyboard keys...