LiMnCo vs LiFePo4

[SF1901]

Hi all,

I have a Crystalyte 4840 Pheonix Cruiser and I'm in the process in buying these Lithium ion batteries LiMnCo, quantity of 2- 37v 20Ah including BMS and a 3A charger and a 72v40A Pheonix controller.

How is the chemistry compared to LiFePo4? are there any difference. Here's a website that my maker will get it from.

http://www.quallion.com/sub-mmil-vehicles.asp

http://www.quallion.com/sub-t-batteries.asp

 

[TylerDurden]

They seem to claim a proprietary chemistry. Looking at the pdf file of their f cell, it looks like old LiCo. It does not resemble LiMnO2 or LiFePO4.

If they are actually getting mil contracts, it is no suprise our troops are getting hammered. That is not very advanced technology... years old, in fact.

:?

 

[Microbatman]

They look questionable to me also.

Would rather go with something know and TESTED.

Stick with LifePO4. Much more forgiving and much safer.

If you know all about LVC (low voltage Cuttoff) and have a good charger then consider 5-10mah RC 4.2 volt per cell type lipo LiMnO2 batteries. If you choose these, be prepared to set up a safe charging environment for lipos as they are prone to catch fire if not charged correctly. And understand that you can kill them after 1 wrong discharge. (lipo death begins at <3.0 volt per cell)

 

[Ypedal]

LiMn is closer to Lithium Cobalt in weight and size per capacity than LiFe... BUT. Safer.

Lithium Manganese/etc, have a cell voltage of 4.2v to 3.0v range, so 10 cells make a 36v pack. Most LiMn cells i've seen are limited to max 5C discharge ( the better one's ) and prefer 1C in general ( except E-Moli cells in Milwaukee tools, higher Crate )

I use 72v 20ah of LiMn on my Norco Chaos *( pic in avatar )

LiFe is 3.2v instead of 4.2v per cell, so you need 12 cells for a 36v pack. 20 % heavier and bulkier than Limn/co per capacity.

All that said..

Go LiFePo4.. the cycle life is supposed to be much better ( proven with A123's, the rest is still pending, but looks good )

I'm told LiMn tends to die after 2 to 3 years regardless of use, like Cobalt cells.. this, also needs to be proven and i'll know by next year ! :wink:

 

[TylerDurden]

What stands out for me is the nominal voltage 3.7V = LiCo.

Also, they spend a lot of effort on pack ventilation, BMS technology, etc... all pointing at unstable chemistry.

I wouldn't buy them, but it sounds like a deal has already been done.

:?

 

[Doctorbass]

the konion (US18650V) are LiMn.

See my post about 2kWh pack: http://endless-sphere.com/forums/viewtopic.php?f=14&t=2764

the 18650V format of those have nominal 1600mAh and weight 44g and can hold 10C (16A)

their cycle life is:

-300cycles at 80% capacity at 1.5A ....ishhh...
-500cycle at 60% capacity at 4.5A

6Wh at 44g = 136Wh/kg.. not bad...

the spec are here:[url]http://trgovina.mibomodeli.si/artikli_slike/BMZ1600.pdf[/url]

 

[SF1901]

Thanks all for your input, and I have decided to go with the LiMnCo. I see that the LifePo's are better suited for ebikes, but I couldn't pass on something that's almost practically for free and all I need to do for this project is ride . They have decided to test the ebike world and so I became the test subject. I'm sure we have an idea what the battery life and performance is like, but what the heck, why not. I'll give you more info and pics later down the line on how this project goes. If you don't hear from me, please contact my family and friends in my Myspace page. :lol:

Doc, Ypedal and others, thanks for your input as well, I will continue to read this forum and ride on.