GM Battery

[Anko]

Hi,

I'm lost in what type of battery the 3612s is, it says
li-iron ? and I see Li-ion and all kind of names, but
what type is the LFP-3612s and how many kg will this
battery be ?

hope you can help out.

[Bikemad]

I'm lost in what type of battery the 3612s is, it says
li-iron ? and I see Li-ion and all kind of names, but
what type is the LFP-3612s and how many kg will this
battery be ?

Anko,

The "iron" must be a typing error as it's actually a lithium manganese battery, made up of 30*3.8V 4AH 26650 size cells.

As the 40 cell LFP3616s weighs 5.5Kg, I'm guessing the 30 cell LFP-3612s will weigh around 4.5kg.

Perhaps Yao will confirm this. (Or correct me if I've got it wrong.)

Alan
 

[e-lmer]

Actually the Fe in LiFePO4 is Iron.
The whole name is "Lithium Ferro Permanganate"

My guess is that he saw Lithium ION.  LiFePO4 is
a Lithium Ion battery.  Golden Motor Lithium Ion
battery packs are LiFePO4.

Other Lithium Ion batteries include Lithum Polimer,
Lithium Cobalt Oxide, or even Lithium Titanium disulfide.

I am guessing, but I think the 3612S means (36)Volt and (12)Amp Hour.

[Bikemad]

Golden Motor Lithium Ion battery packs are LiFePO4.

These Golden Motor Lithium Ion battery packs are not LiFePO4:                                          



It uses these LiMn cells:  

Lithium ion rechargeable battery, 26650 size, LiPF6 electrolyte, Manganese Spinel structure cathode.
High energy density lithium ion battery cell.
Cell capacity: 3.8V 4AH
Cell diameter: 26.24 ± 0.16 mm (top end), 26.16 ± 0.10 mm (bottom end)
Cell height: 65.05 + 0.10/-0.15 mm
Cell weight: 92g

Cell specifications
1a Rated charge(4A) Limiting 4.0 A, 120 min and constant 4.2V charge at 23±2°C.
1b Recommended charge Reference 1a
 
2 Rated discharge Constant 0.8 A discharge until 2.5V at 23±2°C.
 
3 Rated capacity 4.0Ah Minimum of rated discharge capacity after recommended
charge.
 
4 Nominal voltage 3.8V Mean voltage during rated discharge after rated charge.
 
5 Shipping voltage 4.03±0.01V Nominal. Approximate state of charge = 80%.
 
6 Internal resistance at shipping 23±1 m? By AC 1 kHz.
 
7 End of charge voltage 4.20 ± 0.05V
 
8 End of discharge voltage 2.5V Discharge voltage used for determination of rated
capacity.
 
9 Charging time 120min Rated charge.
 
10 Maximum continuous charging current 6.5A
Maximum continuous discharging current 10A
Maximum pulse discharging current 40A
 
11 Operating temperature
Charging 0 ~ 45°C
Discharging -20 ~ 60°C
12 Storage temperature
-20 ~ 60°C
Recommended temperature for long term storage is
23±2°C
 
13 Shelf life 6 months Typical value at 23±2°C, from ship state.
 
14 Self-discharge rate /month ?0.5%

GM state the number of Charging Cycles for these packs is >800 times, whereas the LiFePO4 packs are >1000 times.

Alan
P.S. LiFePO4 = Lithium Iron Phosphate.

[GoldenMotor]

Yes they are Lithium Manganese

[neptune]

well,I'm glad you people didn't make it confusing!Also I was under the impression that li-ion (li-mn)as used in tool packs and refered to as konion,were 3.6 v.maybe some one who does know the specs should post with the manufacturer's test results.Oh yeah,and erase these "expert" statements.My batts are made from makita 18v,5s2p  tool pks limn konion ( sony).There are hundreds of differ
ent lithium battery  chemistries,if not thousands.K.I.S.S.

[GM Brazil]

I thought they were of LiFePO4, since the code is LFP! GM says, in the comparative table at the end of the web page on batteries, the life cycle of batteries Mn is unacceptable!

The Mn batteries are dangerous about explosions and etc?

I thought I had bought a LiFePO4 ....

[Bikemad]

The Mn batteries are dangerous about explosions and etc?

The Lithium Manganese batteries that GM use are not dangerous like Lithium Polymer:

The Lithium Manganese battery chemistry is different to that used in standard Lithium ion and Lithium polymer batteries, which usually come with a Cobalt cathode and are prone to thermal runaway - ie explosion and fire.
Manganese, unlike Cobalt, is a safe and more environmentally benign cathode material.
If you're buying a Lithium powered electric bike from someone else, ask the retailer about battery safety and life expectancy - if they cannot guarantee that they use Lithium Manganese and don't understand the importance of a reliable, well-engineered battery management system, our advice is simple: don't buy!

Lithium ion rechargeable battery, 26650 size, LiPF6 electrolyte, Manganese Spinel structure cathode.

Hopefully that's put your mind at ease.

Alan
 

[GM Brazil]

Thanks BikeMad!

I thought I had bought a LiFePO4.... I found the place that created all the confusion, on the DIY page there is "lithium iron" under one of the photos, I think they mean to write "ion" 

Mine is almost here, the shipment company called me to ask some information about the address. So the pie with the LiMn battery should be here soon!

[Leslie]

The GM batteries are still priced fairly IMO.  

Here is some good reading from ther site below.

http://www.candlepowerforums.com/vb/showthread.php?t=211891

LiMn li-ion cells are a new breed of safe chemistry cell, available commercially as loose cells only in 16340 (RCR123) size from AW, but coming soon in 18650 size, with 18650 and 26670 sizes already available to li-ion powered tool manufactures. (they can be torn down to get at the cells, which many of us have done) This cell chemistry is similar to LiCo in that it shares the same charging requirements and has the same nominal voltage rating of 3.7V. The similarities end there. I would consider these cells to be a notch safer than the LiCo cells based purely on chemistry, as they can not generate their own oxygen during an out-gassing and therefor are incapable of accelerating their own burn in an oxygen deprived environment. (regular lithium CR123s and LiCo chemistry both share this trait of fueling their own fire when something does go wrong, with the potential to become a full blown metal fire). LiMn chemistry cells are good for responsible adult users who know to shut the light off before the battery is over-discharged, as over-discharge will reduce the cycle life of these cells. While this cell chemistry is safer, I would not consider it to be an ideal option for use in a flashlight that is given to a child to play with for fear that the cells may be ruined if the flashlight is left "on" and unattended to completely deplete the cells. Energy density on LiMn cells is about 30% less than LiCo cells, however, in the smaller RCR123 size, since they do not have a PCB consuming a large piece of real-estate (as compared with the overall size of the cell) these cells actually come surprisingly closer to the capacity of the protected RCR123 LiCo cells than do the larger LiMn cells when compared against equivalent size LiCo cells.

LiFeP04 li-ion cells are also a relatively new breed of safe chemistry cell. Commercially they are popping up in many sizes, with RCR123s being the most popular. These are a very safe cell, but suffer from the problem of not being nearly as tolerant to over-discharge as a NIMH cell would be. Since these are "safe chemistry" cells, they, Like LiMn cells, are not sold with PCB circuits to prevent over-discharge. They really do require the user to actively participate in the prevention of over-discharge to prolong the cycle life of the cells, just like the LiMn cells. I would be perfectly comfortable handing a child a light with these cells in it as far as safety is concerned, but the issue of whether or not the cells would survive the attempts to keep the light on long after the battery has gone dead is another issue all-together. As for energy density, combine these cells lower nominal voltage rating (3.2V) with roughly HALF the AH storage as compared with LiCo cells, and these have only about 1/3rd (give or take) the energy density as compared with CR123 primaries or LiCo cells.

It seems that the LiMn cells have slightly higher energy density than LiFePo4 and do not evolve o2 from the oxide chemistry of the Cobalt and others, they do not feed their own destruction.

Good luck with the new pack.  

[Leslie]

The loss of capacity over usage is inevitable.

800 cycles is worst case scenario and an honest advertisment.  With my SLA 300 cycles is worst case scenario, but I still manage to get 600~700 cycles from them before I consider them useless. Because I only discharge them to 50% they last twice as long.

If I rode once a day these SLA's could last me 2 years.

You may only discharge your batteries to only 50% too, just because of the weight of lead my bike uses a lot of power on take offs.  So the GM battery could well hold up to 1600 cycles.

If you rode once a day, the GM battery could well last you nearly 4+ years.  Now thats good in terms of pricing especially when you put the cool accessories into the mix like the aluminium housing and BMS..

[Bikemad]

If you rode once a day, the GM battery could well last you nearly 4+ years.  Now thats good in terms of pricing especially when you put the cool accessories into the mix like the aluminium housing and BMS..

.. and not forgetting the charger, key switch/lock, charging socket,  plug in power cable and the added convenience of a built in carrying handle.

All it needs now is a built in light sensitive LED rear light and reflector unit.

Alan
 

[GM Brazil]

Thanks you all!!

It is a fact that the LiFePO4 have less energy density then the LiMn, looks for the e-bikekit LiFePO4's, they use the same convenient aluminium casing, but as they are LFP's the maximum you can find is the 36v 10Ah, and the package inside is tight!

Do you recommend installing a fuse in the power line? In my case is a LFP4812s working with an MP, a 30 A fuse would be ideal?

Thanks again!

[GM Canada]

The Mn batteries are dangerous about explosions and etc?

The Lithium Manganese batteries that GM use are not dangerous like Lithium Polymer:

The Lithium Manganese battery chemistry is different to that used in standard Lithium ion and Lithium polymer batteries, which usually come with a Cobalt cathode and are prone to thermal runaway - ie explosion and fire.
Manganese, unlike Cobalt, is a safe and more environmentally benign cathode material.
If you're buying a Lithium powered electric bike from someone else, ask the retailer about battery safety and life expectancy - if they cannot guarantee that they use Lithium Manganese and don't understand the importance of a reliable, well-engineered battery management system, our advice is simple: don't buy!

Lithium ion rechargeable battery, 26650 size, LiPF6 electrolyte, Manganese Spinel structure cathode.

Hopefully that's put your mind at ease.

Alan
 

Can I quote you on that, Seems like the best easy to understand description I have heard so far. Check the link..

http://www.goldenmotor.ca/index.php?pr=Lithium_Maganese&nosessionkill=1
 
Gary

[Wheels]

Can anyone confirm the max continuous C ratings for the GM batteries.  the website says max cont C of 20 amps for the 48v 12 ah, but the posting above indicates the pack is built with a max cont C of 2.5  (built with 4 ah cells and a max cont of 10amps).  And I can't quite figure the weight of these.  There are reports of anywhere from 5.23 kg to 5.5 kg, but is that for the 36v 10ah or the larger watthours packs like the 48V 12ah or 36V 16 ah?.
Maybe someone has some realworld experience out there that can shed some light?
Thanks
Trevor