LiFePO4 and LiMn Pack Photos

Batteries, Chargers, and Battery Management Systems.
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oatnet   10 MW

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LiFePO4 and LiMn Pack Photos

Post by oatnet » Aug 29 2007 10:47am

I have two pairs of packs from Vendors that I have seen discussed on this board, and I thought maybe you'd like to see inside.

The larger pair of packs is LiFePO4 72v15ah (2x36v packs) from Ocean Cheer International, as advertised by Aicsu on this board. The smaller pair of packs is LiMn 72v10a (2x36v packs) from Andy at FalconEV.

Whups, just realized that pictures are displayed in reverse order - it might make more sense if you start from the bottom!

-JD

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Post by Ypedal » Aug 29 2007 11:28am

Awwwwwsome !!!

You testing those on your TF bike !?

How's the voltage drop under load with the LiFe pack ?
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Post by DeeL2003 » Aug 29 2007 12:02pm

Have you considered the Santa Ana River bike trail? i think it's a 30+mile trail from Huntington Beach to Corona. Very nice maintained trail. Of course I started on the Corona side(it's near where i live) and made it to about Anaheim. I was limited by battery runtime( I have an 8ah nexcell pack) and running with non-ebike friends, but did 23 miles round trip on 3.5ah. Lots of pedaling & rationing of AH's. :lol: I was planning to go this weekend but it's going to be 100+ degrees. :shock:

Here's the link:
http://www.nearfield.com/~dan/sports/bike/river/sa/

With those new packs I'm sure you can do the whole round trip no problemo with some pedaling.
Last edited by DeeL2003 on Aug 29 2007 5:22pm, edited 1 time in total.

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Post by maytag » Aug 29 2007 12:30pm

couple of questions,

how much?

what are their max and continuous Amp discharge rating?

how long was the wait for the packs to come in?

- Thanks

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Post by savuporo » Aug 29 2007 1:51pm

Cheer Ocean has some specs here:
http://www.cheer-ocean.com/battery2.html

Looks like cells are 2C discharge, so you are going to get anywhere from 133-190W/Kg power density depending on pack size ( better with higher voltage packs ). Biggest, 20Kg pack has a 3,8KW max output spec.

Energy density is just below 100 wH/Kg

Whats missing is $/KwH metric.

And of course, these are paper specs.

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oatnet   10 MW

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Post by oatnet » Aug 29 2007 3:37pm

More pics. The white plastic pack/charger is Ocean Cheer, blue pack/black charger is FalconEV. Note that the nice, sturdy metal case on the 10ah FalconEV adds to its weight.

-JD
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oatnet   10 MW

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Post by oatnet » Aug 29 2007 3:55pm

Here is the Ocean Cheer price list; FalconEV's prices are posted at http://www.falconev.com/
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Here are the prices/sizes I was quoted by Ocean Cheer.
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These are my metric conversion calculations
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Post by AliasMrJones » Aug 29 2007 4:02pm

Will Ocean do 48v packs? Ideally, I'd like a 48v 10-15ah li battery and extrapolating what that might cost from the chart below it sounds like I might have found winning pre-made pack.

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Post by oatnet » Aug 29 2007 5:22pm

Awwwwwsome !!!
You testing those on your TF bike !?
How's the voltage drop under load with the LiFe pack ?
That is one of the Ocean Cheer packs, I had just modded one to fix a BMS issue, and since the TF is 36v it was convenient...

I have not been able to test the FalconEV packs because one of the packs was smashed in shipping (thanks DHL) despite Andy's robust packaging. Andy is doing a great job of working the issue and keeping me in the loop, issues like these are where a quality vendor like FalconEV shines. At any rate, the only bike I have that is interesting at 36v is the TF. I carefully sized these 3c LiMn packs at 10ah at the TF's peak draw of 30amps; unfortunately I did not notice that the TF spikes at 47amps when you first peg the throttle, which trips the BMS and shuts down current for about .5 seconds. My error, but I won't really be able to use these packs until I get both so I can run them at 72v on an x5.

Voltage drop on the Ocean Cheer at 30amps was from 41.1 to 34.5, and it stayed there for most of the ride. The TF's NiMH battery drops to 33.1 on the same draw, so this is a little better.
what are their max and continuous Amp discharge rating?
how long was the wait for the packs to come in?
The Ocean Cheer pack is rated at 2c continious, don't know the max but it handled the TF spikes I mentioned earlier without issue, although I had bypassed the BMS at this point. Owen from OC told me that this is a battery, and not BMS, limitation. I got these packs in about 3 weeks, but I paid $250 to have them sent 2-day air - worth it IMO to not hassle with customs clearing, not to mention having it fast. Nobody else I am dealing with was able to supply product this fast, although obviously there are tradeoffs to doing so.

The FalconEv pack is rated at 3c continious, and it took about 6 weeks from payment to product at my door.

I believe that in the near future increased demand is going to increase lead time, so the longer you wait the longer it will take to ship. OTOH, LiFePO4 BMS's seem to be a bit immature, so early adopters may have some issues to work through.
And of course, these are paper specs.
on that note - I have noticed that most vendors seem to be quoting packs based on cell weight, not pack weight. This helps level the playing field, as the cases can vary wildly, and actually the heavier the case the sturdier. Just don't be suprised when the pack weighs more than you expected!
Will Ocean do 48v packs? Ideally, I'd like a 48v 10-15ah li battery and extrapolating what that might cost from the chart below it sounds like I might have found winning pre-made pack.
Note that the prices do not include shipping/customs from China. Andy's prices DO include international shipping/customs, although you need to pay LOCAL shipping (quite reasonable cost too).

All LiFe vendors can do pretty much any voltage pack, using a BMC makes it more scalable than NiMh. Some might do 2x24v (make SURE that they can be used in serial for 48v!) which is easier for panniers, others might do 1x48v pack, which is convenient in smaller AH.

Keep in mind that LiFePO4 is a budding technology and I am still sorting out BMC issues with most of the packs I have received - including the Ocean Cheer. Given extensive industry experience with BMC's I am suprised it is an issue, but per my perspective it is an issue consistant across the industry. If you go into it with a work-in-progress perspective you will be happy.

The Ocean Cheer pack lacks the factory finish that most of us are used to, and the sizable power supply has a certain flintstones panache, but it is a nice price point. Dealing with China is a crapshoot, but Owen is articulate, actually shipped product, in a good timeframe, has maintained good communications throughout the process, and is still providing post-sales support. I have not identified the cells yet but he asserts they are LiFePO4. I have not verified capacity yet, only taking a gentle 12.5 ah from their packs, but I believe that they will provide the rated AH.

-JD

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CGameProgrammer   10 kW

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Post by CGameProgrammer » Aug 29 2007 5:49pm

$520 for a 36V 20Ah LiFePO4 pack? That's $0.72 per Wh, ridiculously cheap. Suspiciously so to my very cynical mind. The cheapest lithium-cobalt is typically around $1.25 per Wh.

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Toorbough ULL-Zeveigh   100 MW

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Post by Toorbough ULL-Zeveigh » Aug 29 2007 6:33pm

500 bucks for 36V/20Ah would be on par with the best price on nimh, which would be quite the price breakthrough if true.

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Post by numberonekiwi » Aug 29 2007 7:56pm

I am comparing the two packs the falcon ev one looks like a nice piece of kit but I am not sure if I like all those wires coming from the ocean packs on the charger I can only assume that these are the balancing / charger wires so that in theory you would not need a BMS in the battery pack?
Motor Crystalyte 408
Controller Crystalyte 40A 72V
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avg Speed 50ish Km/H
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Post by BiGH » Aug 29 2007 8:33pm

very nice - i especially like the photo of the hangglider sign. Is it possible to get that in a high res version? i'd love to have that as my background on windows!
Bike / Motor: Electric specalized rock hopper with Crystalyte 504 / 26"
Batt: Yesa 72v (36v*2) (getting 6.7ah) LiFEPO4 in a Topeak bag. OR 1x eMTB 48v 20ah pack (straps to frame) -depending on range requirements.
Controller: Unmodified 48a digital with 4110 Fets
Current Prob: Bike is in parts getting painted / drying / testing replacement BMS
Trail of Dead Parts:Avanti Frame, 408 motor *melted*, 35a controller - i broke by trying to mod it 2nd controller - blew it up.
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Post by Ypedal » Aug 30 2007 6:55am

Quote "Voltage drop on the Ocean Cheer at 30amps was from 41.1 to 34.5 "

:shock:

Fresh off the charger at 41v, drops to 34.5v at 30 amps ? is that correct ? or am i not reading that correctly ?

Dropped slowly to a low of 34.5v after 12ah of use maybe ?
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oatnet   10 MW

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Post by oatnet » Aug 30 2007 11:14am

Ypedal wrote:Quote "Voltage drop on the Ocean Cheer at 30amps was from 41.1 to 34.5 "
:shock:
Fresh off the charger at 41v, drops to 34.5v at 30 amps ? is that correct ? or am i not reading that correctly ?
Dropped slowly to a low of 34.5v after 12ah of use maybe ?
During a 30amp TidalForce load, the OC pack drops to 34.5v. The stock NiMh TF battery, freshly charged, drops to 33.1v; 1.4v lower. I have no idea what the controller resistance is, I am sure that plays a part.

Throughout the 12.5ah (on a partial charge) v stayed at 34.5 for a looooong time, then gradually 34.4, 34.3, 34.2, and suddenly it was 33.1 and I stopped since I was bypassing the BMS at the time.

Wish I had them build these with 1 more cell in each pack, maybe in future packs.

-JD

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Post by xyster » Aug 30 2007 11:19am

During a 30amp TidalForce load, the OC pack drops to 34.5v.
That's a very significant voltage drop, especially for LiFePO4, and about double the drop of my lithium cobalt pack. But I suppose not unexpected for a pack rated at 2C. Also means pack resistance is high, which means more heat is generated, which means battery life won't be as long as it would be otherwise.
Ebike: 5304/20", 72V 35A controller, 33AH 80V 20s15p (18650 sized cells) DIY lithium-ion pack
http://endless-sphere.com/forums/viewto ... 47&start=0
Scooter: '06 Stealth s1000, 48V 30A, 4x10ah SLA
http://endless-sphere.com/forums/viewtopic.php?t=148
Ebike: '06 Currie Mongoose, 32V 35A, 32V 22AH hybrid SLA/Li-ion pack
http://endless-sphere.com/forums/viewtopic.php?t=1010

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Post by Ypedal » Aug 30 2007 11:58am

36v LiFe packs are supposed to be 12 cell :!:
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oatnet   10 MW

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Post by oatnet » Aug 30 2007 12:17pm

numberonekiwi wrote:I am comparing the two packs the falcon ev one looks like a nice piece of kit but I am not sure if I like all those wires coming from the ocean packs on the charger I can only assume that these are the balancing / charger wires so that in theory you would not need a BMS in the battery pack?
One would think... but nope, there is a BMS in the pack. I'm not really clear why they do it like that. Also note that the male side of the connector (exposed pins) is on the battery, and the female on the cable... I am not using the BMS for discharge right now (bypassed because the discharge side has 'issues' while the charge side works fine) so at some point I may reassemble/rewire the pack with the BMS on the charge side.

-JD

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Post by Ypedal » Aug 30 2007 12:27pm

A bms is a good thing on discharge as well as charge... prevents single cell failure from ruining a pack ( by cutting the power preventing the user from sucking back power below lvc of a single cell ).. and works as a fuse in case of a short from the pack's wires out of the box.... also prevents overdischarge if not using a meter..

In-Charger bms is a good idea as well.. but that pig-tail is kinda scary ( I have a similar charger/milti-pin thing on the way... may want to bundle that wire into a jacket or something... But it means you canot simply replace the charger with a non-eom charger....
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Post by oatnet » Aug 30 2007 3:09pm

http://www.users.bigpond.com/solarbbq/lithiums1.htm

The page SolarBBQ's posted (copied above) has me concerned for these packs; do you folks think this the OC pack is LiFe?

I knew that the shape of the cells was different from the other LiFe I have handled, long and thin like cobalt packs, but I thought that was manufacturer differences, not chemistry differences. Inside those silver wrappers, the batteries feel like solid blocks, not layers of cells like the LiFe Cells solarbbq shows. I'm not ready to trash the pack by opening a cell, yet. The OC 'LiFe' cells charge to @3.55v, discharge to about 2.9v.

The FalconEV cells are at about 4v right now, but due to the shipping damage I have not been able to discharge them yet so I don't know their SOC. There are 10 cells in a 36v pack. They are the only LiMn I have handled - do any of you gurus know more about the form factor and voltages for LIMN? Should it be packaged like cobalt or like LiFe?

-JD

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Post by Ypedal » Aug 30 2007 6:06pm

Is the QC life pack 10 or 12 cells ?

The 3.55 to 2.9v sounds right for LiFe

Limn would have 10 cells for a 36v pack ( fully charge to 42v then settle to 40-41v overnight, dropping to 38-35v for most of the discharge.

LiFe would require 12 cells to behave the same.
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Post by xyster » Aug 30 2007 6:12pm

Ypedal wrote:
Limn would have 10 cells for a 36v pack ( fully charge to 42v then settle to 40-41v overnight, dropping to 38-35v for most of the discharge.
Does your LiMn self-discharge that much overnight, ypedal? 42v to 41v is a full 10% of the total capacity. I haven't noticed any self-discharge overnight with my LiCo pack.
Ebike: 5304/20", 72V 35A controller, 33AH 80V 20s15p (18650 sized cells) DIY lithium-ion pack
http://endless-sphere.com/forums/viewto ... 47&start=0
Scooter: '06 Stealth s1000, 48V 30A, 4x10ah SLA
http://endless-sphere.com/forums/viewtopic.php?t=148
Ebike: '06 Currie Mongoose, 32V 35A, 32V 22AH hybrid SLA/Li-ion pack
http://endless-sphere.com/forums/viewtopic.php?t=1010

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Post by cadstarsucks » Aug 30 2007 6:46pm

oatnet wrote:
numberonekiwi wrote:I am comparing the two packs the falcon ev one looks like a nice piece of kit but I am not sure if I like all those wires coming from the ocean packs on the charger I can only assume that these are the balancing / charger wires so that in theory you would not need a BMS in the battery pack?
One would think... but nope, there is a BMS in the pack. I'm not really clear why they do it like that. Also note that the male side of the connector (exposed pins) is on the battery, and the female on the cable... I am not using the BMS for discharge right now (bypassed because the discharge side has 'issues' while the charge side works fine) so at some point I may reassemble/rewire the pack with the BMS on the charge side.

-JD
Actually it is against the law to sell Li cells without one. Somewhere I read the regs and it is not technically against the law but there are stipulations that make it so.

To my knowledge the A123 cells are the only ones that can get around it. Industry can not even buy cells with out them, only pack makers who then can not sell cells without making them into single cell packs.

http://www.youtube.com/watch?v=A9ayuFBDrSg

I am in the process of designing the 1.1AHr 18650 cell in now as backup power.

Dan

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Post by CGameProgrammer » Aug 30 2007 7:56pm

xyster wrote:
Ypedal wrote:
Limn would have 10 cells for a 36v pack ( fully charge to 42v then settle to 40-41v overnight, dropping to 38-35v for most of the discharge.
Does your LiMn self-discharge that much overnight, ypedal? 42v to 41v is a full 10% of the total capacity. I haven't noticed any self-discharge overnight with my LiCo pack.
It's a drop of 2.4%. A drop of 4.2V would be a 10% drop.

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Post by xyster » Aug 30 2007 8:53pm

CGameProgrammer wrote:
xyster wrote:
Ypedal wrote:
Limn would have 10 cells for a 36v pack ( fully charge to 42v then settle to 40-41v overnight, dropping to 38-35v for most of the discharge.
Does your LiMn self-discharge that much overnight, ypedal? 42v to 41v is a full 10% of the total capacity. I haven't noticed any self-discharge overnight with my LiCo pack.
It's a drop of 2.4%. A drop of 4.2V would be a 10% drop.
Not in relation to voltage, but in relation to capacity, a drop from 4.20v to 4.10 volts is about 10%. From 4.10 to 4.00 is another 10%. Not much left below 3.60 open-circuit volts -- about the same as lithium cobalt.

The emoli discharge graph below doesn't show an open circuit (0 C) voltage vs capacity line, but should give the general idea.
http://www.wattflyer.com/forums/attachm ... 1148246211
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Ebike: 5304/20", 72V 35A controller, 33AH 80V 20s15p (18650 sized cells) DIY lithium-ion pack
http://endless-sphere.com/forums/viewto ... 47&start=0
Scooter: '06 Stealth s1000, 48V 30A, 4x10ah SLA
http://endless-sphere.com/forums/viewtopic.php?t=148
Ebike: '06 Currie Mongoose, 32V 35A, 32V 22AH hybrid SLA/Li-ion pack
http://endless-sphere.com/forums/viewtopic.php?t=1010

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