LiFePO4 batteries in the 12 volt "gel cell" format

I've been doing a lot of research on battery technology for my e-bike project (36V 10+Ah, left-side drive, crank-forward commuter,) as of now I'm pretty much decided on the LiFePO4 chemistry, and have been looking into my options in this area. The batteries packaged in the "12 volt gel cell" configuration have caught my attention, and I'd like to see what people on this forum think of them for use in an e-bike application. The products being offered by K2 Energy and Tenergy seem particularly interesting. Here's a couple of links to help illustrate what I'm looking at:

http://www.k2battery.com/battery-packs-12v.html

http://www.all-battery.com/Tenergy12.8V7AhLiFePO4RechargeableBattery-31382.aspx

Here's what I find attractive about this format:

1: The fact that these are being aggressively marketed as "drop-in" replacements for 12-volt gel cells indicates to me that manufacturers are gearing up for serious production and are looking to take market share from the existing gel-cell / "valve regulated lead acid" (VRLA) format battery manufacturers. This will likely lead to lower prices and better performance over time as compared to the average "plastic shrink wrapped" custom battery packs available from vendors like Ping and Headway.

2: The batteries supplied by K2 are fully compliant with all relevant UN shipping regulations (certified as compliant to the testing requirements for lithium batteries in Section 38.3; Part III of the UN recommendations on the transport of dangerous goods, fifth revised edition.) This addresses one of my biggest concerns, being able to safely and legally ship e-bikes and their batteries to customers around the country. I imagine that similar batteries being shipped by other vendors either are or will soon be compliant with the UN shipping regulations as well, but further research is needed to either confirm or disprove this. I do know that both the K2 and Tenergy battery packs are being sold on Amazon, with shipping to your door, but that doesn't necessarily mean anything.

There are multiple questions to be considered. These batteries have built-in BMS, and they can handle up to 48V connected in series, but the C ratings remain an open question (claimed versus actual) and the suitability of these batteries for the application of an e-bike is open for debate. I appeal to the expertise of this forum for informed opinion - is this battery technology (LiFePO4 battery packs designed to be "drop-in" replacements for generic "12-volt gel-cells") worth pursuing for e-bikes?

Elliott

nope. they cost 3-4X what ping charges and they have no BMS, are heavy and useless, cannot be worked on without busting up the plastic box which has only a little spade terminal. amazing how far the chinese have leapfrogged technology.

the USPS has flat rate boxes which work well for shipping batteries.

I believe they have BMSes, but yeah, they are expensive.
I've looked at these as i am interested in a 12V lithium starter battery to get the weight of my car down + increase the charging system efficiency for hopefully a little better starting in winter and efficiency boost. But they are just not worth the cash at all.

Headway headquarters sells a 12v battery too, but the price is incredibly inflated on it as well.

Lotta $ for some fancy packaging; dunno what they're thinking - like someone is really going to cross shop a $33 lead acid battery VS a $200 one that should really cost $100.

I just bought 4 12V 8ah sla's for $64 shipped. 4 of those would be $540 +whatever shipping cost are involved. The sla's usually last 4-5 years. My 24s 10ah rc lipo pack cost under $300. It would be over $1000 for just 7ah of those. No freaking way.

I am seeing more brands of these and they have a bms or balancer inside.

K2 is what Currie uses for the trailz li ion upgrade.

K2 makes 24v batteries too.

http://www.ebay.com/itm/K2-Energy-K2B24V10EB-24V-10Ah-Lithium-Iron-Phosphate-Battery-BMS-/230682285798?_trksid=p2047675.m1850&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D11%26meid%3D4623058081410236530%26pid%3D100011%26prg%3D1005%26rk%3D1%26sd%3D190774273521%26

http://www.ebay.com/itm/24V-15AH-LiFePO4-Electric-Scooter-E-Bike-Ping-Battery-/221173423691?pt=LH_DefaultDomain_0&hash=item337ef69e4b

Much nicer container than ping uses.

neptronix said:

I believe they have BMSes, but yeah, they are expensive.
I've looked at these as i am interested in a 12V lithium starter battery to get the weight of my car down + increase the charging system efficiency for hopefully a little better starting in winter and efficiency boost. But they are just not worth the cash at all.

Headway headquarters sells a 12v battery too, but the price is incredibly inflated on it as well.

Lotta $ for some fancy packaging; dunno what they're thinking - like someone is really going to cross shop a $33 lead acid battery VS a $200 one that should really cost $100.

Click to expand...

Not too bad.

http://www.ebay.com/itm/24V-20Ah-Lithium-Iron-Phosphate-LiFePO4-Battery-w-PCM-INCLUDING-CHARGER-/181008554205?pt=US_Rechargeable_Batteries&hash=item2a24f358dd

Lot of new stuff out there.

http://www.ebay.com/itm/11-1V-20Ah-Lithium-Polymer-LiPo-Battery-w-PCM-INCLUDING-CHARGER-/181030488562?pt=US_Rechargeable_Batteries&hash=item2a264209f2

alos are lots of threads about these kinds already you cna look up

amberwolf said:

alos are lots of threads about these kinds already you cna look up

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There is little info about K2 energy batteries or tests.

There must be a lot of them on the road because Currie uses them and how many threads asking how to fix one that won't charge or one catching fire or anything like that ?

Lots of threads not.

I hope they do real good selling those drop in li ion batteries and sell them at walmart for $99.

sorry

$99.00 ea. @ Wal-Mart, I'll take three please. I wish!

The fingers said:

$99.00 ea. @ Wal-Mart, I'll take three please. I wish!

Click to expand...

Why? They are 12V, 7Ah batteries or 84Wh. That $1.18/Wh for normal LiFePO4. Not a good deal.

It would be a good deal if they are made of A123 cells.

SamTexas said:

The fingers said:

$99.00 ea. @ Wal-Mart, I'll take three please. I wish!

Click to expand...

Why? They are 12V, 7Ah batteries or 84Wh. That $1.18/Wh for normal LiFePO4. Not a good deal.

It would be a good deal if they are made of A123 cells.

Click to expand...

I want 3 of these.

http://www.amazon.com/K2-K2B12V10E-Lithium-Phosphate-Battery/dp/B0056BV43U/ref=pd_sim_sbs_misc_3/184-2903736-1182506

https://batteryworkshop.msfc.nasa.gov/presentations/Mod_LFP_Batt_Large_Format_App_JHodge.pdf

wesnewell said:

I just bought 4 12V 8ah sla's for $64 shipped. 4 of those would be $540 +whatever shipping cost are involved. The sla's usually last 4-5 years. My 24s 10ah rc lipo pack cost under $300. It would be over $1000 for just 7ah of those. No freaking way.

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Where the heck did you get that deal?

Standard price for 5ah 4s Turnigy hardcase packs from HK USA warehouse is $23.65. 12x23.65-$283.80. Less with the discount. IIRC the discount just about paid for shipping.

It would be nice to see these, in 20 ah size, for about 99 bucks at walmart. At that price, needing to open the case to work on em would not matter much.

But I'd rather see a balance port built into the case, so you can check cell voltages and run a RC balance charger on them.

Really nice if they had 5c or more cells in em.

http://www.k2battery.com/products-26650P.html

They have cells that will do better than 5c.

This is an interesting report on K2.

http://www.prnewswire.com/news-releases/k2-energy-systems-inc-reports-sufficient-li-ion-cell-inventory-and-manufacturing-capacity-in-response-to-recent-competitor-bankruptcy-filings-174743321.html

All eyes on A123 going down but K2 is plugging away selling batteries and staying alive.

Right at the end A123 started selling these types of batteries too.

Too late ?

http://www.buya123batteries.com/ALM_12V7_p/400520-001.htm

A123 blew their bailout money trying to get the tabs right on the 20ah cells for the electric cars no one wanted to buy ?

K2 did not take any bailout money ?

wesnewell said:

Standard price for 5ah 4s Turnigy hardcase packs from HK USA warehouse is $23.65. 12x23.65-$283.80. Less with the discount. IIRC the discount just about paid for shipping.

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Cheap batteries are just that.

And cheap batteries are not that good.

It has always been that way.

And good batteries like A123 cost alot.

Having played with A123 cells I may be spoiled forever but I really like good batteries.

HK lipo is like having a roadmaster bike from walmart.

A123 is more like a Trek.

You would not put HK lipo on a Trek would you ?

Was it Turnigy, or A123 that had a recall on a bunch of defective batteries? A search shows it was A123, what do you know.

to be fair, tunigy wouldnt' likley do any kidn of recall. :lol:

Re a few posts pack. In case that wasn't perfectly clear, my wish was not just for 5c cells at any price.

The dream was that 12v 20 ah of 5c cells was 99 bucks at walmart. That would truly make ebikes acessible to the poor, who struggle so hard to get to slave wage jobs. The poor cannot possibly live within 5 miles of where they work in the western USA. The rents are too high till you get way out into the trailer slums.

It's about as likely to happen as my other fantasy, a federal tax rebate on electric bike purchases that just about equals the cost of a 36v 20 ah pingbattery.

Turnigy recall? that was a good one. Once you weed out the bad ones, you can have a pretty good battery. After all, where else do you get 30c that cheap? But the maintenance of RC lipo is still not for the careless or slacker.

That's why a simple to use lifepo4 at cheaper prices would be so nice.

Dogman wrote "The dream was that 12v 20 ah of 5c cells was 99 bucks at walmart."

Not there quite yet, but note the price and specifications of this battery:

http://www.batteryspace.com/LiFePO4-Prismatic-Battery-12.8V-20Ah-256Wh-10C-rate-with-LED-Balancing.aspx

It's a 12.8V, 20Ah that can output 40Ah continuously, with built-in balancing for $179. This makes it possible to have a 36V, 20 Ah LiFePO4 pack for under $550 (plus shipping.) Furthermore, these battery packs are (supposedly) compliant with UN shipping regulations. Each of the 12V batteries is made up of four of these wired in series through balancing modules with LED status indicators.

http://www.batteryspace.com/LiFePO4-Prismatic-Module-3.2V-20-Ah-10C-Rate-64-wh.aspx

Also note they sell a version without the LED balancing setup for $124, but you would really want keep a close eye on these to keep them happy. Of course, the usual questions remain such as "are the specifications real" etc. But the price of these compares very favorably with similar products from K2, and I'm wondering if anyone on this forum has any experience using either these or similar "prismatic" cells from batteryspace.com?

ElliottE said:

It's a 12.8V, 20Ah that can output 40Ah continuously,

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can't outptu Ah, only A

That's about the price that has been around for some time. At one point, 2c lifepo4 12v 20 ah bricks were avaliable for close to 99 bucks. But not 5 c cells, and they are pricier now.

And 40 amps, from 20 ah, is uhh, 2c.

Still wishin and a hopin.

I see alternatives in 12v 10ah and 12v 12ah "Gel cell/AGM" formats from:

• 
  K2
  Bioenno Power
  Tenergy
  Shorai

Are any of these batteries ones people on the list can report experiences? I see K2 referenced earlier, but none of the others. There is more information from Bioenno Power and Shorai, the latter in use for motorcycle replacement batteries and other information seems to be targeting scooter battery replacement and of course long term UPS.

Bienno Power 12v 10ah seems to have specs suitable for replacement, especially as direct replacement for the 12v10ah in many of the 24v Currie ebikes I have access to. We have the 24v Lithium charger for the Via Rapido, so perhaps any of these 12v 10ah replacement batteries would work well. At about $125 each that's $250 for drop in replacement into Currie packs. Well under the overpriced Currie RMB Lithium which are over $350 and only 6ah!

Thanks for feedback!