eZip e-400 with LiFePO4?

ipcalit

10 µW
Joined
Nov 4, 2014
Messages
6
Hi everybody,

I got an older eZip e-400 (seems to be the same as Schwinn s400) in perfect condition with depleted SLAs and burned controller. While awaiting for another 24V controller I was looking for Lithium alternatives, which I know don't come cheap unless you have lots of 18650s around or RC gear. This forum has tons of good info and after some reading it seems that there are a couple of options for eBikes, but the scooters are much more constrained in space and power.

The easiest would be the LiFePO4 drop-in replacements, such as CTC 12V10Ah that sustains 10A (~1C) discharge rate:

http://www.ctcbattery.com/LiFePO4-Rechargeable-Battery/CTC-12-8V-10Ah-128Wh-Lithium-Iron-Phosphate-LiFePO4-Rechargeable-Battery

available for $120 from the TNCScooters/ElectricScooterParts (same company)

http://www.electricscooterparts.com/lifepo412v-24vbatteries.html

or the K2 Energy K2B12V10EB available for $160 from Amazon.

http://www.amazon.com/Energy-K2B12V10EB-Lithium-Phosphate-Battery/dp/B0056BWK8I

Now a pair of these should give the same 24V10Ah as the original SLAs, but I don't think they have any internal cell balancing, just simple protection circuitry.

Anybody tried these?

Another alternative would be 8 of the Headway 38120 10Ah cells in series. Any experience with these in such a tight space (probably two packs of 4 inline with some space for BMS)?

Would the stock 400W motor handle 36V? I presume it would provide a 2-3mph speed boost with stock gearing on flat ground. Hence, is 36V worth exploring for more torque with a gear mod? It would most likely require a new controller and throttle (if the motor can handle it) along with more batteries.

Comments, suggestions? Thanks!
 
Seems that there are a lot of viewers here but no opinion/experience to share. :(
Is everybody into eBikes or motorized skateboards only? Where's the fun of the powered kick scooters?

After more searching and reading there are a number of SLA replacements that claim to be plug-and-play, yet some lack true BMS or are of shady origins. The Dakota brand was used apparently before with mixed results. Stark power is another brand mentioned but their specs pages are confusing/contradictory.

It would be great to have a summary page with things that were tried before and worked. For instance:

Batteries
| make | model | volts | amps | chemistry | real capacity | links to tests |

Motors
| make | model | official volts | official amps | max tested reliable volts | max tested reliable amps | links to tests |

Controllers
| make | model | tested volts range | tested max amps | links to tests|

and so on. This would save everybody a lot of trouble searching and reading hundreds of posts.
Any contributors?
 
Hello,
I haven't used them personally but it is definitely something I may do with my next build. If you are looking for a plug and play solution, I would probably just go on hobbyking and match one of their esc's with a few LiFePo packs and then the motor. This may be the easiest option I think.
 
i always recommend the sun-thing28 guy because he had the cheapest prices for the standard pouch cell lifepo4 pack since he uses surface freight to ship the batteries which saves a ton of money.
 
Well, the LiPo (a.k.a. LiCo) are definitely cheap at HK and pack quite a punch, but their reliability and more importantly their safety is questionable. I don't want to have them go into flames in an office environment, which no matter how careful you are is still possible. And fiddling around with RC chargers and repurposed server power supplies is not something I would consider doing on a regular basis.

So the closest alternatives to those SLA replacements are ready-made packs, such as Ping, or popular ebike battery bottles if they fit the available space. And here is exactly where many of them fail. In my particular case, I see just 2-3 options:

a) Headways 38120
b) Custom pack with 18650s - discarded laptop / power tools batteries
c) Custom pack with 26650s - this is what I presume most of those SLA replacements have inside.

Anybody care to comment on the performance of (a) vs (b) or (c)? How is the voltage sag with the 18650s? How reliable are the Headways?
 
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