Currie Electroo drive RMB upgrade to LiFePo4 any good?

[HittheroadJ]

Izip Battery Pack (24V10A) | Izip Electric Bike Battery Pack (24V10A) | Izip Electric Bike Parts and Accesories
and the same here:
Li-Ion / LiFePo4 Battery Pack (IZIP / EZIP)

The new battery skips the other Lithium options and goes straight for the LiFePo4 at a high price ($399 for a 6.5 Ah pack). The old SLA was 10Ah.
Not sure what the price will be in the UK, but probably quite high.

I mainly wonder about the fact that the Low capacity (6.5 Ah) may result in extra wear (the electrodrive pulls a lot of power from the batteries.).

Any early opinions?

thanks.

 

[tillson]

I don't know anything about these bikes, but that 3 year battery guarantee is impressive. Does any other manufacturer offer anything approaching that?

 

[NRG]

Well there's a weight saving to start with and you'll probably go the same distance on the 6.5Ah or slightly further IMHO, especially as the SLAs age. Due to the Puekert effect the 10Ah SLA is more like 7Ah under load and probably worse, the Lithium cells will hold their voltage longer under load and nominal capacity will increase slightly over the first 10~20 discharge / charge cycles. More capacity is always desirable though as it means less stress on the cells and of course range increases.

 

[flecc]

That decision to give a 3 year guarantee and state 1500 charges is courageous*, given the power of most Currie Electrodrive units. Other suppliers tend to qualify this with a restriction on current delivered, at higher currents saying 2 years and 1000 charges.

*Meant in Jim Hacker terms (Yes Minister).
.

 

[HittheroadJ]

Hi Tillson & NRG.

Thanks for your input.

I'm sure the warranty will be harder to determine after a while. If you get back to them after a month with a dead battery I would expect to get a new one, however if you come back after 20 months with a nearly dead battery will it just be exchanged or will you have done something wrong?

The curries are fairly cheap, old and heavy. They sold many slightly fdiffering models with the same engine. They were/are sold at Argos and Tesco (http://direct.tesco.com/q/N.1998743/Nr.99.aspx). In the USA and Canada they were widely sold by Walmart (Asda). You can buy them at Amazon.co.uk for £350 to £375. Or you can buy the kit through electrodrive.co.uk

Several enthusiasts (search on Endless Sphere) have bought LiFePo4 batteries themselves and found they had to resort to creating their own boxes, because they would not fit in the Electrodive's Box (RMB=Rack Mounted Battery which contains 2 12V batteries that are 67mm=2.53 inches thick nobody has found a LiFePo4 supplier that can deliver packs that are thin enough with enough juice).

If you read the comments of the people who put in their own LiFePo4 batteries than 2 things stand out:
1. Ping's 12 and 15 V batteries cannot deliver the amount of power the motor can draw, this results in the motor cutting out if you give full throttle. The Americans have 450w motors and the Europeans have 250, but peak amps are not that dissimilar.
2. Several tried to get Ping and V-power to deliver slender enough packs, Ping even got a box of an electrodrive, but nobody has succeeded. Currie themselves tried a lot announced etc.

But now Currie themselves have come with this alternative. A LiFePo4 battery of 6.5Ah. I must admit that I am in two minds about it. If the Box had been enlarged it would be much easier to simply fit a decent size battery in it. My concern about the 6.5 Ah one is that the stress on the cells may be very high. The electrodrive has good torgue, but this comes at the price of Ah's drawn.

I'll wait and see for a while.

 

[Mark Jenkins]

Hello, just thought I'd throw in my penny worth.

I fitted a curry drive over a year ago now and bought a ping 24v 15ah shortly afterwards.
I agree that a 6ah lifepo4 seems to small. I think that getting a ping and building your own box is the way to go.

These kits may be cheap but the my1018 motors they come with are very robust. The ping I have 24v 15ah delivers up to 60 mile range depending on how much I put in and has good pull up hill. I can even tow both my kids on there bikes up hill without problem.
(They love being towed) slowly of course sub 10mph.

I have done nearly 2000 miles now and my ping is wonderful showing no sign of wear.

The other point is that a ping battery is cheap for the Ah you get. I think mine was a bit under 240 pounds which I'll bet will be substantially cheaper that curry own 6Ah.

Just one more thing, I have never had experience of my motor cutting out at full throttle but I would never go to full throttle from a sanding start or slow speed. I increase my throttle slowly with the increasing speed. The other thing I found with lifepo4, is a slight increase in top speed, my motor will deliver power up to about 17mph now. Slightly not legal I know. But I am not silly with it. I mainly ride at around 12 to 14mph.

 

[muckymits]

I took the easier way out and fitted a standard rack and a pannier to hold my LiPo. I have considered trying to make boxes from acrylic to take headway batteries. Going from SLA to LiPo makes the bike a bit more lively