Oxygen Battery on test

[CeeGee]

Buying the best battery available is a constantly moving target! ....

The question is would pedelec riders prefer to use the heavier 500Wh LifePo4 or the higher powered 575Wh Li Ion? They are about the same price.

Thanks for your help.

Regards

David

Personally I would quite happily put up with an extra kg or so and a little less power for much increased longevity, so the LifePo4 would get my vote every time.

Colin

 

[eddieo]

if "higher power" meant more umph for hill climbing, I would go fo the Li ion .....but if it just extends range a bit pointless IMO

So under those circumstances the LifePo4 probably makes more sense

 

[Wisper Bikes]

if "higher power" meant more umph for hill climbing, I would go fo the Li ion .....but if it just extends range a bit pointless IMO

So under those circumstances the LifePo4 probably makes more sense

The higher power battery at this level will really only add range and will extend the sweet spot on the battery so a rider can complete more miles at maximum power.

My feeling currently is to go for the LiFePo4 or maybe offer a choice.

All the best

David

 

[MAB]

The question is would pedelec riders prefer to use the heavier 500Wh LifePo4 or the higher powered 575Wh Li Ion? They are about the same price.

Thanks for your help.

Regards

David

I have to ask the question, what are the expected prices? If the life expectancy of LifePo4 can be realised, then it has to be this type. (Bit of a no-brainer really?)

Regards,

Mike.

 

[Wisper Bikes]

Cost

Hi Mike

As we are now buying 1000's of batteries at a time, due to economies of scale, we will be able to keep the cost the same as the current 14A Li Po. There is a possibility we could even reduce the price.

All the best

David

 

[flecc]

My preference would be the slightly lower capacity lithium iron phosphate (LiFePO4), subject to it being capable of the same or better discharge rate.

I fully agree on the highest capacity to volume Li-ions, their reliability will be suspect due to greater chemical stresses at higher content densities.
.

 

[Mussels]

I'd be happy to gain 1Kg to get longevity, I probably won't keep an ebike long enough to knacker a battery but it would be nice to increase the resale value.

 

[Wisper Bikes]

My preference would be the slightly lower capacity lithium iron phosphate (LiFePO4), subject to it being capable of the same or better discharge rate.
.

Hi Flecc

We are finding the discharge rate on this batch of test LiFePO4 batteries is actually higher than the Li Ion we are currently using, the charge time is also reduced.

All the best

David

 

[daniel.weck]

Based on my e-biking needs, I'm rather satisfied by the LiFePO4 ratio between price and (promised) longevity. History will tell whether this was the right choice. By the way, I'm talking about the Li-Ping battery with the BMS v2.5:

36V 10AH V2.5 LiFePO4 Battery Pack

So far the 10Ah capacity on my 36V e-bike is proving ideal in terms of range and in terms of ability to handle high current draw. By "high", I mean 400W max (effective), which is relatively low all things considered, but it is perfect for me when pedaling up a steep incline. The average e-contribution oscillates between 50W and 200W (measured by Cycle Analyst), with higher peaks only for climbing or when facing strong winds.

In other words, I like to contribute human power enthusiastically. I realize that other riders prefer to let electric power dominate (i.e. throttle-only / pedal-less motorbike-like riding), so your mileage may vary (pun intended ).

I'm not sure what actual Li-Ion technology is used in the battery of the iZip Via Mezza Enlightened...does anyone know ?

Cheers, Daniel

 

[eddieo]

There is a 2009 GoCycle on London Gumtree. started of at offers around £1000.....this week offers around £900. For anyone who like this kinda fing

 

[Oxygen Bicycles]

Buying the best battery available is a constantly moving target!

We have employed a full time electronics engineer based in Shanghai to help with the quest to find the best e-bike battery, and our new 2011 bikes will come with standard 11 or 16A batteries. Rather than the existing 8 and 14A.

The problem we have found with ever increasing battery capacity is they get less and less reliable, we have tried cells that will give is up to 21Ah (New Panasonic) but under testing found them to be next to useless. We all need to be very careful when chasing the most powerful battery available.

This is where I need some feedback. For two years we have been following the progress of LiFePo4 batteries and have looked at lot of real duds! However we have just finished testing a very high quality 36V 14A LiFePo4 pack that fits nicely into our larger battery box. The weight is 1KG more than our existing 14A battery. As you all know LiFePo4 does come with some rather nice advantages over Li Ion including the claim that they will last 3 times as long and have better environmental credentials.

The question is would pedelec riders prefer to use the heavier 500Wh LifePo4 or the higher powered 575Wh Li Ion? They are about the same price.

Thanks for your help.

Regards

David

Hi David,

I see you just hijacked the Oxygen thread . I have to say we are also looking into new LiFePo4 series and the only problem with them is that you can not put too many Ah and the weight is slightly higher. Otherwise its a brilliant solution and defo best in terms of lifetime. TBH for most of us 10AH is enough in terms of range, I never use the full range that our 13Ah is offering but the perception with Li-Po's is that you always have plenty of power left

 

[Wisper Bikes]

Sorry Andrew, got carried away with the subject matter!

Best regards

David

 

[Teejay]

"I have to say we are also looking into new LiFePo4 series and the only problem with them is that you can not put too many Ah and the weight is slightly higher"

What does this mean? Is it "You can't put too many Amp-hrs IN - sky's the limit" -or- "there's a limit as to how many Amp-Hrs you can put in, above xx A/h it don't reliably work"?

 

[Oxygen Bicycles]

Sorry Andrew, got carried away with the subject matter!

Best regards

David

just kidding David, off course feel free to post here

best regards

Andrew

 

[Oxygen Bicycles]

"I have to say we are also looking into new LiFePo4 series and the only problem with them is that you can not put too many Ah and the weight is slightly higher"

What does this mean? Is it "You can't put too many Amp-hrs IN - sky's the limit" -or- "there's a limit as to how many Amp-Hrs you can put in, above xx A/h it don't reliably work"?

The LifePo4 cells don't have such a high power density as Li-Po's. It means that we are limited by dimensions of our battery cases. The difference in energy density per cell between Li-po and Lifepo is about 30%. In simple words in our battery case we can fit 13Ah of Li-Po but in to the same case we could only fit 10Ah of LifePo4. The would be also the difference in weight. LiFePo4 would weight approx 4.5kg where our Li-Po is only 3.5kg so it's a really good question for which option to go for as the LiFePo indeed saves a lot of weight on the bike.

Best regards

Andrew

 

[CeeGee]

The LifePo4 cells don't have such a high power density as Li-Po's. It means that we are limited by dimensions of our battery cases. ....
Best regards

Andrew

Is their any reason why you can't use a longer case for LifePo4?
To re-hijack this thread , there is plenty of empty air space above the battery case on my Wisper 905, and the case could "easily" be lengthened by an extra 15cm or so if necessary to accommodate LifePo4, as long as the consumer is happy with the extra weight.
Also, wouldn't it be nice for the consumer if there was a couple of BEBA approved universal standard battery cases, one for behind the seat post bikes, another for rear rack bikes.

Colin

 

[Oxygen Bicycles]

Hi Cicgee,

Yes the battery case can be extended by going up a bit. It can also be wider but this involves making a new mould for the case which ain't cheap these days. Also the huge cases are not as practical as small ones and the question which you raised is good.

Are we going to be happy with a 5-5kg LiFePo battery that's got approx 13-14Ah????

Guys probably would, Ladies might be less keen

Re the universal case I totally agree as this would give the consumer a better choice of substitutes. Maybe one all manufacturer get together and make something up just like ISIS standard on the bottom brackets designed by Truvativ, FSA and Race Face

regards

Andrew

 

[garrence]

Are we going to be happy with a 5-5kg LiFePo battery that's got approx 13-14Ah????

No thanks! I'd prefer maximum Ah in minimum weight. If it wears out more quickly then so be it.

Comsumers tend to compare numbers. If one bike has a lower weight and a higher range then they'll think it's better. It takes a lot more sophistication (a minority of consumers) to compare battery technologies and care about longevity.

 

[Wisper Bikes]

There's the rub, we have a choice of 14A LiFePO4 or 16A Li Ion in our larger case, the 14A LifePO4 weighs just under 1KG more than the 16A Li Ion. To make the choice even more (or less) complicated we can offer a 3 year guarantee on the LiFePO4.

My feeling is we offer a limited edition LiFePo4 to see what the uptake is.

All the best

david

 

[Oxygen Bicycles]

Pros and cons

The trial series certainly could be worth a go so that would show what uptake there is. IMHO what we already get from the Li-Po's is very good and the extra 1kg for twice long longevity will be a good option for a frequent every day users.

On the other side of the coin if the 14ah Li-Po pack weights 3.9 kg then the 16Ah will be approx 4.4kg. The LiFePo4 will be than extra kg on top that 4.4kg so we will have pack over 5kg (I reckon 5.3kg in total). It does not matter what cells we are going to use if its Safty or Advanced it's just the Iron (Ferrum) that is so heavy and being one of the major ingredients of LiFePo4 there is no way to reduce this weight is it???

Personally I love the concept of longevity of LiFePo4 but thinking we are crossing that 5kg just in the battery I think it's too much to carry.

I'm still not sure myself if we should try it

All the best

Andrew