Panasonic are quoting 500 charges so under normal usage your 342 seems more likely Flecc, this is the reason we decided to stick with our tried and tested Li Po.
All the best
David
Fastest climber?
- Thread starter Polar753
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All the best
David
Hi Eddie
By the time the cells have been put into a decent case (not the cheap aluminium type) and have a high quality BMS installed, I would think £300 is unlikely unless the cells are the low grade variety available in China. Even the Panasonic cells would make the battery more expensive.
When we tested similar set ups recently, Porta Power weren't overly confident regarding the use of 70 x 0.245 cells as the chances of cell and connection problems were multiplied. Although as a matter of interest I thought the construction looked pretty good.
According to Advanced Energy, (for the size of our large battery case) the state of the art currently for 250W electric bike motors is a 36V 15.5A Li Po power pack. If we were to have a larger battery pack made they could increase this, however IMO the 55 to 85 mile range in urban conditions this battery is capable of is probably about the right balance between battery volume and performance. And of course we can confidently give a 2 year new for old warranty, in the knowledge that this battery would comfortably take a full charge / discharge cycle every day for two years without loosing 25% of it's original capacity.
All the best
David
Yes, it'd be interesting to have some real world stats as the received wisdom is to not fully discharge your battery between charges. So if you're using a huge Li-ion battery for runs well within its range, the capacity degradation may not affect you until it's significantly advanced, and at 1/2 the price (approx) of a Li-Po with a similar starting capacity, it may make economic (if not environmental) sense to go with the cheaper option.
Perhaps manufacturers should offer their customers the choice (expensive in terms of stock, I realise), explaining the facts about each option, as this may vary with regard to the intended use of the machine.
Real world
I think Flecc's figures were real world, my worry is that even Panasonic are saying only 500 charges and then a massive drop over the next 50. In the real world I would expect the figures to be more like Flecc's .
I would really love to use a cheaper battery, we would no doubt sell more bikes! However according to all our road tests we would have to reduce our warranty period back to a year. Judging by past experiences with Li Ion, I don't think it would be wise to go down that rout again on our longer legged bikes. Li Ion on folding bikes is much more acceptable as they are not used for long distance riding.
All the best
David
I think Flecc's figures were real world, my worry is that even Panasonic are saying only 500 charges and then a massive drop over the next 50. In the real world I would expect the figures to be more like Flecc's .
I would really love to use a cheaper battery, we would no doubt sell more bikes! However according to all our road tests we would have to reduce our warranty period back to a year. Judging by past experiences with Li Ion, I don't think it would be wise to go down that rout again on our longer legged bikes. Li Ion on folding bikes is much more acceptable as they are not used for long distance riding.
All the best
David
Maybe Flecc could answer as to whether the charge cycles he quoted were full discharge, for the purposes of the experiment, or partial as most of us do?
The life cycle vs discharge of Lithium has been known for a while. If you continue to charge to 100% and discharge to <10% then the life is shortened considerably. By capping the charge to say 95% and making sure DOD goes no lower than 20% the life is extended considerably. Good BMS configuration limiting cell voltage to 4.10~4.15 max charge and cut off at 3.10~3.00 volts or higher will achieve 800+ cycles.
The first 208 charges were between 80% charge and full charge, a spare battery being carried on the runs to take over whenever the test battery was emptied, and the current drain usage conditions were severe with the motor forced to do all the work to it's limits before assistance with pedalling.
The remaining 134 charges have been between 30% and 50% of charge with more normal and moderate usage conditions. I don't think the life would have been materially different with different usage since that battery was very willing to give all the current the motor could demand without impeding performance. The impression I had was that the passage of time was an important factor in its life, just as it was in the former incarnations of this li-ion battery.
I agree with David, li-polymer compound cathode batteries are the way to go at present for the optimum of number of charges life with adequate performance.
On a separate subject, I'm now far from convinced that frequent part charging is advantageous for long life since an accumulation of evidence over the last four years appears to show no gain, even the opposite to some extent. It's something I'll probably post separately on at some time.
.
Sorry, have been busy hence tardy reply.
"Are you using a 250W motor? If so what does the motor need to have dumped from the battery to run at it's highest efficiency? There is only so much a 250W motor needs to maximise range and power."
Yes, 250W. The issue is the instantaneous power demand, especially if using throttle only on a hill start. We find that nominal voltage is only one part of the equation.
"I would be interested to learn what technology you are using and what the battery chemistry is. "
Lithium Ion is all I am able to say. It is a slight variant on the conventional chemistry, but with very substantial connectors.....
"We have found a battery of exactly the same size as the one you are talking about very disappointing compared to the 14A Li Po we are currently using."
We have measured in excess of 600Wh and real world performance in terms of acceleration (power) and longevity (endurance) in excess of the LiPo's so far realeased on the market.
"Flecc has explained why the 17.5A batteries are not as good as the slightly smaller ones on 250W electric bikes. It would be interesting to hear if you have managed to overcome these problems."
I believe we have overcome them, but an independent test of the two battery set ups on competitor bikes would be fun
"Are you using a 250W motor? If so what does the motor need to have dumped from the battery to run at it's highest efficiency? There is only so much a 250W motor needs to maximise range and power."
Yes, 250W. The issue is the instantaneous power demand, especially if using throttle only on a hill start. We find that nominal voltage is only one part of the equation.
"I would be interested to learn what technology you are using and what the battery chemistry is. "
Lithium Ion is all I am able to say. It is a slight variant on the conventional chemistry, but with very substantial connectors.....
"We have found a battery of exactly the same size as the one you are talking about very disappointing compared to the 14A Li Po we are currently using."
We have measured in excess of 600Wh and real world performance in terms of acceleration (power) and longevity (endurance) in excess of the LiPo's so far realeased on the market.
"Flecc has explained why the 17.5A batteries are not as good as the slightly smaller ones on 250W electric bikes. It would be interesting to hear if you have managed to overcome these problems."
I believe we have overcome them, but an independent test of the two battery set ups on competitor bikes would be fun
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They can't be all bad - they were kind enough to give names to their batteries
Hector and Gavin - and some of the bike colours were pretty.
I do wish companies wouldn't go live with unfinished web sites.
If they can't be bothered to finish a web site before publishing it leaves me wondering if they will develop their bikes before selling.
One bike shop in London has a site so illiterate I didn't even consider buying from them. Maybe it's only me and maybe it's unfair but I doubt that I'm the ony one.
If they can't be bothered to finish a web site before publishing it leaves me wondering if they will develop their bikes before selling.
One bike shop in London has a site so illiterate I didn't even consider buying from them. Maybe it's only me and maybe it's unfair but I doubt that I'm the ony one.
Fixed it for youI am sure you are right Herb, I just get a little grumpy
All the best
David
Just joking I may want a Wisper one day
Seriously it must be frustrating but that seems to be how China works.
You're absolutely right Lemmy, there really isn't any excuse for the state of some sites, and even those that look ok on the surface are often riddled with errors in specifications etc.
I also intensely dislike sites that have no online communication links, giving only a mobile phone number, even though they are often reputable long established companies.
.
Where did you get that photo from? I can't find it in their online brochure.To be fair Bruce has 4 new bikes and only one looks a bit like a wisper.......
As blatant as this? "LIFECYCLE MOUNTAIN SPORTS BIKE"
I must say I enjoyed reading their brochure, lots of 'real world' info on batteries and usage, shame there's no prices anywhere or specs, are the bikes actually for sale yet?
Massive 36v 16Ah battery as well
If the spec is similar to the Wispers and they come out cheaper, then where is the harm in a bit of competition, surely it lowers the prices all round for consumers, which, being a consumer is very good news for me indeed. They also appear to be targetting their bikes better with the off-road version having off-road orientated tyres etc.
That is not one of Bruce's bikes...That is the point I was making, probably not clearly enough, these clones are everywhere.
I feel very sorry for Wisper and David in particular as this kind of blatant copying is scandalous and must hurt........
Electric Bike Company, Electrically powered bicycles, Electric mountain bikes
I feel very sorry for Wisper and David in particular as this kind of blatant copying is scandalous and must hurt........
Electric Bike Company, Electrically powered bicycles, Electric mountain bikes
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Strange, they are selling Wispers at the same price as their Lifecycle range. The main difference I can see is that the frames of the Lifecycles are slightly larger than the Wispers.
Which came first ?
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