Bionx Battery
I have had a Bionx 350PL since June 2008. I now have about 5000 miles on the system and it has performed fairly flawlessly. I ride it year round, pretty much every day and in all kinds of weather. I have found the system very pleasurable to use. The only operational problem has been a very occasional hiccup where the control system locks up - this happens about once a month and the fix is to disconnect and reconnect the controller. it is still riding perfectly.
BUT - the battery is now down to below 75% capacity. I have remeasured this very carefully, doing multiple rides on a standard course I use. All at pretty much the same temperature and wind conditions. Unfortunately, I have no energy measurement system that can accurately measure how many aHr I have used. But the change is extremely noticeable.
I contacted the distributor that sold me the kit before my 1-year battery warranty was up in late June. They suggested I reset the battery monitor ( fully charge the battery, let it sit a while, then put in a code that sets that level to "full" on the indicator) and also completely drain the battery several times.
I did this and noticed no changes. By now it is August as it took me that long to perform the cycles and then retest the range several times.
They then contacted Bionx who said that my mileage in one year ( about 4000 miles) was extreme and maybe that might be the problem. I think they misunderstood my mileage, as 4000 miles per year is nothing. I use to put a good bit more on my commuter bike back before I had an assist kit. We had some back and forth and no resolution.
I then contacted Bionx directly and they immediately responded, saying someone would get back to me but that time and storage can affect battery life. In my case, the battery was only a year from purchase when I first noticed the drop, and I baby the battery - only charge it when it has cooled down, keep it in a heated garage, etc. I also never completely drain the battery except when it was suggested as a way of re balancing the cells.
They've never got back to me and I'm about to give up.
But at this point, as much as I have enjoyed the Bionx system, I have to recommend against anyone purchasing it. Bionx rates their battery for about 400 cycles. Now most rechargeable battery manufactures rate a battery life as the number of cycles until its capacity has fallen to 80%. In my case, the way I use the bike ( always at level 2, no thottle) I get about 35 miles per cycle. So 400 cycles, at 80% of this range, is about 11,200 miles. I was a little over a third this range when it fell to 75% capacity. (Greenspeed and some other distributors advertise 500 or even 600 cycles).
When I made the decision to purchase the bike, I knew the $1000 battery replacement cost was extraordinarily high for a 36V 9.6 ahr lithium battery, but I figured it would be worth it for a nicely performing system over 12,000 miles.
But with my system lasting only a third of this life, I now feel this is not a very good value at all and would not recommend this system to others.
One reason the Bionx battery system is so expensive is that all the control electronics are in the battery case. So you can't just substitute batteries. Bionx should have a refurbishing program where you return the system and they just replace the cells while keeping the electronics, but they don't.
In any case, there is something wrong if I can only get about 130 cycles on their batteries.
With price differences quoted, you can bet that if it were me, I would figure a way to connect my own battery to their controller! I certainly would NOT give them $1,000.00 for only 10 AH at 36 volts!-Bob
Had more back and forth with Bionx. That had me make yet more measurements involving "double charging" the battery then riding it until it was drained. Doing this, the range is down only 21% from new. They seem to think this is acceptable.
I've got a recumbent bike with the Bionx 36V system. And I own two batteries, both of which don't show more than 50-60% on the meter when "fully charged." I'm wondering if the alternate batteries you mention can be used with the Bionx system? And how one would connect them given their proprietary battery mounting/connecting system.
I think the voltage reading after a full charge is a better indication of battery condition than the meter reading. See the fifth link in the following posting:
http://visforvoltage.org/forum/2253-bionx-limn-battery
$1,000.00 for only 10 AH at 36 volts is too much! Go to "batteryspace.com" for that kind of money, you can buy a 21 AH, 37 volt lithium polymer battery, with built-in cell management PCB!---Or, for only $569.95, you could buy a 38.4 volt, 13.6 AH lithium iron phosphate battery, with built-in cell management PCB.-I have bought from them, the batteries worked as advertised!-Bob
Robert M. Curry