Have you noticed that when this forum opened the content was predominately about eZee bikes, but lately it's been getting decidedly twisted? 
With the two NiMh batteries for my Giant Lafree Twist Lite (What were Giant thinking of with that name, must have been a committee job) nearly four years old, renewal was needed. The range had virtually halved and the performance was dropping due to increased cell resistance.
There were three choices:
1) A new one from Giant. Said to be 9Ah and 216 W/h, they've supplied one with only 156 W/h to at least one user, leaving the bike's range unchanged. The price £250.
2) Using Cellpack Solutions to re-cell the battery. They make the same claim as Giant about capacity, but A to B magazine found one they had re-celled to equate to 165 W/h when tried out. This would only give a 5% range increase. The cost £150 plus £8 to send it, £158 in all.
3) Buying a Powacycle battery for the Windsor or Salisbury models and scavenging the cellpack. Virtually all these electric bike 24 volt batteries use a similar 20 x D cellpack, though with different formations. These are claimed to be 8 A/h and 192 W/h, and this has been tested and verified in the A to B test of the Windsor model. That would increase the range by 23%. The cost £99 plus £10 carriage for non-Powacycle owners if applied, so maximum £109.
So the cost per Ampere hour respectively for the above is either:
£38.46 or £27.71 from Giant, depending on what they feel like sending you.
£22.98 (or £17.56 if they live up to their claim) from Cellpack Solutions.
£12.38 (or £13.63 if del. charge applied, mine wasn't) from Powacycle.
In a torment of uncertainty, I struggled with those options for over a fifth of a second before finally making a decision. I ordered the battery online on Sunday, they (guess who) despatched Monday and I received it DHL on Tuesday (yesterday), and last night re-celled one of the Twist's batteries.
At near zero charge, I charged it and went for a first run this morning. As expected, the battery is initially well down on capacity until it's had some four discharge and recharge cycles. I just had time to squeeze in a second run this afternoon after recharging and the battery is already greatly improved. Once the weather permits a couple more of those longer runs I'll be able to enjoy the full range increase, on a standard geared Twist up from 20 to nearly 25 miles, though on my geared up one, from about 17 to 21 miles.
The Powacycle battery is remarkable value. With a cheaply constructed but adequate case, it has a keyswitch built in with a pair of keys. To avoid owners being inconvenienced with carrying two keys, they very thoughtfully include a replacement for the frame mounted battery lock as well. For £99 that's stunning, and there's the bonus that if a Powacycle owner is unlucky enough to drop a battery and shatter the case, there's a new spare case here ready for them now.
However, re-celling a battery is not to be lightly undertaken. Up to 200 W/h of power can do a lot of damage if treated wrongly. It isn't just a case of popping in the cellpack and connecting two wires, far from it, there are other considerations. Batteries have the cell connectors strapped in different formations, there are temperature sensors to be correctly positioned, integral battery meters as per Giant may need to be provided for. There may be metal sensor strips which need to be transferred onto a new cell. The different fuse values and positions are important. It's often not worth it when a new NiMh battery is inexpensive as with Powacycle and eZee batteries.
Some time over the next week or two I'll do an illustrated write up on this for those who feel confident to tackle it, publishing it on my website and announcing that here. It will be detailed for the Twist battery, but with generic advice for other makes.
With the two NiMh batteries for my Giant Lafree Twist Lite (What were Giant thinking of with that name, must have been a committee job) nearly four years old, renewal was needed. The range had virtually halved and the performance was dropping due to increased cell resistance.
There were three choices:
1) A new one from Giant. Said to be 9Ah and 216 W/h, they've supplied one with only 156 W/h to at least one user, leaving the bike's range unchanged. The price £250.
2) Using Cellpack Solutions to re-cell the battery. They make the same claim as Giant about capacity, but A to B magazine found one they had re-celled to equate to 165 W/h when tried out. This would only give a 5% range increase. The cost £150 plus £8 to send it, £158 in all.
3) Buying a Powacycle battery for the Windsor or Salisbury models and scavenging the cellpack. Virtually all these electric bike 24 volt batteries use a similar 20 x D cellpack, though with different formations. These are claimed to be 8 A/h and 192 W/h, and this has been tested and verified in the A to B test of the Windsor model. That would increase the range by 23%. The cost £99 plus £10 carriage for non-Powacycle owners if applied, so maximum £109.
So the cost per Ampere hour respectively for the above is either:
£38.46 or £27.71 from Giant, depending on what they feel like sending you.
£22.98 (or £17.56 if they live up to their claim) from Cellpack Solutions.
£12.38 (or £13.63 if del. charge applied, mine wasn't) from Powacycle.
In a torment of uncertainty, I struggled with those options for over a fifth of a second before finally making a decision. I ordered the battery online on Sunday, they (guess who) despatched Monday and I received it DHL on Tuesday (yesterday), and last night re-celled one of the Twist's batteries.
At near zero charge, I charged it and went for a first run this morning. As expected, the battery is initially well down on capacity until it's had some four discharge and recharge cycles. I just had time to squeeze in a second run this afternoon after recharging and the battery is already greatly improved. Once the weather permits a couple more of those longer runs I'll be able to enjoy the full range increase, on a standard geared Twist up from 20 to nearly 25 miles, though on my geared up one, from about 17 to 21 miles.
The Powacycle battery is remarkable value. With a cheaply constructed but adequate case, it has a keyswitch built in with a pair of keys. To avoid owners being inconvenienced with carrying two keys, they very thoughtfully include a replacement for the frame mounted battery lock as well. For £99 that's stunning, and there's the bonus that if a Powacycle owner is unlucky enough to drop a battery and shatter the case, there's a new spare case here ready for them now.
However, re-celling a battery is not to be lightly undertaken. Up to 200 W/h of power can do a lot of damage if treated wrongly. It isn't just a case of popping in the cellpack and connecting two wires, far from it, there are other considerations. Batteries have the cell connectors strapped in different formations, there are temperature sensors to be correctly positioned, integral battery meters as per Giant may need to be provided for. There may be metal sensor strips which need to be transferred onto a new cell. The different fuse values and positions are important. It's often not worth it when a new NiMh battery is inexpensive as with Powacycle and eZee batteries.
Some time over the next week or two I'll do an illustrated write up on this for those who feel confident to tackle it, publishing it on my website and announcing that here. It will be detailed for the Twist battery, but with generic advice for other makes.
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