[ConnieD]

I was thinking of purchasing one or two components at a time, because I would like to have LiFePO batteries.

Maybe Hill Topper will offer it?

If not, I wonder if I purchase the Hill Topper controller I would be okay?

I know I need a charger that will properly charge the LiFePO batteries. Is your LiPO charger already compatible?

I could not find the specifics of your present LiPO's and the "Light Weight Lithium batteries" promised.

I already have LiFePO or LiPO batteries and charger planned for my amateur radio hobby.

Maybe I can have it work out my LiFePO or LiPO battery pack to do double duty?

I understand if I keep to 250 Watts 24 Volt and maybe a 7.5 AH LiFePO "battery pack" the e-motor is happy.

[Chris Clean Republic]

*Updated and edited for clarity* - Chris 10/27/11

Hi Connie,

Yes the Hill Topper can work with most commercially available batteries. We will happily provide you the motor and controller for your project and we can answer any questions you may have. The motor controller works with any 24 volt battery. Our battery charger is compatible with our specific batteries, so you may need to purchase a charger that your battery manufacturer recommends. I hope this helps. Let me know if you have any other questions.

[dynodan]

So Chris,

What are those specific thresholds? Could a HT LIB controller be simply wired/connected the 24V/20AH Ping LiFePO (see attached link: http://www.pingbattery.com/servlet/the- ... PO4/Detail) and successfully operate the CR HT wheel motor? Would the Ping charger then be safely plugged into/managed by the HT controller?

[Chris Clean Republic]

Hi dynodan,

Good question. Yes any commercially available 24 volt Lithium battery will work with our controller and motor. Any ampere-hour (Ah) rating will work, just as long as the battery is 24 volts. The higher the Ah rating, the longer the battery should last. Any voltage higher, and it will likely burn out the controller as some customers have done when hooking up a 36 volt battery.

The Ping charger will be fine, because the charge wire doesn't run through the controller.

I hope this answers your questions. Thanks.

[dynodan]

Chris,

I have a CR LIB that has gradually worn out from daily running to BMS auto-shutdown over a 6 month period (range now down to 1 mile). But, after it quit working the last time, I noticed that all 4 green LED charge indicators still light when the button is pushed. Before I dispose of the lithium cells, I thought I should probably ask if there is a direct relationship between those indicator lights and the batteries' condition? It seems unlikely that the BMS or controller circuits only would fail in such a progressive manner?

[Chris Clean Republic]

Hi dynodan,

That's an excellent question. The LED indicators light up when the complete battery pack is at or near the 26-29 volt range, which is where it should be. The BMS is likely working perfectly, but what explains the low range?

Each battery pack is made up of 14 Lithium cells, (2 sets of 7 in a series, running in parallel). The BMS is designed to shut off the battery pack when even one of the cells gets to a low voltage, in an effort to keep the cells stable. In this case it seems that you have most of your cells holding a charge, but there might be just one or two that aren't. What this means in practice, is when you are out on a ride, the BMS reads that one or two of these low cells are at the low voltage cutoff and shuts down the entire pack, despite the pack as a whole having a higher charge. If you were to press the LED indicator button, it might read you have a high charge, because most of the cells still do.

The only way to tell for sure would be to test each cell with a volt meter and find the low voltage cells that are causing the problem. Taking the pack apart can be dangerous and we don't recommend doing this for your safety.

[dynodan]

Thanks Chris. Quite illuminating.
I assume the BMS shuts down when any cell reaches a minimum voltage threshold in order to protect that cell from damage due to over-discharge. One MIGHT think that the remaining good cells could be separated & combined with other salvaged cells to construct another working LIB, but I'm guessing that once a few go bad, the rest can't be far behind. Looks like my next stop will be the recycling center.

[Chris Clean Republic]

dynodan,

Glad I could help. Yes you are correct the BMS does shut down when any cell reaches minimum voltage. One would be right that the high voltage cells could be salvaged and combined with high voltage cells to construct another working Lithium battery pack. It would require testing each cell with a volt meter and finding out what cells would still have a higher voltage. By combining new cells with older cells you may run into this same problem later down the road though. Additionally, this may damage the new cells. Mixing and matching new and old cells can manifest unforeseen consequences, including the new cells burning out much faster. We as a company cannot endorse or ensure the safety of such a project and would highly discourage anyone from attempting.

Good luck!

[fishbender]

Hi all,
I'm using a standard battery on my bike. I've been riding almost daily since I got the hill climber kit in July. But now, my battery runs out of power within a few minutes of use. I'm not over exerting it, like powering me up a hill without peddling, etc. Is it time to buy another battery?

Terry

[Chris Clean Republic]

Hi Terry,

It could be time for a new battery, but it depends on how much use it has. If a battery is used every day on very steep hills and hauls a heavy load, it will run out faster. Have you checked to make sure that it is being charged properly? If you have, then yes it may be time to purchase a new battery. We do offer a discount on returning customers buying a replacement battery. E-mail me for more details: chris@cleanrepublic.com