Well so far so good, took the bike for a good few blasts over the weekend and todate the battery hasnt even flinched
Must have done a good ten miles today and at full bore
![Shocked :shock:](./images/smilies/icon_eek.gif)
got back home and it was still felt like it was fully charged
Jeremy wrote:The voltage will stay a bit flatter with LiFePO4 than with your old SLA, so you're right, the bike "power meter" will probably not be that useful.
That would explain the full power feel during the whole journey, where as with the SLA's you notice the voltage drop off.
Jeremy wrote: Fitting a Watts Up or Cycle Analyst is a pretty good idea, as this will show how many amp hours have been taken from the battery, along with some other useful information.
What
![Shocked :shock:](./images/smilies/icon_eek.gif)
more expense
![Shocked :shock:](./images/smilies/icon_eek.gif)
, crumbs these LiFePO's are quite money hungry arnt they
Jeremy wrote:Fully charged and hot off the charger, you should get around 3.65 volts per cell, so around 29.2V for your 24V nominal pack. This quickly drops off charge, to a cell resting voltage of around 3.25 to 3.3 volts, around 26 to 26.4v for your pack. Under load the cells will drop to about 3.2V per cell (25.6V for the pack) and stay there until nearly flat, when they will drop quite quickly down to the BMS cut-off point of around 2.5V per cell.
Cheers Jeremy, thats REALLY useful info for a LiFePO virgin
Jeremy wrote:Using a volt meter type power indicator isn't very useful with these cells, because of the flat discharge curve. Your best bet is to either get a Watts Up or Cycle Analyst or do some range testing where you can ride home from the point where the pack runs out. You'll find that the pack capacity will slightly increase over the first few charge/discharge cycles, so if you do a calibration range check now you should have a bit of power to spare in the future.
You can buy a Watts Up in your local model shop, or from one of the on-line model shops. The Cycle Analyst is sold by ebikes.ca from their on-line shop.
Jeremy
Looks like another purchase is coming up then
Crumbs these LiFePO's need a lot of stuff, and there was me thinking it was just a case of bunging them in
The quest continues, but early signs are looking VERY good
ChrisB