Awful battery life?

[Nickolp1974]

got my race van all done so thought it time to take my bike to the lake district. Had some fun out with the mrs but she'd had enough as she ended up pushing rather than riding. So I went off on my own, sorted a nice loop but only 6 miles in and about 1500ft of climbing I was down to just 2 bars(shimamo bt8010/e8000) the last 300 ft was a bit boggy and windy but not too bad. The last bar i barely get 3 miles on the flat so I had to turn back, gutted.
So my bike has now covered 2200km, battery health is at 87% with 63 cycles and I weigh approx 96kg fully loaded.
My battery obviously does not like to be under load for long periods. Bike was in a de-tunned trail mode for the ride. I got back to the van grabbed my other halfs nearly new battery and went off again, different trail but steepish and techy, did 7.5 miles on 1 bar!

Do you think I should be sending my battery in under warranty?

 

[Bellefield]

try to do the same loop (or even a road loops as its easier to replicate conditions) keeping it in the middle setting for both batteries from a full charge and see if there is much difference. If there is make sure you record route and settings and give the dealer a call and explain the fall off in power to him. 2,000km is nothing for these bikes and batteries

 

[DrStupid]

Try leaving the battery on the charger until the lights go out (may take several hours).

I suspect your pack is not balanced.

 

[STATO]

Bettery indicator means nothing really, a guestime based on usage upto that point. My e7000 motor will eat 2 bars in the last climb to my house. Its steep and prolonged with a few mile of flat or downhill before it. This means the prediction of range is based on easy assist, not full blast max effort, so it sucks the battery flat half way up the climb pretty regularly.

 

[DrStupid]

The Shimano system on my KHS (e8000) started cutting out at 2 bars! The bike only had about 550 easy miles. I bought a Watt Hour Meter to take a rudimentary measurement of the battery performance while taking a charge.

Before the meter arrived, I believe I had already solved the trouble, by leaving the battery on the charger until the lights went out (letting it balance?).

Shimano completely leaves the balancing terminology out of their info-text (please correct me).

Am I free to speculate?

I suspect that the Shimano system, is like most other lithium BMS systems, and balances the pack at the end of the charge cycle, in trickle mode. Whatever the case, after two cycles leaving the battery on the charger until the lights went out, my battery seems to be holding up much better at the end of the discharge cycle. The last two rides, I rode it into the garage, with zero miles on the range, but still performing nominally in boost baby! My last charge on the watt meter showed 460 watt hours and the fact that I was still climbing hills in boost, leaves me to believe the battery has a normal capacity.

Take this as you will, try it, let me know. I may very well be wrong.

 

[Nickolp1974]

Nearly always leave it till lights go out. It does get flattened every ride.its in the shop for a test tomoz so I'll see how that goes. Will also do a like for like test at the wkend with both batteries. Thanks for the input chaps