Giant Fathom E2 battery problem?

[Zlatan]

Recently purchased a new Giant E2 Fathom. Really impressed with bike.
However, in first week noticed battery doesn't show 100% full even straight after full charging.
Phoned shop, explained situation they said they would have a look at first service.
First service arrived, by which time, battery rarely charged over 96%.
They checked out battery said it was fine,but by this time I had realised range of bike was just about identical to my previous bike (Haibike Hard7 with 400wh battery,
and Giant is in theory 500wh, both use yamaha motor)
Carried on using bike (now done 16 rides) and last week put battery on charge (after using 97%) and it was still charging following day. (Led blinking on battery)
Took bike back to store, checked battery again. They are saying bike battery health is 92% and suggest I run battery down more before charging. (I, ve done 16 rides, averaging 32km,average battery use 80%, 13 complete cycles)
Shop refusing warranty, saying use battery to lower levels whilst riding to increase its health? (which is difficult since I need at least 80% to do planned ride and on 2 occasions I, ve run battery down to 5%)
I, m not too happy.
Shop saying bring it back in a month to retest? In hope battery health increases?
This is my 3rd purchased new ebike and I, ve built 3 others. All those charge to 100% and show full after at most 4 hrs charging.
Anybody any thoughts.
Not mentioning shop yet in hope they sort it.???
(To note, Haibike battery which has done around 6000 miles over past 5 years, still charges to spec in expected time and still shows 100% full on display after charging)

 

[Nealh]

Not all batteries charge to 100%, it depends on the default BMS top end balancing.
I have one that stops charging and balances to 4.15v per cell, doing so preserves the battery life cycle a little longer.

 

[cyclebuddy]

80% of a 500w battery in 32km/20miles seems like pretty heavy usage to me.

I have two 400w batteries that need to be charged differently to top them up. By default, they only charge to 40-41v when the charger light turns green. On one (TranzX), you need to unplug the charger, then put it back on charge. It then charges for another hour (using much less current) to fine balance the cells and get a measured 41.7v. The other (Fiido) again charges to 40-41v UNLESS you first switch it on (touch button), then it charges again to 41.7v. On my two other batteries which have no pretence of being "smart", they always charge straight to 41.7v first time.

Unless you measure final battery charge and/or what your charger is doing/consuming, it's not immediately obvious what exactly is happening. My guess is the manufacturers deliberately undercharge to prolong life.

This laptop does exactly the same thing. When the battery says it's fully charged, it isn't. Delving into the system, it's programmed to show it's fully charged when in fact the battery is only 80% full; that's when charging is set to stop by default.

 

[Zlatan]

Thanks for replies. The figure I was concerned about was this 92% battery health (which I haven't a clue what is measures). (They said battery was charged to 97% at time)..
Shop suggesting this figure will improve if I drain battery further during use seems rather odd?? But, been out this morning and bike/ battery performed fine. (started at 98%,which is highest I, ve seen it, and finished with 6%...)see how long it takes to charge and if charger switches off this time???

 

[soundwave]

giant make there own display and batts but still use the Yamaha motor but the batts health wont increase the more you use it if anything the batt health will go down over time not up as it losses capacity.

as long as your getting the expected miles from it id not worry about it as got 2 years of warranty to kill it off

 

[cyclebuddy]

The old Halfords Carrera batteries had a battery health function. IIRC, it was just a measure of how many times the battery/cells had been cycled. I'd guess it's a quick way for a retailer to tell if the batteries had been hammered to death when dealing with a warranty claim - Deliveroo riders and the like.

 

[Zlatan]

Thanks for input all of you. Much appreciated.