range completly naff with 13.4ah battery

[footpump]

last year I purchased a yospower 10.4ah bottle battery and used this with my Carrera subway with tdz 250 moter have now covered about 2100 miles.
range 30-35ish one journey 12 miles outward fairly hilly return journey 2 steepish hills did 25 miles battery showed 4 bars out of 8, next day 6 miles of flat battery ran out completely I mile from home.

did virtually the same hilly journey and wondered wether I would make it home.
I have an ebc battery 13.4 ah which has done about 600miles had a mixture of 15 full charges or top ups which I fitted to the Carrera as the battery connections are the same.

the ebc has now had 6 full charges since I fitted it to the Carrera but range is still poor about 26 miles , this is flattish terrain using sport mode (which is what I use when 10.4 was fitted)

i seem to get less out of 13.4 than the 10.4
spoke to someone Friday exactly the same ebc battery, but running there 500watt rear wheel kit about 30 miles flattish terrain.
i would expect nearer 40 miles from 13.4ah considering i tend to poot;le along about 12mph.
also running slimmer tyres.
now means anything hilly ill get even less range/cannot find anything obvious binding brakes etc

 

[Woosh]

your battery may be unbalanced.
A 36V cell string consists of 10 blocks of 3.6V each. If one block has lower voltage than the rest, when you pull a lot of Amps through the string, the one with the lowest voltage may dip below 3.1V, the BMS will cut off the power.
The fix is to run dowwn the battery as much as you can then recharge it to full, leaving the charger on an extra 30 minutes after the LED on the charger has gone green to rebalance the pack.
To avoid unbalancing the pack in the future, don't recharge it after only a few miles, leave it until you have done 15-20 miles and once or twice a month, leave the charger on an extra 30 minutes after the LED on the charger has gone green to rebalance the pack.

 

[footpump]

tried recharge+30mins have done 22 miles display jumps between 1 and 2 bars out of 8, but range still poor.
have now met 2 people same ebc battery but running 500w rear moters about 30miles range approx.
I am out of warranty as regards battery I did get nearer 40miles but on lighter bike mode 1 0r2 .
still seem to get less from 13.4 than 10.4 I originally used with Carrera?

 

[Woosh]

FP, you now need to measure the voltage of the battery to find out where the problem is with your 13AH battery.
Measure the voltage after a full charge
Ride about 10 miles, it does not matter if it's 15 milles instead of 10, please post the distance and voltage here.
Based on the range that you got with the 10.5AH battery, you should get about 30 * 1.3 = 39 miles with the 13AH. The expected voltage after a full charge is 40.5V and after 10 miles is 38V.
Ride until the battery starts to cut out then check the mileage and voltage again.
That should tell us where the problem may be and how to fix it.

 

[footpump]

i gave battery a full charge green light on +30 mins voltage 41.9v
15.3 miles covered 36.9v in sport mode flattish terrain
did a mixture of sport/turbo/throttle to run battery down to zero to one bar
and rear wheel raised off ground running throttle until moter was intermitant.

32 miles 34.3v total milage

not too sure what all this means thank you

 

[Woosh]

i gave battery a full charge green light on +30 mins voltage 41.9v
15.3 miles covered 36.9v in sport mode flattish terrain
did a mixture of sport/turbo/throttle to run battery down to zero to one bar
and rear wheel raised off ground running throttle until moter was intermitant.

32 miles 34.3v total milage

not too sure what all this means thank you

Your battery is not brilliant but OK.

The 100% SOC (SOC = state of charge, 100% SOC: battery is full) corresponds to 41.9V (as measured by your voltmeter), the 0% SOC will be 31.9V on your battery. 34.3V corresponds to 100% - (41.9 - 34.3) * 10% = 24% SOC.
Your average battery consumption is thus:
13AH * 36V * 76% / 32 miles = 11.1 WH/mile
That's average.
You can probably get another 4-5 miles out of the battery if you ride on minimum assist level.

 

[JuicyBike]

Foot Pump, can I ask what your tyre pressures are?
Main cause of reduced range is low tyre pressure. Might be preaching to the converted of course...

 

[footpump]

thanks all for replies tyre pressures I keep at 60psi.
the most frustrating thing for me is my 13.4ah does not give any more range than generic Chinese 10.4ah at the same setting sport mode and same terrain.

 

[flecc]

thanks all for replies tyre pressures I keep at 60psi.
the most frustrating thing for me is my 13.4ah does not give any more range than generic Chinese 10.4ah at the same setting sport mode and same terrain.

Depends which discharge rate each has been quoted at. If the Chinese battery has had it's capacity measured at a higher discharge rate than the 13.4 Ah one, the true capacity might well be the same for both.

Nominal capacity isn't cast in iron as shown, and realised capacity in use depends on the discharge rate during riding.
.

 

[Woosh]

thanks all for replies tyre pressures I keep at 60psi.
the most frustrating thing for me is my 13.4ah does not give any more range than generic Chinese 10.4ah at the same setting sport mode and same terrain.

there are factors like internal resistance that have an effect on the range.
To make an objective comparison, you need to charge your old 10.4AH battery to full, measure its voltage, run it down like you did with the 13.5AH battery, record the mileage and measure its voltage again.