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Author Topic: Battery capacity testing  (Read 1364 times)

zlagger

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Battery capacity testing
« on: July 11, 2013, 07:46:25 AM »

I have recently added a Cycle Analyst to my 2010 zero X.

I added it to get accurate info from my battery and measure performance.

Zero says that the 2010 X battery is 35Ah on their specs page.  Here is what I got on mine after doing a ride to empty today.



So 27Ah is only 77% of claimed performance.  Has anyone else checked theirs?
« Last Edit: July 11, 2013, 07:48:02 AM by zlagger »
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zlagger

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Battery capacity testing
« Reply #1 on: July 11, 2013, 07:51:05 AM »

Oh and if you want kWh then I got 1.279kWh from a pack rated at 2kWh.

So what do you guys think?  Is Zero over rating packs, or do I have an underperforming battery?
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WindRider

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Re: Battery capacity testing
« Reply #2 on: July 11, 2013, 08:06:25 AM »

How many charge cycles are on that battery pack and was it ever left off charger for an extended period of time?

I don't remember what the longevity rating was for 2010, 2011 models but I remember that when the 2012 versions came out the longevity ratings went way up so it could be that you are starting to see some lifetime issues with that pack?
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zlagger

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Battery capacity testing
« Reply #3 on: July 11, 2013, 08:21:37 AM »

I don't know the cycles... Just bought the bike.  The guy I bought it from said zero redid the pack in early 2012. So that was a factor at the time of purchase
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Doctorbass

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Re: Battery capacity testing
« Reply #4 on: July 11, 2013, 09:28:36 AM »

Zlagger if you search for the thread i started about this on my DS 2011 you will find that after i added my cycle anlayst, i got  3000Wh from the claimed 3.9kWh wich represent 2.5Ah per cell that are rated 2.9Ah.

it is pretty similar to you. but the problem is that our battery are not new so it is difficult to know if it'S because of the battery age or not...

Gladd to see you also added this great very usefull tool!.. for me it is now became inpossible to run out of juice sinc ei know exactly the Wh i'm using!

Doc
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protomech

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Re: Battery capacity testing
« Reply #5 on: July 11, 2013, 11:54:53 AM »

The nominal capacity for your pack is 14s * 3.7 V = 51.8V .. 51.8V * 35 Ah = 1.81 kWh. Zero typically emphasizes the absurd maximum capacity rating, which is end-of-charge max pack voltage times amp hours. You're seeing 71% (1.279 kWh / 1.81 kWh) of rated capacity.

1.279 kWh / 26.95 Ah = 47.5V average.. not too bad, considering the pack is probably discharging pretty quickly. Also even when new Zero probably didn't quite allow for 100% discharge .. figure 95-100% start charge down to ~10% "bike off" charge = 85% to 90% available capacity when new.

Molienergy rated the cells used in the 2008 - 2011 Zeros at a few hundred cycles to 80%. They're not terrifically durable, though your pack presumably has some / all newer cells?
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Richard230

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Re: Battery capacity testing
« Reply #6 on: July 11, 2013, 08:24:58 PM »

The 50 Ah rated High Power batteries on my Electric Motorsport GPR-S (when new) would go flat after using 40 Ah according to the CA installed on the bike.  My understanding is that getting 80% of the rated maximum capacity out of LiFePo4 battery cells is as good as it gets.
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eyeinsky

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Re: Battery capacity testing
« Reply #7 on: July 12, 2013, 02:25:34 AM »

Hi Guys can you post a link to where you got the battery annalist.

I'm looking for good one too

Thanks jerry
« Last Edit: July 12, 2013, 07:31:34 AM by eyeinsky »
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Doctorbass

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Re: Battery capacity testing
« Reply #8 on: July 12, 2013, 07:21:02 AM »

The nominal capacity for your pack is 14s * 3.7 V = 51.8V .. 51.8V * 35 Ah = 1.81 kWh. Zero typically emphasizes the absurd maximum capacity rating, which is end-of-charge max pack voltage times amp hours. You're seeing 71% (1.279 kWh / 1.81 kWh) of rated capacity.

1.279 kWh / 26.95 Ah = 47.5V average.. not too bad, considering the pack is probably discharging pretty quickly. Also even when new Zero probably didn't quite allow for 100% discharge .. figure 95-100% start charge down to ~10% "bike off" charge = 85% to 90% available capacity when new.

Molienergy rated the cells used in the 2008 - 2011 Zeros at a few hundred cycles to 80%. They're not terrifically durable, though your pack presumably has some / all newer cells?

According to my measurement, the 2011 and 2010 battery BMS are cuting once one or more battery bank reach 3.0V. the Molicells are rated 2.5V for the lvc but it is recommanded to go as low as 3.0V minimum.


The HVC is at about 4.15V so the zero cells  from the 2010 and 2011 are used in a range of 3.0V to 4.15V

i suspect that the capacity loss is due to the cell ageing and cell being left on the charger 24h/24  wich degrade more the cells life.

I got one of the "2kWh" pack from a x 2009 that i tested and the lowest cell bank was 27.5Ah and the highest was 31Ah out of the 35 rated. I recall this pack is 4 years old...)

Doc

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Zero Drag racing bike: 12.2s 1/4 mile and 7.3s 1/8 mile

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zlagger

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Battery capacity testing
« Reply #9 on: July 12, 2013, 08:23:21 AM »


Hi Guys can you post a link to where you got the battery annalist.

I'm looking for good one too

Thanks jerry

It is found here http://www.ebikes.ca/drainbrain.shtml
Make sure that you get the high current model and a shunt with a suitable rating.
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zlagger

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Battery capacity testing
« Reply #10 on: July 12, 2013, 08:25:34 AM »

Completely agree, it's a great tool.  I will add one to any EV project.

Zlagger if you search for the thread i started about this on my DS 2011 you will find that after i added my cycle anlayst, i got  3000Wh from the claimed 3.9kWh wich represent 2.5Ah per cell that are rated 2.9Ah.

it is pretty similar to you. but the problem is that our battery are not new so it is difficult to know if it'S because of the battery age or not...

Gladd to see you also added this great very usefull tool!.. for me it is now became inpossible to run out of juice sinc ei know exactly the Wh i'm using!

Doc
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