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post #1 of 17 (permalink) Old 12-18-2016, 03:58 PM Thread Starter
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Measured Battery Capacity

I FINALLY got the dealer to give me an actual measurement of the condition of my HV-battery instead of just giving me a PASS/FAIL indication. My battery was measured at 50.9Ah. The initial specified capacity was 52Ah, meaning I've lost 1.1Ah or 2.1% of battery capacity in two years and 14,500 miles of driving.

How does that compare to your experience?
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post #2 of 17 (permalink) Old 12-19-2016, 08:11 AM
 
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Sadly, you can't learn much from a single number.

It's not really a measurement, just what the BMS thinks the capacity is from it's internal model. The number varies about +/- 1 Ah from one reading to the next. Also, you don't know what the actual capacity was initially. That, too, could be an Ah or two off nominal. So your battery may have degraded a lot more than you think, or not at all.

The only way you can track the aging process is to buyild the odyssey box, read the capacity regularly, and fit the data to get a trend.
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post #3 of 17 (permalink) Old 12-20-2016, 10:16 PM Thread Starter
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@SuperSmartie : The BAP contract is based on the measurement the car makes. As such, it is really the only measurement that matters. If nothing else, having ~5 years of data would help establish a trend. In any case, having ~5 years of a "PASS" test result is of no use.
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post #4 of 17 (permalink) Old 02-11-2017, 05:10 PM
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Today @ 8,918 miles was year two "B Service" on our leased MY15 ED w/BAP.

Beginning with the baseline capacity of 52 Ah, the current reading came in at 50 Ah a loss of 2 Ah.

Question - would a charge level of less than 100% (79.7%) be of any impact on the capacity reading?

Note, to get a measure of the current HV-battery capacity you need to ask for a printout of the report titled "Check of high-voltage battery (maintenance)."

BAP prepaid all HV battery testing and did include the desiccant cartridge (part was in stock), part and labor.

I did opt to have the brake fluid flush performed at a cost of $90 + $20.

A 451 Pure was provided as a loaner, do find it odd that they aren't using a 453 to tease some of their current/loyal customers?
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post #5 of 17 (permalink) Old 02-12-2017, 06:05 AM
 
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Question - would a charge level of less than 100% (79.7%) be of any impact on the capacity reading?
The charge level at the time of readout has no effect on the number.

The BMS stores a new capacity estimate every time conditions are right. (discharged to < 40%, waited long enough, charged to >90%, waited long enough). The smartcenter just reads out the number from the last time that happened, which could be weeks ago depending on your typical use.
Star (or the odyssey box) will also tell you how many days ago that was, but conveniently it's not printed on the report.
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post #6 of 17 (permalink) Old 02-12-2017, 11:05 AM
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The BMS stores a new capacity estimate every time conditions are right. (discharged to < 40%, waited long enough, charged to >90%, waited long enough). The smartcenter just reads out the number from the last time that happened, which could be weeks ago depending on your typical use.
Thanks for confirming my thoughts that this "test" is yet another ED "guestimate" and in this case looks back at historical data to the last point that the conditions were "right."

Again raises the question as to why the Euro test wherein they actually force the <40%/>90% is not conducted in the U.S.? Guessing that the Euro test requires more hours be charged to the customer or smart?
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post #7 of 17 (permalink) Old 02-12-2017, 10:31 PM
 
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... raises the question as to why the Euro test wherein they actually force the <40%/>90% is not conducted in the U.S.? Guessing that the Euro test requires more hours be charged to the customer or smart?
I can't figure it our either. Mostly I just chalk it up to the general lack of interest - and consequently a DGAS attitude regarding EV's among US car dealers and the people who work there. On my first year service at my local dealer (not the one 230 miles away I had to go to to get an ED), I specifically made sure it was driven to below 30% before charging full a few days before the service date. I don't even bother to ask the service rep. any questions because the answer is most likely to be wrong. Like when I asked about why they don't sell Smart ED's and the guy said that "electric cars won't go up the hills around here".

Oh, and they refused to provide a loaner. Thankfully the dealer in in the city with public transit I could use to get back home.

You are pretty easy on the miles. I'm at a little over 17K miles with the 2 year point still 3 months away. I'm going to be right at 30K at the end of the lease.
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post #8 of 17 (permalink) Old 02-13-2017, 07:32 AM
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You are pretty easy on the miles.
That's a product of too many cars (2 smarts the other a modded ICE cabrio) - only regret is that ED is not a cabrio but the upgrade was too expensive.

Miles are also light because the public charging opportunities in (non-CARB) NC remain limited and have proven to be not very dependable (occupied or broken). 97% of all charging has been done at home.

After driving ED at the road show tried for two years to get our local dealer to order with no luck. Wanting to be a part of the great EV Beta Test, finally had one built to order and delivered to CA with shipping to NC - sometimes the things we do just make no sense?
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post #9 of 17 (permalink) Old 02-13-2017, 09:16 AM
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I can't figure it our either. Mostly I just chalk it up to the general lack of interest - and consequently a DGAS attitude regarding EV's among US car dealers and the people who work there.

I don't even bother to ask the service rep. any questions because the answer is most likely to be wrong. Like when I asked about why they don't sell Smart ED's and the guy said that "electric cars won't go up the hills around here".
Because inquiring minds want to know, I asked the question - why is the Euro ED battery testing protocol different than the U.S.? "The Technician is not sure what the numbers mean overall but the HV battery tested ok and there is no faults in the system."

To which I said that "number" can be pretty important to your customer who may be renting the HV battery under the BAP program - The response, "without there being any codes, the battery is perfect."

My response - PERFECT - not true, "capacity" (degradation) will never throw a code.

Their response - "we are not sure that our software will allow us to conduct the Euro version of the test but if you bring the car back we will try, ALL at YOUR COST!"
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post #10 of 17 (permalink) Old 02-13-2017, 01:38 PM
 
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The only thing different about the so-called "euro" test is that they force a new estimate to happen by doing just what the BMS looks for: discharge to <40% internal SOC (<20% on the dashboard gauge to be sure), let it sit for 2h, charge to >90%, let it sit again. No real measurements in old Europe, either.

The US tech would have to do that, too, if your driving style is such that the estimate doesn't happen by itself. If the last estimate is too old, it won't give a capacity on the test report and probably not say "PASS", either.

You can just do the above ritual the day before you go in for the battery check and get the fresh results. No cooperation of the technicians required.
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