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Discussion Starter · #1 ·
Two questions:
1. Why has Mercedes chosen a very large battery buffer (13.8 kwh), which is significantly larger than other manufactureres' buffers?
2. If one wishes to hold charging to 80% of the EQA's actual 79.8 battery capacity, the usable charge is about 64 kwh. If one holds to 80 percent of the advertised 66 usable capacity, the usable charge is about 53 kwh. The difference is a considerable 11 kwh!

Will some wise person tell me why I should not charge to 64 kwh, based on the above, rather than the very conservative 53 kwh?
 

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There’s no problem with charging to the indicated 100% if you ar going to drive right away, it’s only a bad idea to leave the car sitting for some time with the battery at 100%
 

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I assumed, possibly incorrectly, that the large buffer was to minimise warranty claims on the battery. I believe the car has an 8 year battery warranty in most countries. This seems like a reasonable timeframe.

And I'll be happy to charge the battery to the full mid 60's kWh on this basis.
 

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Minimise warranty claims would seem another benefit to the manufacturer. And I suspect there is a log somewhere of charging behavior in case somebody tries their own method of charging not recommended in manual
 

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Two questions:
1. Why has Mercedes chosen a very large battery buffer (13.8 kwh), which is significantly larger than other manufactureres' buffers?
2. If one wishes to hold charging to 80% of the EQA's actual 79.8 battery capacity, the usable charge is about 64 kwh. If one holds to 80 percent of the advertised 66 usable capacity, the usable charge is about 53 kwh. The difference is a considerable 11 kwh!

Will some wise person tell me why I should not charge to 64 kwh, based on the above, rather than the very conservative 53 kwh?
Hi
The EQA actual battery size is NOT 79.8kWh...it´s actually only 68.2kWh so the buffert is really small...Have not got this confirmed by Mercedes but from a reliable other source..
 

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I’ve seen various figures for the gross battery capacity on the EQA, they all agree usable capacity is 66.5kwh. Even the drivers manual has a table saying EQA250+ usable capacity is 70.5kwh and all other EQA models are 66.5kwh but both tables say it takes the same time to charge from 10% to 80%!!
Extrapolation from that 10 to 80% time (also quoted in the sales brochure) would suggest a gross capacity (I.e. 0 to 100%) of about 76kwh
 

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Discussion Starter · #10 ·
I’ve seen various figures for the gross battery capacity on the EQA, they all agree usable capacity is 66.5kwh. Even the drivers manual has a table saying EQA250+ usable capacity is 70.5kwh and all other EQA models are 66.5kwh but both tables say it takes the same time to charge from 10% to 80%!!
Extrapolation from that 10 to 80% time (also quoted in the sales brochure) would suggest a gross capacity (I.e. 0 to 100%) of about 76kwh
I’ve seen various figures for the gross battery capacity on the EQA, they all agree usable capacity is 66.5kwh. Even the drivers manual has a table saying EQA250+ usable capacity is 70.5kwh and all other EQA models are 66.5kwh but both tables say it takes the same time to charge from 10% to 80%!!
Extrapolation from that 10 to 80% time (also quoted in the sales brochure) would suggest a gross capacity (I.e. 0 to 100%) of about 76kwh
This is what Mercedes says about it:
Mercedes-Benz EQA powertrain
For the first version of the EQA, Mercedes-Benz says that the vehicle is equipped with 66.5 kWh battery pack.
However, that’s the useable capacity. The pack is rated 190 Ah at 420-volt, which would mean a total capacity of 79 kWh – leaving a giant, almost 13 kWh buffer.
 

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This is what Mercedes says about it:
Mercedes-Benz EQA powertrain
For the first version of the EQA, Mercedes-Benz says that the vehicle is equipped with 66.5 kWh battery pack.
However, that’s the useable capacity. The pack is rated 190 Ah at 420-volt, which would mean a total capacity of 79 kWh – leaving a giant, almost 13 kWh buffer.
Sorry, my writing error, the extrapolation I made doesn’t produce a “gross “ capacity of 76kwh instead a 0 to 100% capacity which is of course the usable capacity, so your 79kwh gross figure (including buffers) may well be correct. I was attempting to show the usable capacity of 66.5kwh doesn’t always agree with Mercedes’ calculations on charging times in the printed information.Their range calculations in the sales brochure also work only with a usable battery capacity of 76kwh e.g. A claimed range of 263 miles (423km) (WLP) and a power consumption of 179wh/Km, only works with a 76kwh battery capacity.
saying that practical experience with charging my EQA at 11kwh for three hours adds about 50% to the battery, which agrees with a capacity of 66.5kwh. So who knows what the real figures are.
 

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Discussion Starter · #12 ·
Well, my hope is that Mercedes will respond to market pressure and offer a programming update increasing the usable portion of the gross capacity, still leaving a market-leading size buffer :)
 

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I recall seeing a comparison of vehicles being fast charged, and how the charge rate reduces around 80% and beyond. The EQA had one of the fastest overall charge times as there was less reduction. I guess this is due to the buffer.
 
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