How do you check a Honda e before purchase?

[happyV]

The readout of the SoH is in Ah. But because the cells are 50Ah each in pairs. Ah equals %.

It almost doesn't change. During driving it doesn't change at all. After charging it sometimes changes within 0.2 %.
Maybe some full charges so it can balance the cells (but I actually doubt that it balances, because I cam read out the highest and lowest charged cell and the difference is at least 1%) will change the SoH.

[londiniumperson]

The readout of the SoH is in Ah. But because the cells are 50Ah each in pairs. Ah equals %.

It almost doesn't change. During driving it doesn't change at all. After charging it sometimes changes within 0.2 %.
Maybe some full charges so it can balance the cells (but I actually doubt that it balances, because I cam read out the highest and lowest charged cell and the difference is at least 1%) will change the SoH.

Thanks, if a few of us can access this info and report on it over time, then we should get a good picture of any battery deterioration.

[Rei]

From what I can gather the battery warranty is 8 years and 70%, so a further 15.53% needs to be lost to trigger a free repair/replacement. But that assumes that they use the same SoH value. Most cars report a different SoH and SoC on the dashboard and on some official diagnostic tools to what you get out of the ODB-II port.

But that 85% figure is suspiciously close to what you can actually get from the battery, a bit less than 30kWh. Maybe 85% is actually what it reads when brand new.

In other words it doesn't include the buffer, so even if the car has in fact lost a few kWh from the buffer, it can still get 85Ah out of the batteries so Honda would argue that the SoH is 100%.

The example I read about where the battery was replaced under warranty did involve a bad cell, resulting on the SoC dropping suddenly as the owner was driving. The Leaf does the same thing when it has a bad cell. Honda don't do battery repairs apparently so they replaced the whole pack. That's the kind of thing I'm worried about really, it's the kind of failure you get when a car has been sat around stationary for a long time.

[happyV]

My app reads out the same values as the iHDS from Honda itself.
There are e out there who have over 60.000km and an SoH of 90%.

Just compile the app yourself and run it. You'll see the SoC from the dash and the "actual" SoC.

[Rei]

Sure, but I mean the Honda app might display it differently. A lot of cars show a different SoC on the dashboard to what the BMS reports over OBD2.

Anyway, it's worrying that yours has only 85% if others with 60k km have 90%. What sort of mileage does yours have? What age?

[happyV]

40000km, about three years.

Yes, the SoC on the dash is the "usable" capacity. And "the honda app" ? there is my App and the iHDS, which is the genuine OBDII-Tool from Honda.
My app is reading the exact same values off of OBDII as the Honnda-OBDII-Tool.
And the BMS-SoC is of course higher (and lower, depending on the SoC) than the dash-SoC.

[Reuben80]

There is also Power Check control app but on the E cannot read cell voltage. Mine after one year SOH went down to 88% but then stayed 88% for the following 2 years (58000km). Don't know how much trust worthy it is.

[Rei]

That sounds very much like an unbalanced cell. It makes the SoH go down, but then gets corrected by a full charge or rapid charge.

The SoH can never go back up again. So stays put until it comes back down again, however long that takes.

[EEEE]

If you think about it logically, you want the most abused battery you can find. That way you are more likely to get a free replacement within the 7 years. Go for broke I say!

I have never checked the SOH on my battery, and id never want to I don't think. Its just a black box telling you what another black box tells it. Black boxes are full of lies and deceit (or bad software).

There is no concrete information on the pack/cells/calibration/etc , so its all just made up numbers. Some cells might be better than others, but would Honda calibrate each pack and set a software value accordingly? I doubt it very much...

[Rei]

Some people do suggest hammering the battery as much as you can to get the SoH down, especially if you seem to have a bad cell. I don't know what Honda are like, but Nissan won't do anything unless you get below the threshold, even if you car is suddenly dying without warning.