We commonly get people asking if they should be concerned about the State of Health (SoH) of the battery in their Leaf or eNV200 dropping by several percent just after they have purchased it. In many cases this is an expected result of the method of charging changing from primarily fast charging (very common in Japan) to slow charging. This is illustrated in Figure 1 below, showing how sequential fast charges cause SoH to increase, perhaps by as much as 8%. When slow charging is resumed, SoH then drops back down. There is also often normal variation in SoH of about 1-2% even when the Leaf or van is continuously slow or fast charged.
Figure 1: Battery State of Health (SoH) as a function of odometer. There is large variation in SoH, especially with sequential fast charging. Even when only slow charging there is still variation on the order of 1-2%.
Hence if you do experience a drop in SoH following purchase, or see variation over time, this can be normal behaviour. When buying a car it can be useful to take into account that the SoH may drop by several percent post purchase if after a car with a certain SoH.
Daniel Myall, Henrik Moller, Dima Ivanov
I really like this description and infographic. I’ll add this to my short list of links from Flip the Fleet that I regularly post to potential Leaf purchasers on social media.
Thanks Petra!
When I bought mine I had a large number of quick charges showing on the leaf soy app. I started cycling the battery slow charging only and over the next few months my battery SOH increased from 91 to 95 at the peak. I assumed this was changing the style of charge and with moving in to the summer months.
Yes, you can also see an increase in SoH post purchase if (1) the car was previously used in a cold area and now used in a warmer environment, (2) the previous estimate of SoH was low and fuller cycling of the battery lets the car see that it actually has more capacity.
So from a buyer perspective you would want to ensure the car you are viewing does not get ticklled up with fastcharging
To show a higher SOH% and therefore a higher asking price – what would be the best way to ensure that?
Hi Mark,
Good question! Sadly, we aren’t aware of a means of doing this check at present.
Dima 🙂