Charge vs Capacity after full Charge

[nehandertal]

Hi all

I've got a 2019 model, 1 year old now with 13000 km.
Current Capacity as per Whatchdog is 36,8Ah, so I have lost 20% of the total capacity.

I live in Spain, and I think I am taking good care of the car.

I have been doing some personal testing to see what is happening, and this is the outcome:

- I daily do about 30 km daily and leave the car charging at night, using a wall charger limited to 16A (220V).
- Capacity reduction is more or less -0,1 Ah every 500km, except for two times that was -0,5Ah.
- The car usually charged below the total capacity about 0,1 - 0.,3 Ah, but some times the car charged 1Ah above the capacity. I noticed that when charging at my parent's house using the charger supplied by Mitsubishi.
- I thought that maybe the reason was the charging speed, since it was 10A against the 16A of my wall charger. But no, changing the limit of the wall charger to 10A changed nothing.
- In the end I thinkl I have found the reason: if I got the car depleted until the ICE fires up, then I got a charge above the capactiy after a full charge.. The charging limiter is set to 10A yet, so I still have to test if at 16A the results are the same.

Therefore, the conclusion is that BMU always sees that after a full charge the car is not getting to the current capacity so the current capacity is lower and reduces that 0,1Ah. I expect now that I will not have this -0,1Ah so often.

This week I am driving until ICE is fired, the car is chargin up to 37,8Ah (capacity remains 36,8Ah). Will continue doing the same for a while and then change charger limiter to 16A and see if the car still charges above capacity.

Has someone seen the same? Or is it all nonsense?

Thanks

 

[nehandertal]

Hi Again

Second episode of my particular TV Series:

I have been charge charging at 10A (220V), and always waiting to charge until the ICE switched ON:

-17 Sept: Charged 0,9Ah above capacity.
-18 Sept: Charged 1Ah above capacity.
-22 Sept: Charged 0,9Ah above capacity.
-23 Sept: Charged -0,1Ah below capacity.
-24 Sept Charged 0,9Ah above capacity. Here, after this charge, Whatchdog informed about a loss of capacity of -0,1Ah.

Now capacity is 36,7Ah (490km since the last capacity loss).

After that loss of capacity I tried to charge without waiting the ICE to switch ON:

-27 Sept: Charged -0.4Ah below capacity.

"Charge Cost" read from the car is aligned to these readings. When watchdog read higer charge, the charge cost went also up. Therefore, I think the gain in charge is real.

My conclusion is that it is better to let the ICE start before charging, although it does not work always.

I hope someone can explain why is this happening.

 

[Fjpod]

Haven't the foggiest....

Are you trying to say this...? That the deeper you discharge the battery, the better it charges?

 

[nehandertal]

Thanks for answering.

No, the point is that if ICE does not power on (battery depleted), the BMU charges always below the capacity of the car (e.g. capacity 36,8Ah, Charged 36,4Ah).
But if you deplete the battery until ICE switches on, then the BMU charges beyond the capactity (e.g. capacity 36,8Ah, Charged 37,8Ah).

And, if you repeat this operation over and over, it reasonable that the BMU could think that the capacity is lower (when charging everytime less than the capacity).

This is what I have seen.

 

[Keefy]

I think the capacity is Governed by the BMU and is pretty constant other than the fact you loose capacity over time.

When you say it charged over capacity, how are you measuring the charge?

It might be easier to use Wh or kWh as a measure. That way the variable voltage is taken out of the equation. That is V x Ah = Wh.

The difference in Ah may be a product of the fact that the voltage is different all through the charge cycle?

Just a thought.