Hi Phil,
I forgot to write it down when I measured, but it was low enough that there
was essentially no charging current, so I think closer to 13V.
As a hack to keep my older battery charged, I disconnected the current
sensor on the aux battery terminal, so the car would constantly see a large
(negative) current from the bidir sensor that I think outputs a 0-5V for
something like -100 to +100 A of measurement, 0A being in the middle so
2.5V.
I still use that hack today, to keep my smallish Lithium aux battery
charged up to 14V.

Oh, when I check old screenshots of LeafSpy, then it shows either 12.96 or
13.04V, I presume that is the ADC resolution (0.08V on a 5V range means 6
bits??) and a charge current of 1A.
Without sensor connected, it shows 13.92V at a reported current of -105.37A
due to the unconnected sensor input.
Cor.

On Sun, Aug 2, 2026, 11:02 AM (-Phil-) <[email protected]> wrote:

> Yeah, they didn't implement a proper temp-compensated 3-stage, but I
> remember the float being 13.5v?  (measured at the battery)   Am I wrong?
>
> On Sat, Aug 1, 2026 at 11:16 PM Cor van de Water <[email protected]>
> wrote:
>
>> Phil,
>> Sorry but I got to correct you there, the Leaf will *charge* the aux
>> battery for a short time after starting the vehicle, whether driving
>> or charging (when contactors are closed, as you write), HOWEVER, as
>> soon as the charge current drops below 10 Amps and on an older battery
>> that is almost instantly, the DC/DC stops charging it and switches to
>> a maintenance voltage which will essentially NOT charge the 12V
>> battery any further. If I am not mistaken, the charge voltage is 14V
>> and the maintenance voltage is at or below 13V which means that almost
>> no current is absorbed by the aux battery, which is what you WANT for
>> a fully charged battery, but since an older battery can be almost
>> empty but due to not accepting 10 Amps of current at 14V, it will get
>> 13V and stay essentially empty the whole time, that is why Leaf
>> batteries die early. They never properly get charged, let alone
>> balanced (occasionally overcharged to re-balance the 6 cells) by the
>> car.
>>
>>
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