where can I buy the panasonic and bosch batteries ?

[rog_london]

That's correct Rog, battery on it's LED and label face. They may have used a common positive, but that doesn't fit well with using a BMS for the charge control. An alternative is that they've done away with the monitoring connection on the 36 volt version, perhaps feeling it not as necessary with the much higher 504 Wh capacity. The original 26 volt battery only had 208 Wh (8 Ah) so could conceivably be more subject to stress.

You may remember me referring to the way the 36 volt charger works in my run-down on the Kalkhoff a few weeks back....

It charges flat out until the battery indicates 'full' and then cuts off quite suddenly. I know this because I had a wattmeter on it during charging. I have a feeling that the battery monitors itself and simply tells the charger when to stop. It's not typical behaviour for a lithium system - most others reduce the charge as the battery heads towards being full.

Rog.

 

[flecc]

That does seem to fit not having the monitoring connection then, but as you say, an unusual way to charge. They must have plenty of confidence in their cells.

 

[eddieo]

I pointed the OP in the direction of German forum when he first posted, he joined and using auto translator asked for old Panasonic and Bosch battery's without disclosing anything regards motives or who he waslol ..Was sussed in about 5 seconds flat and given some stick but good naturedly pointed in right direction...must be a real shoe string operation. there really is no stopping the Chinese

 

[rog_london]

That does seem to fit not having the monitoring connection then, but as you say, an unusual way to charge. They must have plenty of confidence in their cells.

Ah, I cocked up - sorry Flecc - just had a close look at the battery and the bike connection plate - and there are indeed five poles on the battery, though these are not all used on the charger or the bike connection plate.

They do match your schematic more or less:

5 - positive out from the battery - bike connection only
4 - positive in from the charger - charger connection only.
3 - control signal (digital I suspect). Not labelled. Bike and charger connection.
2 - common negative. Bike and charger connection.
1 - (I think) charger main power control (enable). Not labelled anywhere. Charger connection only.

The only thing I can add is that when the charger cuts off (the LEDs on the battery go out) the charger uses less than a watt - so to all intents and purposes it is indeed 'off', although there's a green LED lit on the charger. If you remove the battery that goes out and power into the charger is zero.

Terminal 3 is used both on the bike and on the charger - and I therefore suspect it's a digital signal from the battery which on the bike allows a repeat of the five battery LEDs on the handlebar display, while in the cradle it provides similar information to the charger. I suspect that terminal 1 - only used on the charger - may be an enable signal to indicate that the battery is in the cradle.

The cut out notch - located above pole 4 on your 24V photo - is located midway between poles 3 and 4 on the 36 volt battery, so you can't inadvertently put the wrong type of battery into the bike or into the charger. A sensible precaution.

Rog.

 

[flecc]

Thanks for the information Rog.