Thank you for a nice and clear experiment. I assume the protection signal can be connected to a brake sensor.
36V Bosch tool battery for e-bike use
- Thread starter WheezyRider
- Start date
If you can work out what the data format is and read it with a suitable small micro, then you ought to be able to sense a high temperature condition and use a transistor to trigger one of the brake sensors. Ideally you would want to turn off the display\controller, but that might be a significant hack.
I presume ARRC conversions have custom hardware and software in their controller to read the data and flag an over temperatue condition.
Does anyone know anyone with an ARCC Brompton conversion ?
I presume ARRC conversions have custom hardware and software in their controller to read the data and flag an over temperatue condition.
Does anyone know anyone with an ARCC Brompton conversion ?
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I have found, by experiment, that if the BUS line on the battery is connected to +5V via a high value resistor, 27K in this case, the battery wakes up and sends 4 blocks of data, which might be bytes. But that is all it sends, so it looks likley that the battery is waiting for a response from the charger, before it continues to send temperature data, which is what happens during charging.
That's interesting. If you set the BUS line high momentarily, does the battery send 4 blocks of data again?
If you leave the resistor pullup in place, then only one block of data is sent.
Remove the pull up and then put it back and another block of data is sent.
Hence the battery does appear to be waiting for a response from the charger before it keeps sending what appears to be the temperature data.
Ok, is the data block always the same for the same temperature of the thermistor?
Not checked, but whether it is or is not I doubt is significant.
For an eBike situation the key would be decoding the stream of data sent approximatly every 5 seconds, which is much longer than the intial wake up block.
Might be worth replacing the thermistor temporarily with a potentiometer so you don't have to keep heating it. If you need to encode a range of say 100 C with 1 Deg resolution, you'd need at least 7 bits?
Or maybe it doesn't even need to measure the actual temp and it just gives a good/no good signal? Or maybe it is transmitting temp - does ARC stand for accelerating rate calorimetry? So the rate of change of temp is important if that is the case.
Or maybe it doesn't even need to measure the actual temp and it just gives a good/no good signal? Or maybe it is transmitting temp - does ARC stand for accelerating rate calorimetry? So the rate of change of temp is important if that is the case.
Let's say you simply connect the middle pin to a pullup resistor. The battery sends a block then waits. You then heat up the thermistor. Would the line goes low?
Well before going into the detail of the intial wakeup, it really needs to be shown if the BUS data is bidirectional or not.
My guess is that the board waits for a high signal on the BUS, then transmits some data, then waits for the BUS to go high again and then sends updated data.
It seems unusual to have just a single BUS line. Most protocols normally have at least two connections. I wonder if it is some form or variation of 1-wire coms:
Not so unusual in the sensor world.
The BUS line appears to be used for temperature sensing and eleswhere those are often read with a 1 wire protocol, such as that used by the DS18B20 temperature sensors etc.
Batteries of less than 100Wh/8.4Ah capacity are allowed on airlines apparently, so if you wanted to use your own ebike for pottering short distances on holiday, say from your palatial holiday villa to the local market and back, and your bike folded into a suitcase...
Grin Technologies sell special 100wh batteries for that, which clip together to make bigger ones.
LiGo Batteries - Grin Products - Product Info (ebikes.ca)
I think 100Wh corresponds to just over 2.6 Ah for 36 V packs. 8.4 Ah sounds a bit large!
Oops, yes.
Using Bosch batteries with your folding ebike on holiday, is a good reason to upgrade cells in old genuine Bosch packs. Airlines will go by capacity quoted on the battery pack labels, probably. Alternatively, rent a couple of Bosch tool batteries near the airport or your private infinity pool, for about £60 a week...
The thought of DIY 'upgraded' lithium batteries on aeroplanes, what could possibly go wrong .................
The thought of weak DIY welds makes me nervous, which is why I'm unlikely to ever make a battery pack - it's either welds or compression using kits like Vruzend's, and the one below, but never both, which might be a good idea should welds fail?
VRUZEND – Battery building made simple
No more spot welding… and no more soldering either! VRUZEND lithium battery building kits were designed to solve that problem. The plastic end caps slip tightly over the end of the most common lithium battery cell format, the 18650 cell. They can be snapped together like Lego™ bricks to create...
vruzend.co.uk