Giant Twist battery, what are the 4 pins, and 5 on charger XLR please?

Arctan

Finding my (electric) wheels
Jan 2, 2024
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0
Hello to all fellow members. I didn't use my bike for about four months. It uses a 36v 8ah battery. I gave the battery a top up charge after two months or so. When I decided to give it a top up recently, it looked like the battery had died, when I pressed the test button. The five led column wouldn't light, and. after further presses, lit up two LEDs in the middle. The test button has aways been a bit mechanically uncertain, although I now have an idea that multiple presses or a long press may toggle the display over in to a diagnostic mode! I Put the battery on charge, fingers crossed. Charger was showing it's red light for a few hours, then green. But still the odd central pair of LEDs on the battery pack. Then the led went out on the charger. Panicking, I watched some youtuube videos, imagining I had an ugly low resistance or shorted battery, and that internal inspection was needed. After getting the casing open, an accidental press of the button gave me a full LED column. I thought 'just the charger then'!. A quick measure across the outer pins of battery gave 40 or so volts, and I thought 'this battery hasn't died'. A more specific look reveals 40.8 volt across battery pack terminals 1 and 4, and 37 volt across pins 1 and 2.
1)So, with all LEDs showing, is this a healthy battery? 40.8 suggests partial discharge. (I can measure the individual clusters of parallel cells, now that the box is open).
2} What are the two different voltages on offer across different pins? How does that relate to the motor, display electronics etc?
I should say that I think I just about understand the purpose and behaviour of a BMS! There is a huge PCB in the battery, with 'balance wires'.
(Speaking of pins above, I mean the battery connector where it connects to the bike)
Then there is the defunct charger. I see lots of low cost 42 volt 2 amp offerings on amazon etc. But both the male and female XLR 's of the Giant bike charging system have all pins going somewhere, wires attached that is. I'd be delighted if a simple cheap two wire item could replace the un affordable Giant replacement charger. I've yet to open the charger, looking for an obvious fail. But waiting on Torx security bits. I understand more traditional PSU's (Analogue, regulated), but I appreciate that switched mode is much harder, and so a replacement might be easier!
Regards to all, John.
 

Arctan

Finding my (electric) wheels
Jan 2, 2024
5
0
Just measured the individual parallel packs. 10 of 4.08 volt. If I'm lucky, that means balancing operates, and cells might or might not be ok?
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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Giant use handshaking /Canbus , a generic battery or charger won't work .
40.8v is low if that is a full charge , try putting it on charge again and see it if increases to at least 41.4/41.5v.
 

Arctan

Finding my (electric) wheels
Jan 2, 2024
5
0
Giant use handshaking /Canbus , a generic battery or charger won't work .
40.8v is low if that is a full charge , try putting it on charge again and see it if increases to at least 41.4/41.5v.
OK, yes, I thought the 4.08 was a bit on the low side. Hopefully I can revive the Giant charger . I can connect a 4 .2 volt charger in the short term to perhaps charge individual parallel packs, just so they don't discharge further? I don't want to let them rot. And Giant using cantus is both interesting and further complicates my plan! I appreciate that signalling SOC and temperature and stuff to the charger is useful. Today I'll pick up the Torx security bits and open the charger. Is the canbus stuff just for the charger, or is it also for the bike connection please? Many thanks for the clues!
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,274
8,264
60
West Sx RH
CANbus is the whole system, charger to battery then battery to controller and display.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,274
8,264
60
West Sx RH
There are quite a few of us that acknowledge that one is dealing with the devil when it comes to Canbus or any other proprietary comms, one is at the mercy of a brand dealer and the exorbitent charges that can a rise from electrical replacement parts .
These types of bikes are not user friendly when it comes to diagnsoing issues or repairing, after all it is generally just a bicycle . Mechanically repairs aren't an issue for diy though some special tools may be needed.
 
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saneagle

Esteemed Pedelecer
Oct 10, 2010
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Hello to all fellow members. I didn't use my bike for about four months. It uses a 36v 8ah battery. I gave the battery a top up charge after two months or so. When I decided to give it a top up recently, it looked like the battery had died, when I pressed the test button. The five led column wouldn't light, and. after further presses, lit up two LEDs in the middle. The test button has aways been a bit mechanically uncertain, although I now have an idea that multiple presses or a long press may toggle the display over in to a diagnostic mode! I Put the battery on charge, fingers crossed. Charger was showing it's red light for a few hours, then green. But still the odd central pair of LEDs on the battery pack. Then the led went out on the charger. Panicking, I watched some youtuube videos, imagining I had an ugly low resistance or shorted battery, and that internal inspection was needed. After getting the casing open, an accidental press of the button gave me a full LED column. I thought 'just the charger then'!. A quick measure across the outer pins of battery gave 40 or so volts, and I thought 'this battery hasn't died'. A more specific look reveals 40.8 volt across battery pack terminals 1 and 4, and 37 volt across pins 1 and 2.
1)So, with all LEDs showing, is this a healthy battery? 40.8 suggests partial discharge. (I can measure the individual clusters of parallel cells, now that the box is open).
2} What are the two different voltages on offer across different pins? How does that relate to the motor, display electronics etc?
I should say that I think I just about understand the purpose and behaviour of a BMS! There is a huge PCB in the battery, with 'balance wires'.
(Speaking of pins above, I mean the battery connector where it connects to the bike)
Then there is the defunct charger. I see lots of low cost 42 volt 2 amp offerings on amazon etc. But both the male and female XLR 's of the Giant bike charging system have all pins going somewhere, wires attached that is. I'd be delighted if a simple cheap two wire item could replace the un affordable Giant replacement charger. I've yet to open the charger, looking for an obvious fail. But waiting on Torx security bits. I understand more traditional PSU's (Analogue, regulated), but I appreciate that switched mode is much harder, and so a replacement might be easier!
Regards to all, John.
You didn't give any details of which version of the bike you have, and there are many. If it's an older one, I don't think they have comms. The extra wires could be for anything, like lights, remote switching or temperature sensing.
 
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Arctan

Finding my (electric) wheels
Jan 2, 2024
5
0
There are quite a few of us that acknowledge that one is dealing with the devil when it comes to Canbus or any other proprietary comms, one is at the mercy of a brand dealer and the exorbitent charges that can a rise from electrical replacement parts .
These types of bikes are not user friendly when it comes to diagnsoing issues or repairing, after all it is generally just a bicycle . Mechanically repairs aren't an issue for diy though some special tools may be needed.
You didn't give any details of which version of the bike you have, and there are many. If it's an older one, I don't think they have comms. The extra wires could be for anything, like lights, remote switching or temperature sen


Ok. Silly me. I've been on other forums and alway declared the item. It's a Giant Twist, as per title, and the model is the Esprit. I'm the second or third owner, and looking through reviews, I'd estimate the model year to be around 2012. It appears to have hardly seen any service.
2012 may indeed pre date the use of CANbus? My limited understanding of it from replacing a sensor on my Volvo is that it requires a few wires- a logic high and a low, a ground reference, and power. The connections from Battery to bike are three- one common and two different power, 37 volt and around 40 volt. Maybe the 40 is for the motor, and the 37 for other control electronics?
Looking inside the charger, there is a fuse on the mains in. Unfortunately for me it is intact, with live and neutral present on PCB. And no obvious evidence of distress, burnt components etc. On the output low voltage side there is an unlit LED, the one that previously indicated charge/charged, now dark.
Looking at the five wires on the output connector of the charger, I see
a pair of thicker wires, marked Gnd and Vo. I'm guessing these are higher power stuff for the actual charging.
Then three thinner wires. A pair with the legend TH1. The word Thermistor comes to mind, a sensor that protects the battery pack?
And a final wire, marked Vc. Control maybe, from the battery BMS to the SMP, able to tell the SMP to reduce or remove charging power, and turn the LED to 'charged' etc? Who knows, with a dead PSU and no circuit diagram!
So, please let me know if you think the following is unwise! I'm thinking of disconnecting the thicker charging wires out of the charger, and offering them 42 volt to the battery, from another two wire regulated charger, after establishing polarity. Maybe put in a diode to lose half a volt or so. With current limiting and temperature monitoring in place, but outdoors! And frequent periodic battery voltage checks , without charger connected. Were this to be a success, then it remains to be seen if the BMS can do any work with balancing. It's hard to know how the BMS is powered. Either from part or all of the pack of cells, or from a connected charger? In the event of no joy with the above, I think the bike will be a write off.
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
4,661
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If you can measure battery voltage on any of the charge socket pins, you can charge the battery through the socket.

I'm pretty sure that Giant Twist didn't have comms in 2012. If 4 pins are connected, there must either be a remote battery switch or a temperature sensor or something like that.

Your information is still very vague, which makes it difficult to help you. Why don't you show some photos?
 
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Arctan

Finding my (electric) wheels
Jan 2, 2024
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0
All sorted now with a cheap e-scooter charger and a couple of silicon diodes. Cut charge at 41.5, and battery slowly dropped back to 41. Settling or balancing perhaps? I'll add a voltage and current lcd module later, in place of DMM. Battery University has comprehensive info on voltage vs number of charges vs stored energy, very informative. In time I'll examine the three wires, additional to the main charging pair. Because I won't be traveling far, even 40 volts might do, with monitoring. Took it out for a short spin, great fun. Curious about mid frame motors, coming from RWD Volvos, and met a man with a
TSDZ2B 36V 250W Torque Sensor Tongsheng Mid Drive Motor
which I can dream about adding to my lovely Schwinn hybrid bike, at a later stage...
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
4,661
2,270
Telford
All sorted now with a cheap e-scooter charger and a couple of silicon diodes. Cut charge at 41.5, and battery slowly dropped back to 41. Settling or balancing perhaps? I'll add a voltage and current lcd module later, in place of DMM. Battery University has comprehensive info on voltage vs number of charges vs stored energy, very informative. In time I'll examine the three wires, additional to the main charging pair. Because I won't be traveling far, even 40 volts might do, with monitoring. Took it out for a short spin, great fun. Curious about mid frame motors, coming from RWD Volvos, and met a man with a
TSDZ2B 36V 250W Torque Sensor Tongsheng Mid Drive Motor
which I can dream about adding to my lovely Schwinn hybrid bike, at a later stage...
Glad you got it sorted.

For everybody else, the Battery University stuff is mainly about single lithium cells. Some of it is relevant to ebike batteries, but other stuff isn't, so don't change anything in your charging procedures or use of your battery without running it past this forum first.