Pendleton ebike Demeter battery issue

[Erch007]

Hi everyone Im new to the site and would like some help if this is ok? I bought my wife a Vic Pendleton ebike a few years ago and its been sitting in the garage for a while after a house move and has not been on charge. I have searched youtube and online and have made some progress:
When the battery was plugged into the charger it only had the red and green light showing - not charging.
When I disconnected the battery from the charger I didnt have any lights showing any charge. I opened up the battery to check for any corrosion - none evident. I then noticed when I plugged in the charger lead that I got an arc and the battery charger was then showing 2 red lights. Mmm charging I thought??
When I pressed the battery test light I got all green lights except for the 20% light which was red. I disconnected the charger when the light went green / red and again no lights.
I have opened up the battery again and checked for voltage and I do have 40.2v on the BMS from the VP and VG connections. When I check for voltage again at the DSG and VP connection I dont get any voltage. Im assuming there is a problem with the BMS??
Can anyone help please?
Its a DEMETER 36V battery

 

[saneagle]

Hi everyone Im new to the site and would like some help if this is ok? I bought my wife a Vic Pendleton ebike a few years ago and its been sitting in the garage for a while after a house move and has not been on charge. I have searched youtube and online and have made some progress:
When the battery was plugged into the charger it only had the red and green light showing - not charging.
When I disconnected the battery from the charger I didnt have any lights showing any charge. I opened up the battery to check for any corrosion - none evident. I then noticed when I plugged in the charger lead that I got an arc and the battery charger was then showing 2 red lights. Mmm charging I thought??
When I pressed the battery test light I got all green lights except for the 20% light which was red. I disconnected the charger when the light went green / red and again no lights.
I have opened up the battery again and checked for voltage and I do have 40.2v on the BMS from the VP and VG connections. When I check for voltage again at the DSG and VP connection I dont get any voltage. Im assuming there is a problem with the BMS??
Can anyone help please?
Its a DEMETER 36V battery

If it's entered sleep mode, you need to leave it on charge for about 10 minutes to wake it up. Did you try that?

 

[Erch007]

Thanks for the reply, yeah Ive tried that. When I plug the charger in the status lights on the charger dont change to 2 reds.

 

[Ghost1951]

I had one of these with an identical problem some three years ago now. We bought it for about £350 as needing a new battery. The bike had barely ever been used and had spent a winter and more unattended in a garage.

I cured it by very very carefully charging it for about ten minutes on its output port.

There are people here who still hate me for advocating doing this. It would obviously be VERY dangerous to charge a battery like that for a long time and going away and leaving it unattended, but it worked for me and it has worked for other people too.

ONLY A FEW MINUTES and measuring the voltage on that port as you do it. You ought to see the voltage on the output port rise to something like 35v. Then try it by the proper charging method. You will need to rig up some wires to make the connection between the charger and the port. You sound like you know what you are about so will be able to do it. If not - don't.

It still even now will run for well over 25 miles.

 

[Erch007]

I had one of these with an identical problem some three years ago now. We bought it for about £350 as needing a new battery. The bike had barely ever been used and had spent a winter and more unattended in a garage.

I cured it by very very carefully charging it for about ten minutes on its output port.

There are people here who still hate me for advocating doing this. It would obviously be VERY dangerous to charge a battery like that for a long time and going away and leaving it unattended, but it worked for me and it has worked for other people too.

ONLY A FEW MINUTES and measuring the voltage on that port as you do it. You ought to see the voltage on the output port rise to something like 35v. Then try it by the proper charging method. You will need to rig up some wires to make the connection between the charger and the port. You sound like you know what you are about so will be able to do it. If not - don't.

It still even now will run for well over 25 miles.

View attachment 62780

Hi I saw your suggested fix on another thread. I wasnt overly confident of doing this as I dont undserstand what you meant by the output port. Is it like back charging and py-passing the BMS? Ive also just found out that the fuse holder had some dirt in it and was not showing voltage at the battery connectors it is now after cleaning it up

 

[Nealh]

Depress the battery button for 30 secs to see if it will wake up and charge.
Or
If one has the battery open disconnect the BMS multi wire/ribbon connector , then reoconnect it to see if the battery then wakes up.

 

[EthaneFerguson]

Hi everyone Im new to the site and would like some help if this is ok? I bought my wife a Vic Pendleton ebike a few years ago and its been sitting in the garage for a while after a house move and has not been on charge. I have searched youtube and online and have made some progress:
When the battery was plugged into the charger it only had the red and green light showing - not charging.
When I disconnected the battery from the charger I didnt have any lights showing any charge. I opened up the battery to check for any corrosion - none evident. I then noticed when I plugged in the charger lead that I got an arc and the battery charger was then showing 2 red lights. Mmm charging I thought??
When I pressed the battery test light I got all green lights except for the 20% light which was red. I disconnected the charger when the light went green / red and again no lights.
I have opened up the battery again and checked for voltage and I do have 40.2v on the BMS from the VP and VG connections. When I check for voltage again at the DSG and VP connection I dont get any voltage. Im assuming there is a problem with the BMS??
Can anyone help please?
Its a DEMETER 36V battery

• You're seeing voltage on the VP/VG (battery pack positive/negative), but no output on DSG (discharge line) — that usually means the BMS isn't allowing discharge.
• The battery test lights briefly coming on, then nothing, supports the idea that the BMS is shutting things down.
• The long storage time without charging could have triggered low-voltage protection, or even degraded some cells.

 

[EthaneFerguson]

I had one of these with an identical problem some three years ago now. We bought it for about £350 as needing a new battery. The bike had barely ever been used and had spent a winter and more unattended in a garage.

I cured it by very very carefully charging it for about ten minutes on its output port.

There are people here who still hate me for advocating doing this. It would obviously be VERY dangerous to charge a battery like that for a long time and going away and leaving it unattended, but it worked for me and it has worked for other people too.

ONLY A FEW MINUTES and measuring the voltage on that port as you do it. You ought to see the voltage on the output port rise to something like 35v. Then try it by the proper charging method. You will need to rig up some wires to make the connection between the charger and the port. You sound like you know what you are about so will be able to do it. If not - don't.
Nothing compares to the thrill of winning website a battle royale when you’re the last one standing out of a hundred players.
It still even now will run for well over 25 miles.

View attachment 62780

Could you explain more about how you safely rigged the wires to the output port for charging?

 

[Algee]

Hi everyone Im new to the site and would like some help if this is ok? I bought my wife a Vic Pendleton ebike a few years ago and its been sitting in the garage for a while after a house move and has not been on charge. I have searched youtube and online and have made some progress:
When the battery was plugged into the charger it only had the red and green light showing - not charging.
When I disconnected the battery from the charger I didnt have any lights showing any charge. I opened up the battery to check for any corrosion - none evident. I then noticed when I plugged in the charger lead that I got an arc and the battery charger was then showing 2 red lights. Mmm charging I thought??
When I pressed the battery test light I got all green lights except for the 20% light which was red. I disconnected the charger when the light went green / red and again no lights.
I have opened up the battery again and checked for voltage and I do have 40.2v on the BMS from the VP and VG connections. When I check for voltage again at the DSG and VP connection I dont get any voltage. Im assuming there is a problem with the BMS??
Can anyone help please?
Its a DEMETER 36V battery

Have come across this several times with Lithium type batteries not taking a charge. There is a caveat that I'll come to at the end, but with simple BMS and battery charger the approach is quite straight forward. Lithium batteries don't have the same internal resistance that lead acid batteries have. This means that if lithium batteries with too low a discharge voltage are connected to a charger it will act like a short circuit, therefore protection is needed.
What to do, first check the voltage on each group of cells, or individual cell, they should all be very similar. All similar? yes?, now connect the battery bank or battery to a power supply that the voltage and amps out can be controlled. Set the volts to suit the battery set up, I usually set/limit the current/amp out to 200 to 300ma and leave to charge, checking for any heat buid up. After an hour or so with no heat detected and the charge voltage is going up I'll increase the amp setting going out from the power supply. I'll still limit it to 1 amp or just under for safety.
The caveat, I have been given a Shimano battery to look at by a friend. This battery had been sitting for ages not being used, the voltage available was only about 20v (36v battery pack) and it wouldn't accept a charge from the Shimano charger. I found that the BMS wouldn't pass any charge, I bypassed the BMS and charged via my adjustable power supply. Battery pack is now sitting at, or just under 36v, but nothing available at the output. The internal BMS has taken the huff for being so low or as punishment for bypassing it, either way it encourages you to buy another battery.
It appears that the Shimano BMS needs to communicate (canbus?) with the charger and vice versa. Not finished yet, work in progress, but I'll be only buying an e-bike set up that has a charger output with only two wires, +ve and -ve. The Shimano has, besides the two main charge wires, three other comms wires.

 

[saneagle]

Could you explain more about how you safely rigged the wires to the output port for charging?

What happens is that when any cell reaches a certain low value that's set in the BMS logic and typically around 2.5v, the BMS switches off the charge control MOSFET/s, so no charging allowed. The idea is to open the battery and find the positive and negative main wires from the cell-pack to the BMS, and charge them directly there until the lowest cell/s are above 2.5v and normal charging w ould be allowed again.

Before attempting that procedure, you really need to check the individual cell voltages. It's difficult to say what's too low, but It's probably not a good idea to try to revive the battery if any cells are much below 2v. If you procede with the procedure, you must be mindful of the voltages of the higher cells because you could have the situation where all cells are sitting abobe 4.1v, but only one group is down. In that case, the high ones might go to a dangerously high voltage before the low one rises again. In that case, it would be better to only charge the low cells on their own with a USB charger or something like that, but, again, you need to monitor it carefully to make sure it doesn't go too high, bearing in mind that the voltage increases very slowly when in the middle range, but as it approaches full, it speeds up substantially, which can take someone by surprise.

In summary, if you understand how battery's work, these charging procedures are relatively safe, though not 100% safe. Some people do these things without understanding, and they get away with it because circumstances are on their side, but if the circumstances conspire against you, it can be very serious. Personally, I tend to only advise people to do these things when measurements have been taken, though it is possible to make some judgements, depending on circumstances.