48v 15.6ah battery problem on Jorvik Trike advice please

I have come by a fairly unused but out of warranty Yorvik JMT6-2 Trike . Sadly initial owner hardly used it but now passed away and family cannot be certain of how battery has been stored charged etc. Initailly the battery level indicator showed a bit of life but after battery and charger being allowed to get to room temp , I attempted to charge the battery pack. charger indicted green fully charged battery straight away. There is 53V showing at charging port but no out put at base two pin connector and certainly wont power up the trike and no sign of life at all on battery status gauge.. Both charging and output fuses are fine key switch is operating correctly and no visible or tested connection issues. I suspect the battery as above (silverfish ) has either been left discharged for a long period , left outside in very low temps or attenpted to be charged when very low temp. I am buying a new battery regardless but would appreciate advice re likely issue with the original battery ie cause . Within the battery block of cells, although not visible when top or bottom of battery are opened , is there a battery protection board within the pack that may be the issue , preventing output ? For obvious reasons I am not going to start disassembling the battery but any advice on likely cause and problem appreciated , may the actual individual cells /block be ok as showing 53 Vollts ? is there any cost effective UK source of fault finding, repair that would lead to me being able to recover the battery as a spare .

53v is too vague. What is the actual voltage?

 

Don't jump to conclusions about what's wrong. Some of the ideas you propose about the cause don't hold any water. You test and measure to find out what's wrong, which probably isn't much.

53v is too vague. What is the actual voltage?

 

Don't jump to conclusions about what's wrong. Some of the ideas you propose about the cause don't hold any water. You test and measure to find out what's wrong, which probably isn't much.

It was showing 53.35 V was just rounding the V up to nearest volt , does the .35 make a difference. I am ok with mechanics but in asking advice openly showing no real knowledge in this matter. In accepting my thoughts are off the mark then, what may be the issue and or what can I check coarse of action to take etc . really appreaciate thoughts as much as anything to learn gain some knowledge . cheers Martin

53.35v suggests a weak/dead or low cell as does the green charge light.

Green charge light in this case indicating no current is being asked for by the BMS, so BMS has sensed a fault.

0.35v makes a big difference. The fully charged voltage should be 54.6v (13 x 4.2v), so you're missing 1.25v. The lowest any cell could be is therefore 2.95v. At that voltage, charging would be allowed, but discharging wouldn't; however it's not that likely that all the lost voltage would be in one cell group.

 

if it were 53.0v, the lowest possible cell voltage would be 2.6v, which is in the range where charging wouldn't be allowed.

 

The best course of action would be to measure the cell voltages and check the BMS, which is very simple. Take the top and bottom off the battery, and push up the contents until they stick out at the top. The BMS (protection board) will be sitting on the top. peel back any heatshrink as necessary. You'll now see a multipin connector. Disconnect it and measure the individual cell voltages by sticking your probes into the tiny strips on its side. The difference between each adjacent pair of pins is one cell voltage. You need 13 results. Sometimes the 13th result is between the last pin and the cell-pack main positive or the cell-pack negeative and the first pin.

 

Look at the BMS> It should be marked where wires are attached.

B- Cell-pack negative

P- Power negative

C- Charge negative

 

All the BMS does is allow or interupt the conection between B- and P- for discharge, and B- and C- for charge. With your red probe on the cell-pack or power out positive, check those three positions for the cell-pack total voltage, whether the power out is switched on and whether the charge in is switched on.

 

It was quite common to get key switch failures on silver fish batteries - either bad soldering or burnt contacts, so if the BMS checks out OK, look there next.

 

If you have 53.35v on the charge socket, it indicates that the charging is switched on, so the question is why you have no output. Logically, your key switch is faulty, but you're close to the range where the BMS could switch off output. When you know whitch of the two it is, the solution will be simple.

0.35v makes a big difference. The fully charged voltage should be 54.6v (13 x 4.2v), so you're missing 1.25v. The lowest any cell could be is therefore 2.95v. At that voltage, charging would be allowed, but discharging wouldn't; however it's not that likely that all the lost voltage would be in one cell group.

 

if it were 53.0v, the lowest possible cell voltage would be 2.6v, which is in the range where charging wouldn't be allowed.

 

The best course of action would be to measure the cell voltages and check the BMS, which is very simple. Take the top and bottom off the battery, and push up the contents until they stick out at the top. The BMS (protection board) will be sitting on the top. peel back any heatshrink as necessary. You'll now see a multipin connector. Disconnect it and measure the individual cell voltages by sticking your probes into the tiny strips on its side. The difference between each adjacent pair of pins is one cell voltage. You need 13 results. Sometimes the 13th result is between the last pin and the cell-pack main positive or the cell-pack negeative and the first pin.

 

Look at the BMS> It should be marked where wires are attached.

B- Cell-pack negative

P- Power negative

C- Charge negative

 

All the BMS does is allow or interupt the conection between B- and P- for discharge, and B- and C- for charge. With your red probe on the cell-pack or power out positive, check those three positions for the cell-pack total voltage, whether the power out is switched on and whether the charge in is switched on.

 

It was quite common to get key switch failures on silver fish batteries - either bad soldering or burnt contacts, so if the BMS checks out OK, look there next.

 

If you have 53.35v on the charge socket, it indicates that the charging is switched on, so the question is why you have no output. Logically, your key switch is faulty, but you're close to the range where the BMS could switch off output. When you know whitch of the two it is, the solution will be simple.

Wow and a massive thanks for such comprehensive info, advice and what to check, I now understand why my thoughts were premature and looking for cause not fault , I was missing a shed load of knowledge . I thought the voltage was higher than the minimum needed as above stated 48V , I sure was way off on that one let alone not realsie why that .35 was important. Maybe my next dumb question but if I have checked across the switch and can see it is operating ie tested open and closed circuit when key turned , could it be reading that ok but due to poor connection or soldering have too high a resistance and therefore cause my problem ? As I have battery pack open a test of the switch is quicker easier when I have to try get my thoughts and head around the instructions re the BMS and cell check. I really wish I had studied understood electronics , electrics but a big thanks for moving me in the right direction . I did not want to give up just because ordering a new battery , wanted to learn ,understand the workings , likely fault etc . I will read again with a rested brain in the morning and digest and act on your advice guidance Regards Martin

Wow and a massive thanks for such comprehensive info, advice and what to check, I now understand why my thoughts were premature and looking for cause not fault , I was missing a shed load of knowledge . I thought the voltage was higher than the minimum needed as above stated 48V , I sure was way off on that one let alone not realsie why that .35 was important. Maybe my next dumb question but if I have checked across the switch and can see it is operating ie tested open and closed circuit when key turned , could it be reading that ok but due to poor connection or soldering have too high a resistance and therefore cause my problem ? As I have battery pack open a test of the switch is quicker easier when I have to try get my thoughts and head around the instructions re the BMS and cell check. I really wish I had studied understood electronics , electrics but a big thanks for moving me in the right direction . I did not want to give up just because ordering a new battery , wanted to learn ,understand the workings , likely fault etc . I will read again with a rested brain in the morning and digest and act on your advice guidance Regards Martin

You don't need to know anything about electronics to understand and fix batteries. They're very simple - just an arrangement of wires and switches. All you need is simple logic and a small amount of understanding.

 

I've had bad solder joints on the key-switch that broke down under load and stayed connected when there was no load. It's a possibility but not likely.

 

The voltage measurements will tell you all you need to know about what's wrong. It's always best not to guess.