My battery keeps dropping to 12v within a second.

[quackstar84]

Hello, me again . My bike keeps cutting out and I have to turn the battery on and off to get it to start again. I probed the battery and when I turned the lcd on and it turned off the voltage went from 52v to 12v then it gradually increases one volt per second until it is at its max charge. If I turn it on again it drops to 12v again. My bike loves having one issue after another . Hope you're all well.

Darren

 

[vfr400]

Your BMS is probably switching off.

 

[quackstar84]

Your BMS is probably switching off.

Yes it definitely is. Does It happens as a safety mechanism ?

 

[vfr400]

It does it when your battery is knackered.

It can also happen when there's a short circuit, like when a mosfet is blown.

 

[PC2017]

like when a mosfet is blown.

So could this mean the battery is ok but the controller is knackered?

 

[Nealh]

BMS has mosfets as well.

 

[vfr400]

So could this mean the battery is ok but the controller is knackered?

Or the motor cable damaged or the controller wires melted.

 

[PC2017]

Oh dear, any ideas on how do diagnose this issue, assuming you could visually inspect all the cables.

 

[quackstar84]

I tried opening the battery however one of the screws is too tight and id end up stripping it if I continued. I need to get in either way for testing. Ill try again when I have time. This bike sure likes to make new issues lol. I think it is time I bought a brand new bike.

 

[quackstar84]

Hello I managed to get it open. Surprisingly it's got LG cells

 

[quackstar84]

I found how how to do it watching this video at 2.30min

 

[quackstar84]

All measure 4.08 to 4.09v at a total voltage of 53.2v. 53.2 ÷ 12 (12 white cables) is 4.43 thought? ÷ by 13 is 4.08 thought.

 

[quackstar84]

When the battery was dropping to 12v my controller was still connected. Simply turning the lcd on for a moment would shut down the lcd. Ill get it to begin to shut down again then remove the controller and keep the multimeter connected to the battery to see if it drops to 12v again.

 

[vfr400]

Do a mosfet check:

Disconnect the motor cable and battery from the controller. Measure the resistance (200k scale) between the red battery connection and each of the three phase wire connections, then repeat with the black battery wire. Each set of 3 readings should be the same as each other and in the range 7K -22K. Though can be higher as long as they're all the same. Due to the capacitor across the battery wire, you can get a constantantly changing measurement while it charges. In that case, try swapping your probes round. Even though can be a moving result, the only important thing is that all three move in a similar way.

 

[PC2017]

Do a mosfet check:

Assuming you mean a controller only mosfet check? So if there's no reading/value then his controller is knackered?

 

[wheeliepete]

All measure 4.08 to 4.09v at a total voltage of 53.2v. 53.2 ÷ 12 (12 white cables) is 4.43 thought? ÷ by 13 is 4.08 thought.

Your battery is 13S, so 4.08v is correct. BTW, there's 14 wires, the black one goes to battery -.

 

[quackstar84]

Hello vfr400. All three are 09.8 at 200k and 9.86 at 20k when I probe the black battery wire with both the red and black probes.When I place the red probe on the black wire all three phase cables begin to charge slowly from -60 on 200k. When I place the red probe on the red wire there's no reading.

Thank you.

Do a mosfet check:

Disconnect the motor cable and battery from the controller. Measure the resistance (200k scale) between the red battery connection and each of the three phase wire connections, then repeat with the black battery wire. Each set of 3 readings should be the same as each other and in the range 7K -22K. Though can be higher as long as they're all the sam Due to the capacitor across the battery wire, you can get a constantantly changing measurement while it charges. In that case, try swapping your probes round. Even though can be a moving result, the only important thing is that all three move in a similar way.

 

[quackstar84]

Hello. I managed to figure out that the battery voltage remains at its full charge state until I connect just yet power leads to the controller on their own. Then it will go back to being the voltage at the current second so when I reconnected it it was 32v. So I'll look for a new controller now. Thank you .

 

[quackstar84]

I would have been interested in a double mode 22 from here however all different amps are all sold out.

They have an 22amp sinewave however it's a three week wait for delivery.

https://m.aliexpress.com/item/10000423707501.html?spm=a2g0n.detail.0.0.3ab210c6tBy1t6&gps-id=platformRecommendH5&scm=1007.18499.139690.0&scm_id=1007.18499.139690.0&scm-url=1007.18499.139690.0&pvid=509e37db-d026-4f7b-8f62-7be90f866186&_t=gps-id%3AplatformRecommendH5%2Cscm-url%3A1007.18499.139690.0%2Cpvid%3A509e37db-d026-4f7b-8f62-7be90f866186%2Ctpp_buckets%3A668%230%23131923%230_668%23888%233325%2313_8499%230%23139690%236_8499%234696%2321885%2312_668%232846%238116%232002_668%235811%2327179%2338_668%232717%237560%23231__668%233374%2315176%23743&browser_id=afdb73f118684df291e0246b8baa3b85&aff_trace_key=&aff_platform=msite&m_page_id=amaigrxjsimcavra179dd3914ab72369de7d0b850b&gclid=

 

[vfr400]

The controller needs about 4w even on standby. That could be enough to trip your BMS if it's faulty. You need to text tour BMS with an alternative load of some sort. Have you got any 36v lights?