electrical danger battery sound at fault ?

I wonder what people might think about this . I purchased a 4 year olf Cyclotricity Revolver from ebay a few months ago for about 150 pounds and yesterday had it serviced and so spent about 80 pounds for new cassette, chain, bottom bracket . Today ( the servicing didnt touch the electrics and the battery was locked on) I couldnt easily get the connector onto the battery and it kept shorting even with the battery switched off. Now it is evident the connector is damaged ( its a 4 pin socket that fits into the battery) and the cable has come adrfit inside the connector and is burned. I stripped the wire out and tried to connect the now wireless connecter into the bike with the battery off and with the battery switched off BANG and more flashes of light.

Does this sound like a battery switch malfunction ? Surely with the battery switched OFF on the battery switch then connection attempts should be free of risk of shorting ? ???

I had noticed little pops before when connecting the battery but not had sparks or flashes that I could see and the bike has performed well, charges well

My feeling is that even with new connectors ( if I acquire them) the battery will still be dangerous and unreliable. My feeling is that buying a battery is a questionable expense given that the electric parts as regards type of wiring, motor and controller are different now and no longer stockd.

But that flash of light bangs and burned wires was scary and safety must come first

Any advice much appreciated

Assuming you connected up the wiring in correct sequence,

then suspect a fault or short on the battery side of the connector. Only way of knowing is to open it up and have a look.

Could be a loose or damaged wire contacting or even water damage/corrosion causing arcing.

It's normal to get the snap-like sparks when connecting a battery to a controller when the battery is switched on. You should always switch off the battery when connecting - if the battery has a switch.

The connector to the battery has 4 pins with 4 wires soldered to it. two of the wires are positive and two negative. They have to go to the right pins. You need to explain again what happened because it's not clear, but if a wire came adrift, it's very dangerous because it will almost certainly touch one of the other pins, which makes a dead short.

You shouldn't be messing with these things without testing everything with a meter first so that you know what's live and which way round the wires go. Never trust the colours.

Assuming you connected up the wiring in correct sequence,

then suspect a fault or short on the battery side of the connector. Only way of knowing is to open it up and have a look.

Could be a loose or damaged wire contacting or even water damage/corrosion causing arcing.

Thank you

It's normal to get the snap-like sparks when connecting a battery to a controller when the battery is switched on. You should always switch off the battery when connecting - if the battery has a switch.

 

The connector to the battery has 4 pins with 4 wires soldered to it. two of the wires are positive and two negative. They have to go to the right pins. You need to explain again what happened because it's not clear, but if a wire came adrift, it's very dangerous because it will almost certainly touch one of the other pins, which makes a dead short.

 

You shouldn't be messing with these things without testing everything with a meter first so that you know what's live and which way round the wires go. Never trust the colours.

The bike was assembled in every sense when I purchased it, it is simply that the bike appears to have been shorting when connecting the 4 pin plug to the battery when the battery is switched off. After this burned the wire and blew the wire off the plug (inside it) I stripped the plug down to the plastic and tried attaching it away from the bike with the battery switched off, yet more shorting, cracks flashes. I think the battery is almost certainly the real problem, its 4 years old and looks weatherworn but it was hoilding charge acceptably for its age. Now my issue is do I bother buying a new battery ( around 200 on e bay for a 4 pin type about 10 amp hours ) because even then the rest of the bikes wiring is old and cyclotricity dont sell the bits as they have a new type of set up since that bike (2013) I have to face the issue that 200 quid is just one step away from uneconomical repair . The chatge in those b atteries is fierce=, melted connector flew ontyo my kitchen table and burned the surface and trying to move some flaming spot form the table burned a small section away from my kutchen knife. I think I was lucky for worse not to happen. Ive put the battery outside now as I cannot risk it indoors. But I cannot imagine how a switched off battery would short when putting the bikes connector onto the battery. It is a switch at the base close to the connector

The bike was assembled in every sense when I purchased it, it is simply that the bike appears to have been shorting when connecting the 4 pin plug to the battery when the battery is switched off. After this burned the wire and blew the wire off the plug (inside it) I stripped the plug down to the plastic and tried attaching it away from the bike with the battery switched off, yet more shorting, cracks flashes. I think the battery is almost certainly the real problem, its 4 years old and looks weatherworn but it was hoilding charge acceptably for its age. Now my issue is do I bother buying a new battery ( around 200 on e bay for a 4 pin type about 10 amp hours ) because even then the rest of the bikes wiring is old and cyclotricity dont sell the bits as they have a new type of set up since that bike (2013) I have to face the issue that 200 quid is just one step away from uneconomical repair . The chatge in those b atteries is fierce=, melted connector flew ontyo my kitchen table and burned the surface and trying to move some flaming spot form the table burned a small section away from my kutchen knife. I think I was lucky for worse not to happen. Ive put the battery outside now as I cannot risk it indoors. But I cannot imagine how a switched off battery would short when putting the bikes connector onto the battery. It is a switch at the base close to the connector

When you disconnect the connector from the battery, the wires are still live because the capacitors in the controller hold the voltage; however, there isn't much charge in the capacitors, so you get that snap-like spark once. After that, there's no charge in the capacitors so no more sparks.

As I said, you need to check the battery with a meter to see if it goes off with the switch.

I'm still struggling to understand your description of the fire. The wires can only catch fire or burn when connected to the battery. I guess you crossed over the wires . You have to be very careful with that because you can blow the controller like that. From your description, I'd say that there's nothing wrong with your battery. If you can't solder or use a meter, you can get a replacement connector and lead from Cyclotricity.

The problem is though that the shorting occurred even when the battery was switched off. Even off the bike with the battery switched off for sure ( easy to see the switch when off the bike) it was when i tried to insert the 4 pin plug into the battery that there was the drama and flash and bang and bits coming off and burning

I cannot imagine it is at all normal for a switch to fail to switch off an e bike battery and if it does then there is a dangerous fault Ones fingers are activively engaged in connecting the 4 pin into the battery each time and I wouldtnt fancy being burned

You will only get the short-circuit when the connector is wrongly wired or when a wire has come off. The switch isn't designed to protect against those.

To be honest, you bought one of the cheapest bikes. If they covered every single possibility of user errors and life-cycle errors, like they do on a Bosch bike, you'd have a bike that would cost a lot more and be less convenient.

If I understand your description of your problem, a wire came off, you incorrectly wired it and tried to reconnect the connector when you believed that you had switched off the battery, but didn't check it with a meter. One normally only makes that mistake once. many of us have done similar as part of our learning experience. You have now learnt that ebike batteries can be very dangerous and need to be treated with caution. Put a multi-meter on your Xmas list, then always use it to check anything on your bike instead of making assumptions. Sorry if this sounds hard on you.

This is a good forum to get help on such matters. If there's anything you're unsure of, there's a good chance that someone can explain how to deal with it.

With batteries you can't guess or imagine things can't fail or go wrong, the only way to be sure is check and test.

Diagnosis is the only safe option, although not common there have been the odd switch fault on this forum reported and found.

You will only get the short-circuit when the connector is wrongly wired or when a wire has come off. The switch isn't designed to protect against those.

 

To be honest, you bought one of the cheapest bikes. If they covered every single possibility of user errors and life-cycle errors, like they do on a Bosch bike, you'd have a bike that would cost a lot more and be less convenient.

 

If I understand your description of your problem, a wire came off, you incorrectly wired it and tried to reconnect the connector when you believed that you had switched off the battery, but didn't check it with a meter. One normally only makes that mistake once. many of us have done similar as part of our learning experience. You have now learnt that ebike batteries can be very dangerous and need to be treated with caution. Put a multi-meter on your Xmas list, then always use it to check anything on your bike instead of making assumptions. Sorry if this sounds hard on you.

 

This is a good forum to get help on such matters. If there's anything you're unsure of, there's a good chance that someone can explain how to deal with it.

Thank you no you are not sounding hard on me and I'm learning a lot But I have not rewired anything nor have I sted or suggested it in my posts. I have found shorting has occured when connecting the lead to the battery ( I mean fully assembled as it has been for 4 years ) with the screw on 4 pin connector. I do not think this is my fault as I have not wired anyhthing or assembled anything. What I am sure of is that when the switch on the battery is off that any attempted connection ( even with a incorrectly wired plug if anyone for some reason did such) there wojuld be no fizz, flash and bang and damage to the pins or anything else. Am I right in thinking that a battery that is switched off should ensure no incident when inserting the controllers 4 pin plus ? Someone yesterday evening suggested Cyclotricity would supply a replacement part,. That may well be not the case because they do not provide older parts ( 3 years old means old generation controller and wheel motor with different connection sustem and a different battery and connection) I beleive that a 4 yuear old battery is 'old ' in e bike terms and the impact of age, weather, cooling/ heating/ internal condensation etc may have had an impact and affected the switch circuit causing the battery to be 'on' when it is 'off' I think the idea of gettimng a meter is really a ver good suggestion and I shall do so for my own safety as well as being a useful device for many other reaosns other than e bike

A meter can be had cheaply for about £5 and do the job very well check the specs and get one with a continuity buzzer (ideal for checking wire breaks or circuits) as not all have the option.

Thabnk you, I will look in Argos and Halfords but I am concerned because if a proper connector caused fireworks what about the meter, wont one of those potentially provoke another ? Presumably the idea is to find out if in actuality there is charge at the external connection when it is switched off and if so is it at the correct level etc

The connector is really crappy. It's almost certain that a wire will come off after three years of frequent connection/disconnection. The wires are really close together, so when one comes off, it'll touch the one next to it, which makes a dead short. These connectors are OK for occasional use, but not suitable for daily battery removal. You can't easily change the one on the battery, so you're pretty well stuck with it. If you get a replacement, it could last you another three years.

The only way to know if the switch has failed is to test the output terminals with a meter.

Plenty on ebay, as long as you don't allow the probes to touch when testing you should have no issues, all they do is register a reading depending on what you are testing for.

We all started out like you with some or little knowledge, the addition of a meter is a must step with leccy bikes.

Batteries and other fault finding should hold no fears it is just a case of thinking about what you are going to do and applying logic in a methodical order.

there are 4 pins , how do I know in which configuration to touch them with the meter ? I agree the system is rubbish for regular battery removal The wires are encased in a outer cable that is so short its hard to do the regular removal etc without putting tension on that short cable and I'm sure that has undermined the connection.

Of the four pins two should be for battery discharge and two for charging. With a working battery off the bike two pins should give a voltage reading (discharge circuit) and two should give nothing (charge circuit). How they are aligned you will have to find out, as long as you don't allow meter probes to touch each when on the pins no short circuiting should take place.

On one of mine I have 2 +/pos next to each other and 2 -/neg next to each other, by testing I get voltage reading(discharge) on the two outer pins and nothing on the inner pins (charge circuit) I double checked by opening the battery's receivers connection.

there are 4 pins , how do I know in which configuration to touch them with the meter ? I agree the system is rubbish for regular battery removal The wires are encased in a outer cable that is so short its hard to do the regular removal etc without putting tension on that short cable and I'm sure that has undermined the connection.

Trial and error. Two are around 36v and two are ground. Choose any pair. If it shows 0v, they're either both 0v or both 36v. if you see around 36v, the red probe is on the 36v and the black on the ground. If you see -36v, the black is on the 36v and the red on the 0v.

You can test the battery, then the connector with the wire needs to match it. In this case you have to assume that the red wires are for 36v and the black for ground. If you don't have those colours, you have to follow them to the controller, where they will be connected to red and black wires. I've never known controller red and black to be wrong. Charger blue and brown are often blue positive and brown negative, and anything else on the bike can be unconventional.

UPDATE. purchased a multimeter, set it to fit within the voltage range checked battery switched off then touched just one of the 4 male pins on the battery and BANG FLASH another near nuclear explosion again. That battery is dangerously faulty

and the incident blew a mm off the tip of the multimeter

Firstly, absolutely and for certain I touched just one pin . I didnt get as far as putting a second one on any other pin because the instant almost blinding flash was enough to make me desist from further testing. The switch on the battery was off. I was outside in good light and proceeding very cautiously. It doesnt matter what that meter was set to if the switch was off there should be no bang or flash. ? The metal casing of the 4 pin socket had a little hole blown in it when I tried to connect to the bike yesterday. When I purchased the meter I asked the person who sold it which settings for my intended purpose and followed that knowing anyway that with the switch off there should no shorting. For volts there is 20, then 200 I set 200 in a section with a V and a line with dashes under it. I cannot remember right now which sockets on the meter I chose for plugging in the meters own leads. But there were three to choose from

As regards that one pin only was touched and there was still a short I cannot explain that. But then i cannot explain why it shorts when switched off either

The meter is one of these

https://www.espares.co.uk/product/es1583041?utm_source=google+shopping&utm_medium=shopping&utm_campaign=google+shopping&mkwid=sGt4jns3i&pcrid=174054713172&kword=&match=&plid=&pdv=c&gclid=EAIaIQobChMIo4fetOf41wIVg73tCh1liwvFEAQYBSABEgJRUvD_BwE

There's only one possibility that matches some of what you say: If one of the wires has come off the back of the connector in the battery and is touching the metal case, then when you probed the pin, you touched the surrounding metal at the same time as the pin. If that's what you did, it's very bad practice. That could blow away a bit of the probe because the power would flow between the two contact points, but there's no way it can travel up the wire to the meter. It can only do that if the other probe is also connected to a different voltage point.

If you did short between the pin and the case, you should be able to see the two burn marks.