19.2 V battery question !!

[Tynan]

Hi there

New member here with a very basic question (I am no electrician!). :saddam:

I have a 19.2 V / 9000mAh battery (for an electrically assisted bicycle) and the wiring on the charge end needs a little attention. Basically one end of the battery gets plumbed into the bike and supplies it with power and the other end is the end that gets plugged into the charger when recharging.

At the charge end one of the wires is broken and needs soldering together, I am ok with the soldering / heat-shrinking and general repair duties but have zero knowledge of how electricity works with these batteries - so to my question . . . . .


When the battery is unplugged from the mains and the charger (and disconnected from the bike) is it safe for me to touch the red wire in this diagram ? (diagram below) ? To clarify I am talking about the red wire coming from the battery at the charging end, when the battery is disconnected from everything (from the charger / mains and the bicycle) is it ok to handle the red wire that protrudes from the battery ?


Thanks in advance for any help on this !!




Tynan.

 

[Des 56]

OK I will try and give you opinion
The design appears to be poor,in that the charger trailing wires are permanently connected when the battery is fitted to the bike,I would have thought the battery housing should have a removable plug/socket arrangement at the housing

Soldering produces heat that will migrate upwards,when soldering try and keep the lead upright or use an heatsink near where the soldering is to be done

Dangerous voltages are 30 volt RMS (household type supplies) and 50 volts DC ( battery supplies)therefore your battery voltage is within that safe limit
Damage to the battery itself can occur if you inadvertantly short out an adjascent wire whilst soldering, by melting into the insulation,

 

[Tynan]

OK I will try and give you opinion
The design appears to be poor,in that the charger trailing wires are permanently connected when the battery is fitted to the bike,I would have thought the battery housing should have a removable plug/socket arrangement at the housing

Cheers for the reply Des.

I am not an electrician . . . . . or . . . . an illustrator !

The diagram is for illustration purposes only, in reality the battery housing has a removable plug/socket arrangement, I've only draw the basic mechanics of the connections. (hope that makes sense)!.

Here's where the removable plug/socket arrangement lives (white cross)

Soldering produces heat that will migrate upwards,when soldering try and keep the lead upright or use an heatsink near where the soldering is to be done

Cheers for the tip.

Dangerous voltages are 30 volt RMS (household type supplies) and 50 volts DC ( battery supplies)therefore your battery voltage is within that safe limit

Cheers for the info, so I should be safe soldering the broken wire when everything is disconnected ?

Once again, thanks for the reply, much appreciated.

 

[Des 56]

The diagram is for illustration purposes only, in reality the battery housing has a removable plug/socket arrangement, I've only draw the basic mechanics of the connections. (hope that makes sense)!.

Now please dont get me worried that I have given advise that could be harmful

The charger must not under any circumstances be plugged into the mains supply whilst soldering

Reading your post after you ammended the description.there is now suggestion in my mind that you may do this repair whilst it is still mains connected

 

[Marvo]

You should be fine if everything is isolated and disconnected. Batteries can deliver many hundreds of Amps if their output is accidentally shortcircuited and this is a very real fire hazard. I would use a ferrule crimp and double heatshrink sleeve over it but solder would also work.

 

[Tynan]

You should be fine if everything is isolated and disconnected.

The battery will be out of the bike and disconnected from the charger, my concern was really getting some kind of shock from the battery itself.

Batteries can deliver many hundreds of Amps if their output is accidentally shortcircuited and this is a very real fire hazard.

I am super cautious in these situations, everything will be separated and covered/protected before I do anything.

I would use a ferrule crimp and double heatshrink sleeve over it but solder would also work.

I've not got a ferrule crimp unfortunately, but I'll use your idea of the double heat-shrink sleeve.

Cheers for the input.

 

[Tynan]

The charger must not under any circumstances be plugged into the mains supply whilst soldering

Not to worry I wouldn't dare work on anything if it was connected to the mains ! You are talking to someone who dons rubber gloves to change a light bulb !

But thanks for your concern, I appreciate it.

 

[Marvo]

...my concern was really getting some kind of shock from the battery itself.

If it's a straight forward battery with a 19.2 volt DC output then you won't get a shock from it.

The only down side to soldering is you'll need to check for sharp protrusions that might pierce the heat shrink. If need be you can always add a few turns of self amalgamating tape afterward for extra piece of mind.

 

[Tynan]

You should be fine if everything is isolated and disconnected. Batteries can deliver many hundreds of Amps if their output is accidentally shortcircuited and this is a very real fire hazard. I would use a ferrule crimp and double heatshrink sleeve over it but solder would also work.

"Batteries can deliver many hundreds of Amps if their output is accidentally shortcircuited"


Just to clarify: the wire I am looking to repair is the 'input' wire from the charger (rather than the battery's output).

 

[Tynan]

If it's a straight forward battery with a 19.2 volt DC output then you won't get a shock from it.

Good to know !

The only down side to soldering is you'll need to check for sharp protrusions that might pierce the heat shrink. If need be you can always add a few turns of self amalgamating tape afterward for extra piece of mind.

I will keep an eye on that, I will remove the tips of any sharp burrs with a scalpel . . . . I've not got any self amalgamating tape, but I might grab some on Tuesday, thanks for the tip !

 

[Marvo]

Just to clarify: the wire I am looking to repair is the 'input' wire from the charger (rather than the battery's output).

Unlike the charger, a battery doesn't have an input and output as such, just the + and - terminals. The wire you're working on is probably directly connected to one of the battery terminals. There might be electronics in between but assume it's connected directly to the battery and treat accordingly making sure you don't contact anything else accidentally.

 

[Tynan]

Unlike the charger, a battery doesn't have an input and output as such, just the + and - terminals. The wire you're working on is probably directly connected to one of the battery terminals. There might be electronics in between but assume it's connected directly to the battery and treat accordingly making sure you don't contact anything else accidentally.

Absolutely, I approach electricity with a lot of caution (hence my research on this forum before even thinking about repairing a simple wire break on a battery).

Cheers for the your input Marvo, genuinely appreciated if you never hear from me again please have the following inscribed on my grave:

He died doing what he loved: being connected to a 19.2 V / 9000mAh battery !

: )

I'll report back if I survive.

 

[Marvo]

Good luck, I'm sure it will be straight forward.

Out of interest how did the wire get broken in the first place?

 

[Tynan]

Good luck, I'm sure it will be straight forward.

Out of interest how did the wire get broken in the first place?

Let me take a photo to better explain . . . . . . hold on a minute . . .

 

[Tynan]

Here you go . . .

It's basically a long battery that sits inside the frame of an electric bicycle, the connector broke and got pulled out of the end of the battery and although it still works fine it's getting damaged over time, so I am going to repair the connector - get it fixed back into it's rightful place on the end of the battery - but first I want to make sure the wires are all cleanly connected, shielded and secure before they get pushed back into the battery housing.