Live cable connection.

[jimmydoc]

Hi, I'm replacing the battery on my Pulse Ebike with a chinese battery, but the battery has arrived almost fully charged (37volts) with no way to switch it off. As the red wire is live, how do I safely couple it to my controller? Do I have to discharge the battery ? If so, how do I do that safely? (not too hot with electrics)
I also see that the battery charger cable that comes with the battery has a standard negative/positive push in end that plugs into the battery, rather than a 5 pin push in end. Does this mean that there is no protection inside the battery pack? Thanks for any help, Norrie.

 

[Nealh]

37 volts is approx. 50% charge and not 100%, you need to plug it in to charge up and should see 41.5 - 42v for a fully charged 36v battery.
You can't discharge a lion battery to a safe level other wise it would be only fit for recycling, even at minimum voltage (30 - 32v) a battery will still be a potent force.
Soldering battery cables direct from a battery usually only occurs with LIPO hobby packs, as long as wiring isn't allowed to short then it is safe. All wire ends should be isolated/protected with a bit of tape or similar and only one wire at a time should be cut/soldered, then any bare joint should be protected with a covering of heat shrink if a connector isn't utilised.
The battery should sit in a cradle/receiver usually supplied with the battery, simply remove the battery/case from said receiver and wire the receiver with no power.

Better still show us a pic of your new battery.
The charger pin is quite normal and sounds like it is a std 5.5 x 2.1 or 2.5 dc socket one, the battery will/should have a BMS inside.

 

[Nealh]

One thing you MUST do before attempting to carry out any connections is to confirm with a meter that the battery polarity is correct other wise you will see a flash and possibly KFF's. It has been known for China batteries to have reverse polarity, any miss connection can damage the battery and controller.
With a meter place the Red and Black probes to the same corresponding wires on the battery/receiver, a bad or wrong polarity connected battery will show up with a minus symbol in front of the voltage reading.
Anyone who thinks of wiring there own electronics should always have a meter at hand to carry out basic checks first to prevent accidents happening.

 

[jimmydoc]

I've just noticed the cradle/ receiver you mentioned, separated the two and of course I've disconnected the power supply from the battery! Now I can connect safely. You've also given me peace of mind about the BMS protection . I'll now charge my battery fully. Can't thank you enough for your help, and your speedy reply.

 

[jimmydoc]

I checked the polarity, It's correct.