Connecting a charger correctly?

[Fordulike]

This has probably been covered a zillion times before, but as usual, I can't find any threads on the subject

I've got one of those generic Samsung celled frame battery packs:



The horrible, translated from Chinese, instructions states to connect the lead to the battery first, then plug into the mains. When I do it this way, there is a little spark when I push the connector into the battery.

If I have the charger plugged into the mains and powered up, then connect the battery, there is no spark.

Obviously, I like the no spark method. Sparks to me indicate high current discharge on terminals.

So, what is the correct way to connect the charger to the battery, so that it minimizes any damage to the charger or BMS?

 

[RobF]

It's what I've always done - connect battery to charger then charger to mains.

I reverse the process when the battery is charged - pull the mains plug first.

 

[Deleted member 4366]

I always do it the other way to avoid the spark, which can damage your battery. The spark puts a rough edge on your charger connector, which then hooks out the earth strip. Next time you plug in, the earth strip shorts to the middle pin and blows your charger. How do I know?

 

[Fordulike]

I always do it the other way to avoid the spark, which can damage your battery. The spark puts a rough edge on your charger connector, which then hooks out the earth strip. Next time you plug in, the earth strip shorts to the middle pin and blows your charger. How do I know?

Bet you've got the t-shirt Dave lol

 

[flecc]

For me it's always mains connect first, battery connect second. Lets the charger circuit stabilise before the battery load is applied.

And that's everything, electric razor, phone etc.
.

 

[Fordulike]

For me it's always mains connect first, battery connect second. Lets the charger circuit stabilise before the battery load is applied.

And that's everything, electric razor, phone etc.
.

Well, if you and Dave have always done it this way and not blown anything up, then it's good for me too

 

[mike killay]

My Woosh bike specifically said to connect charger to bike first, mains after.

 

[shambolic]

My Woosh says that too and yet I have a small mobility buggy and that says connect charger to mains and then charger to battery both Lithium batteries. Is it possible there are different set ups that require different order?

 

[D C]

My Cyclotricity instructions also say this, "Always disconnect the charger from the mains before disconnecting the charger from the battery"
I've been doing this religiously and reversing the process to connect since I first charged my rear rack battery.
Now I'm quite confused as d8veh and flecc who I'm confident know more about electricity than I ever will, both say the opposite.
Dave.

 

[Cyclezee]

For me it's always mains connect first, battery connect second. Lets the charger circuit stabilise before the battery load is applied.

And that's everything, electric razor, phone etc.
.

Ditto

 

[shambolic]

Could it be that different ciruitry requires a different order? Both of my instruction manuals are emphatic about not doing it the other way around or things may be damaged.

 

[trex]

I always connect the battery to charger first, mains second.
You may see smoke but no way will you see a spark.

 

[D C]

I always connect the battery to charger first, mains second.
You may see smoke but no way will you see a spark.

Why would you see smoke?
Dave

 

[Fordulike]

I always connect the battery to charger first, mains second.
You may see smoke but no way will you see a spark.

You're just pulling our legs..... right

 

[Deleted member 4366]

I've seen smoke a few times too. My Ping charger was a stormer. It filled the house. I had to go outside until it cleared. I think the mains lead was half in and half out so it was buzzing, then the smoke started. Moral of the story: whichever method you use, be decisive. Don't half-connect the mains.

 

[flecc]

My Cyclotricity instructions also say this, "Always disconnect the charger from the mains before disconnecting the charger from the battery"
I've been doing this religiously and reversing the process to connect since I first charged my rear rack battery.
Now I'm quite confused as d8veh and flecc who I'm confident know more about electricity than I ever will, both say the opposite.
Dave.

There is a difference between connecting and disconnecting though Dave. By all means disconnect the mains first when at end of charging if you wish, you won't do any harm by doing that.
.

 

[Cindy]

Where is the best place to get a new charger? the one that came with my second-hand trike is a botched up jobbie that will probably set my house on fire!

 

[trex]

the low internal resistance of the battery (0.1 Ohm) causes a large inrush current when you connect 42V at the charger output to the battery input, that high current passes through a small contact area at the battery port causes a spark. It's kinder to the electronics to keep the sparks away by connecting the charger to the battery first.