Charging Procedure

[PCeBiker]

I don't care what the instructions say. Capacitors are nothing to mess with......

^^^ Yes
I would rather have that huge surge and spark at the wall socket rather than at the battery's charge port.

If you have a huge surge at the battery charge port, that surge is either going in or out of the rather delicate BMS circuit.

Keep in mind that the picture of that charger and instructions are most likely for a lead acid battery and that following the instructions means that the surge is done at the wall outlet so the capacitors are charged and the chargers output voltage is ~matched to the battery so there shouldn't be much of a spark or surge when the charger is connected to the battery.

The problem may well be that if the charger is connected to the battery before the wall plug, the capacitors in the charger may pull that charge/surge from the battery, but that's not too big a deal with a huge lead acid battery with no BMS, and a simple power diode (rated for more than the chargers rated output) will prevent reverse charging of the capacitors from the battery.

@Ravi Kempaiah
I want your take on this.
Perhaps chargers designed for lithium batteries are better designed to protect the battery and the BMS inside it, but most of the instructions go against what you say in your video.

 

[JGcycle]

I would like to say thank you to all those who posted. I really appreciate all your great feedback.

 

[6zfshdb]

As previously mentioned, on some bikes the order of connection doesn't matter but on others it could. Follow the manual if it mentions the procedure.

On one of my bikes, the charging connector arcs when I connect it to the battery with the charger plugged into AC. On others, it doesn't. The arcing doesn't appear to cause any immediate harm but over time, it could damage the contacts. For me anyway, I've gotten in the habit of connecting the battery first and then plugging in the charger.
YMMV.

 

[Mr. Coffee]

You know, your battery charger should just NEVER arc when you are connecting a battery to it. The cost of the parts to prevent that from happening in a battery charger is less than $1.

To clarify what @Stefan Mikes said, it should never matter which order you connect things. If it does that is a design and safety flaw in the charger.

 

[PCeBiker]

You know, your battery charger should just NEVER arc when you are connecting a battery to it. The cost of the parts to prevent that from happening in a battery charger is less than $1.

I made a 10 amp full wave bridge rectifier for less than a buck.




You only need one diode to stop reverse current flow.

 

[Gionnirocket]

You know, your battery charger should just NEVER arc when you are connecting a battery to it. The cost of the parts to prevent that from happening in a battery charger is less than $1.

To clarify what @Stefan Mikes said, it should never matter which order you connect things. If it does that is a design and safety flaw in the charger.

Yet it is often stated in the instruction manual. And I'm not just talking about battery chargers, I'm speaking to most all devices with a power supply and/or electronics
And though not explicit... even the sacred Bosch battery manual states an order.
I'd rather follow the instructions than a self proclaimed expert on all.

 

[PCeBiker]

The cost of the parts to prevent that from happening in a battery charger is less than $1.

The cost of building a battery charger is more than buying one.

Mine cost $110

I plug it in at the wall first.
The power needs to be on to read the display.
It doesn't spark when I plug it in.

 

[AHicks]

Much easier than worrying about it (or buying/adding a new anything to the design), bordering on brain dead, to just plug the charger into the battery prior to plugging it into a wall. KISS.....

 

[PCeBiker]

Yup.
Just follow the procedure and don't worry about it.
If you do it wrong it sparks, so you probably won't do it again.
You get at least a few bad starts before you wreck something.

It's like starting your car when it's already running.

 

[Slaphappygamer]

WOW! I never gave charging much thought. I've always plugged the mains, then the battery and when done I'll disconnect the battery, then the mains. After reading this thread, I'll change my habit and do it the opposite way now. I was backwards! I've never heard (or seen) a spark, so hopefully I haven't damaged anything.

 

[AHicks]

WOW! I never gave charging much thought. I've always plugged the mains, then the battery and when done I'll disconnect the battery, then the mains. After reading this thread, I'll change my habit and do it the opposite way now. I was backwards! I've never heard (or seen) a spark, so hopefully I haven't damaged anything.

SOME designs are safe like that, impossible to hurt anything or screw up. Others though, will scare the beejesus out of you with a big flash and related POW as they let you know they aren't happy with the connection order you've used. That's a mistake you're only going to make once, and it may leave a black mark that will be fine as long as it doesn't happen several times. At that point you may have to remove the black to get a good connection going again.

 

[PCeBiker]

,..it may leave a black mark that will be fine as long as it doesn't happen several times.

It can melt metal too.
That's how an arc welder works.
I've had to replace wall sockets from being sparked up too much from plugging in high amp devices.

 

[PCeBiker]

My LED drivers (power supplies) spark like crazy when they turn on.
I didn't want all that sparking going on inside my timer, so I added a Heavy Duty contactor to take the heat.

I can turn half a city block on and off with that thing.

(I didn't want to keep switching my power supplies on and off, so I leave them on and switch the 20 VDC output on and off with the contactor instead.
So the bare terminals you see are only 20 volts. They are OK to touch)

 

[Chibbie]

I mentioned earlier in this thread that if the bike’s manual and the battery’s/charger’s manual are inconsistent regarding charging procedure, I’d be inclined to follow the latter. I’m now doubting that, in that I’ve now come across a second instance (out of the two e-bikes I own!) where they’re inconsistent, but this time the charger’s manual says to connect the charger to the wall power source first and then connect it to the battery, whereas the bike’s manual says the opposite. (See attachments: the first is from the bike’s manual; the second is from the charger’s manual).

I’m probably going to just follow what seems to be the logical and standard procedure, which most folks on this thread seem to do: plug in to the battery first and then into the wall. (Same way as when charging a car’s battery with a battery charger: connect to positive then ground on the battery; and only then plug the charger into the wall.)

But am I missing something? I’d be interested to hear if y’all think I should instead follow the opposite procedure in this instance simply because that’s what the charger’s manual says and - as I suggested in my earlier post - presumably the company that makes the battery and charger has greater expertise in how to charge it properly. (I’ll contact the bike’s manufacturer too, of course.) Is there something about this specific battery/charger combo that would dictate plugging into the wall first and then into the battery?

 

[PCeBiker]

(See attachments: the first is from the bike’s manual; the second is from the charger’s manual).

Believe the chargers manual.
The charger knows how it should be operated.

Any charger can be plugged into any outlet and charge any battery (provided the voltage matches the battery, the plug fits the battery, the polarity is correct and you don't push too many amps into a small battery.)

You have a semi-smart charger that blinks if it is short circuited.
Following the chargers instructions is probably important for that to operate properly.

As long as you have the correct instructions for the charger, then do what is printed on the charger, or the directions for the charger.

Your ebike owners manual is out of date and wasn't updated when the ebike manufacturer provided a different charger with their ebike.
Shame on them.

 

[smorgasbord]

Another way to look at it is that you don't want arcing near the battery, so connect/disconnect the battery only when the power is not connected. And, better to blow out your charger than to blow out your battery.

I use a power strip with a switch for the two Luna chargers we have. Interestingly, the second charger has its own power switch, whereas the first came with instructions to set everything up before plugging it in to the wall and then unplugging from the wall first.

 

[PCeBiker]

Another way to look at it is that you don't want arcing near the battery,

His fancy new semi-smart charger will not spark when plugged into the battery.

If the battery tries to spark, the charger will register a blinking red light, indicating a short circuit.

 

[PCeBiker]

If the battery tries to spark, the charger will register a blinking red light, indicating a short circuit.

My fancy new bench power supply has an alarm that goes off indicating a short circuit.

You can override the alarm because there are instances where you want to deliver a certain amount of current to a load with almost no resistance and no voltage drop.
(Like if I want to find out how much current a wire can handle before it heats up enough to melt or burn the insulation on the wire.)

 

[bobf]

I also think it makes sense to connect battery to charger before plugging charger to the wall. But I noticed the instructions for Specialized Turbo Creo say to plug charger first, then connect to the bike. Just a guess, but maybe the reason is that the charger has some self-diagnostics and this order of doing things gives the charger a chance to report it has failed before it can hurt the battery.

I would add that I've done charging both ways and they both worked.

 

[tomjasz]

Thanks so much Stefan--much appreciate it.

Bad information, as a general rule. Jeez Stefan WTF?