Battery Chargers = plug in the wall, or battery first

[imorton]

Hi Guys, I have two LifePo4 / Lithium-Ion chargers (the cheapie kind) and there is no instructions as to how to plug them in. I have two LifePo4 chargers, a SMALL 3amp model, and a LARGER 6amp charger.

Does anyone know the technical reasons/instructions on how to properly use (plug in and not destroy) these chargers…? From an engineering point of view, what did the mfg.'s recommend?





Should I be doing #1 or #2…?

#1) Do I plug in the wall first ?

#2) Do I plug in the battery first?

Thanks of your replies, IAN…

 

[amberwolf]

I've seen both ways on manufacturers' stickers, sometimes on what appear to be identical chargers inside and out. So that's not much help.

I almost always plug into the wall first, then into the pack. Mostly, it's because it's easier on the connectors, with no spark between them as I plug the charger in. (it's also probably easier on the output/filter stages of the charger).

One exception is with one of the "HiPower" chargers I had, that will ONLY start charging if it is plugged into the pack first, and *then* into the wall. If I plug it into the wall, and then into the pack, it won't charge. Even if I then unplug from the wall, then back in, it still won't charge. Same with unplugging from pack and back in. Only if I then disconnect from everything and let it sit for a minute or so, then plug into pack first, then wall, does it work. It might be "broken", or it might be designed that way; I don't know.

 

[imorton]

Amberwolf, I agree with what you are saying, the instructions the heard are on both sides.

I thought the "method" of plugging it in had more to do to the "type" of charger ( different switching etc...)

What I see on ebay relating to "harder instructions" seems to be mostly "cut & paste text" all saying the same things.

I was thinking more on a technical/longevity basis. IAN

 

[999zip999]

I always had plugged in the wall.first right or wrong ?

 

[Russell]

I have my chargers plugged into a power strip with an on/off switch so I don't get a spark plugging them into a wall outlet each time I want to use them. I turn the power strip on then plug the charger into the battery so there's no spark there either. I also have a lamp plugged into the power strip which reminds me I have the chargers on cuz sometimes I forget about them, not that it would hurt anything leaving them on.

-R

 

[arkmundi]

My Smart Charger from batteryspace manual instructed to always do the wall plug, then the battery pack. When doing that, its logic circuit flashes all 6 LED's first and then with the battery connected, initiates its charge cycle. With my laptop, a simpler charger, I've done it both ways with no ill effect and same result.

 

[dnmun]

always power up the charger first so you don't burn the contacts in the charging plug from the current flowing out of the battery into the output caps.

 

[imorton]

I have never had any "paper instructions" included with any of these chargers… (cheap chinese chargers)…

Here's an excerpt from an eBay ad about a 6amp charger… Read the bottom section in grey.



I just wish we had the "real design/engineering manufacturers instruction"

IAN.

 

[amberwolf]

Just a note:

None of the laptops I've had or fixed for others have the spark-on-plugin problem, when plugging hte charger into the laptop before plugging it into hte wall (or plugging the ac cord from the wall into the back fo the charger block; sometimes it's disconnected and I don't realize it till after I plug into the laptop end). I'm guessing that's because of the charge control electronics being inside the laptop, so there's no battery current able to flow back out the wall adapter plug port.

In general with ebike batteries, that won't be the case, even with a typical BMS on the pack with a separate charge port from discharge port, it'll still allow current flow into the charger from the pack. Some might not, but all of the few I've had and repaired and tested have so far.


If you ever really had the need to, though, you could add either a circuit like Fechter's precharge unit, or a big fat diode (ideal diode would be best), to he charge port on the battery, and prevent teh problem no matter which order you hook it up. Generally that's just a nother thing to fail and more complication, so...I haven't bothered.

 

[imorton]

I guess I'm lucky with the sparking as my system is only 48v and only generates a small spark.

I guess my question was more related to properly plugging in the chargers to prolong their longevity.

I keep hearing about people saying that their chargers only lasted 1 month, or they only used it 10 times and it died on them. I thought some of the "charger dying problem" was related to the "plugging in order" to the wall or battery first.

I figure if a connector gets pitted or damaged, I can easily change it and install a new one. But if the charger dies after only using it for a month because of my plugging sequence, than I would like to learn if there is a technically better way to do it.

I know on my eZip E750 scooter, they wanted us to plug the battery first, than the wall outlet.

But from what I see, most people tend to plug the wall outlet first, than to the battery.

IAN…

 

[amberwolf]

I keep hearing about people saying that their chargers only lasted 1 month, or they only used it 10 times and it died on them. I thought some of the "charger dying problem" was related to the "plugging in order" to the wall or battery first.

Could be sometimes, but mostly it isn't--it's just crappy manufacturing and/or design, or poor choices of actual parts used in it, or sometimes misuse of a charger in some way. Sometimes it's a chainreaction failure: crappy fan in charger either dies or never worked in the first place, so rest of charger overheats and various parts die.

In the probably rare case of connect order cuasing a problem, it's either connector failure (itself often caused by poor choice of connector type, or improper crimping of the wires leading to loose connections that wprobably would've failed eventually even if they had done it the othe rway round), or possibly capacitor damage from the inrush of current (not very likely unless they were pretty crappy to start with), or possibly passive parts or semiconductors in the current path being damaged by the sudden inrush of current--again I doubt much of that happens either, except things that could well have failed a little later on on their own anyway.

 

[imorton]

So I guess the summary of it all is:

1) cheap chinese chargers can fail at any time from a multitude of reasons, and the "plugging sequence" has very little to do with it..

2) general charger observations are important: EX: vibration damage (if transporting), fan is working properly, used in a dry environment, condition of the battery/wall outlet connectors, and using your hand to check normal operating temperatures.

3) And lastly but not least, I should have a contingency plan, EX: have a backup charger so when the "daily use charger" dies, I am not out of commission…

Am I missing anything here?

IAN

 

[amberwolf]

Not that I can see.

Almost anything can go wrong, or be built wrong.

I've even had the AC power cord itself be the problem, where it's IEC-end contacts were spread apart or made wrong, and not fully contacting the IEC pins on the charger itself for hot or neutral. It'd work most fo the time, but sometimes just stop charging, and appear to be off. Eventually I smelled plastic burning, and found it actually arced inside the contact area. I cut the ends off the cord and saved the wire itself, and used a totally different AC power cord for it and have not had problems with it since then.

I've also run across an AC cord that was miswired, though that was in teh computer world: Been too long to remember for sure, but I think line and ground were swapped at one end, so the power supply caught fire just before the wall-supply's breaker popped at the breaker box. Similar thing happened to my dad decades before when working with old teletype terminals. Not common but it happens.


I can't count the number of "dead" things I've been given that I opened up and found capacitors installed backwards on, and the input fuse blown becuase of the current draw. Sometimes the caps aren't toasted yet, sometimes they're mostly confetti hanging out of the can. :lol:

 

[dnmun]

So I guess the summary of it all is:

1) cheap chinese chargers can fail at any time from a multitude of reasons, and the "plugging sequence" has very little to do with it..

2) general charger observations are important: EX: vibration damage (if transporting), fan is working properly, used in a dry environment, condition of the battery/wall outlet connectors, and using your hand to check normal operating temperatures.

3) And lastly but not least, I should have a contingency plan, EX: have a backup charger so when the "daily use charger" dies, I am not out of commission…

Am I missing anything here?

IAN

yes, you are missing what i said. power up the charger before you plug in the battery. how hard can that be to understand?

 

[imorton]

yes, you are missing what i said. power up the charger before you plug in the battery. how hard can that be to understand?

dnmun, WE ALL HEARD WHAT YOU SAID… and this forum post can now be closed…

Thanks for setting it all straight for us.

All the members of Endless Sphere and the visiting internet readers appreciate you sharing your words with us, and we all wish you a great day…