Li-ion battery charger: Input, Output, volts and amps...what's it all mean! :)

[WitlessWonder]

Hi, I'll be honest - I have a little electric moped as my only transport so feel I should get a 2nd charger for it. I don't fancy the idea of paying £300 for one from the manufacturer so wanted to make one up myself.

The existing charger is Li-ion Input AC 180V-240V 5.0A max. Output is 60V 10A. Am I oversimplifying to ask what the critical numbers in are please? - i.e. which have to be that number and which can be a little different (and what's the impact of that).

For example, I've seens a Li-ion charger with input AC 200-240V 8.5A, will that be OK? What would that extra ampage input do? It has an extra output voltage of 67.2V? Whhat'll that do please? Thanks and hope that makes sense.

 

[Geoff1946]

I wouldn't risk it. Have you seen the news items about serious fires started by overheating Li-ion batteries?
Decent chargers use heat sensors in the battery pack to ensure overheating doesn't occur. Obviously only a charger supplied by the equipment manufacturer will have this capability.
£300 could be cheap compared with burning your house down, possibly whilst you sleep!

 

[Richard-the-Ninth]

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Witless wonder, when you change any power supply the output voltage and current must be the same on the new power supply as the old one* If it is a higher voltage it will cook what it is connected to, if it is a lower voltage it will not charge / operate what it is connected to.

Assuming you found one that has the same rating, but is "generic" you have to ask yourself "Do I want to connect this to my £1,000+ device and risk destroying it in seconds, or should I buy the right one and have no worries" There is the recent video by a well known YT person who opted for a generic charger and the result was he destroyed his expensive kit in seconds. (Pity his phone was not recording)

Also what Geoff1946 said is true, matched items also "talk" to each other, so they work together. Generic stuff, does not talk.


*The current is how much the device can deliver, it is also how much the device requires. Depending on which device you are looking at. So a power supply rated at (for example 5A) can easily have a device plugged in that requires 3A. BUT you can't/shouldn't plug in a device that requires 8A as it will "pull" the 8A it needs, but as the power supply is only 5A the power supply will soon burn out / catch fire.

 

[WitlessWonder]

Can you see how I picked my name now?

OK chaps, thanks for taking the time to talk me out of it, it's appreciated.

Time to put my hands into my pockets!

 

[MikeJhn]

Lithium Iron batteries need to be cell balance charged, i.e each cell must match the other cells in a pack to remain stable, this requires individual monitoring of each cell with a + and - connection, charge rates are in general not above 10C this is 10% of the overall capacity, the battery discharge rate is also important never to be exceeded.

 

[WitlessWonder]

Lithium Iron batteries need to be cell balance charged, i.e each cell must match the other cells in a pack to remain stable, this requires individual monitoring of each cell with a + and - connection, charge rates are in general not above 10C this is 10% of the overall discharge capacity.

Got you. I naively thought that as long as the charger was a Li-ion one it would therefore have that ability but I think i'm oversimplifying.

 

[MikeJhn]

The charger is generally matched too the battery with specific connections to each cell in the pack, most have monitoring circuits and most have temperature monitoring as well through the connecting cable, if you can see the plug that fits into the battery you will see multiple pins to perform this function, unless the electronics are built into the battery witch would be very unusual.

 

[WitlessWonder]

The charger is generally matched too the battery with specific connections to each cell in the pack, most have monitoring circuits and most have temperature monitoring as well through the connecting cable, if you can see the plug that fits into the battery you will see multiple pins to perform this function, unless the electronics are built into the battery witch would be very unusual.

Thanks Mike, I really appreciate people with the knowledge explaining why my idea was a bad one as I do like to learn.

Your point specifically helps as what I hadn't mentioned was the question was going to be if it matters that the original plug that fits into the battery (a chogori) has a different number of the lower small pins than the back up chogori that I can find! Your reply answers that this is another reason too not do this!

 

[SPECIAL LOCATION]

As a side note, is their any warranty cover remaining on this moped and/or its battery?
As I guess it would be invalidated using a non manufacture's product.

 

[WitlessWonder]

Good point; another year, another reason! I'm wondering now if this is the worst idea I've ever publically expressed

 

[Richard-the-Ninth]

There is no such thing as a mistake, only lessons.

 

[WitlessWonder]

There is no such thing as a mistake, only lessons.

Yes, in my younger days I'd have not asked and just had a go so I guess wondering witlessly is an improvement! Thanks all that helped me keep on the straight and narrow

 

[SPECIAL LOCATION]

Good point; another year, another reason! I'm wondering now if this is the worst idea I've ever publically expressed

It is always better to ask and seek some more qualified guidance to the best solution to a problem you are unsure about.

AND.. it is ALWAYS best to be open and honest about where you are coming from with your current experience and understanding of any problem you are trying to solve...

We get far too many people on here asking for advice to solutions they think they can solve themselves..
without admitting their very limited skill-set...
When in reality they either need professional help or better kit to do a proper job..

So... I will just crack open another Friday night lubrication tool and say..
Big respect to you for asking, and Not pretending you are something above your ability and experience..

I just hope you feel you have been answered in a friendly helpful way, and are not put off from asking any future questions..?

ALSO.. remember that other people with similar problems may read this thread and be thankful that you had the balls to ask a question they were too sh1t-scared to ask!!!!!!!!!!!