Help! Checking Charger Output

[Barnsleyrob]

I’m hoping someone can help me solve something that I should know the answer to but can’t get my head around !

I would like to check how many Amps a charger is pushing out using my trusty voltmeter. It’s easy enough to measure the voltage but I suspect that the current is lacking. The connector is the same jack plug type that ebike use, although it’s actually a charger for my battery powered Sealey pressure washer that refuses to charge using the supplied charger (I have to remove the lead acid battery and use a car charger).

Short version then is “How do I check the current being supplied by my battery charger ?”

Any help grateful received.

 

[sjpt]

You need to connect it in series. One of the paths from charger to battery must be broken, and insert the voltmeter (set to an amps range of course) in the path. The easiest way to break the connection will depend on how your leads/connectors work.

battery + --------|-- meter --|------- + charger
battery - ---------------------------- - charger

(the forum doesn't respect fixed with fonts properly)

 

[vfr400]

I’m hoping someone can help me solve something that I should know the answer to but can’t get my head around !

I would like to check how many Amps a charger is pushing out using my trusty voltmeter. It’s easy enough to measure the voltage but I suspect that the current is lacking. The connector is the same jack plug type that ebike use, although it’s actually a charger for my battery powered Sealey pressure washer that refuses to charge using the supplied charger (I have to remove the lead acid battery and use a car charger).

Short version then is “How do I check the current being supplied by my battery charger ?”

Any help grateful received.

You can't measure it unless your meter has a shunt in it and a separate socket for the probe. Even then, you'd have to make up a special lead with the jack plug on on end and a socket on the other, otherwise you have to cut your charger's lead.

Although it's possible in theory, I've never seen or heard of a charger giving out insufficient current. I would say that it's a lot more likely that you have a connection fault between the jack socket and the battery. Is there a charge fuse?

 

[Andy-Mat]

You need to connect it in series. One of the paths from charger to battery must be broken, and insert the voltmeter (set to an amps range of course) in the path. The easiest way to break the connection will depend on how your leads/connectors work.

battery + --------|-- meter --|------- + charger
battery - ---------------------------- - charger

(the forum doesn't respect fixed with fonts properly)

He should remember to use the (usually) 10 amp range on his multi meter, as most lithium bike chargers that I have seen, are either 2 amp or 4 amp, though of course they could be of a higher amp-age.....
One should not forget that the slower the charging rate, the lower the battery damage, and the longer the battery life.
Your diagram is excellent, by the way!
Andy

 

[WheezyRider]

He should remember to use the (usually) 10 amp range on his multi meter, as most lithium bike chargers that I have seen, are either 2 amp or 4 amp, though of course they could be of a higher amp-age.....
One should not forget that the slower the charging rate, the lower the battery damage, and the longer the battery life.
Your diagram is excellent, by the way!
Andy

Also, I would suggest using a thin bit of wire in your leads to the multimeter, or an inline fuse of say 5A or so. The 10A connection on multimeters is not generally fused, so if you get things wrong, the consequences can be spectacular! Depending on the BMS rating and the output fuse, batteries can pump out massive currents when shorted.

 

[Andy-Mat]

Also, I would suggest using a thin bit of wire in your leads to the multimeter, or an inline fuse of say 5A or so. The 10A connection on multimeters is not generally fused, so if you get things wrong, the consequences can be spectacular! Depending on the BMS rating and the output fuse, batteries can pump out massive currents when shorted.

Excellent idea, and simple to achieve, as even say a 10 amp fuse from a 13 amp plug, if say soldered in place, would do it. (probably a 5 amp one would for most chargers, just check the label first!)
Also, those who worry about voltage, it really does not matter what the voltage is for the fuse (220 - 240 for 13 amp plug fuses) as long as it is above the voltage being tested!
regards
Andy

 

[WheezyRider]

If you need to do more than 10A, you can get one of these:



But generally, most chargers are only 2 to 3 amps output.

 

[WheezyRider]

I’m hoping someone can help me solve something that I should know the answer to but can’t get my head around !

I would like to check how many Amps a charger is pushing out using my trusty voltmeter. It’s easy enough to measure the voltage but I suspect that the current is lacking. The connector is the same jack plug type that ebike use, although it’s actually a charger for my battery powered Sealey pressure washer that refuses to charge using the supplied charger (I have to remove the lead acid battery and use a car charger).

Short version then is “How do I check the current being supplied by my battery charger ?”

Any help grateful received.

Just re-read your post. Can you clarify exactly what you are trying to do and what your system is? Are you trying to recharge a lithium e-bike battery with a lead acid charger? Or have I totally misunderstood?

 

[vfr400]

Just re-read your post. Can you clarify exactly what you are trying to do and what your system is? Are you trying to recharge a lithium e-bike battery with a lead acid charger? Or have I totally misunderstood?

He's trying to charge his 12v pressure washer battery that can't be lithium because it would have blown up by now charging it with a car battery charger!

I've got to hand it to you guys, you know how to make a simple task difficult.

 

[Barnsleyrob]

He's trying to charge his 12v pressure washer battery that can't be lithium because it would have blown up by now charging it with a car battery charger!

I've got to hand it to you guys, you know how to make a simple task difficult.

Lol.

The charger has an LED indicator which shows red when charging and green when the battery is fully charged or if it’s not connected but plugged in.

When I first plug the charger into the wall socket, but not the Sealey, it glows green as expected. I then plug it into the Sealey and it goes red, also as expected. Unfortunately, if never goes green again and the battery doesn’t charge (as evidenced by little/no power in the discharged battery). If I charge the battery off a Ctek it is fully charged in a couple of hours - no errors etc.

The charge port is a simple jack socket that connects in parallel to the on/off switch directly to the battery (so the switch has to be “off” to charge) and because it’s a lead acid battery it really is just a wire to each terminal (+/-).

On/Off switch works fine as do the leads to the battery (since the unit works perfectly when the battery is recharged).

All of the connections have been cleaned with wirewool and contact cleaner. If one of the wires was broken from the charger, the LED would show green as there wouldn’t be a load.

 

[Andy-Mat]

You need to connect it in series. One of the paths from charger to battery must be broken, and insert the voltmeter (set to an amps range of course) in the path. The easiest way to break the connection will depend on how your leads/connectors work.

battery + --------|-- meter --|------- + charger
battery - ---------------------------- - charger

(the forum doesn't respect fixed with fonts properly)

What you have written applies to most of the normal battery chargers in the world, provided the expected amps are within the range of the meter, or you have an add-on, to increase the range read, as someone recently posted about.
Adding an enclosed ceramic fuse, is always a good idea if you are not sure about the current that may be drawn.....
Regards
Andy

 

[vfr400]

What you have written applies to most of the normal battery chargers in the world, provided the expected amps are within the range of the meter, or you have an add-on, to increase the range read, as someone recently posted about.
Adding an enclosed ceramic fuse, is always a good idea if you are not sure about the current that may be drawn.....
Regards
Andy

He already plugs it in to the battery charge socket directly. He doesn't have a fuse and nothing blows up. Use some logic. How can the current go up by measuring it?

 

[WheezyRider]

He already plugs it in to the battery charge socket directly. He doesn't have a fuse and nothing blows up. Use some logic. How can the current go up by measuring it?

If things are connected properly it's likely to be fine, but I've often found when connecting things up for measurement you can do things like leaving the meter in amps mode when trying to measure volts, then shorting the meter. Or accidentally, you can touch things that cause a short. If you have no fuse in the multimeter it can cause serious problems. It's just good to be cautious.

 

[vfr400]

If things are connected properly it's likely to be fine, but I've often found when connecting things up for measurement you can do things like leaving the meter in amps mode when trying to measure volts, then shorting the meter. Or accidentally, you can touch things that cause a short. If you have no fuse in the multimeter it can cause serious problems. It's just good to be cautious.

A 10 amp fuse won't save his meter if he doesn't use a shunt (internal or external). If you had a fuse that could protect his meter, the charge current would blow it. You're not thinking this through!

 

[WheezyRider]

A 10 amp fuse won't save his meter if he doesn't use a shunt (internal or external). If you had a fuse that could protect his meter, the charge current would blow it. You're not thinking this through!

The 10A connection on a multimeter does go to a shunt inside, but, more often than not, the circuit isn't fused. Take a multimeter apart and have a look.

 

[Andy-Mat]

A 10 amp fuse won't save his meter if he doesn't use a shunt (internal or external). If you had a fuse that could protect his meter, the charge current would blow it. You're not thinking this through!

Consider the fact that he may have an intermittent problem, a loose connection for example, then try to think ALWAYS - SAFETY FIRST!
Especially when its not your house, not your family or pets, not your eyes and not your fingers!!!
GOT IT?

 

[vfr400]

try to think ALWAYS - SAFETY FIRST!

It's better to ALWAYS THINK FIRST!

 

[Barnsleyrob]

The output is 14.5 Volts (which checks out) at 1 Amp (the bit I want to check). The only fuse in the system is on the cigarette lighter input which presumably carries a heavier current (and has thicker wire) as it drives the unit directly.

My only other thought is that the centre pin on the receiving jack isn’t contacting properly. I might resort to fag packet foil except I gave up 11 years ago.

 

[Andy-Mat]

It's better to ALWAYS THINK FIRST!

I agree, but it must be, for any normal person, THINK safety FIRST, especially when instructing others, people online, where you have COMPLETELY NO IDEA of their level of knowledge or ability!
Doing anything else is simply being a Dictator and is wrong, wrong and still wrong!
Its a character fault that I do believe many (Trump!) have little or possibly no control over......sadly! Time will tell with Trump.....
But do please try to improve your safety advice.....Please remember, Pedelec is not your private web site, many come here for good, safe advice from experts.
I myself, as a person who was taught IT in the Royal Navy a great many years ago, who maintained it through working with several US Computer firms over a great many years, probably all long before you were born, know the need for safety when instructing others.....
Unless a person actually "delights" in causing possibly unnecessary pain of course....
The Germany actually have a word for it "Schadenfroh!"
But I cannot believe that of anyone with a reasonable and moral character.
This is all meant in a friendly manner, but I do believe it will not be "received" as such......of course your choice either way!
Do have a nice day. I am!
Andy

 

[vfr400]

I agree, but it must be, for any normal person, THINK safety FIRST, especially when instructing others, people online, where you have COMPLETELY NO IDEA of their level of knowledge or ability!
Doing anything else is simply being a Dictator and is wrong, wrong and still wrong!
Its a character fault that I do believe many (Trump!) have little or possibly no control over......sadly! Time will tell with Trump.....
But do please try to improve your safety advice.....Please remember, Pedelec is not your private web site, many come here for good, safe advice from experts.
I myself, as a person who was taught IT in the Royal Navy a great many years ago, who maintained it through working with several US Computer firms over a great many years, probably all long before you were born, know the need for safety when instructing others.....
Unless a person actually "delights" in causing possibly unnecessary pain of course....
The Germany actually have a word for it "Schadenfroh!"
But I cannot believe that of anyone with a reasonable and moral character.
This is all meant in a friendly manner, but I do believe it will not be "received" as such......of course your choice either way!
Do have a nice day. I am!
Andy

Thanks for the explanation. I had heard about the way the military train their operatives to follow their system without thinking.