Battery chargers

[Andy-Mat]

Yes it feels cool when disconnected.

...but the mains is still connected, just connection to the battery broken?
If yes, then it "suggests" that the charger uses "Switched Mode" type of electronics design, available cheaply in chips and is to my mind the best method nowadays!
It is generally around 90% efficiency as a "ballpark" figure, sometimes even better! It wastes only a little power when the battery is fully charged.
regards
Andy

 

[cyclenut1952]

...but the mains is still connected, just connection to the battery broken?
If yes, then it "suggests" that the charger uses "Switched Mode" type of electronics design, available cheaply in chips and is to my mind the best method nowadays!
It is generally around 90% efficiency as a "ballpark" figure, sometimes even better! It wastes only a little power when the battery is fully charged.
regards
Andy

Totally disconnected, Andy

 

[Deleted member 25121]

...but the mains is still connected, just connection to the battery broken?
If yes, then it "suggests" that the charger uses "Switched Mode" type of electronics design, available cheaply in chips and is to my mind the best method nowadays!
It is generally around 90% efficiency as a "ballpark" figure, sometimes even better! It wastes only a little power when the battery is fully charged.
regards
Andy

Of course its a switching mode supply (SMPS), it couldn't possibly be a linear one with that size.

Efficiency of a switching mode supply is typically in the 80 to 90% range but cheap ones from the Far East are often lower.

Both switching mode and linear power supplies of any sensible design will give off less heat when the load is reduced. The test to see whether this was the case with cyclenut1952's power supply was to check that it was working OK in that respect!

Electronics has moved on since the 1970's!!!

 

[cyclenut1952]

Of course its a switching mode supply (SMPS), it couldn't possibly be a linear one with that size.

Efficiency of a switching mode supply is typically in the 80 to 90% range but cheap ones from the Far East are often lower.

Both switching mode and linear power supplies of any sensible design will give off less heat when the load is reduced. The test to see whether this was the case with cyclenut1952's power supply was to check that it was working OK in that respect!

Electronics has moved on since the 1970's!!!

Thanks ebiker99

 

[Andy-Mat]

Totally disconnected, Andy

Then its not a proper test. Anything removed from the mains will cool down naturally!
If you wish to repeat the test, charge up the battery, observe that the charger heats up, but when the charger indicates full charge, generally a green LED, or you could pull the connection to the battery out, see that it cools down over the next 20 minutes or so.
The cooler the better the circuitry!
Generally speaking, any charger/power supply, should not get so hot, that it makes it uncomfortable to hold for any length of time.
Being hot (sadly!) eventually shortens the working life of affected components inside the unit.
If I can assist further, just ask, as there are many here who can help.
regards
Andy

 

[Deleted member 25121]

Then its not a proper test. Anything removed from the mains will cool down naturally!
If you wish to repeat the test, charge up the battery, observe that the charger heats up, but when the charger indicates full charge, generally a green LED, or you could pull the connection to the battery out, see that it cools down over the next 20 minutes or so.
The cooler the better the circuitry!
Generally speaking, any charger/power supply, should not get so hot, that it makes it uncomfortable to hold for any length of time.
Being hot (sadly!) eventually shortens the working life of affected components inside the unit.
If I can assist further, just ask, as there are many here who can help.
regards
Andy

I think cyclenut1952 has already tried to disconnect the battery leaving the mains on, as I suggested.

 

[Andy-Mat]

I think cyclenut1952 has already tried to disconnect the battery leaving the mains on, as I suggested.

Unclear, but that would make sense.....
Andy

 

[Deleted member 25121]

Unclear, but that would make sense.....
Andy

DUH

 

[cyclenut1952]

Then its not a proper test. Anything removed from the mains will cool down naturally!
If you wish to repeat the test, charge up the battery, observe that the charger heats up, but when the charger indicates full charge, generally a green LED, or you could pull the connection to the battery out, see that it cools down over the next 20 minutes or so.
The cooler the better the circuitry!
Generally speaking, any charger/power supply, should not get so hot, that it makes it uncomfortable to hold for any length of time.
Being hot (sadly!) eventually shortens the working life of affected components inside the unit.
If I can assist further, just ask, as there are many here who can help.
regards
Andy

Many thanks

 

[Andy-Mat]

DUH

Then may I ask what is your opinion?
"DUH" does seem to be very unclear to me!
Andy

 

[Amoto65]

Surely it being hot to touch is subjective as everybody has a different pain threshold.

 

[Andy-Mat]

Surely it being hot to touch is subjective as everybody has a different pain threshold.

Correct.
But the threshold apparently does not vary quite as much as makes any huge difference for people uninjured and have no nerve damage.
The threshold for heat‐induced pricking pain (48.5 ± 1.8°C) was significantly higher than the threshold for thermal pain induced in normal skin areas (42.1 ± 2.8°C, P < 0.001) (Fig. A)
Generally speaking, above 42°C would be uncomfortable for most people, which is an excellent value for electronics!
Though there are people that can seemingly "switch off" thermal pain and actually allow themselves to achieve tissue damage!
But I did not feel the need to mention that, or that it had any great value here! I am also pretty sure that skin areas affected would be "known" and avoided for testing "how hot" something is!
The fact that also some people will feel uncomfortable at an even lower temperature, is all to the good, as few people always have accurate method to measure temperatures handy!
Andy
PS. Reference:- https://academic.oup.com/brain/article/125/3/501/519104