Ebike Chargers running too hot -- a solution .

[Andy-Mat]

Ah l was talking about efficiency of the actual transformer and not the entire power supply. l guess it's the power supply as a whole that matters really, as you say.

Ah!

 

[Bonzo Banana]

So the typical cheap power supply's supplied with cheaper ebikes which tend to be quite light presumably switch mode power supply's as definitely no weight for a transformer inside are these good or bad in theory (obviously practice may vary). I remember reading about someone who had an early 24V ebike and the charger failed and it was a serious lump of a charger and was replaced with a cheap 24V charger with no issues that perhaps weighed a fifth of the weight of the original. I read it in a forum somewhere. I can't remember if the battery pack was an early li-ion type pack or lead acid presumably it would have had to have been li-ion for the charger to work, not sure I guess even for lead acid when the battery stops taking charge the charger would sense the reduction and stop charging. I'm not sure how much logic is in charger especially a cheap one.

 

[WheezyRider]

So the typical cheap power supply's supplied with cheaper ebikes which tend to be quite light presumably switch mode power supply's as definitely no weight for a transformer inside are these good or bad in theory (obviously practice may vary). I remember reading about someone who had an early 24V ebike and the charger failed and it was a serious lump of a charger and was replaced with a cheap 24V charger with no issues that perhaps weighed a fifth of the weight of the original. I read it in a forum somewhere. I can't remember if the battery pack was an early li-ion type pack or lead acid presumably it would have had to have been li-ion for the charger to work, not sure I guess even for lead acid when the battery stops taking charge the charger would sense the reduction and stop charging. I'm not sure how much logic is in charger especially a cheap one.

Just about any charger now will be Switch Mode. Transformers are way too heavy and the copper is expensive.

The chargers have a constant current circuit to limit current when charging, until a set end point voltage is reached, when the current will gradually drop and the voltage is kept constant. At a certain current level, the display LED will be triggered to go from orange to green as the current drops below a set low level.

They contain a few control op-amps, but that's about it.

 

[passionate off roader]

Mine does get warm, but not so hot it's uncomfortable to handle.

The wire bird feeder sounds like an interesting idea though.

 

[Andy-Mat]

So the typical cheap power supply's supplied with cheaper ebikes which tend to be quite light presumably switch mode power supply's as definitely no weight for a transformer inside are these good or bad in theory (obviously practice may vary). I remember reading about someone who had an early 24V ebike and the charger failed and it was a serious lump of a charger and was replaced with a cheap 24V charger with no issues that perhaps weighed a fifth of the weight of the original. I read it in a forum somewhere. I can't remember if the battery pack was an early li-ion type pack or lead acid presumably it would have had to have been li-ion for the charger to work, not sure I guess even for lead acid when the battery stops taking charge the charger would sense the reduction and stop charging. I'm not sure how much logic is in charger especially a cheap one.

If its any help, I myself always plump for SMPS types for any power supply or charger that I buy, but over about 20 years, not a single one has failed up to now.
The SMPS chips are pretty refined, and for large manufacturers, cheap to buy in 1,000 and above quantities....Making the end product cheaper, cooler and less likely to fail.
regards
Amdy

 

[Bonzo Banana]

If its any help, I myself always plump for SMPS types for any power supply or charger that I buy, but over about 20 years, not a single one has failed up to now.
The SMPS chips are pretty refined, and for large manufacturers, cheap to buy in 1,000 and above quantities....Making the end product cheaper, cooler and less likely to fail.
regards
Amdy

I've just charged two of my 48V batteries and made the point of putting my hand on the two identical chargers at the mid point of charging both charging exactly the same model of battery and both chargers weren't even warm to be honest, I could barely feel any heat at all. Both batteries have I believe Samsung 2500mAh cells which I think are setup as 13 in series and 5 in parallel giving a 65 cell capacity. I sort of think maybe battery capacity has some effect on charger heat. I mean if my battery had 10 cells in parallel it would take twice as long to charge and the charger would have more time to build up heat but also I wondered if that would be any more strain on the components of the charger. I guess I'm thinking of the old lead acid batteries where the more capacity of the battery the hotter the charger would run as it would draw more power but there was no logic circuitry inside such chargers.

 

[Andy-Mat]

I've just charged two of my 48V batteries and made the point of putting my hand on the two identical chargers at the mid point of charging both charging exactly the same model of battery and both chargers weren't even warm to be honest, I could barely feel any heat at all. Both batteries have I believe Samsung 2500mAh cells which I think are setup as 13 in series and 5 in parallel giving a 65 cell capacity. I sort of think maybe battery capacity has some effect on charger heat. I mean if my battery had 10 cells in parallel it would take twice as long to charge and the charger would have more time to build up heat but also I wondered if that would be any more strain on the components of the charger. I guess I'm thinking of the old lead acid batteries where the more capacity of the battery the hotter the charger would run as it would draw more power but there was no logic circuitry inside such chargers.

It really doesn't matter as to the "state" of a battery with regard to the charger.
The usual good e-bike Li-ion chargers charge at a max of 2 amps, which extends the life of the battery, in comparison to fast chargers which charge at around 4 amps, generally speaking.
It is the current drawn that might make a charger warm up, and the design of the charger. SMPS versions have aproximated 1/3rd of the losses of older linear designs, which are heavy and have a transformer.
Its the losses that warm up a charger.....bigger losses = more heat in the charger circuit.
My guess is that both your chargers are SMPS designs, and they would stay very cool, never heating up to endanger skin!
regards
Andy