Home-made accumulator charging problem

[ElectroDummy]

Hi guys,

I just found old flashlight and due to inability to use any of the new batteries I decided to create new one from 4xAA batteries (NiMH aku AA;1,2V/2000mAh Panasonic "Eneloop").

I created simple circuit and used old flashlight switch in it. It works just fine. Then I added DC charging connector and connected it to the new accumulator with the 2 wires from the circuit. It means the connector is under voltage when the flashlight is charged.

Today I plugged in the charger and while holding the flaslight in my hand I accidentally touched the metal stove cover and "I felt the current" and got a little burned (just felt like it is very hot in the fraction of a second I made the contact).

I used multimeter to measure current between flashlight and the stove cover and it was 3,65 mA. Of course the flashlight is made of metal.
How I could solve this problem? Should I izolate all of the components of the flashlight or use some ground?

Thank you for any tips!

 

[rjenkinsgb]

That's a fault in whatever you are using to charge it, rather than a fault in the torch.
(Or a problem with the house wiring / grounding!)

Check between the stove and something that is definitely grounded properly. If there is no reading then, it's the charger that is "leaky", possibly just due to excess capacitance or possibly from a fault.

If the charge plug or cable are reversible, try it the other way around and see if you still get the problem?

(Or if you do get a significant reading between the stove and any other grounded connection, you need the house wiring checking rather urgently..)

 

[Nigel Goodwin]

Most likely no fault at all - it's probably a type 2 charger, so no earth connection - it's normal to have a small leakage current, and this is often through the special safety components, which is what they are there for.

 

[ElectroDummy]

Ok, thanks for replies!

I have one more question. When I change the connector adapter of the charger (it is universal charger with optional voltage and multiple charge adapters) and turn it around (180 degrees), I switch the + and - of the charging jack. When the torch was fully discharged (the bulb was not able to produce any light at all) and I connected the charger with this reversely connected jack and turn the torch on, it shone like if it was fully charged. But when I change the + and - again, the torch is charging properly and of course after few seconds after I plugged in the charger it did not produce any light. How is that?

 

[ElectroDummy]

Most likely no fault at all - it's probably a type 2 charger, so no earth connection - it's normal to have a small leakage current, and this is often through the special safety components, which is what they are there for.

Yes, the charger has removable end adaptors with only two wires inside.

 

[Pommie]

How does less than 4mA make something hot? Assuming 3,65mA is the same as 3.65mA.

Mike.
Edit, hard to read that meter but is that an AC sign to the left?

 

[rjenkinsgb]

Leakage is supposed to be under 1mA
From a quick search, the UL approval limit is 0.5mA for ungrounded / 2 wire equipment.

3.6mA is enough to cause significant discomfort; it's not massive but it's not small either.