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Nitecore i4 and i2 charger teardown (update p2)

djQUAN

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Re: Nitecore i4 and i2 charger teardown

Maybe the i2's circuitry is less efficient? same power input, less power output = more heat. :D


edit: I got home from work and checked the two chargers.

The i2 is rated at 8W input and the i4 is rated at 10W input.

 

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djQUAN

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Re: Nitecore i4 and i2 charger teardown

Update:
My i4 just died. After charging four Panasonic 3400's overnight, I left it plugged in without anything connected. Just heard a pop and it's dead. I initially thought the AC-DC converter died so I tried powering it off of 12V using a bench supply through the barrel connector. No go as the input was shorted to ground. Going to investigate what exactly happened once I get the time (just came back from a bad case of Amoebiasis).
 
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djQUAN

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Re: Nitecore i4 and i2 charger teardown

So I did a little investigation on what happened and here are my findings.

I found the rectifier diode of the AC supply (little thing on the right) was shorted so I removed it. Powered it off the bench supply through the 12V port and it worked.


I also needed a ViPer22A chip and didn't have any in stock so I need a donor. I have this charger which often pops fuses due to inrush current (poor design) and can't fit protected cells so I don't use it anymore.


This is what I needed.


I didn't have the 5amp SR560 diode in stock so I used a lower rated 1N5822 but I think it should work in a pinch. Left the leads long so that it adds additional heatsinking.


I thought it should work so I plugged it. BANG! Almost fell off my chair hahaha


Damn bridge diode is shorted on all 4 terminals.


Soot on parts haha. blew some traces off the board.


Replaced everything and plugged it in again. No power. I said screw it and just made a plug that powers this i4 from 12V solar. With how much these things cost, must be cheaper to just get a new one.
 

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Zeebit

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Re: Nitecore i4 and i2 charger teardown

So what's the culprit?
 

djQUAN

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Re: Nitecore i4 and i2 charger teardown

Possibly a failed output rectifier which led to failed parts up the powersupply chain. Not really sure how or why it failed since it was doing nothing when that happened, possibly a voltage spike.
 

dvdtrwck

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Not impressed with the I4 2014 ver. 3 of the sockets blink one light all the time. Have had the unit for only 1.5 years. Started acting up some time back with strange flashing. One socket still charges but am looking at replacing the unit as it no longer completely charges the 18650s I use for vaping. Moving to another Co. Will be buying an XTAR charger. Will open the unit because it is out of the 1 year warranty called (limited lifetime warranty). Lifetime is only 1 yr....poorly built. Made in china.
 

RedCowboy

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I have 2 of these and they work fine, slots 1 and 3 are on one circuit then 2 and 4 are on the other, so if you have 2 different kinds of cells put them in that way or if you have just 2 say 26650's and want to charge as fast as possible use slots 1 and 4

Mine charge to 4.17 - 4.18 and it's not a super fast charge, but it's supposed to sense the safe charge rate.

They seem to work well enough.
 

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ped

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I have an inherent distrust of Chinese mains chargers, even branded ones. I only ever buy ones that can be powered from 12V.

My i4 went t1ts up a long time ago.
 

Cartel

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Hello OP.
I joined to discuss the nitecore i2 I have.
Its worked good since 2013 but I have had a issue before and another yesterday.
The first issue was the spring connection to the board was loose and showed batteries charged when they were not.
I soldered it up and it worked great again.

This time U9 shorted from the source to drain and it nearly killed a 18650 that was in the charger.
All 3 lights on that side remained on even with no battery.
I guess I need a Si2302DS (A2sHB).
My question is, what does U9 do?
After I removed it, the charger seems to work on that side, although I wont use it till I find out if it may overload other components in the circuit.

Also I'd like to post my finding to help others with these symptoms.

thanks
 

Cartel

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I got the part coming....cheaper than buying a new one.
I can only imagine I put the battery in backwards and didn't notice.
 
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Cartel

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well I got the parts and put it in...works on both slots now.

:)
 

Accutronitis

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There is nothing better than fixing something yourself and for little money is even better !
 

Cartel

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Thanks!

I'm glad it was an easy fix.

For reference, here's the part I replaced.

 
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