48V , 5A LiFeP04 Charger Repair?

I'm wondering if anyone would think it would be worth it to try repairing my current CC/CV charger or just replace it? I'm of very limited electronics expertise, but I have a local guy that might help me as a favor, but if it's a many hours process, I'd probably just order a new one.

I thought it might be good to learn a little about how a charger works since I have lots of time on my hands compared to how much money I have to spend. :wink:

It would seem that it is no longer putting out the proper voltage, it was initially putting out 55V, and now is more like 52V and wouldn't charge the battery to above 51V.

Here are some pics, it's just your basic OSN 48V 5A CC/CV charger for Lithium batteries:

http://www.osnpower.com/productID/product_detail-7134383.html

And here is my personal one at home that I have opened up and briefly inspected for damage, nothing looks or smells of "magic smoke" but I am told that the package was dropped once received at my door by an over enthusiastic family member who tried to carry both packages at once and dropped them (if ONLY they had just let the delivery man place it at the door for me to get more carefully! :lol: ) so I am guessing this is probably when it got a dent on one corner (I only recently learned this from a different family member lol!) oh well.

Here are the pics anyway:

Since it is still operating, it should be relatively easy to troubleshoot.

I have the 4A version of that same charger, AFAICT. It is probably made by KingPan; it'll say on the PCB silkscreening probably in a corner on the AC end of things. There are some existing threads about adjusting the voltage on these things that may give you some ideas, but my first guess is that the OVP is tripping for some reason.

If you can try adjusting the voltage *down* from it's original voltage, it may prevent the OVP from doing this. You may want to mark the original pot positions.

It could also be over-current tripping. Most of these seem to work internally kinda like Fecter's limiter, in that there will be some voltage reference point in there at about 2.5V that when it goes above or below that point will trigger different behaviors (increasing output voltage to sustain higher current or decreasing it to reduce current). If you can find that point and see what it reads, it might help find the source of the problem.


Since it was dropped/recieved an impact, it may simply have a cracked solder joint on some part, and you might be able to just check the joints and see if any are cracked.


Beyond that, I am not sure exactly what specifics to check.

amberwolf said:

Since it is still operating, it should be relatively easy to troubleshoot.

I have the 4A version of that same charger, AFAICT. It is probably made by KingPan; it'll say on the PCB silkscreening probably in a corner on the AC end of things. There are some existing threads about adjusting the voltage on these things that may give you some ideas, but my first guess is that the OVP is tripping for some reason.

If you can try adjusting the voltage *down* from it's original voltage, it may prevent the OVP from doing this. You may want to mark the original pot positions.

It could also be over-current tripping. Most of these seem to work internally kinda like Fecter's limiter, in that there will be some voltage reference point in there at about 2.5V that when it goes above or below that point will trigger different behaviors (increasing output voltage to sustain higher current or decreasing it to reduce current). If you can find that point and see what it reads, it might help find the source of the problem.


Since it was dropped/recieved an impact, it may simply have a cracked solder joint on some part, and you might be able to just check the joints and see if any are cracked.


Beyond that, I am not sure exactly what specifics to check.

Click to expand...

Thanks for that, I am quite limited in my electronics knowledge, what is an OVP and can you possibly point it out in the pics? Also, I have only a cheap HF meter at this time to test with, testing current might be problematic, since it can only do a max of 10A DC.

I REALLY need to get a good meter ... :lol:

That or make sure I visit my friend locally who has one! 8)

If your other option is to replace the unit, then you have little risk in playing with it.

That has an interesting "flying board". What keeps it from shorting out on the main board?

Anyway, you might be able to adjust the output voltage using the trim pot. It's a bit hard to see in the pics, but I suspect the blue things have a screwdriver adjustment (possibly burried under paint), one of which should adjust the output voltage.

See if you can find the screwdriver adjustment.

Adjusting the wrong thing can be bad. If turning one does not change the output voltage, make sure you can put it back exactly where it started.

I think the adjusters are here:

Digressing a bit, stuff inside like that flying board is why I don't recomend mounting chargers on bikes.

if you can tell which of those blue trimpots is connected to the output voltage through a trace on the board, that is the one to adjust the voltage with. the other adjusts the output current.

Only adjust a small amount while checking or can blow

I know this thread is old and dead.
I just stumbled across it while searching how to adjust the output voltage on my new charger (same type)
and I saw that the wrong poti was marked in this thread.
So just in order to prevent others from making mistakes, please follow these instructions instead:
http://www.linushelgesson.se/2011/10/output-voltage-adjustment-on-240w-kingpower-charger/

This guy found the right poti, and it is the same that is pointed out in several other threads here on ES:


I tried it with my charger that has *almost* the same layout and it worked nicely!
Many similar models all seem to have the voltage-adjust poti in that bottom-left corner.

Cheers,
Ulli

Thanks for the update. That is useful information.

999zip999 said:

Only adjust a small amount while checking or can blow

Click to expand...

I have the same charger. In an attempt to slightly adjust the output voltage I start turning the potmeters like a wildman. :?
Little did I know they appeared to be the current adjust/coarse pots. I couldnt set them to the original value unfortunately because I hadnt count the amount of turns.

After I found out I tried the real voltage adjust pot meter. But it didnt work anymore. VOltage dropped to about 28/30 Volt and wasnt adjustable anymore no matter which pot i turned.

up0, could you check the values of all three potmeters and please let me know? I think other people now and in the future will be helped greatly

Hi Monstarr,

I am not sure it would help if I published the values of my charger, because they all seem to be SLIGHTLY different.
I have used Google Picture Search on "Kingpan, Kingpin, PingBattery, etc...." and found many pictures that
had a similar layout (final Voltage adjust in the bottom left) but other elements were sometimes in different places.
Particularly those 2 other potis were *somewhere* on the left half of the board, but it would be hard to distinguish the 2.
As an example I add a picure of my own charger (BEFORE my mods!) which is different than the picture I posted earlier in the thread (found that one on the web).

But the main problem for me is that I have added a Voltage+Ampere-meter in the same housing so I can't really remove
the bottom shell to get to the main board, due to the U-Shape .
I tried if I can access anything to measure near the potis:

But didn't find anything. I had to install a separate power-supply in the housing for the meter, so everything is cramped in there
and I don't want to de-solder any of the connections I made in there.

Hope you understand,
Sorry,
Ulli

up0 said:

Hope you understand,
Sorry,
Ulli

Click to expand...

Don't worry a bit mate :wink:
Thanks for your effort in checking though.

I already ordered a new one