Ebike charger 42V Model SSLCO84V42 repair - troubleshooting – FAQ

[Kiriakos GR]

This thread is here to serve as source of information to all ebike owners who facing problems with their battery and charger.

Intro:
Sans Electronic Co Ltd is actually one non existing branding, possibly one factory in China just add labels on their products and selling them.


Technically:
The charger is a advanced piece of equipment as it does use recently made electronic components with smart functions.
The PCB (circuit board) and soldering is high quality.
It is fused at the mains input, and it has good efficiency regarding mains consumption.

Actual specifications:   
As mentioned and above the labeling on those chargers is generic.
The specific model is designed to serve Lifepo4 battery packages.
Lifepo4 cell needs 3.65V as charging voltage and a 36V battery pack has inside 12 such cells in series.
Lets multiply then 3.65V by twelve times and we get 43.8V and this is the actual voltage that this SSLCO84V42 charger it does deliver to it DC plug when is healthy.
And it does that right away as soon is plugged to mains.
Therefore even if the real Volt output does not agree with the label, at least is the correct one.

Regarding supplying DC current, in my test the charger it did deliver 1.9A stably which is very good as proof that is not underpowered and that this specification is sincere.


Usual Malfunctioning symptom and cause:

The charger after been connected with an empty battery the red LED switches to Green much faster than expected and the battery stays discharged.

This is a problem which I faced too and the solution was to repair the charger by using my tools and skills.
The visual indication and proof that this specific problem has occurred is that the charger output is not at 43.8V any more but at 32V or less.
The confirmation can be made by a simple measurement with any multimeter.

As repair man I will say that the problem of this charger is the poor quality of electrolytic capacitors that the company selected to use.

All charger which shown such behavior can be repaired, and I will advise you to not throw it away, there is many experts performing electronics repair professionally few  blocks away from your home.
With specific test and measurement equipment (LCR meter) they can diagnose and replace the faulty parts with new, a successful repair will extend the life of the product from two to four years.

I also followed this path and other than repairing just the problem, I did replace too and the basic capacitors at the output with much better ones regarding low ESR and higher volts tolerance.

Practically the average user is defenseless about to prevent this failure due those prematurely failing capacitors.

Also I do not believe that the far more expensive chargers in metal box with a fan, that they have any advanced circuitry other than better capacitors which their retail value are just 4 EUR when the cheap ones cost half of that. 


My message to other repair man is that I replaced the capacitors in the output even by looking or even measuring as good as new, because they seemed to be at the first stage about to start leaking.
As I did see leaking traces to just starting forming underneath them. 
 
The dissipation factor of the old capacitors at the LCR was 0.300 and because I got replacement capacitors identical in value from different vendors, as two and two, the ones from the non-reputable vendor had the same dissipation factor with the ones of this charger.
The better ones which I did use in my repair, they have much lower dissipation factor at 0.150 and I selected them at 63V 105C instead of 50V 470uF that this charger is using.

I did take some pictures mostly as souvenir from my adventure which ended with a happy end.