Chinese made 12v 6 amp lead acid battery charger info

[CapLeaker]

Re: Chinese made 12v 6 amp lead acid battery charger info

I don’t see anything that suggests that there is big pulsing power inside. I only had luck desulfating car batteries with huge power. And even at that it takes a few days in order to desulfate a heavily sulfated battery. Desulfating does work, but like I said, it’s not going to happen with these self powered circuits, or these small chargers. Maybe it will get a battery done in a year or 2. Minimum gotta be a voltage doubler with 4 large caps almost the size of a small coffee cup, 2 caps in series for each side.

[redwire]

Re: Chinese made 12v 6 amp lead acid battery charger info

Helps to see pics of the underside of the board, where the IC's are.

The SMPS runs steady to power the front panel, fan etc. and there is a rectifier - the SSP7509 extra mosfet must do the pulse generation.

It looks the same build as another chinese charger I bought. Fair quality, oddball semiconductors and built for very low cost.
One problem is the inrush current is very high, loud ca-bang when you plug it in as there is no NTC or resistor for the primary cap. The two caps run hot, they are stressed. 6A output is a bit optimistic. It should have second fuse F2 populated so a short does not burn it up. There is no Y-cap to prevent a little zap when you touch the car, no EMI filter CM choke, X-cap etc.

Out of the 10 reasons lead-acid batteries fail, sulphation is but one of them. This has been is known for over 100 years, everything tried.
I looked at research papers using electron microscopes to look at the crystals because they are also the cause of lead-acid battery charge lifetime being like 500 cycles. Every discharge cycle, sulphate crystals form until the plates are pretty much covered.

The crystals can be different sizes and shapes, stuck in the pores of the plates. I did not see really solid proof desulfators work unless they are crazy high in pulse power, kW level. Knocking the crystals off the plates is unheard of, they get stuck there and I think you can only hope to dissolve them a little.

I've built my own desulfators but did not see anything spectacular for results, so I am now a non-believer.

[dalek1967]

Re: Chinese made 12v 6 amp lead acid battery charger info

The circuit I built mine from is open source. I downloaded the gerber files, had the boards made. Then I put the components on it that I got from Newark or somewhere and tested. There is videos where people, including the guy that did the circuit, have put scopes on it and it does produce a spike. The one I built has a diode and capacitor that holds that spike so you can tell if it is finished desulfating or not. If you measure the spike and it is 28 volts and hours later it is still 28 volts, it has likely done all it can. If the voltage is still dropping, it is still working. I've had batteries that were weak start out with spikes around 40 to 50 volts. When done, I've seen it as low as 25 volts or so and holding. Some batteries go lower than others. Difference in way plates are made or something I guess.

I have a battery that is around 20 years old. It was my car battery 2 or 3 batteries ago. I been charging it on occasion since I used it to jump start a old mower but it was weak. When I built my first desulfator, I tested it on that battery. I tested it using a fence charger as a load that was out in the woods. I had a deer food plot out there. At first, it would run about 2 days. It would be really run down tho. The fence charger would just barely do it's thing. After a few cycles and putting the desulfator on it, it got up to where it would last a week and still have a good charge left on it. I'm tempted to see if it would start my car again. It holds a charge very well now.

I did buy some small desulfators off ebay. The coils are really small. I'm not going to say they don't do anything but I suspect it doesn't do a lot. I'm not sure these battery chargers do any better really. No way to really test it. The ones I built tho, I'm sure they work. I just figure the chargers do enough to use in between times of using the desulfators I built. The biggest reason I got these chargers, you can leave them connected all the time and not overcharge the battery.

The coils on the ones I built are about 1.25 inches by .6 inches on a ferrite core. I've thought about making one like I saw on a video that are really large. The larger the coils, the more current the spike pushes into the battery. Supposed to work faster. The guy in the video used it on some really large batteries. That may be to big for my little batteries. Still, I've thought about. Likely have to hand make the coils tho. The ones I got from ebay, the coils are about the size of the tip of my pinky finger. Can't expect much out of that.

I have a friend that has a real expensive fishing boat. It has like 3 or 4 batteries on it. It has a expensive charger on it and it has a desulfator built into it. He says his deep cycle batteries last at least a decade or so before he replaces them. On his previous boat with just a old transformer type charger, he'd replace the battery every 3 to 4 years tops. Some claim desulfators don't do anything. At first, I was skeptical myself. After using it on several batteries over the years, it's hard to argue they don't work. As you say, there are some that are just junk. It's why I made the ones I use.

Thinking about posting pics of the boards in another TV I have. Might help someone if a cap literally blows up.

[stj]

Re: Chinese made 12v 6 amp lead acid battery charger info

that actually looks really good inside.

as for trying to get crystals off the plates, i cant see anything there that would do it.
the best devices for that do things like dumping huge inductors into the battery to create current spikes.
you wont do that with a switching psu.

[CapLeaker]

Re: Chinese made 12v 6 amp lead acid battery charger info

Did you put an oscilloscope and a CT on it to see what this “desulfator” is actually doing? I put desulfator in brackets on purpose, because there are too many gimmicks around that claim do desulfate, but are worth sh*t. I’ve built quite a few desulfators, but mine are much bigger than that and you can hear the battery posts humming. I can’t see this thing doing much besides increasing the charging voltage a little bit. I suppose you get that same effect with an old battery charger and let the battery boil for a bit.
Not that I wanted to dump cold water on this, but I’d say you have more luck desulfating a battery using a small electric fence spiker.

[dalek1967]

I posted another thread like this for a TV power supply. This is for information purposes for anyone who has a bad one and wants to repair instead of replace. There is no model number on these but internally they appear to be the same, fan being the only difference I can find. If a component is damaged and can't be identified, this may help. One I have has the brand name XinJieBao on the front above the display. The other isn't marked.

My impressions. I can't say for sure on the chips and such but the HV capacitor is a very low quality one if I think. I tried to google it and also checked the Tom's Hardware tier list. It isn't listed. For me, if it isn't listed there in one of the top tiers, it isn't of good quality. They don't list every brand of low quality capacitor made but they do seem to have a complete list of the high quality ones. Of the three chargers I have , one has a brand, others does not. Inside, the difference is the fan. The one with a brand name has a very quiet fan. The one without has a low quality fan. One was bad out of balance and stopped working within a hours use. If it has a red and black wire for the fan, quiet and works well, so far. If it has a blue and black wires, not good. I've already ordered replacement 50mm fans. Fan seems to kick in when charge amps is above about 2 amps.

These chargers actually function quite well as far as design goes. It has a pulse repair feature that I use quite often. It does work pretty well. I tend to use a desulfator once or twice a year tho to really condition a battery. This charger seems to work well enough for day to day use. It also seems to do a good job of maintaining a charge. I've left these chargers hooked to a battery for months with no damage. So far, these are under $20 on ebay.

The pictures are attached. Hope it helps someone. If nothing else, if someone is planning to buy one of these, you have a idea what you will be getting. In a year or so, I plan to replace the HV cap. At least it may make it last longer, if other components are of reasonable quality.