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Old 11-30-2019, 01:07 PM   #1
redwire
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Default 12V 2A battery charger/maintainer

Bought this chinese 12V 2A car/motorcycle battery charger/maintainer $7. It looked OK hardware wise in pics.
But... everything runs quite hot at 2A - IC, transformer, capacitors, output rectifier. Estimate over 85°C.
The primary cap is tiny 15uF 400V, output 470uF 25V. I would say the ripple currents are too high. So I'm not sure if I will use this charger, it's not going to last.
What do you guys think?


The way it works: if load is over 600mA (bulk charge) it's 14.4V setpoint and 13.8V if less (float charge). The YX008 IC hard to understand, it's a "coin timer" IC but I did not see any timing action.
"Note: Charging motorcycle under 20A, after 3 hours must cut off." I have no idea what that means.
There is no inrush NTC. Other versions of it add a charge bar graph or voltmeter or have 10uF primary cap or use a TO-220 IC on heatsink instead of CR8642S. It seems to be made by the same company that makes the IC's Guangzhou Yuexin Electronic Technology Co. Ltd. YX1202X6918
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File Type: jpg 12V_2A_car charger 001.jpg (50.9 KB, 40 views)
File Type: jpg 12V_2A_car charger 002.jpg (46.6 KB, 27 views)
File Type: jpg 12V_2A_car charger 003.JPG (65.0 KB, 36 views)
File Type: jpg 12V_2A_car charger but Ver 2.jpg (230.5 KB, 85 views)
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Old 11-30-2019, 02:38 PM   #2
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Default Re: 12V 2A battery charger/maintainer

Two things about this board
The first one is there are no heat sinks on this board really
They used house part numbers really

The only two thing I see going for it is that it has a resettable fuse that is a nice feature
The other thing that it has going for it that it has an optic sensor on it is for feedback to the switching regulator or dose it have one

One other thing I do not see how this charging board could do 2 amps maybe 750 milliamperes maybe with out over heating
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Last edited by sam_sam_sam; 11-30-2019 at 02:47 PM..
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Old 11-30-2019, 03:34 PM   #3
stj
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Default Re: 12V 2A battery charger/maintainer

not house numbers,
YX prefix is used by "YX Shining ic" a company that makes a lot of dedicated parts for thinks like solar chargers / lights.
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Old 06-13-2021, 08:33 AM   #4
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Default Re: 12V 2A battery charger/maintainer

Hi,
There is a resistor R15 = 2k2, located next to the transformer. If you increase the resistance value a bit, then you will lower down the output voltage. Try to replace this resistor to 2k7, and measure the output voltage, it will be drop to about 12V.

Or you can replace it with a potentiometer, ranging around 2-3 kilo Ohms, then you can tune the output voltage...
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Old 06-13-2021, 08:41 AM   #5
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Default Re: 12V 2A battery charger/maintainer

R15, 2k2
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Old 06-13-2021, 01:57 PM   #6
redwire
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Default Re: 12V 2A battery charger/maintainer

The output voltage is two step. It has high (bulk charge 14.4V) and low (13.8V float) output voltages. I had no problems with them, the voltages work fine for a car battery. Increasing R15 would lower both charging voltages.

There is no usual TL431 and I did not finish drawing a schematic because the IC "YX008A Pulse Controlled Coin Timing Charge Control IC" datasheet is terrible. Somehow it's getting 5V power, and toggling based on current (sense), and doesn't seem to have a coin timer lol.

My problem is the charger runs hot and a loud spark when you plug it in.
But for a car parked, going nowhere due to pandemic lockdowns, it does keep the battery charged.
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Old 06-15-2021, 07:08 AM   #7
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Default Re: 12V 2A battery charger/maintainer

Not sure how it is over in western Canada, but here on the east coast I have trouble with flooded battery sulfation, which one has to replace batteries every 2-3 years. To get around that, I made home brew desulfators (not the tiny wizbang crap etc., there is some power behind it) and now I get at least 8 years out of them. They only fail now because the plates are shedding and a cell shorting out, or the terminals are leaking. Got about 11 years out of one AGM, the others are still working good. A U1 lawnmower battery got me 15 years of service life! A generic generator battery got me 10 years. Tractor batteries lasted 10 - 14 years.
Recently I bought a BatteryMinder 1510 to put on the wifey's car and to my supprise the battery actually got better over time. So it does work when the battery has light sulfation. For heavily sulfated batteries I use a CIP (Charged Inductive Pulse). That is kind of hard on the battery. Problem here is: If the battery is swollen because of sulfation, the CIP will clean that up, but if the cells are buckled and broken, it will shed some lead and short out the cell. Been playing with that for many years now.
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Old 06-15-2021, 04:54 PM   #8
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Default Re: 12V 2A battery charger/maintainer

Modern cars with ECU-controlled alternators undercharge the battery. They keep them around 80% charge and AGM do not seem to matter, it's all to get more MPG. When you are decelerating, down a hill the ECU ups the alternator's voltage and dumps energy into the battery. It's like a regen. Cars also have more parasite drain with TPMS, keyfob remote RX always on, fuel pump anti-percolation, canister purge etc. functions happening with the key off while you are sleeping lol.
This all falls apart when the battery gets older, you need to charge them more, or in winter. Toyota firmware certainly isn't doing much at 13.4V in -20C weather for a flooded-type and AGM needs even higher voltage.
So I'm finding I have to do an equalization charge once a year and decent float charge every month or two. That's up to 14.4V then float at 13.8V, and the car stays around 13.4V but it goes to 14V for a short time after starting.

I built a desulfator (555/IRF9Z34 1mH, 220uH in pic ) and found it did not help. Hard sulphation is really stubborn, so I suspect you need huge current pulses to really knock the crystals off, and even then it apparently works to a limited extent. Right now I'm not a believer in desulfators because the scanning electron microsope pics of sulphate crystals shows they don't come off much.
Recovery of discarded sulfated lead-acid batteries by inverse charge they connected them backwards(!) new acid, to get 80% recovery.

edit: that desulfator circuit is stupid, the 15V zener is in the way lol.

Last edited by redwire; 06-15-2021 at 05:00 PM..
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Old 06-15-2021, 05:52 PM   #9
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Default Re: 12V 2A battery charger/maintainer

Quote:
Originally Posted by redwire View Post
edit: that desulfator circuit is stupid, the 15V zener is in the way lol.
Looks ok, R3 makes it "work" however much these things "work". Would agree it would be completely useless if R3=0Ω ...

TBH I do wonder how many "sulfated" batteries are simply "dead" batteries due to internal destruction versus sulfation. I don't think I've ever come across a sulfated battery yet, all of the dead batteries I've come across are internally compromised due to corrosion. Expecting desulfators to work on compromised batteries is expecting a miracle that's just not going to happen...
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Old 06-15-2021, 06:27 PM   #10
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Default Re: 12V 2A battery charger/maintainer

Quote:
Originally Posted by redwire View Post
Modern cars with ECU-controlled alternators undercharge the battery. They keep them around 80% charge and AGM do not seem to matter, it's all to get more MPG. When you are decelerating, down a hill the ECU ups the alternator's voltage and dumps energy into the battery. It's like a regen. Cars also have more parasite drain with TPMS, keyfob remote RX always on, fuel pump anti-percolation, canister purge etc. functions happening with the key off while you are sleeping lol.
This all falls apart when the battery gets older, you need to charge them more, or in winter. Toyota firmware certainly isn't doing much at 13.4V in -20C weather for a flooded-type and AGM needs even higher voltage.
So I'm finding I have to do an equalization charge once a year and decent float charge every month or two. That's up to 14.4V then float at 13.8V, and the car stays around 13.4V but it goes to 14V for a short time after starting.

I built a desulfator (555/IRF9Z34 1mH, 220uH in pic ) and found it did not help. Hard sulphation is really stubborn, so I suspect you need huge current pulses to really knock the crystals off, and even then it apparently works to a limited extent. Right now I'm not a believer in desulfators because the scanning electron microsope pics of sulphate crystals shows they don't come off much.
Recovery of discarded sulfated lead-acid batteries by inverse charge they connected them backwards(!) new acid, to get 80% recovery.

edit: that desulfator circuit is stupid, the 15V zener is in the way lol.
just reminded me of the time i went and forgot about a friends car battery i had on charge backwards to revive it . he went and put it on the car the next day . had to fix his alternator for him after that .
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Old 06-15-2021, 07:12 PM   #11
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Default Re: 12V 2A battery charger/maintainer

Quote:
Originally Posted by redwire View Post
Modern cars with ECU-controlled alternators undercharge the battery. They keep them around 80% charge and AGM do not seem to matter, it's all to get more MPG. When you are decelerating, down a hill the ECU ups the alternator's voltage and dumps energy into the battery. It's like a regen. Cars also have more parasite drain with TPMS, keyfob remote RX always on, fuel pump anti-percolation, canister purge etc. functions happening with the key off while you are sleeping lol.
This all falls apart when the battery gets older, you need to charge them more, or in winter. Toyota firmware certainly isn't doing much at 13.4V in -20C weather for a flooded-type and AGM needs even higher voltage.
So I'm finding I have to do an equalization charge once a year and decent float charge every month or two. That's up to 14.4V then float at 13.8V, and the car stays around 13.4V but it goes to 14V for a short time after starting.

I built a desulfator (555/IRF9Z34 1mH, 220uH in pic ) and found it did not help. Hard sulphation is really stubborn, so I suspect you need huge current pulses to really knock the crystals off, and even then it apparently works to a limited extent. Right now I'm not a believer in desulfators because the scanning electron microsope pics of sulphate crystals shows they don't come off much.
Recovery of discarded sulfated lead-acid batteries by inverse charge they connected them backwards(!) new acid, to get 80% recovery.

edit: that desulfator circuit is stupid, the 15V zener is in the way lol.
I can get rid of hard Sulfate on with my CIP. Takes about a week. That CIP plugs into the wall, so yes… it has power all right. Those little desulfators in that circuit you shown are not good for anything much more than keeping a good from sulfating. Got one of the little guys sitting on my generator and I get twice the battery life out of it than another generator I maintain that only has a battery charger on it.
However there is another Voltage Doubler design of this. I built a couple of them and I gave mine the nickname “sparky”. The battery posts will start singing pretty good on this thing. So yes it does work, but it needs real power behind it. The voltage doubler circuit you need good diodes and large caps in series. Mine has 4 64000uF caps and it needs a power supply, other than that the battery is flat in a few hours. The charged inductive pulse (CIP) has a built in PSU. The battery posts will really sing on that one too.
Now my F-150 has a AGM and it will charge the battery to 14.9V if I take my foot of the gas pedal. I found specifically since we got COVID and the lockdown happened, just driving periodically and most of them short distances, I had to charge my truck and my wife’s car. Hopefully things return soon back closer to normal.
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Old 06-16-2021, 05:52 AM   #12
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Default Re: 12V 2A battery charger/maintainer

what if you vibrate the guts with the element from an ultrasonic tank??
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Old 06-16-2021, 03:39 PM   #13
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Default Re: 12V 2A battery charger/maintainer

Probably the Sulfate falls off, taking some lead from the plates with it? Not sure.
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Old 06-16-2021, 03:50 PM   #14
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Default Re: 12V 2A battery charger/maintainer

Everything has been tried, chemical additives, pulse charging etc. Either the battery dies from sulfation or it's corrosion causing mechanical failure of the interconnects or plates. Ultrasonic I think would just dissolve the plate material.
Desulfators I would not run with the battery in a car, decent amplitude voltage spikes would be good for battery but not the car's electronics.

I bought a Ali 15V 4A SMPS for $7 and it looks OK. Dianqi MS-60 and drew the schematic and I will mod it for car battery charger use. I think it's built better than the yellow 2A charger in OP as far as beefier parts. The primary cap looked a little shady 68uF 400V so I put in a 100uF 250V Nichicon. I have to make the PSU controlled by an MCU like Arduino or whatever I have lying around.
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Old 06-16-2021, 06:16 PM   #15
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Default Re: 12V 2A battery charger/maintainer

I had a Cyclon 6V pack that I tried feeding 90VDC straight into it. Didn't budge, still deader than a doornail - open... plates must have disconnected. Then again it running out of water is possible too, hmm. Still did not try opening it as it would still be useless if it leaked...
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Old 01-09-2022, 02:35 AM   #16
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Default Re: 12V 2A battery charger/maintainer

I am not Big Clive, but I did try to reverse engineer a similar power supply. It is labeled on the circuit board as YX1202-4-2003. (It appears to be 12V, 2A.) See attached PDF of hand drawn schematic. /Paul Robinson
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Old 01-10-2022, 12:10 PM   #17
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Default Re: 12V 2A battery charger/maintainer

Thanks for the schematic, I forgot to finish mine. It looks almost identical to the one I have. This charger is really good for the car, I don't like the brittle cables when it's cold out or the hot running caps... but it's still working fine.
The main SMPS IC appears to be a Chip Rail part CR6229 and other models use a mosfet+heatsink instead. At best it's 25W or so output.

The IC's are house labelled to hide the advanced technology and prevent copying
YX008 seems to have a voltage reference, comparator and current-sense op-amp.
What it does is really simple but works good. At high current loads >600mA it charges to 14.4V and when the current drops below that it switches over to 13.8V float charge output and stays there.

Canadian Tire has rip off pricing for something like this, 1-2A for $60 is gouging consumers.
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Old 01-11-2022, 04:16 PM   #18
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Default Re: 12V 2A battery charger/maintainer

Oh! Crappy Tire is totally overpriced.
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Old 01-17-2022, 12:01 PM   #19
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Default Re: 12V 2A battery charger/maintainer

i've bought dozens of cheap chargers and tenders, took them apart and reversed the circuits. i found one at HF that had a wrong value resistor that caused my truck battery to boil out acid from charging at 15.5V..yikes!

Then i moved up to the next price level and tested some more. The best i found is the Yuasa 1A smart charger sold at motorcycle shops for about $40. Yuasa makes more lead acid motorcycle batteries than anyone, it is the OEM in most motorcycles.

It will work in a car to desulfate the plates but takes several days due to the low current. Sometimes i use a 3 or 4 amp charger to raise the bulk, then put the Yuasa on to do the balancing and sulfate cycling.

A lead acid battery must always be kept fully charged. Permanent sulfation damage can occur in a week in a discharged battery. In the pandemic with less driving many folks are finding dead batteries.
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