Charger does not charge (green light only) help!

Hello everyone, I bought this charger and it has the famous green light problem. The red light and fan does not turn on to start charge.

I need your help to make this charger trigger on and function again.
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One thing I think might help are the two potentiometers in the picture that I do not know what they do. I know the bottom single one controls the output voltage, but I am scared to mess blindly with the other two.[/strike]

It worked when it arrived last month but required each time more plugging and unplugging to start, until even with half an hour of plugging in and out the wall/bicycle did not work.

EDIT: battery reads 36v at charging port, charger reads 42v when plugged in the wall with green light on, battery charges with a 42v 1.5A lead acid charger I have around.

EDIT 2: Tried hooking an incandescent bulb to the charger. Lights dimly for a second then everything shuts down.

EDIT 3: The charger now passes the incandescent bulb test but still not works properly.

EDIT 4: Charger appears to work but with a clicking noise.

EDIT 5: Charger failed during a charge, no green light anymore and no output voltage is measured.

Here are pictures of the charger:

One of them changes the Current and the other one changes the cut-off current at the CV stage.

But are you sure that everything else is fine? For instance the BMS is refusing to charge because one or more Cells have become too unbalanced. or maybe a bad charge port.

I would try it on another pack or bypass everything and hook it directly to the battery just for a few seconds to see if that turns the light red.

It is unlikely adjusting anything in the charger will fix the problem.

Usually this kind of problem is caused by the battery. Often, it's BMS is protecting you against a fire becuase one or more cells is too low to safely charge the pack anymore. There are many threads around the forum on how to troubleshoot this, often under titles such as "battery won't charge" or similar, but it will require opening up your battery and using a multimeter to test the cells at the balance wires.


Sometimes, this kind of problem is caused by a broken charge-power wire inside the insulation of the cable, either on the charger or inside the battery case. Or a contact backed out of a connector at the battery or the end of the charger cable. Usually this can be found by moving the wires around and having it work sometimes and not work others. Then using a multimeter to do continuity tests of the wires to find the location of the problem.

What voltage is the battery and you get any voltage out of the charger with the multimeter

I believe the battery is fine, the charger port of the battery reads 36v (the current state of the battery) and it charges with a 42v 1.5A lead acid charger I have lying around. (didn't do a full charge with the lead acid charger, read around it is dangerous).

I do need to find out if it can turn on at all, I was thinking about shorting it with thin wire but do not know if it requires to read some voltage from the battery to turn on. When I plug in the wall the charger light stays green and it reads full 42v. If I plug in the battery light stays green and if I pull out and on again just a single red led appears and it drops to 5v when I pull out and measure. The led slowly fades when I take it out again as if the battery is charging the capacitors from the charger since if I plug back to the battery the single red led goes on again and fades slowly. I have to unplug from the wall, wait for the led to fade out completely and on to the wall again to make the charger go on stand-by again.

I am also thinking about hooking the charger to the BMS output instead of the one with charging negative, let me know beforehand if it is a bad idea. Will post results. I cannot hook up directly to the battery since it is completely sealed in packing tape, made the battery myself in a very ghetto way.

Another idea, should I put a massive diode to the bicycle charging port so that it will not have backing current from the battery?

Here is a picture of the bms. Can it handle the lead acid charger?

eee291 said:

One of them changes the Current and the other one changes the cut-off current at the CV stage.

Click to expand...

What if I decrease the cut off current so that it won't cut off and start the charger? Maybe the battery is not accepting the full 5A of the charger and it is considering as full, I dont know, brainstorming here, tests will be ran tomorrow.

Update: I hooked the charger directly to the bicycle controller and tried to turn it on. It failed, shutted off immediately and did not even light the dashboard. Fuses are still intact. I am still unable to make the charger output power.

Update 2: Tried hooking an incandescent bulb to the charger. Lights dimly for a second then everything shuts down.

I am pretty certain the charger is at fault. If possible I would not like to replace because it is expensive to me. I am still attempting to fix.

The charger you need is a cc-cv . The sla charger does trickle charge after hitting 42 volt. You can use the SLA charger to get it to 41 volts or even 42 volts but you must unplug it as soon as it hits 42 volts I would try for 41volts and unplug. The problem is you watch the charger and walk away the charger will hit 42v or more. Make sure that charger is 42v or lower. To see if the battery will charge. You must monitor the charger and battery and not go to the bar or asleep.

Its a bad wire connection on the charger plug, or where it connects to the charger itself. classic symptoms. As AW said. Intermittent contact and sounds like getting worse. It could be the wire itself, but usually where it connects on one end or the other. Not so likely the same wire and plug on the battery, since it seems to work with the other charger ok. But it could still be that.

The SLA charger I got measures 41.5v in the output. Charged with the bicycle on to check it's voltmeter, seems ok so far, as you said, it stops at 41v, I am ok with that for now.

Will replace wires and post results.

Update!

It started working again, charging but with clicking noises and then a FET smoked. Do not know how to replace. I have a few computer power supplies around, they have FETs, wonder if I can just swap them regardless of model (most likely not, but I already think of this as lost cause).

Update:

The smoking was caused by gunk I left on the FET's feet when reinforcing the general soldering of the charger. Cleaned and is "working" again with the clicking which is not normal. I am scared of this charger in general since I absolutely cannot leave it unsupervised. Please help.

I am researching power supply clicking, seems to be the same issue.

Update: Bored with research, decided to plug back to the bicycle and see what happens.

The bicycle is charging with the clicking charger!

The bicycle right now is at 41v. Charging in this state makes the clicking, maybe it is the CV state? Will post results after I try to charge a depleted bicycle.

I also messed with the charger's potentiometers, do not know if that is the cause of clicking.

I do not know what I did so far to get where I am.

If any part of the charger gets hot enough to cause residues to smoke, something is wrong there.

If the ticking is not a fan touching a wire, then it is probably shutting down and restarting repeatedly, from an overload, internal or external.

You might look up the many charger threads Dnmun posted in, and follow the basic pattern he suggests in these threads for troubleshooting.

The smoke was because of a short of dirty flux in the FET, each spark generated more coal which made it worse. With my soldering I also made the gap smaller.

I am sure the ticking is because of turning off and on repeatedly as the light blinking in rythm with the sound confirms.

Is an overload caused by messed potentiometers? Will check later by turning at random. Digging through posts right now.

Turning the Pot randomly will most certainly break the charger. happened to me once, I turned the current pot in the wrong direction, thinking I was zeroing the current but instead I turned it up to 30A and it blew within half a second.

You should not use to lvc. It's not good for the battery. Leave a little something at the bottom in the battery. What's the info on the battery.

Update: Turned the potentiometers a few turns to each side but no change in the frequency of the clicking was observed. Test was conducted with indandescent bulb as load and green light only. It appears that the bigger the load the faster it clicks as with no load is very slow, with bulb faster and in bicycle very fast. I would say it ranges from 1-5 clicks a second.

The battery is a li-ion 10s8p made with LGDAS31865 cells from old never used recycled laptop batteries and the bms above. It is working properly with no issues except a 4v voltage drop during max throttle in my 350w e-bike which I do not know if it is the standard voltage drop for everyone.

It is not 100% working as it still presented the original problem once in 10 tries. I believe I created the clicking noise with my fiddling and the original problem was a bad contact somewhere as dogman dan said since I effectively did nothing to fix the charger but take it apart and put it back together several times. Wires were not changed yet.

I am tempted to leave it like this if no new issues arise, the clicking is not loud, I can live with that. New test will be conducted to ensure safety and reliability, will keep thread updated.

Well, you got a weird charger, and a battery made from scavenged cells.

Definitely don't store or charge that thing inside. Don't make your house look like mine did.

Wow, that looks bad, thank god it was only one room and not the whole house.

I charge it outside since taking the risk as a certainty and preparing for the worst is a better option than trying to avoid it forever (which makes me not take precautions at all, you can see from the mess in the background of the pictures).

Here are pictures of my bikes.

I buy scrap bikes since it is cheaper than buying the parts separately especially the motor. Paid around 80-100 dollars for each bike and am getting a nice deal on used batteries, 30 cents each, bought 2500 of them obviously.

People here do not like to replace SLAs when they fail so they tend to get rid of the bikes for cheap just because of no battery. By the way, those bikes brand new were expensive.

The scooters are a 2007 model, 500w, pretty weak. They do not have the controllers so I am buying a 1000w sensorless and a 1500w sensored controller just in case one of the motors have busted halls. Did not test them yet.

I tend to prefer scooters because the batteries I make tend to be pretty big because of low C rate and the fact they are made from a lot of packing tape which adds girth. I try to fit the maximum amount of batteries possible on each bike.

Update: Apparently the overloading stress or something caused the charger to stop during a charge and now I do not get even green light or output voltage anymore. Took it apart and applied more magic stare with no success. Also wiggled all the components and wires with a plastic stick while trying many times turning on at the wall to get voltage, the test failed.

Fuses are ok. When I plug in the wall I get a single dim fading red light and 2v decreasing at the output.

Replaced the wires from the AC plug to the charger board, no effect.

Nothing appears burned or damaged in the charger.

Will turn on tomorrow to see if it's in the mood, who knows.

EDIT: charger is not in the mood.