Charger won't charge

I have this 36v charger from BMSBattery.
http://www.bmsbattery.com/alloy-shell/23-alloy-shell-180w-lifepo4li-ionlead-acid-battery-ebike-charger.html
It has 43.5v at the output, but won't charge the battery. The battery charges OK from a similar charger from my other bike. The faulty charger can give current OK because it'll run the motor if I connect it direct to the controller. It seems to think that the battery is full even though the battery's at 35.5V. When I first go it. it would charge the battery, but not fully. Now nothing at all. Is there anything I can do to make it charge?

I hope that's not the charger I have. Is it the 36V 4A? When I plugged it in the other day I had to tap it to get the fan going. Did you have similar problems before the charger stopped working?

if the charger put out the 45V and the pack will not take it then the BMS charging mosfet is turned off or the charging leads are disconnected.

you need to tell us the make, or post up pictures of the BMS, nothing is wrong with the charger from what you said.

Be sure it is set to the correct voltage. If the charger is set to 220v input and is plugged into 110v, it won't charge but will show the proper unloaded voltage.

The really common cause of this is, as said above, it's unplugged. I'd check the plug first thing, both on the charger and on the battery side. Broken srands on the wires eventually disconnect plugs in many cases. I assume you didn't see anything wrong where the wires solder to the board. I had a "funny charger" that had a bad solder there once.

If if was the bms, why would it charge ok with a different charger? But equally odd that you can see voltage at that plug, if the fault is on the charger side of the plug. Bad plug would more likely result in either no output, or at best intermittent output.

Mabye it is a charger defect, like the fet that switches between green light and red.

i also thought it might be a bad connection. the guy who started this never replied. why do people even start asking questions if they have no interest? stupifies the imagination to wonder why they ask and never ever reply.

he said the other charger worked, but not this one. either the other charger had charged the pack up to HVC and that shut off the charge, which he coulda tested if he cared to, or the connection inside the plug on this charger is bad. of course we don't know if this charger ever worked and then failed either.

whatta waste.

Thanks for the replies. I asked the questions on a friend's behalf and didn't get any replies for three days with frequent checking, so I had given up.

To make it clear:
We have two identical chargers. One charges the battery and the other doesn't. To me, that rules out the battery as the problem. Both chargers have the same output voltage - measured with a voltmeter.

The faulty charger can give current at the correct voltage. I connected it direct to the controller , and it can spin the motor at full no-load speed - probably at least 2 amps. To me, that seems to rule out the charger lead/connector.

The only thing it doesn't do is charge the battery, which is an absolute mysteryWhen we first had it, it would charge the battery to about 2/3 full, and we had to finish off with another charger, but that was only a couple of times.

I'll go over there tonight and check the input voltage. We're using 230v.

It is my charger that d8veh has been helping me with. Tonight we cant find anything to change the input voltage. No switch or anything.The charger is marked 220 v

How does the charger sense that the battery is fully charged and is it possible to adjust it.

Many thanks.

It may be hidden on the inside of the charger.

if you shrink his picture you can see the line voltage goes right to the ICL and choke. it seems to be wired for 240 because there would be a jumper or switch under where the blue wire is if it is 120.

did you measure the same voltage on the battery as the voltage on the charger when you are charging? does it have 45 on one and 35 on the other like you said? did you decide it doesn't charge because the charging light turned off? is the charging mosfet on the BMS turned off when your charger does not charge?

dnmun said:

if you shrink his picture you can see the line voltage goes right to the ICL and choke. it seems to be wired for 240 because there would be a jumper or switch under where the blue wire is if it is 120.

did you measure the same voltage on the battery as the voltage on the charger when you are charging? does it have 45 on one and 35 on the other like you said? did you decide it doesn't charge because the charging light turned off? is the charging mosfet on the BMS turned off when your charger does not charge?

Click to expand...

The charger is marked WWW.EMCHARGER.COM and EMC 180 (180w).

We measured the voltage on the battery and the charger at the same time with the same voltmeter. We'd just returned from a long ride, so the battery was well down. The voltages were 43.5v and 35v. We also tried to charge my battery with it, but still nothing. Mine is the same as Saneagle's: 20aH 36v Shrinktube battery from BMSBattery.

There's two LEDs: a red one and a green one. The red one is always on and the green one glows slightly when the charger's connected to 230v, and then it glows brighter when connected to the battery - like when the battery is fully charged. It should change to red when charging. Also the fan doesn't start up, but did when it was charging before - as did the green LED change to red.

I don't know if the BMS MOSFET is turned off. The BMS is not easily accessible.

I tried turning the voltage of the charger up a bit to about 46v, but it didn't have any effect. I also tried turning the other two pre-sets up and down by one turn, but that didn't have any effect either. I put them all back how they were.

We are using the battery happily with the other charger, but we can't get any charge out of this one. Everything is pointing to the charger thinking that the battery is full, even though it isn't

Thanks for your time and I appreciate your help.

if the charger was connected to the battery through the plug then the voltage would be identical on each side of the plug. it sounds like the plug on the charger either doesn't make proper contact from charger negative with the C- lead on the BMS or the positive lead from the charger doesn't make contact with the positive terminal of the battery. check continuity.

dnmun said:

if the charger was connected to the battery through the plug then the voltage would be identical on each side of the plug. it sounds like the plug on the charger either doesn't make proper contact from charger negative with the C- lead on the BMS or the positive lead from the charger doesn't make contact with the positive terminal of the battery. check continuity.

Click to expand...

That's what I thought, but it drove the motor when I put on an adapter lead. We then wired the end of the adapter to the battery, but it still wouldn't charge, but however we connect to the battery, the green LED changes from dim to bright, so continuity must be OK?

They must send out random chargers with their batteries. I have the same battery from bmsbattery but it came with a different charger. A couple of days ago I plugged my charger in and the fan wouldn't start. I tapped the controller a couple of times and it started up. I haven't had a problem since then and I ride almost everyday. I think their chargers are kind of sensitive to how they are placed when charging. I think they have to be completely flat and upright while charging. You know 220V sounds kind of high for a standard wall socket. I think my charger is for 120V or so standard wall socket. Of course I'm in the US and I didn't read where you're from before I replied.

I've had that with other chargers. This one (when it was working) and an identical one that I got with my battery seem to have intelligent fans. They don't come on at first, but start up and change speed a bit later presumably according to a temperature sensor or something else.