Charger schematic or fix.

[pdonahue]

Hi All,

Has anyone drawn up a schematic for the 48V charger?  Specifically the DC side of the charger.   I hooked mine up with reverse polarity and let the smoke out.  For now I am using my old charger, but I can hear the caps ringing when it's under heavy load so I don't expect it to last much longer.  I'd like to try to fix the fried one before my old charger breaks.

Pete

[Leslie]

all I get is xin the king 1650 in this one.. npn or pnp?  look at where the source and drain come from and lead to.

Look for blown diodes and zeners and bad caps Dont trust the colors white and black...

Maybe in the one that works up the farad in the caps, the resitor and zener wattage.  Just maybe the fets can do this trip.

Oh and make sure you have the fets heat sinked properly if you want more current.

[Nicobie]

Do you think it is ok to plug the charger into the wall without hooking it up to the batteries in order to check polarity?

I did this on a GM 36v charger to check (It was wired right). Then I unplugged it, hooked up the batteries and plugged it back in. It then promptly fried itself. Did I do something wrong, Or did I get a bum charger?

Nick

[Leslie]

Do you think it is ok to plug the charger into the wall without hooking it up to the batteries in order to check polarity?

I did this on a GM 36v charger to check (It was wired right). Then I unplugged it, hooked up the batteries and plugged it back in. It then promptly fried itself. Did I do something wrong, Or did I get a bum charger?

Nick

Shouldnt a gm charger just plug in to a gm battery pack without testing?

If this this the case then it doesnt matter if it wired wrong I call it DOA.

And one biggy I made once upon a sad story was I tested the charger with my multimeter leads reversed polarity and went by colors to confirm the polarity.

Oops two chargers down the drain.....

Rule 1:
Never use multimeters in reverse polarity, even if its just to test the continuity of a circuit or to test voltage, "always" make the effort to put hook them up correctly. 

Rule 2:
"Always" check your multimeter polarity is correct before testing a charger for polarity.

Rule 3:
"Always" check twice your multimeter polarity is correct before testing a charger for polarity.

I don't know how this came to be, maybe bad light or I changed from aligator clips in haste for an unrelated reason. But the lesson was learned...  I used these 24v chargers that you cant fry, revesed polarity, shorted.  I got lazy...

[Lanchon]

> Do you think it is ok to plug the charger into the wall without hooking it up to the batteries in order to check polarity?

it's definitely ok.

> I did this on a GM 36v charger to check (It was wired right). Then I unplugged it, hooked up the batteries and plugged it back in. It then promptly fried itself. Did I do something wrong, Or did I get a bum charger?

you did nothing wrong.

[Nicobie]

Thanks for the info.

My cheap meter displays a  -  when polarity is reversed. I can't see where it would hurt a charger to hook up the meter backwards. Hooking up the battery backwards is a different story. But seeing as I really know squat about this stuff, take everything I say with a grain of salt

Nick

[Leslie]

Thanks for the info.

My cheap meter displays a  -  when polarity is reversed. I can't see where it would hurt a charger to hook up the meter backwards. Hooking up the battery backwards is a different story. But seeing as I really know squat about this stuff, take everything I say with a grain of salt

Nick

Correct.

But if you test the charger with the meter hooked up backward not realising you get a false positive. One would then continue to hook up the battery reversed polarity on the results from an incorrect reading.

As much as some would not like to admit it, not including yourself, it is more a common human error than many would not like to admit after the error has been made.

The 3 rules stand strong.  In my experience and my lesson learnt in wrecking two chargers in this manner, is testimony of "my" past mistake.

I just hope that no one else makes the same mistake too. It was a tad expensive.  Now I'm going to cry...  I knew I should not have joined this thread...  I did say it was once upon a sad story.

BTW. Anyone know where I can get a 1650 transistor or comparable chip...

[Nicobie]

I just received a GM 48v charger and it says on its side to never plug in to the wall without batteries connected. This will make it hard to check polarity before hooking it up to the batteries. In fact, I can't see any way to do it. So I guess I'll just take a chance......

[Leslie]

Maybe never plug a powered up charger onto a flat battery. I cant see how turning it on and testing is going to hurt it. Turn it on, test it the charger before its hooked up,  turn it off before you hook it up to the battery, hook it up to the battery then switch the charger on..

But then again just do exackerly what the sign says :|

 

[Nicobie]

But then again just do exackerly what the sign says :|

 

I did just that and the new charger gave a pop and let the smoke out like the other one did.

[Leslie]

I did just that and the new charger gave a pop and let the smoke out like the other one did.

I want to cry....  Honestly...  Check the voltage coming from the batteries. do you get above 48 volts? Or any volts at all?

[Nicobie]

53v on on my watts up meter sla that have been charged 3 days ago.

[Leslie]

53v on on my watts up meter sla that have been charged 3 days ago.

Thats all good. exactly what is your chemistry.  Are you using LiFePo4 or SLA's are you using a LiFePo4 charger on SLA'S or vice versa.

[Lanchon]

> I just received a GM 48v charger and it says on its side to never plug in to the wall without batteries connected.

it's probably a simpler way of saying don't plug to battery if the charger is powered on.

> the new charger gave a pop and let the smoke out like the other one did.

what did you do to make it smoke? did you test polarity before plugging it to the battery?

[Leslie]

> I just received a GM 48v charger and it says on its side to never plug in to the wall without batteries connected.

it's probably a simpler way of saying don't plug to battery if the charger is powered on.

> the new charger gave a pop and let the smoke out like the other one did.

what did you do to make it smoke? did you test polarity before plugging it to the battery?

Did he test the polarity of the battery/batteries too, I only say do what the sticker says because I'm not going to say don't do what the sticker says.