Big mistake I guess

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ebike11

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Hi guys
I was watching a youtube video where someone was adjust the potentiometer adjusters inside their battery charger to increase voltage rather than paying more for a higher voltage rated charger. I opened my 72V charger up and noticed 88V stamped
So since I have a 20s pack, I increased the voltage to around 82V. I failed to notice that the charging amps of the charger was rated 4A, and I stupidly turned up that pot adjuster to 6.5A. 20 min. later of charging, I heard a pop and the charger turned off and no longer works. Buying another one isnt a problem, just wondering if the damage is commonly repairable or off to the garbage heap??
Thanks
 
if you put volts up, amps should go down. ive had a couple fried chargers from that. you know where the power chord plugs into your charger from the wall. that receptacle is soldered to the board. look there to see if its smoked/burnt. ive had to resolder that once. look at the components attached to the heatsinks or charger case for burnt legs. I call them mosfets but other things look mosfets so if it has a burnt off leg google what it is and replace it and hopefully it works. good luck
 
open up the charger, and see if there is any black marks indicating a bad component, also check the fuses
that is the easy part
the hard part is do you replace the parts, and solder them in and see if it works, because something else down the line may have fried as well. I fried a few Meanwell chargers.
 
markz said:
open up the charger, and see if there is any black marks indicating a bad component, also check the fuses
that is the easy part
the hard part is do you replace the parts, and solder them in and see if it works, because something else down the line may have fried as well. I fried a few Meanwell chargers.
Click to expand...

Hi..I see black residue on a large yellow componant, not a capacitor though. Not sure if its worth fixing though.
 
On the bright side, you did not burn your house down, overcharging your battery to 4.4v per cell. That would have at least, ruined the battery in one charge.

84v maximum, which is where your 72v charger was set to begin with.
 
ebike11 said:
Hi..I see black residue on a large yellow componant, not a capacitor though. Not sure if its worth fixing though.
Click to expand...

Snap a photo and post it. Sometimes it is fun to fix something just to see if you can. Also, you could use it as a spare if you get a new one anyway and it is one tiny bit less bit of junk in a landfill somewhere.
 
dogman dan said:
On the bright side, you did not burn your house down, overcharging your battery to 4.4v per cell. That would have at least, ruined the battery in one charge.

84v maximum, which is where your 72v charger was set to begin with.
Click to expand...

Hi..the charger itself was a 72V and rated 4A from the factory. However my pack that I got recently is 20s so I thought to increase the charger voltage to 82V or so (4 1x20 cells)
The charger had 88V printed on one of the larger componants inside the charger. If I had left the amps at 4A and only increased the voltage, wouldnt that be safe and ok for a 20s pack??
 
a device (charger, power supply, controller, etc) that converts from one thing to another has a wattage rating it can handle, beyond which the heat it creates begins to damage things.

so generally you end up needing to decrease the current output if you increase the voltage output.

however, the charger failure is probalby not from that, it is probably from a component that could not handle the higher voltage.

just becuase one component in a device has a certain rating does not mean that any other component in there has a rating that high.

in order to use a device at a certain voltage/etc., *all* components that see that voltage/etc must be capable of it.

so you have to reverse engineer the device, trace out the whole circuit, to see which components will see what voltages, currents, etc., to be able to safely turn up the voltage / etc.

you can make a guess taht if the major parts like caps and fets and power diodes all are rated for the voltage and current you're turning it up to, the device will probably work...but there's no guarantees. ;)
 
amberwolf said:
a device (charger, power supply, controller, etc) that converts from one thing to another has a wattage rating it can handle, beyond which the heat it creates begins to damage things.

so generally you end up needing to decrease the current output if you increase the voltage output.

however, the charger failure is probalby not from that, it is probably from a component that could not handle the higher voltage.

just becuase one component in a device has a certain rating does not mean that any other component in there has a rating that high.

in order to use a device at a certain voltage/etc., *all* components that see that voltage/etc must be capable of it.

so you have to reverse engineer the device, trace out the whole circuit, to see which components will see what voltages, currents, etc., to be able to safely turn up the voltage / etc.

you can make a guess taht if the major parts like caps and fets and power diodes all are rated for the voltage and current you're turning it up to, the device will probably work...but there's no guarantees. ;)
Click to expand...
Thanks a lot for your helpful advice.
The chargers arent that expensive so at least I could experiment. So on average..its fairly safe to increase the voltage as long as i turn down the amps?? Just good to know for future reference. As u said..all componants should be able to handle the power levels so it still could be risky
 
ebike11 said:
So on average..its fairly safe to increase the voltage as long as i turn down the amps??
Click to expand...

Re-read his post. What he's telling you isn't that simple.
 
I missed it where you said 82v. A 72v nominal charger should have come set to 84v anyway. If it was outputting 72v, its really a 60v charger, or thereabouts. So that would be pushing it a bit, to set it to 10v more.

Bear in mind,, even good stuff just sometimes has a weak link built in. It passed test at factory, but still can't run a very long time. You may have just had a part about to fail early anyway, and then turning it up fried it. Unfortunately, you voided any warranty when you tweaked the pots.

But yeah, in simpleton terms, if the thing is intended to run at x watts, and then you turn up the watts, it fails sooner. So if you jack up volts a lot, you should turn down the wattage, ( turn down its amps) back to spec. That's better than taking a 200w charger, and running it at 250 or 300w.

But in your case, you were running at around 300w, and turned it up to 530w. I would expect a fail doing that.
 
dogman dan said:
I missed it where you said 82v. A 72v nominal charger should have come set to 84v anyway. If it was outputting 72v, its really a 60v charger, or thereabouts. So that would be pushing it a bit, to set it to 10v more.

Bear in mind,, even good stuff just sometimes has a weak link built in. It passed test at factory, but still can't run a very long time. You may have just had a part about to fail early anyway, and then turning it up fried it. Unfortunately, you voided any warranty when you tweaked the pots.

But yeah, in simpleton terms, if the thing is intended to run at x watts, and then you turn up the watts, it fails sooner. So if you jack up volts a lot, you should turn down the wattage, ( turn down its amps) back to spec. That's better than taking a 200w charger, and running it at 250 or 300w.

But in your case, you were running at around 300w, and turned it up to 530w. I would expect a fail doing that.
Click to expand...

Thx again..yes lesson learned
Since my 20s pack is 72v (84v fully charged)
I just ordered an 84v 3A charger and wont touch it. Well...ill leave the amps at 3A but ill turn the voltage pot down a bit to 82V so 4.1v per cell to extend the pack life
 
You could do a split battery pack, get two 84v3a chargers and charge up the battery in half the time, if the C-rating is healthy.

I have a 36V 27Ah split into halves, using Dell chargers of 20.50V and 8A, cheap $10-$15 Dell laptop chargers. So I only get 41.00V out of 42.00V. I could use a step up converter to get that extra volt. Another option for me is I could get chargers that are 20V and 12 or 15A but those chargers are $50+ each.

Something to consider if your rocking your own battery pack.

The Meanwell chargers HRP were bulky but spat out plenty of amps at an adj voltage. Not as durable as LED psu's which then get you down to single digit amp rating, and pricing aint that appealing.
 
markz said:
You could do a split battery pack, get two 84v3a chargers and charge up the battery in half the time, if the C-rating is healthy.

I have a 36V 27Ah split into halves, using Dell chargers of 20.50V and 8A, cheap $10-$15 Dell laptop chargers. So I only get 41.00V out of 42.00V. I could use a step up converter to get that extra volt. Another option for me is I could get chargers that are 20V and 12 or 15A but those chargers are $50+ each.

Something to consider if your rocking your own battery pack.

The Meanwell chargers HRP were bulky but spat out plenty of amps at an adj voltage. Not as durable as LED psu's which then get you down to single digit amp rating, and pricing aint that appealing.
Click to expand...

Hi
I wont be able to do that nor want to risk it. Its a pack i just got from em3ev so im hoping ill get long life from it.
 
If you charge that battery to 4.1v all the time, it will never have enough charge to get the bms to balance it. So once in a while, you will have to turn it back up, and do a few cycles charging it full, to get fully balanced again.

You will know when its time, when the battery won't hold even 80v after you unplug from an 82v charge. At that point, you may have some cells that are at 4.25v each charge, and some at 4v. But when the charge finishes, the bms will drain the high charged cells to 4.2v. But meanwhile, you got some groups that never reach 4.1v. So if you can't hold 79v, when normally you see 81, its needing a balance.

It should normally drop some voltage by morning after a 4.1v charge. What I mean is when that gets to be more overnight voltage loss than you normally get, its telling you its waaaaaay out of balance then. Same thing if you notice it cuts off at higher voltage than usual.. if the bms stops early, its because one cell group is completely empty.
 
dogman dan said:
If you charge that battery to 4.1v all the time, it will never have enough charge to get the bms to balance it. So once in a while, you will have to turn it back up, and do a few cycles charging it full, to get fully balanced again.

You will know when its time, when the battery won't hold even 80v after you unplug from an 82v charge. At that point, you may have some cells that are at 4.25v each charge, and some at 4v. But when the charge finishes, the bms will drain the high charged cells to 4.2v. But meanwhile, you got some groups that never reach 4.1v. So if you can't hold 79v, when normally you see 81, its needing a balance.

It should normally drop some voltage by morning after a 4.1v charge. What I mean is when that gets to be more overnight voltage loss than you normally get, its telling you its waaaaaay out of balance then. Same thing if you notice it cuts off at higher voltage than usual.. if the bms stops early, its because one cell group is completely empty.
Click to expand...

Ok thanks!!
The reason I set it to 4.1v is I read on here that the cells will have a longer life and there isnt a need to get to the max 4.2v..but ill do as u mentioned and fully charge now and then.
What about the very first charge cycle of a new pack? Should it totally be fully charged then totally discharged to 3.6v? Or does it matter
Thanks
 
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