Adjusting King Power chargers

Here's the guts of an e-citypower.com/bmsbattery.com 600W charger. Sorry for the awful pic, I'll be upgrading the camera soon. The current adjustment pot will let you go down to about 500mA before the shutoff relay triggers. Does anyone have a guess what the third pot is for, the one right next to the CC current adjustment pot? When the charger's in CV mode it seems to affect both the output current and fan speed, one at the expense of the other.

The fuse holder is in the lower left corner of the pic. Strictly decorative, it isn't hooked to anything. I'm gonna fix that before I close it up again.



The inside of the 5A aluminum case Ping charger is very similar, they look like they came from the same place, except in the Ping the fuse is hooked to the charger output. I was able to throttle the current in the Ping charger down to about 120mA before it shut off.

yes, they are both from the same source. ping sent me one with the other type B 5A charger he sells.

the chargers are made by King power, we had already seen the label before on a charger someone got from jack.

ping verified that and i think he also has king power modify the charger so it works better to charge the lifepo4 by restarting the charge after the charger shuts down. he had mentioned this on a previous thread 3-4 months ago where he discussed how the ecitypower charger will shut down and stay off once it reaches voltage endpoint, which is good for lipo. ping observed that it is better for lifepo4 to allow the charge to restart again to make the cells continue to balance.

he had shown where to cut the leg off the switching transistor on the daughter board, and i think this is the mod that he has king power do for him now. so it should be a better charger for lifepo4 than the ecity power charger which is set up for lipo.

i haven't opened my king power charger yet i got from ping, i break stuff so i was putting that off.

Retitled the thread since these chargers are being sold by Ping, ecitypower.com, bmsbattery.com, and who knows how many others.



After playing with the Ping charger for a bit, I think the third pot adjusts the current level at which the auto-shutoff triggers. At least on the Ping charger, it seems to.

If the charger is already putting out a very low current (adjusted CC current down to 200mA, output voltage is set to 60.5V, measuring 54.5V at the battery terminals), if I turn that pot clockwise, the current goes up to about 300mA as the fan slows down, then if I turn it a little farther the charger shuts off (current 0, fan off, green LED).

If the charger is putting out a higher current, I have to turn the third pot farther clockwise to get it to shut down.

If I turn the third pot far enough counterclockwise, the charger keeps running even when it's not putting out any current at all. Haven't tried this with the 600W ecity charger yet.

Whoops, after adjusting the auto-shutoff pot, the Ping charger doesn't seem to be turning itself back on after the BMS shuts it down, unless I cycle the power switch. Have to figure out what's going on there but I'm outta time for today.

I have one of the 48v lifepo4 600W ones too. It tops out at 58.4V

Is there a voltage trim pot inside? If so does anyone know how far up and down it can be pushed?

voicecoils said:

I have one of the 48v lifepo4 600W ones too. It tops out at 58.4V

Is there a voltage trim pot inside? If so does anyone know how far up and down it can be pushed?

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The pic in the first post of this thread is the guts of that exact charger - 48V, 600W, set to 58.4V by default, so yes there's a voltage pot. I didn't experiment to see how high or low it would go. ecitypower.com's web site says 2V-120V for the 600W charger. But take a look at the voltage rating printed on the caps. Mine's closed up now but I'd be pretty cautious above 75V.

Hey Jules

Is the voltage pot sensitive? I'm planning on going from 41V to 41.5V. About how much rotation is that and in what direction?

I didn't adjust the voltage much, just up and down a little while I had a meter on it, to confirm which was the voltage trim pot, and I don't remember which way was which, but it was pretty sensitive. If I remember right, a half volt would be only about ten or fifteen degrees rotation.

Anyway, I wouldn't try adjusting it without a voltmeter on the output. And I'd prefer a little plastic screwdriver, but I don't have one so I've just been really careful not to touch anything but the pots. I'm sure there'd be a nice light show if I dropped my metal screwdriver in the wrong place, and I'm not sticking my fat fingers in there while it's running. Even after unplugging it, I'm sure those big caps hold enough charge to fry components.

I wonder if I've got any scrap plastic around the house I can make into a makeshift screwdriver. I've got some acrylic, I should Dremel that into something close enough. It would be pretty brittle, but if I can get a sharp edge on the tip it should work fine for adjusting pots. Safety first, they keep telling me...

I have a watts up wired to mine so I can monitor everything it does.



Thanks I may give it a try this weekend or next

That setup looks awfully familiar. :lol:

julesa said:

I didn't adjust the voltage much, just up and down a little while I had a meter on it, to confirm which was the voltage trim pot, and I don't remember which way was which, but it was pretty sensitive. If I remember right, a half volt would be only about ten or fifteen degrees rotation.

Anyway, I wouldn't try adjusting it without a voltmeter on the output. And I'd prefer a little plastic screwdriver, but I don't have one so I've just been really careful not to touch anything but the pots. I'm sure there'd be a nice light show if I dropped my metal screwdriver in the wrong place, and I'm not sticking my fat fingers in there while it's running. Even after unplugging it, I'm sure those big caps hold enough charge to fry components.

I wonder if I've got any scrap plastic around the house I can make into a makeshift screwdriver. I've got some acrylic, I should Dremel that into something close enough. It would be pretty brittle, but if I can get a sharp edge on the tip it should work fine for adjusting pots. Safety first, they keep telling me...

Click to expand...

they make a plastic adjustment screwdriver you can buy, it has a cone tip so it stays on the screw, but the caps will discharge when the power turns off because there is a bypass resistor built into all the power supplies that connects the high and low sides of the output. about 4-5k usually, but you can change it to 50k-100k and reduce the power lost to the bypass resistor. the high voltage on the input is only about 160V RMS DC with spikes to 385V which is why they use 400V caps on the input diode rectifiers. it doesn't hurt much, tingles when you rest your arm on it.

the adjustment pot is in combination with other resistors to make up the bridge between output and ground, with the resistor bridge tied to a voltage reference or zener such that the cathode of the reference and the cathode of the led arre tied together to fix the voltage that drives the led in the opto transistor which provides the feedback to the oscillator pwm IC current controller in the front end.

you can move the range a bit more by changing those other resistors and then tweaking with the trim pot.

but the voltage limit will be the ratings of the output caps, and the voltage rating of the schottky diode to the output. also the 19V that drives the elctronics comes off the transformer too and will have to stepped down where it comes out of the transformer by adding another zener diode in series to the one on the board to keep the voltage input to the regulator in range, or replace the zener with a higher value altogether. you will need bigger diodes on the output too if you exceed their range with a higher voltage battery, and you will need to change the resistor bridge that provides the voltage feedback from the output to the op amps that switch it from CC to CV, and drive the charging signal leds. outside of that, you only have to worry about exceeding the transformer power rating, so you can go the current detection bridge on the negative return side and add some resistance in parallel to the low side of the bridge so the current is reduced as the voltage is increased.

outside of that it is straightforward. the schottky will be the costly item. big high voltage electrolytics cost a little bit too.

dnmun said:

they make a plastic adjustment screwdriver you can buy, it has a cone tip so it stays on the screw

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Nah, if I can make one in 5 min out of stuff I have lying around, that's probably what I should do unless I'm gonna go into business adjusting these things all day every day.

dnmun said:

but the caps will discharge when the power turns off because there is a bypass resistor built into all the power supplies that connects the high and low sides of the output. about 4-5k usually, but you can change it to 50k-100k and reduce the power lost to the bypass resistor.

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The LEDs take 30 seconds or so to fade out after it's unplugged, so at least one of the caps are discharging pretty slowly. Anyway I usually try to err on the side of caution. Less worried about getting zapped than accidentally frying something in the charger.

dnmun said:

the high voltage on the input is only about 160V RMS DC with spikes to 385V which is why they use 400V caps on the input diode rectifiers. it doesn't hurt much, tingles when you rest your arm on it.

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In my experience the impact of electrical shock is based much more on the resistance of your skin than any other factor. It will vary a lot more than you would expect. If you're sweaty, or even if it's a humid day, it can mean the difference between a mild tingle and OUCHF^%$!!!!

dnmun said:

the adjustment pot is in combination with other resistors to make up the bridge between output and ground, with the resistor bridge tied to a voltage reference or zener such that the cathode of the reference and the cathode of the led arre tied together to fix the voltage that drives the led in the opto transistor which provides the feedback to the oscillator pwm IC current controller in the front end.

you can move the range a bit more by changing those other resistors and then tweaking with the trim pot.

but the voltage limit will be the ratings of the output caps, and the voltage rating of the schottky diode to the output. also the 19V that drives the elctronics comes off the transformer too and will have to stepped down where it comes out of the transformer by adding another zener diode in series to the one on the board to keep the voltage input to the regulator in range, or replace the zener with a higher value altogether. you will need bigger diodes on the output too if you exceed their range with a higher voltage battery, and you will need to change the resistor bridge that provides the voltage feedback from the output to the op amps that switch it from CC to CV, and drive the charging signal leds. outside of that, you only have to worry about exceeding the transformer power rating, so you can go the current detection bridge on the negative return side and add some resistance in parallel to the low side of the bridge so the current is reduced as the voltage is increased.

outside of that it is straightforward. the schottky will be the costly item. big high voltage electrolytics cost a little bit too.

Click to expand...

You are a wealth of information, man. Thanks

you can use a normal small screwdriver. all the high voltage is under the pcb in any case unless you get to the base of the capacitor on the input or the legs of the rectifier diodes.

i have been studying the chargers and the switch mode power supplies for a month or so. found some good info in the data sheets for the IC pwm current controller that drives the oscillator circuit in the front end. they have a nice circuit diagram that helps understand what is happening in the oscillator. if i knew how to hang a pdf up here i would copy that here too.

i wanna do a conversion of a 24V 800W power supply to 88V for a 72Vlifepo4 power supply/charger like tiberius and jeremy talked about so i have been trying to figure out how to do it, and to learn how to repair the chargers.

Further screwing around with my 600W charger revealed that the voltage adjustment pot increases voltage with clockwise rotation, and it's not as sensitive as I thought -- about 180 degrees per volt.

The shutoff adjustment pot decreases the shutoff amperage with counter-clockwise rotation. If you're using a Ping/Signalab V1 BMS or one of the e-city resistor bleed BMSs you''ll want to lower that to about .05A. Mine was set to 1A by default. I think if you have a Headway BMS you could set it as high as .15 or .18A, though -- those will shunt up to .2A, won't they?

as i recall the large shunt resistor gary designed for is 6.8 ohms so that is 500mA shunt current.

I have the 240w version of this charger and it outputs 4A at 54.6V. My batteries are only rated for a 2.2A charging current. Will the CC adjust pot allow me to reduce the output current to 2.2A?

Any help is much appreciated.

John

My 600W King Power from bmsbattery is set for 58.4v10A.

It gets VERY hot and once hot it makes a loud ticking sound.

Anyone else experiencing this? I've been unplugging it and letting it cool down then switching it back on and it doesn't start ticking till it gets hot again. I don't really want it blowing up on my, right before I tweak the voltage up to 61.5v for my 15S lipo pack.

How hot is it getting? Mine get pretty warm at 600W, but I can still easily pick 'em up and hold 'em in my hands, even on the hot side.

Is your fan working right? It should be running unless the status LED is green. Mine used to get hotter until I got the fan working. You could probably skate by for a while by turning the amps down a ways.

The ticking sound is probably a capacitor starting to fail. If you can figure out which one the ticking sound is coming from, you should replace it unless your heating problem is really bad, in which case you need to fix that.

floatingdog said:

I have the 240w version of this charger and it outputs 4A at 54.6V. My batteries are only rated for a 2.2A charging current. Will the CC adjust pot allow me to reduce the output current to 2.2A?

Any help is much appreciated.

John

Click to expand...

Yes.

dnmun said:

as i recall the large shunt resistor gary designed for is 6.8 ohms so that is 500mA shunt current.

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Yeah, the original design shunts at 500mA, anyway. Andy's been building some with smaller resistors, I think those must be shunting at a lower rate, though I have no idea why you'd want to do that.
http://www.rechargeablelithiumpower...d-p-49.html?osCsid=n2up4ke7ekv120nus1ptp9rok6
You don't save much on the components. The only difference would be slower balancing, and less heat generated. Maybe that's it, if the BMS is in an enclosed space you might want a lower shunt current so you don't generate so much heat, even if it takes longer to finish the balance phase.

Thanks Julesa!! I adjusted my 240W bmsbattery.com/ecitypower.com version of this charger from 4A to 2A output and 54.6V to 58V. The trim pots are in a little different positions on the board but in the same orientation. The voltage pot is over by the fuse. (The fuse was fully wired by the way.) The CC (amp) pot was next to another pot just as shown in the picture in the first post.

John

julesa said:

How hot is it getting? Mine get pretty warm at 600W, but I can still easily pick 'em up and hold 'em in my hands, even on the hot side.

Is your fan working right? It should be running unless the status LED is green. Mine used to get hotter until I got the fan working. You could probably skate by for a while by turning the amps down a ways.

The ticking sound is probably a capacitor starting to fail. If you can figure out which one the ticking sound is coming from, you should replace it unless your heating problem is really bad, in which case you need to fix that.

Click to expand...

Too hot to hold on the side where the fets are bolted on. (I assume that's where they are)

I'll check the fan, I think it may not be running on 'red LED'.

Can caps make a ticking sound? I'll make a short youtube clip if I can't easily get the fan up and running. Turning the amps down a bit is a good idea too. 8A or so would probably be an acceptable balance between fast charging and explodingly hot. Cheers

Yeah the ticking is basically a spark jumping the dielectric inside the cap. Not good for the cap. The heat is probably making the dielectric break down. In one of my chargers the fan's plastic was cracked and the blades couldn't turn because they were rubbing against the case. I fixed it with a dab of superglue. If you fan's just dead you can probably get a replacement at an electronics store or on eBay.

Hi,

maybe I'm a little out of subject but I have a simple question about these chargers : Are they insulated ? I want to use 2 of them to charge a 16s LFP pack. Each one will charge 8 cells.

Thanks.

i don't think the ticking is a cap, they would just blow. if your fan is not running, it may have a bad connection where the little plug is pushed onto the pcb, or maybe the resistor in line with the fan is dead, or maybe the ticking sound is an open circuit in the fan circuit from the transformer through the resistor to the fan, and the fan could have a control circuit on it too, maybe off an opamp that drives the charging circuit. have not opened them up yet so just guessing.