Adjusting King Power chargers

Happy holidays guys!

Just a quick note on my 600W bmsbattery/kingpower charger...

I've opened mine up and did 2 things:

* Fixed my cracked fan (outer case snapped and so the fan wasn't spinning, the fan case now epoxied together so it spins fine)

* Tweaked my voltage up to 61.5v for my LiPoly pack (15S at a conservative 4.1v/cell). I took a decent amount of counter clockwise turning IIRC and I did it with a nearly full battery pack connected. (counter clockwise with the charger facing so the voltage trim's on top and the 2 current pots are below)

Raising the voltage raised the current and it's now up to 10.5A or so. I'd actually prefer to tweak the current down to 9.5A for cooler operation and longevity. Anyone know which of the 2 current pots is the one to tweak and if it's counter clockwise or clockwise?
 
hey, guys

I've been having trouble getting my charger to charge my cells through a Gary/Fechter Bms. I was having some issues with the bms but now I've successfully charged and balanced them once with a variable transformer.

How are people testing which pots do what. Mine doesn't show voltage unless it's attached to the cells, and at this point to I would only do it through the bms. When it's through the bms I get a reading of the cells voltage and not the output so I don't know what's changing.

How can you test which is the CC ? I think that is really my problem since It turns off before the pack can balance.

I'm using a 900W charger bought from e-city. here is a pick of the inside and out.
chargerOut.jpg
chargerIn.jpg


I don't really want to play with it any more attached to the cells and bms. I'm afraid it's going to mess them up. I just tried it again and the pack was gaining voltage really fast and the bms lit up weird and the main led was green and some of the cells charged faster than others.

I mean maybe it's not hurting it, I'm just really nervous about it since I really have no idea what it is doing.

Any advice?
thanks
 
For anyone else with my model, here is what I found.

The Pot on the far Left is a voltage adjustment pot. The pot on the far Right is also a voltage adjustment pot, but more sensitive, making larger voltage increments. Turning the pot counter clockwise increases voltage on both of them.

The pot just left of the sensitive voltage adjustment is the current cut off adjustment pot. Turning it counter clockwise decreases the current it will cut off at. To clarify, If I were to turn it far counter clockwise it would never shut off.

The other pots are still a mystery to me. I've seen little changes while moving them and haven't done enough testing. My guess is that one will change the current during regular charging. My charger outputs 9.6 A while charging and I may want to adjust that a little lower.

The charger's heat seemed fine, but the shunts on the bms were really hot.

Also, The idea of using a toaster as a 900w 15 ohm resistor to simulate the cells didn't work for some reason. It may have been my toaster, or maybe the way the charger is programed, who knows?

good luck with charger adjustments.
Greg
 
julesa said:
dnmun said:
as i recall the large shunt resistor gary designed for is 6.8 ohms so that is 500mA shunt current.
Click to expand...

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.
Click to expand...

You got it - it's about heat. The BMS with 250mA shunts can stay enclosed during balancing. The 500s need to be in the open air or have forced air if enclosed.

Andy
 
Kaplag said:
hey, guys

I've been having trouble getting my charger to charge my cells through a Gary/Fechter Bms. I was having some issues with the bms but now I've successfully charged and balanced them once with a variable transformer.
<snip>
Any advice?
thanks
Click to expand...

What are you seeing, Kaplag? Which version of the G/F BMS are you using?
 
AndyH said:
What are you seeing, Kaplag? Which version of the G/F BMS are you using?
Click to expand...

I think I've got it ok now, The charger was cutting off early. I think what helped was increasing it's charge voltage and also playing with the current cutoff until it was at a point that when the green light on the bms comes on, the green light on the charger also comes on and it turns off.

I'm Using version 2.6. I want to discharge the cell a little more and try another charge up to make sure it's all working ok. I can post what I find. the last few tests, It would charge until shunting began and then the charger would stop. when I plugged it back in and tweaked some things it continued to charge until the green light happened.

Andy, my bms may be inclosed and is running at 500ma. Can I put a heat sink across each set a 4 shunt resistors? I also think I will be able to use the fan in the charger to channel air through where the bms is housed.
 
Hi,

I'm owning a 10A charger. I noticed that after charging (when green led is on and fans are off) the voltage on cells stays quite high : approx 3.62-3.65V /cell (lifepo4)
I was thinking the charger was shutting down at this point but it seems to maintain a floating charge. Is it normal ? I wonder is applying high voltage to cells during hours can harm my cells ? So is it possible to disable this floating charge ?

Jerome
 
Hi guys, sorry to drag up an old thread,

I got a charger From evessemble and I requested it be set for 16S LiPo charging to 4.1v per cell for a total of 66.4 volts.

I eventually got the charger and connected it to the battery and it immediately went to green and I heard the relay click.

How do I adjust it without the battery connected? I'd doesn't want to do anything without the battery!

I think the charger was set for lower voltage and it thinks that even at 60 volts the battery is charged, or else it's broken!
It looks the same as the one in the pic above.

Also what current should I set it to stop charging at?

I appreciate the help guys, I was looking forward to getafew charges without having to break up the pack for my Icharger,

Mark
 
does any one know what the FULL voltage adjustment range is on one of these 400 or 600W chargers ?
could you actually take a charger that was pre-set for say 36v and adjust it internally to give 48v or 66v,
..or back down to 12 v ?
.....without fireing up the soldering iron !

Thanks
 
I have two of the 38V, 8A chargers, and recently converted them for 51V, 6A. No problem adjusting up to 58.4V. Haven't tried going the other direction, though. Just turn the blue multi-turn potentiometer that is located under the fuse.
 
How can these chargers be adjusted without being connected to a battery?

It only switches on if you have a battery connected!
 
Unless your KP charger is vastly different from mine, the charger will produce its maximum voltage when it is plugged in and the switch is turned on. The red and green lights will be go but the fan will not run until the battery is connected. Do you have a voltmeter to measure it?

Measure the voltage without the battery connected. Then when you connect a partly-discharged battery, the green light will go off, the fan will run, the voltage will drop and the charger will go into its constant-current mode. At that point you can adjust the charging current if you want to. Just don't exceed the power rating of the charger. Current multiplied by the max voltage equals max power.

Always connect the battery after plugging in charger and after turning on the charger switch (if it has one). This will prevent a spark and preserve wear on your connectors.
 
I notice that on bmsbattery the picture for the 900W and say the 1200W are the same casing at least. So theoretically the 1200W version is just a 900W with the current limit turned up? I mean correct me if I'm wrong but I would think the main power limit for these things (so long as the voltage doesn't exceed the rating of the caps and stuff) would be the size of the heatsink and the fan? Of course I could be totally wrong. Who knows if they use different components on the board.
 
OK

I have a King Pan charger from EV Assemble. Its (according to the sticker) selotaped to the box a 58.4v 4a unit I bought with a 48v 16ah 16s Headway pack.

My problem is basically the 16ah pack has never given 16ah of capacity the LVC tripped regularly at around 12ah according to my cycle analyst. Now however I'm down to 6-8ah with the LVC and the cells appear to be well out of balance.

I ran battery down until the BMS cut out, the voltage was 51.1v Each cells charge was:
1 3.27v
2 3.27v
3 3.27v
4 3.27v
5 3.27v
6 3.23v
7 3.24v
8 3.27v
9 3.21v
10 3.01v
11 2.65v
12 3.22v
13 3.24v
14 3.27v
15 3.20v
16 3.22v
So it seems cell 11 and possibly 10 are the weak cells.
After charging to 54v the cells are:
1 3.36
2 3.38
3 3.38
3 3.37
4 3.59
5 3.35
7 3.35
8 3.58
9 3.32
10 3.31
11 3.31
12 3.34
13 3.35
14 3.37
15 3.32
16 3.33

What is your advice on the following questions:
1) The pack has never charged to 58.4v hot off charge it 54v, should I adjust the voltage charge of the charger up to 58v?
2) The charger plugged in to the mains with red plus green light lit but without the battery connected to the charger is showing 58v on the charge cable. But when I put it on the battery to charge this sinks to 54v during charging. Does this confirm the charger is set to too low a voltage? If I want it to charge to 58v then what voltage should I adjust it too unloaded? or should I do whilst it is charging?
3)Should I bother or just got for a decent 16s balancing charger? If so any recommendations?
3) Is the battery as I think well out of balance?
4) There is talk of a daughter board that prevents this charger going into battery balance mode. Is this the cause of the imbalance do you think? If so is it easy to modify the charger to be better suited to LIFePO4?
5) Since the battery has had only 55 cycles of charge and is about 9 months old has never had more that 56a max drawn from it, would you say cell 10&11 are stuffed or just well out of balance?

I appreciate any advice I can get.

Dave
 
Hi Hillhater

I happened upon this thread http://endless-sphere.com/forums/viewtopic.php?f=14&t=11718 and it seemed like my situation in a nut shell, so I decided to go ahead and make the modification to my Kingpan charger.

The charger is now cycling between the green light mode where the charge cable has 58.4v and the red light on fan running mode where the charge cable is showing 54v. I am assuming given other members posts the BMS is now in cell balancing mode. The BMS is also displaying 2 red LED's although I don't know what that means as I don't have much detail for the BMS board. At least I hope that's what is happening as after watching it for an hour I got bored and left it to it.

I gather the balancing process can take some hours.

Prior to the removal of the transistor on the daughter board, "the modification", the charger would just stop when the battery was at 54v and would cycle once then stop all together. I think some sort of charger protection was activating requiring the charger to be switched off at the mains before it would restart.

I did consider reducing the voltage of the highest cell, by placing an appropriate load across it for a while until it cam down to the other cells, and charging the low cells to bring them up to the others, but all I have is a model helicopter LIPO charger that can charge 1-5cell LIPOs. I was reluctant to use that as it claims output of 4.2v for a single cell, the Headway 16h cell spec. says charging should be 3.65v. Do you thing that the RC LIPO charger is appropriate or rated too high to bring an individual cell up to the group?

Cheers

Dave
 
daygon said:
I decided to go ahead and make the modification to my Kingpan charger.
,...... I hope that's what is happening as after watching it for an hour I got bored and left it to it.

.Dave
Click to expand...

Thats a brave move ! :shock: ....
...modify your charger , then walk away and leave it running on your pack not really knowing what it is doing ! :shock:

Like i said, i would use the RC charger to INDIVIDUALLY bring the low cells up to the rest. ..monitoring all the time !
 
Hmmm

I did watch the charge rates for an hour and it was pretty consistent in it's behavior and also with other poster experience with BMS in balance mode.

So what do you think about using the LIPO charger outputting 4.2v for a 16ah Headway cell? Too high a charge voltage or not ?

Dave
 
In response to daygon's original post:

1. No
2. This is normal. When you connect a discharged battery to a charger, it'll go into its CC (constant current) mode, the voltage will drop a few volts and the current will be at its maximum value (in your case, 4A). When the the BMS detects that a cell or cells have reached HVC (high voltage cutoff), it'll stop the current flow. At that point your charger should show 58.4V when connected to the battery.

If the cells are unbalanced, the slower cells to charge will not be fully charged. When you remove the charger, the pack voltage will rapidly drop a few volts.

Do not adjust the charger while it is charging. It should be at 58.4 V when NOT charging.

3. Yes. Cell #11 is what caused the BMS to shut off the pack. You may have to replace that cell. You were right to measure the cells at or near LVC; that's the only way to clearly identify a weak cell.

4. See my post on the EP/KP charger thread http://endless-sphere.com/forums/viewtopic.php?f=14&t=11718&p=461172#p461172. Yes, it's easy to make the modification IF your charger has this daughter board.

5. I ran into similar problems with my 38V 15AH pouch batteries after about 70 cycles, and they were rarely discharged more than 50% DOD. I was desperate to have reliable packs for a long, difficult ride coming up, so after testing to find the weak cells in my packs, I scavenged some good cells from my worst pack and used them to repair the other two. Then it took about a dozen cycles of charge/discharge with modified chargers to achieve balance and regain their rated capacity.

Cell #11 is definitely bad. You'll need to fix it and then remeasure at LVC again to see if any other cells are weak also. I found two in one of my batteries and three in the other. As Hillhater recommends, individually charging the weak cells might help, but is unlikely for #11. I tried that with my batteries and it didn't help much.
 
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