# Zivan NG5 Voltage Adjustment



## GizmoEV (Nov 28, 2009)

ElectriCar said:


> There are actually two pots at that location and the adjustment screws are about 1/4" apart. If you're looking at the two pots, it's the one located furthest from the LED hole or the closest one to the Zivan label.


Assuming it is like the NG1 and NG3 the other pot is labeled "I" and is the current calibration screw. The other pot, labeled "U", is for voltage calibration. When turning either one it changes the voltage/current of all of the set points, not just the terminating voltage or current.

Given how these pots behave it looks like the desired profile is programmed in and then the pots are adjusted until the output matches the desired values.


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## ElectriCar (Jun 15, 2008)

Gizmo let me run this by you. I've noticed after adjusting the voltage that the charge current is now higher than before early in the charging process yet is lower than before when nearing the end. Ie the CA will read 5.2Kw early in the charge then with 20+ Ah to go, it will have dropped to 4.3Kw. Initially I believe it would charge around 4.8-4.9Kw until the last Ah or two. With it cutting back so early, it's taking me a good bit longer to charge. 

Any ideas on how I might adjust the current pot? I've played with it but I just don't have a feel for how the two interact thus how to adjust it or if I need to do a series of adjustments to get it right.


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## GizmoEV (Nov 28, 2009)

Interesting. I didn't look at the power into the batteries just the current, and that was after initially setting my ending voltage so I don't have data on what my NG1 did. I have since tweaked the voltage down a little as I have observed that with a 3.465vpc ending voltage the pack sat a little higher than 3.4vpc after a 12+hour sit. I'm now at 3.455vpc ending voltage but I haven't played with the current pot.

What I did was to watch my Kill-a-watt meter and adjust the power from the wall until it was pulling a little over 1000W (~1100-1200 IIRC) and not much over 12A. My CA says the current into the pack is ~14.5A which is ~1.5A over the sticker they put on the charger when I got it reprogrammed.

Remember I have a 200Ah pack so the current is quite low as far as C rate is concerned. As such, I don't see current cutting back until around 5 Ah are left to reach full.

Did you adjust the voltage up or down? If down that would explain the lower current near the end. I'm a bit puzzled about the beginning current.


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## ElectriCar (Jun 15, 2008)

I turned it down. I might try and adjust them both again and see if I can straighten it out. I'm also thinking about adding another charger or trying to use a DC drive to get some quick charging.


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## GizmoEV (Nov 28, 2009)

It is nice that the Zivan chargers are isolated. It makes multiple parallel chargers a breeze.

I do notice that my NG3 cuts back current sooner than my NG1 but I figured that was for two reasons. One is that the NG3 cranks out ~40A. The other is that I charge through a 20' long cable between the charger and the battery pack. Due to the voltage drop the charger thinks the pack voltage is higher than it really is. The NG1 only has about 8' of cable to go through.


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