Help! Am I missing something?

[Benjahmin]

I have two batteries and chargers.
Both chargers read 41.7v at output and charge my batteries to 41.6-41.65v
I'm not sure if this is balancing the cells, so I thought I would try and turn up the o/p voltage to 42v.
I opened the YZPower charger but couldn't see a pot (photo). Is this a preset charger?
My other charger is a different make and I need to augment my screwdriver set to get it open.

 

[vfr400]

Before changing anything, how do you know that your meter is calibrated to give the correct result?

 

[Nealh]

Charger voltage is fixed.

 

[RossG]

Bit of an odd design, note how the heat sink top left had to be bent to allow for clearance of the transformer which meant that diode or whatever had to be bent in turn.
I'd be inclined to stick a 1k - 10k Pot across the resistor situated under the two electrolytics on the right and adjust.

 

[Benjahmin]

Before changing anything, how do you know that your meter is calibrated to give the correct result?

Well, that was my thought as both batteries and chargers give the same reading. However, I've just had the wifes Big Bear battery back from Jimmy. Charged that and checked it and it gave a full 42v on the same meter.
Haven't got anything to calibrate the meter against.
I do have an Avometer that I use for work and that gives the same reading, so I'm assuming they're near enough.

 

[Benjahmin]

Bit of an odd design, note how the heat sink top left had to be bent to allow for clearance of the transformer which meant that diode or whatever had to be bent in turn.
I'd be inclined to stick a 1k - 10k Pot across the resistor situated under the two electrolytics on the right and adjust.

Yeh, it's a cheapy. I'm hoping the other charger will be better - when I get it open.
My days of mucking about with circuit boards are long gone in the days of Practical Electronics - remember that?

 

[Nealh]

If you need a charger with adjustment then a Meanwell will suit from the HG range.

 

[RossG]

Yeh, it's a cheapy. I'm hoping the other charger will be better - when I get it open.
My days of mucking about with circuit boards are long gone in the days of Practical Electronics - remember that?

Ah yes good old PE...many happy electrocutions

 

[Benjahmin]

I finally got into my other charger, an altogether more substanrial 4A device with the brand name HighPower.
I found the output pot and started to adjust the voltage. I've turned it up about 0.15v.
The cheap TIS meter read the adjusted output as 41.8v but the Avo meter read it as 42.08. I'm going to assume the Avo is the more accurate reading and that the TIS is between 0.2-0.3v out of whack. Not much error when looking for a 230v live but could be crucial in this application.
Time will tell if my range increases from better balanced batteries.