Why does my voltage rise to 15.1v ?

[Two on Tour]

To start with mains has nothing to with it we are measuring 12v DC.

You rather missed the point I was making there.

 

[autorouter]

This meant that when getting a reading of 12.7 at the panel, and thinking that the leisure batteries were fully charged, in fact they were not quite, and probably only reading 12.4 - 12.5v. I must admit I was initially a bit surprised at the voltage drop, and have to assume it is down to cable diameter and length between the CBE distribution unit, and the panel.

Have you actually measured the voltage at the panel, with a meter? I'd also be surprised if there was such a big voltage drop, maybe the panel meter is just inaccurate. Especially if it's still inaccurate when the amps value is very low.

 

[autorouter]

I thought there was a pot on the pcb that allows you to adjust the calibration, they won't mention it as it is not supposed to be accessible to the user.

In theory there should be two pots. one to adjust the zero, and one to adjust the value at a high level, about 15 to 20V. Or it might be a software option, pots are sooo last century.

 

[andy63]

I have a Victron Mppt 75/15 connected ,now , to an Yuasa 85 AH battery fed from 2 x 100w panels. (previous battery was a 120Ah lead acid )
I changed the previous mppt controller,which was a reasonable chinese one, because it kept showing 15,1v when charging?
I noticed the other day that when fully in the sun the victron is showing the same? just checking it now & it has dropped to 14.9v & according to the flashing lights is on absorption. I've never noticed it before at 15,1v on this controller & was wondering why it goes that high? Is there a problem.

Hi gus... just looking at your post and the first thing that comes to mind when you mention high voltages is obviously to confirm what you are seeing is right.. if it is have you looked at the setting options to see the time the controller may apply what I think is called an equalisation charge.. that could hike the voltage..and have you a temp sense facility connected...
Andy..

 

[JockandRita]

I thought there was a pot on the pcb that allows you to adjust the calibration, they won't mention it as it is not supposed to be accessible to the user.

What, as in flower, jam, or tea?

Yes, I know, I'm on my way..........

Have you actually measured the voltage at the panel, with a meter? I'd also be surprised if there was such a big voltage drop, maybe the panel meter is just inaccurate. Especially if it's still inaccurate when the amps value is very low.

No, not yet. Inaccuracy was my thought, if it wasn't a voltage drop, hence me looking in the manual for re calibration.

In theory there should be two pots. one to adjust the zero, and one to adjust the value at a high level, about 15 to 20V. Or it might be a software option, pots are sooo last century.

I wouldn't know, but it's one of these panels, with nothing in the program menu which relates to volts/amps readout calibration. A decade and a half away maybe, but certainly not last century.

<Broken link removed>

Thanks for the replies guys.

Cheers,

Jock.

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[Lenny HB]

My mate had his CBE panel adjusted by a friend as it read high, that was in a new Carthago.

 

[autorouter]

I wouldn't know, but it's one of these panels, with nothing in the program menu which relates to volts/amps readout calibration. A decade and a half away maybe, but certainly not last century.

If it's not a menu option (possibly a hidden menu with password access) then a panel like that might have a connection used in the manufacturing process to calibrate it - a couple of metallic contacts that a special programmer is connected to, that does the calibration using something like a serial bus or I2C. Not much help, I know, it's difficult to reverse-engineer.

 

[Raul]

Hi gus... just looking at your post and the first thing that comes to mind when you mention high voltages is obviously to confirm what you are seeing is right.. if it is have you looked at the setting options to see the time the controller may apply what I think is called an equalisation charge.. that could hike the voltage..and have you a temp sense facility connected...
Andy..

I did mentioned this in post 15. The temp compensation is on as default 16mv. Not a big increase, despite not having a external temp sense, it will use the charger temp built in, and do the temp compensation. 15mv per deg form 25degC is not a big increase, unles is minus 20C in the van.

 

[andy63]

I did mentioned this in post 15.

I just read the initial post by gus.. I'm afraid I'm guilty of not reading the whole thread...sorry..
Just posted my thoughts but no idea if it's applicable to the unit in question..
Can the equalisation profile cause such a problem.. I've never experienced it ..just read about it ..but I believe it is programmable and was wondering if he had looked into that..
Andy

 

[Raul]

You are perfectly right Andy, yes it can cause this unwanted high voltage if the equalisation settings are not appropriate, hence me pointing out to disable such function.
Equalisation should only be active if you have accessible electrolyte and can replace the lost water. It’s a controlled overcharge to force the weak cells to catch up. And should only be done manually, after you took acid samples, and found the difference between cells, is greater than 30 points, 1,270 -1,240.

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[autorouter]

Can the equalisation profile cause such a problem.. I've never experienced it ..just read about it ..but I believe it is programmable and was wondering if he had looked into that..

Yes, it can happen. When my EBL charger failed, I bought a budget smart charger to replace it. It kept going into equalisation mode, about 16V, and I couldn't find any way to disable it. I eventually bought a Victron IP65 15A smart charger, which works fine.

 

[andy63]

And should only be done manually, a

Thats an issue then.. cause I'm sure on one of my controllers it's defaulte setting is once every 28 days for the equalisation charge..and you have the ability to alter it to every day....
Thats on lead acid...so it has never been an issue for me running a lithium profile..
Andy

 

[KimSteve]

I have a Victron Mppt 75/15 connected ,now , to an Yuasa 85 AH battery fed from 2 x 100w panels. (previous battery was a 120Ah lead acid )
I changed the previous mppt controller,which was a reasonable chinese one, because it kept showing 15,1v when charging?
I noticed the other day that when fully in the sun the victron is showing the same? just checking it now & it has dropped to 14.9v & according to the flashing lights is on absorption. I've never noticed it before at 15,1v on this controller & was wondering why it goes that high? Is there a problem.

it seems high as it's recommended that 14.3? is the max charge to battery to protect it from damage. Possible controller fault?

 

[autorouter]

it seems high as it's recommended that 14.3? is the max charge to battery to protect it from damage. Possible controller fault?

The OP solved his problem, it was a faulty display reading high, the battery voltage was actually about 14.2V, about the recommended voltage as you say. See post #7. The rest is a discussion of some of the questions raised.

 

[the1andonly]

I recently read something, maybe on here, where someone was getting incorrect readings on a multimeter. Turned out needed a new battery in the meter, worth a look just in case.

Multimeter

A Fluke multimeter would be a bit of an overkill. Handy for someone with several uses for it. Just for the motorhome the simpler ones mentioned are great for us.

www.motorhomefun.co.uk

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