New batteries and monitor install questions.

BUFFALO · 02-09-2022, 12:13 AM

I have installed 4 new Lifeline GPL24T batteries and a Victron BMV-712 monitor.
Trying to get it set up properly and reading quite a bit of info on the monitor settings.

I'm slightly confused on the settings and how it relates to the 100% state of charge. I see lots of people have issues with the monitor resetting to 100% even though they think the batteries are not quite full. I would like to avoid this.

I see that the monitor uses the charged voltage, tail current and time limit to reset to 100%. My questions lie in this area.

Does anyone have experience and knowledge with the 712 to help me out getting it set up properly?

Some details of my very simple electrical system;
Lifeline GPL24T 80 ah deep cycle AGM batteries. 4 of them.
Victron BMV-712
Powermax converter PMBC-100 3 stage converter/charger
No solar
No onboard charging. Planning to install a Victron 12/12/30 Orion Smart dc/dc charger soon.

Typcial use case will be, plug in to ac power and use the Powermax to charge the batteries while at home.
Go camp for a few, or more days. Use the dc/dc charger when driving between spots.
Monitor the batteries via the 712 and then plug back in at home.

Settings in the 712 as of now;
Battery capacity, 320 ah
Charged voltage, 13.2v
Discharge floor, 50%
Tail current, 3%. 9.6amps
Charged detection time, 10 minutes
Peukert exponent, 1.25
Charge efficiency factor, 95%
Battery starts synchronized, off

The rest are all the defaults.

It also looks like the Powermax is not reducing voltage. It is currently showing, 14.61V and 1.42A.
This seems like it should be in float mode at this input current.
Lifeline says .5% of capacity which is 1.6 amps should register float charge. 13.2-13.8V.
So not sure if there is an issue with the charger or the monitor at this point. Would assume the charger. Why it's not adjusting, I don't know.

If anybody has some information or experience with any of these components or a similar type of setup, please chime in and let me know your thoughts.

Thanks.

Scalf77 · 02-09-2022, 06:15 AM

The first place I would look at is the charger, although with the parameters you have shown the BMV should have probably synchronized. The key parameters being voltage and tail current.

Did you check to see that you were ever above the tail current setting. You might need to discharge the batteries a bit and start a new charge cycle. At this time it looks like neither your charger nor the BMV have met the requirements for a charge cycle to be complete.

The Peukurt value for lifeline is 1.12 volts, although I wouldn't expect to be the cause.

-greg

BUFFALO · 02-09-2022, 08:57 AM

Thanks Greg.

How long can I run the charger waiting on it to settle in voltage before I begin doing any damage to the batteries?

I don’t think the tail current was ever above the minimum in this instance.
Speaking to that, 3% is 9.6 amps. Doesn’t that seem like a lot to still be charging and be considered full?

Also the charged voltage at 13.2. If it stays up at 14.6, that’s still above and the parameter is met, or the monitor needs to see right at 13.2?

I haven’t run the batteries down yet and am just trying to get a baseline and see what it’s going to look like and then manually synchronize.

I will change the Peukurt value thanks!

Scalf77 · 02-09-2022, 10:39 AM

So the criteria for the monitor to synchronize is

"In case of a 12 V battery, the BMV resets to ‘fully charged’ when the
following ‘charged parameters’ are met: the voltage exceeds 13.2 V and
simultaneously the (tail-) charge current is less than 4.0 % of the total
battery capacity (e.g. 8 A for a 200 Ah battery) during 3 minutes."

The charge voltage needs to be at or slightly above float, but it doesn't have to be your 13.2 setting. Basic charging profile is bulk, which is generally considered to be "Constant Current", so in the case of your charger 100 Amps. Ss the battery charges it will reach the absorption voltage which in the case of your charger should be 14.3 to 14.4. Once that condition is met, we enter the absorption phase. This is constant voltage, with a controlled current. It is this phase that you will see the current start to drop and reach the tail current. Many chargers will let you set the tail current or at least have some settings that you can control.

Sadly your charger has limited data about there settings, obviously it doesn't know anything about the battery bank you have installed, so the only data it is going off of, is the size of the charger. I would expect the tail current for it's crossing to float would be slightly higher than your input. Don't believe that would be a big issue or your problem.

So when I asked about the current being above the inputted tail current, I mean the charger should have been above (in this case 100 amps, if the battery was pretty close to charged it would then be in absorption. So we would expect to see the current start to drop and reach the tail current setting.

Possibly the charger has a power supply mode? I would disconnect charger, and discharge the battery at least 20 to 30 percent. At this point it probably wouldn't hurt to manually synchronize, so you can track discharge.

It might be a good time to look at a more programable charger (I would try to see If I could match the DC to DC controller you are planning on installing). The 100 amp charge is a bit oversized for the size of your battery bank.

-greg

BUFFALO · 02-09-2022, 02:09 PM

Thanks for taking the time to assist.

I think I am mostly following all that you are saying.

I also think the Powermax may only be a power supply and not a charger. This may be the issue. It is an older unit.

So maybe the 3 voltages it indicates can be set but not self adjusted while being used.
I will take a closer look at it.

What would you recommend as a properly sized charger? As far as amp output.
And any specific charger recommendations for a setup like mine?

BCam · 02-10-2022, 10:29 AM

Quote:

Originally Posted by BUFFALO

Thanks for taking the time to assist.

I think I am mostly following all that you are saying.

I also think the Powermax may only be a power supply and not a charger. This may be the issue. It is an older unit.

So maybe the 3 voltages it indicates can be set but not self adjusted while being used.
I will take a closer look at it.

What would you recommend as a properly sized charger? As far as amp output.
And any specific charger recommendations for a setup like mine?

Here's a link to the Powermax's manual. There's a switch to control whether or not it uses 3-stage charging or constant voltage charging. It appears that the fixed voltage charging level is adjustable but the 3-stage charging is fixed at 14.6V/13.6V/13.2V. If yours isn't reducing the voltage, it's probably switched to the constant voltage mode.

https://powermaxconverters.com/wp-co...anual-2018.pdf

Scalf77 · 02-10-2022, 12:12 PM

Quote:

Originally Posted by BCam

If yours isn't reducing the voltage, it's probably switched to the constant voltage mode.

https://powermaxconverters.com/wp-co...anual-2018.pdf

Exactly, that would be my first thought.

65 amps would be great but you could go between 60 to 80 amp charger.

-greg

BUFFALO · 02-10-2022, 02:03 PM

Thanks for linking to the manual.
Unfortunately mine is an older unit that does not have a display or more importantly, the switches to adjust the settings.
I emailed Powermax and got a pretty prompt reply;

“On these older units unless an adjustable dial has been fitted to the unit the voltage on them cannot be changed. They have a standard 3 stage charger with the following outputs 14.6/13.8/13.2V. The voltage will drop from 14.6V to the 2nd stage after 15 mins.

Hope this helps”

So, I will verify what is going on and go from there…
I may start researching chargers here pretty soon.

Scalf77 · 02-10-2022, 03:56 PM

I have found the KISAE AC1260 Abso 60A to be a pretty reasonably priced charger, it can also charge a secondary battery (like your starter). I have paired this with their KISAE DMT1250 Abso 50A DC-DC Battery Charger that will pretty much cover your charging options. The DMT 1250 combines a DC to DC with solar. I am pretty sure I drawings of this setup on the forum.
-greg

BUFFALO · 02-16-2022, 06:46 PM

Thanks Greg.
I do like that charger you mentioned.
Do you think the 40a version would be okay for my bank size? I know it just might take a little longer to get a full charge. I think that would be okay.
Since I already have the Victron battery monitor, is there any benefit to staying with that brand for a charger? As far as the separate units being able to communicate with each other.