Old Magnum MS2812 and new Lithiums

[Richpatty]

As some of you may know, I am in the process of upgrading to Battleborn lithiums. I have an older (2017) magnum MS 2812 charger/inverter. For those of you who have Magnum inverters (without a built in lithium setting) what setting do you use? I have heard you can use AGM2, but was wondering if custom was a better option.
Thoughts?

Thanks
Rich

 

[Joe Hogan]

We have used a Magnum 3012 Hybrid inverter using custom settings. Battleborn or your supplier should give you the appropriate charging settings for the inverter. Our settings for our LifeBlue battery packs are probably different from the Battleborn settings.


The appropriate settings are discussed by Battleborn here Charging LiFePO4 Batteries

 

[Richpatty]

Thanks Joe. And although they give the settings (Charge voltages- 14.4 absorb/bulk and 13.6 float) there is no specific info on the Magnum units. I was looking for some real world info and experience from folks who have used lithiums with the older magnum charger. I am probably over analyzing things, but it would not be the first time….

Rich

 

[Joe Hogan]

We charge LiFeO4 packs with a Magnum 3012? Settings very close to those specified by Battlebirn recommendation.

You can find the method to set your Magnum in the user manual. Magnum MS2812 Manuals | ManualsLib

 

[Richpatty]

The manual does not cover lithium... I have reached out to Magnum and I will see what their take on it is.

Just looking for experienced opinions and what others have seen and done.
Thanks.

 

[Joe Hogan]

 

[Rob180]

There will been some differing opinions on this, and slightly different settings are not "wrong". I run the Magnum inverter and Lithium batteries. I am also a master electrician and long time RV'er. Below are the settings I use, have tweaked over time and recommend:

Absorb Time: 2hr. for every 100Ah of battery capacity
Charge Profile (Battery Type): Custom
Absorb: 14.4V
Float: 13.4V
Equalize: 14.4V
Charge Rate: 100%
Final Charge: Silent
Rebulk: 13.2V

 

[Richpatty]

Thanks Rob. I appreciate the additional info which matches up well with Battleborn.

The absorb time would probably vary depending on how many amps you are feeding into the batteries…

What did you set your LBCO to?

My other thought was being able to charge based on SOC to keep the batteries at around 80% as I am told lithiums are not happy sitting at 100% like LA batteries are. (I would charge to 100% when needed) Has anyone done this?

I am also thinking of adding a battery cutoff to the 12v loads, completely isolating the lithiums when not in use (I.e. in between trips). That way I would not need to leave the RV plugged in. My only concern would be the chassis batteries, although I could put them on a trickle charger separately….

Thoughts?

 

[Rob180]

Remember this is only the max absorb time. I don't have my LBCO recorded here at work, (I will check my programming), I know I've played with it. It'll probably be lower than you would ever want to take your batteries in order to prevent a cutout on the voltage drop associated with a high instantaneous load. The rebulk is at 13.2V which roughly equates to 70%, so it'll cycle between that and 14.4V. There is merit to holding the peak charge capacity down from a lifespan standpoint, I've never been willing to sacrifice the operational capacity however.