I have a Multiplus 12V 2000VA that I plan to use with a 4*100Ah LiFePO4 battery bank in my boat. The manual says that the multiPlus is Lithium compatible but there is no hint to what configuration to use.
Any ideas on were to find this information?
asked
MultiPlus settings for non Victron LiFePO4 batteries
You don't mention the battery brand / type, but as far as I know most LiFePO4 battery cells have about the same voltages.
Only thing you really want to know is: is there a minimum voltage to reacht to make the batteries balance the cells? (should be in the manual)
I'd set low voltage cut-off around 11-12 volt (depending on how much power you draw)
float charge voltage: 13,2-13,5, bulk / absorbtion 13,8- 14 volt.
The battery datasheets/manuals will have the (optimal) charge parameters and instructions on other things that you may have to perform (e.g. manual balancing). If the parameters are different from the default on the multiplus you'll need to reconfigure the multiplus (VEConfig or VRM iirc)
Here’s some answers I got when programming my charger, although I’m using a Phoenix charger and Victron Lithiums. It may help though. Has worked fine for years. Excuse my notes style.
Lithium in general don’t need a charge curve like lead acid.
When charging the voltage will remain quite flat. Due to the very low internal resistantce the current can be large without affecting the voltage much.
When the battery is full ( around 90-95% ) the voltage goes up quickly, so you can stop charging.
Especially with high charge currents there can be a sort overshoot on voltage so setting this at 14.2 its good.
Absorbtion isn’t needed but, as there is a balancing built in the battery which only works on charge voltage, however the absortion period is used to make the battery cells equal. Mostly an hour is enough for this. Do every few months to balance cells.
Q- Do I choose Fixed or adaptive or adaptive + battery safe?
A - Fixed only, as the absorntion doesn’t need calculation, always 1h is perfect.
Q - What about repeated time and interval and max absorption time please?
A - Not needed.
Q - Do I tick or untick stop after excessive bulk and storage mode?
A - Bulk ON, only when not full after 10h is something that can happen depending on the size of the battery charger. In your case 10h x 25A is 250Ah which is less then what needs to be charged , so OFF
A - Storage OFF
We advise 14.2 /13.3 and 1h absorption.
Charge current max 50% of capacity ( for a long life span ).
If a BMV - The charge efficiency setting in the BMV should be set at 98%.
In order to have the synchronisation right the absorbtion voltage is the Vc ( charge threshold ) whilst the tail current should be set at 10%.
The charge voltage setting (Vc) must be close to the absorbtion voltage and the tail current is not relevant so can be set to the maximal level (10%).
The time for the synchronisation trigger can be shorter the 9 min as the battery should be full after a few minutes..
Peukert factor ( for lithium 1.05 ) and the charge efficiancy (for lithium 0.98
The discharge floor is DOD 50% default, so that can be set to DOD 90% with lithium as thats then the empty indication for the "time to go " and percent age calculation.
Note: it follows from that the batteries must be regularly (at least once every three months charged to at least 4 x 3,4 = 13,6 V in order to balance the cells.
If not fully isolated when not in use be aware of any residual drain like bilge pumps etc otherwise batteries can be damaged from over discharge.
Thanks for your help and input. I think that I am beginning to understand how to think regarding the setup.
Regarding manufacturer, I am planing to order directly from factory in China. The cost is app. 250€/ 100Ah + import costs.
