Using victron inverter/generator to charge diy battery first time

[josephc]

I'm thinking of building a battery pack using purchased prismatic cells to supplement the sok battery bank I already have. I do not want to purchase a lithium plug in charger for the first charge if I don't have to. Hopefully I can build the bank and give it an initial charge using my victron charge circuit with a generator. It is already configured to lithium settings. Is there a reason not to do this? I would disconnect my current bank and connect the new battery. Then fire up the generator and let the victron do a full charge. Set the new and old batteries up in parallel and go back to living.

 

[sunshine_eggo]

Fundamentally, no problem with that approach at all, except the issue will be balance. 99.9999% chance your cells will not be to top balanced, and they will trigger over-voltage protection preventing full charge unless you top balance them.

Set absorption to 3.45V/cell, fixed absorption period of 8 hours, float at 3.40V/cell.

Never charge without the BMS in place. Set BMS to balance above 3.40V and when dV is 20mV or more.

If you use something like a DALY or Overkill with passive balancing, it may take months to sort out. If you use something with active balancing like a JK, then it can likely be resolved in days.

Worth a read, beginning to end:

Top Balancing LiFePo4 Cells using a low cost benchtop power supply.

To get the paper, click on the orange at the top of this page. This is a tutorial with detailed steps on how I top-balance my LiFePO4 Cells using a low-cost benchtop power supply. To get the tutorial, click on the orange "Download" button...

diysolarforum.com

 

[josephc]

Thank you for the advice. I read the balancing doc and it was very helpful and easy to understand.

 

[josephc]

I purchased a wanptek power supply, gps3010d, I followed the initial charge instructions but I can't get the voltage settings to change. I spin the knob the display changes but after a few seconds it defaults back to the original voltage. Not sure what I'm doing wrong. This is with the leads disconnected

 

[sunshine_eggo]

Please immediately disconnect the power supply and re-read the guide especially as it pertains to how and when you set your voltage.

 

[josephc]

Please immediately disconnect the power supply and re-read the guide especially as it pertains to how and when you set your voltage.

With the power supply disconnected, set the voltage to your target pack voltage.
For a 12 V system: 3.65 X 4=14.6 Volts. (Or 14.4 V for 3.6v top balance)
For a 24 V system: 3.65 X 8 = 29.2 Volts. (Or 28.8 V for 3.6v top balance)
For a 48 V system: 3.65 X 16 = 58.4V. (Or 57.6V for 3.6V top balance)


This is the relevant section of the balancing guide. That is how I'm trying to set the voltage. It is probably just user error on my part. The manual is of no use. The knob has a click function that moves the adjustment between the digits of the voltage. I spin it till it reads 29.2 and after about three seconds it just switches back to 25.0

Thanks

 

[sunshine_eggo]

With the power supply disconnected, set the voltage to your target pack voltage.

So you're making these adjustments as above?

 

[josephc]

So you're making these adjustments as above?

Yes that is correct

 

[sunshine_eggo]

The display reports measured voltage.

When setting the dial and nothing is connected, there is no load, so it should the set voltage is the same as the measured voltage.

If you then connect the leads to the battery, the display will drop to show battery voltage.

If you are saying you adjusted the voltage, and it changes to a different value, and the leads are never connected to the battery, that sounds like a malfunction or odd behavior.

 

[josephc]

The display reports measured voltage.

When setting the dial and nothing is connected, there is no load, so it should the set voltage is the same as the measured voltage.

If you then connect the leads to the battery, the display will drop to show battery voltage.

If you are saying you adjusted the voltage, and it changes to a different value, and the leads are never connected to the battery, that sounds like a malfunction or odd behavior.

Looks like I got a bum steer. The voltage maxes at 25v any setting above that goes back to 25. Now I have to start the return process.

 

[sunshine_eggo]

Looks like I got a bum steer. The voltage maxes at 25v any setting above that goes back to 25. Now I have to start the return process.

Once set to 29V, and it reverts back to 25, have you attempted to charge?

It might be an odd behavior though it still functions.

Some of the LFP batteries seem to display 12.9V after charge protection engages, but as soon as a load is applied, it jumps up to an actual 13.4-13.5V.

 

[josephc]

Just to be sure I checked the 230/120 volt on the rear of the supply. It was set to 230. That was the problem. Charging the bats now!

Sadly my 200ah bank is probably not gonna be up to the charging task and I'll probably have to fire up the generator. Plus we are headed into an overcast week. I'm just too excited to wait.