Recent content by toms

The REC BMS drops the current at the end of its bulk charge cycle while the cells balance - then changes to float voltage. Maybe that’s what the charger is trying to achieve?

The wings indicate an overcrimped connection. The risk is that the point where the lug finishes and free strands begin has been squeezed so tightly that it fractures the free strand wires. Coming from an automotive background I have seen lugs shear apart due to over crimping. Probably not...

I have a Victron Phoenix 48/5000 inverter, I’m not sure if they make one suitable for 120V. I didn’t need the charger, and it was cheaper than the Multiplus.

I installed my first LiFePO4 system in 2012. High AIC fusing was well known as a requirement then, as well as fusing between parallel packs, and using pre-charge for arc protection of contactors. It seems in many ways the increased use of YouTube for “learning” has decreased the availability...

Great units, for those that are interested just keep in mind this alone isn’t suitable for a 48V system.

Thanks for sharing, obviously a ton of thought and attention to detail in your build. Some have guessed at your background/tech experience, i’d love to know what background resulted in this system.

Its fine to use as long as you keep it away from surfaces that need to be conductors. ie: use conductive antioxidant between battery and terminal, then coat outside of terminal with dielectric grease to prevent moisture damage.

If the system voltage has been high that should show up in the diagnostic trouble codes of the body module as a history code. That will be separate to the failed component codes.

I imagine one battery 2P4S (two cells in parallel, connected together four in series), the other is just four in series. If that is the case then they are OK to parallel as long as the chemistry is the same (eg both LiFePO4)

Yes, it will work fine as long as they are the same chemistry and series cell count.

Nobody really knows for sure yet, as simulations of <.5C current cycles have to be done in real time. Above that it is literally a different chemical reaction in the cell. The first cells I know that have been constantly gently cycled (3.0 - 3.45V) at maximum 0.5C were commissioned in 2007...

I’m completely off grid in South Australia and have been for over 12 years. I started off with a SMA Sunny Island, which is now CEC approved as a grid tie hybrid. Compatible with SMA Sunnyboy grid tie inverters, and most commonly available batteries. I recently purchased a second hand grid...

I remember seeing a lot of those cells on the market around seven years ago. When I dug a bit deeper they were all coming from cell brokers that were known to deal with factory seconds and refurbished cells. Fully charge that battery, then subject it to the highest load you can and measure...

My LiFePO4 battery is over 12 years old now. It often goes all winter without being fully charged or activating balancing. I wouldn’t worry about it if I were you.

With my LiFePO4 that doesn’t have inverter comms I set my BMS cell LVD to 3.0V, and my inverter LBCO to 50.0V This seems very conservative, but I regularly run that system to inverter shutdown and get over 80% of battery capacity, so I see no reason to stretch the cells any further.