spudgun avatar image
spudgun asked

PV, Wind, Lead Acid and Lithium

Have a 24V system with Lead acid batteries. PV and Wind do the charging but the batteries are now 8 years old and losing capacity (not losing enough to throw them out). Looking to add 2 x Victron Lithium LiFeP04 24V, 200Ah batteries. The PV charging isn't a problem as Victron MPPT's will look after that. The problem that I'm unsure on is how the Lithium batteries will work with the Wind Turbine. I would like to use the wind turbine to charge the Lithium batteries and when they are charged I will use a heavy duty relay to switch the turbine back to the Lead Acid.

The wind turbine has it's own controller with the voltage settings as in the attached image. The wind turbine can output 90A and when the Lead Acid reaches 28.5V a 1Kw dumpload is switched on. A second dumpload is switched on at 28.7. There are also some AC dump loads that are switched on at higher voltages.

The Lithium battery can charge up to 28.8V but recommended is 28.4V. If I use a MiniBMS to control the heavy duty relay to switch the wind turbine from Lithium to Lead Acid and vice versa and leave the wind turbine controller voltage settings as they are then I'm thinking that I should be OK?

Thanks for any help or suggestions.

Lithium Battery
2 |3000

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1 Answer
ben avatar image
ben answered ·

I don’t know how your turbine works, but unless it has protection built in I would be concerned about a BMS disconnect (or your proposed relay) unloading it suddenly.

Another option you might consider is leaving it set up to charge the lead acid, the way you have it now, and use a battery-to-battery charger to dial in precise charging for your lithium bank. In essence you would use the lead acid as a buffer.

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