Rolls Battery Engineering - The Importance of Absorption Time

The importance and proper calculation & programming of Absorption Time settings for lead-acid battery models.

[@ifyoucantjointhem]

Is Steve still working with Surrette? I love listening to him talk about batteries, he has a real passion and ive watched all his videos many times over 🤙

[@reginaldpotts2037]

Glad you emphasized 'actual' charge current when calculating the absorption time using your formula. I have two 4 KW arrays, one East and the other South charging through two Tristar 60A MPPT controllers and I first calculated 1000Ah/ 120A x .42 = 3.5 hrs but after 3 months noticed several cells were low on SG even after a full absorp. At this time I noticed even on sunny days the max charge I was 'actually' getting at any time was 70A so recalculated absorp time 1000Ah/ 70A x .42 = 6 hours. After re-programming the Tristars i'm pleased to say all the cells have recovered after 2 months of the longer absorp period. What I really need is another 60A array facing East to get a quicker bulk phase and let the South facing array take care of the long absorb.

[@RollsBatteryEngineering]

Yes, too many think that they have a 60 or 80 controller, and that means that they are getting 60 or 80 amps from the controller... Just doesn't happen in the "real world"...

[@chitinakennicott7045]

Good info. Got some Rolls AGM batteries this summer for my off grid cabin in Alaska. Still learning.

[@electricengineer624]

Excellent bro man, amazing content. Thanks abunch

[@kasapis6]

Thanks for the information , can you please do sometime on lithium battery's

[@RollsBatteryEngineering]

I have to ask... what you what on Lithium Battereis?

[@RollsBatteryEngineering]

While being a new "Tech"... They are just so boring, as the Battery Mgmt System really does all the work... Most Lithiums with a decent BMS all you do is supply voltage and current and the BMS does all the work.

[@Dnnap]

@@RollsBatteryEngineering Yes, I agree not much info can be supplied that isn't already on the spec sheets found on the Rolls website other than maybe describing how the BMS operates when the cells are in a parallel string. How are the individual BMS on each cell connected together and will they communicate with say a Magnum Me-Arc remote controller?

[@RollsBatteryEngineering]

@@Dnnap The BMS needs access to the internal firmware of the product that is connected... There are two types of communication. Open Loop and Closed Loop. Right now there are no comms options for the Magnum product so you would have to use Open Loops comms... which means there is no shared information between the battery and the Magnum inverter. Now with Outback, Schneider, and many other companies, they have a comms software in place... This is closed loop, this means that our battery will control the inverter and tell it when to and when not to charge. Currently, this is not something that is available with Magnum due to their communication problems. There will be more indepth webinars in the near future, but this information is available in our manuals on our webpage, this was an introductory done back in August.