No magic smoke, but no $ savings because I played with AC charging.

[ksmithaz1]

I never use 0-100% of my batteries but they are still counting cycles.

Yea, I think mine increment every shift even if very small.

 

[robbob2112]

If my motorcycle sputters to a stop because I ran out of gas, I just reach down and flip the valve over to "Reserve."

The full capacity of ESS or EV is how car you can go until the lights go out or you roll to a stop.
You might choose to stop with 10% ~ 20% remaining then recharge because you get more cycle life and value, but you've got that reserve in case you need it.

And if you forget to flip the switch back when you fill it up then sputter again you feel like an idiot and have to hitchhike or call someone to bring you gas.

Don't ask me how I know this.

I generally only use the top 25% of my battery and top it up everyday. According to the paperwork that came with it that should get me 15 years with only a 10% loss. Deeper discharge means more loss. Higher C rate charge or discharge means lower life.

At least all the paperwork says it... but who has a 15 year old LiFePO4 battery laying around and knows it wasn't abused to check this? Raise your hand high so I can see it over the monitor.

 

[plympton]

At least all the paperwork says it... but who has a 15 year old LiFePO4 battery laying around and knows it wasn't abused to check this? Raise your hand high so I can see it over the monitor.

Had to hunt it down, but this guy! https://marinehowto.com/happy-15th-birthday-to-my-lifepo4-battery/

 

[Brucey]

Had to hunt it down, but this guy! https://marinehowto.com/happy-15th-birthday-to-my-lifepo4-battery/

Those Winston/Thundersky cells are premium priced but certainly seem to have withstood the rest of time

@Daddy Tanuki

 

[Daddy Tanuki]

personally I think that the BMS should be counting the number of watts used and anytime the total number hits the capacity of the cells that should count as one cycle so basically it should be able to calculate the used wattage and even if you recharge before full it should keep the used amount in memory until it resets, so if the cell is good for 10 watts of energy once it uses 10 watts that is one cycle regardless of if it uses 100 watts in one night and gets recharged to full the following morning, or every three days as it uses the 100 watts.

 

[Brucey]

personally I think that the BMS should be counting the number of watts used and anytime the total number hits the capacity of the cells that should count as one cycle so basically it should be able to calculate the used wattage and even if you recharge before full it should keep the used amount in memory until it resets, so if the cell is good for 10 watts of energy once it uses 10 watts that is one cycle regardless of if it uses 100 watts in one night and gets recharged to full the following morning, or every three days as it uses the 100 watts.

in think that's how the Victron smartshunts calculate it:

 

[Daddy Tanuki]

in think that's how the Victron smartshunts calculate it:

View attachment 217884

thats how magnum and bogart do it as well, but the bms's obviously do not or they would tally much closer to the shunt based battery monitors.

 

[automatikdonn]

Not a magic smoke post, but a newbie error I made, hope to educate other newbies.

I went live with Solar and Batteries in November of 23.

I had several thoughts in my head, re batteries.

1 - It's cool to run off batteries
2 - I need to fully cycle batteries, to keep them healthy

1 is correct, 2 is not so much, at least with Lithium Iron Phosphate.

So I ran off batteries as much as possible. When they got low, because December and January solar sucked, I would charge them back up with grid.

Then I run off batteries.

Well, stupid me, neglected to take conversion losses into account, so while it was fun, I wasted $ and my electric bills really didn't change, somewhat due to charging new EVs, but also related to all that back and forth with the batteries.

I really want my batteries for UPS of the house. I have 12 LIfePower4s, connected to my 18 KPV set up for whole home backup. 50% SOC would carry me for more than a day, in case of an outage and no solar.

So that is where I have my settings now, 50% when on grid, let the system do its thing. NO more playing with charging, discharging, percentages, etc.

I have had the direct opposite experience - my bill has went down by 80% doing exactly what you are doing. However during the crappy months I saw no savings. So over the course of the year it works out to about 65% total savings and I am off grid only - no feeding to the grid at all (for now)

 

[D71]

personally I think that the BMS should be counting the number of watts used and anytime the total number hits the capacity of the cells that should count as one cycle so basically it should be able to calculate the used wattage and even if you recharge before full it should keep the used amount in memory until it resets, so if the cell is good for 10 watts of energy once it uses 10 watts that is one cycle regardless of if it uses 100 watts in one night and gets recharged to full the following morning, or every three days as it uses the 100 watts.

You have a valid point. After a year of using my emergency system it has 6 cycles on it for batteries. Notice if it drops below 50% and recharge then logs a cycle. If charge it over and over before then seems to never log next cycle. That 80% to 100% charge part is always the slowest.
Never ran my batteries down below 20%.

Like most want more so …… it is in the works. I feel the ancient - neglected grid will be more problematic in the future. Be nice if new green deal was concerned with upgrading transformers that will be failing in near future. I assure everyone the new transformers will not last as long as the old transformers have lasted.

The replacement transformers will no doubt be chinese. Again they - new replacement transformers won’t last long.

Like OP want batteries - my system as emergency backup. The grid if rebuilt as reliable as it was in days gone by will still be my go to. It - local grid cost me ~$1400 a year. Nothing can beat that when it works properly.