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Pretty Clear, would like degrees F with C or a little chart at the end. The point about storing at 50%C is interesting.
Thanks for keeping this simple but not skipping the fundamental distinction between "calendar aging" and "cycle capacity loss". I was aware of both but not in a way that would have allowed me to distinguish between the two as you have done. I was also not aware that the cycle capacity loss was lowest at 35 degC while aging was twice as fast compared to 25degC.
I like the multi-dimensional table although I'm not convinced a graphic might not have been better. One thing that still confuses me is what does SOC means on the left column. Is this cyclic depth of discharge?
Philtao
Philtao
Thanks for the feedback. Good idea for the graph - it will require 3 graphs as a single 3D graph will be confusing. I will try and post an update if I can get something meaningful.

SOC corresponds to the average State Of Charge of the cells. It has an important impact for calendar ageing.
For example cycling the battery regularly between 60% and 100% soc would roughly correspond to an average soc of 80 %. That's why it is better to cycle the battery through its full capacity (within reason!) to lower the average soc when the installation is in full use (absolutely avoid float).
When the installation is in "storage mode" for a long time with low power usage (example: only a fridge and some safety equipment / lighting) it is better to cycle between for example 30% and 60% soc and do a full charge every 30 to 45 days (that's where an intelligent BMS can help ;-), but lowering the voltage of the solar regulator (13.2v?) will also avoid keeping the battery full all the time - it will just do micro charges every day and I do not know if that is good or not? )
Good overview PDF of Calendar Aging vs Cycle Aging. Addresses different strategies for a few climates/use cases. Temperature, SOC, are emphasized as factors in battery degradation. Useful resource that highlights the benefits of thermally managing your cells.
Philtao
Philtao
Thanks for the feedback. It feels good to know that the time and effort to prepare this is useful to others.
I appreciate the info, but I don't love how the "download" is just a link to your personal website where you promote your wares for sale. This site would be awful if more companies were adding links and generating "content" this way.
This helpful 'resource' which promises to present info about how to extend the life of your batteries does so by telling you how the TaoBMS system's features can do the job. This kind of seems like an undercover advertisement.
Philtao
Philtao
I agree with you that I failed to set the reader's expectations properly. I have edited the description to make it clear that I also explain how the features of the BMS can help extend the life of a battery (I think there are only 3 highlighted sentences that mention the BMS).
I will also replace the link with a PDF. Thanks for the feedback, we are all learning...
These charts seem to take into account voltage loss only and not ampacity. For a 2000 wattt inverter, the charts recommend 2 AWG or smaller wire for shorter runs, but with the 155 amps an inverter could pull at these wattages, 2 AWG is not rated for this.

If the inverter goes to a low voltage cutoff of 10 volts, the same wire could see 200 amps of current, making these recommendations way to small.

In my Experience, inverter runs are so short that usually voltage loss is not as much of a problem, if at all, compared to making sure not to exceed wire ampacity.
Q
Quantum Thread
I don't know. Renogy quoted me the same information the chart gave.
It a good article covering technical topic of pre-charge circuit, why need arises, fundamental education, valuable resource. Thank you.
Philtao
Philtao
Thanks for your encouragement.
Nice overview: But it seems direktly from TOA or do they take it: https://www.taoperf.com/2021/06/16/bms-comparison-chart/
And it's only 12V Variant. Would be great to get this for 24/48V BMS too.
Philtao
Philtao
thank you for the review and your comments. I confirm that this is done by TAO Performance based on data that is available on each BMS. I asked the manufacturers and distributors to send me correction or additional information they would like me to include, but nothing specific received... maybe telling me that it is not too far from reality.
Some BMS have not yet been included as specific data is hard to find.
Which 24/48V BMS would you like to see included?
This has been so tremendously helpful for planning my system, thank you! Curious about why "# of days to recharge while under load" is a user input. How am I determining the answer to this question? Shouldn't this spreadsheet be able to tell me that?
FilterGuy
FilterGuy
>Curious about why "# of days to recharge while under load" is a user input.
> How am I determining the answer to this question?
> Shouldn't this spreadsheet be able to tell me that?
It is asking how quickly the user wants the system to recharge from fully drained and then uses it as an input to determine solar panel sizing. Some users will want just one or two days, others might be willing to wait more days to fully charge.
The alternative is to ask the user for Solar Panel size and then calculate the number of days it will take to recharge, but that would kinda defeat one of the purposes of the spreadsheet.
A failure to understand Peukert's Law. It has nothing to do with degraded performance due to age or cycles. It is only concerned with "effective" capacity depending on discharge rate (the higher the rate of discharge, the lower the effective capacity)
Thank you for sharing valuable information, Is it possible to parallel a 2p16s with 1p16s?
and if one of the group of different Ah capacity

With Regards
Wow, Such great information! Do not attempt to install a PV solar system, inverter, battery backup, etc., without reading all 4 parts.

I made it my mission today to thoroughly read, study and digest all four parts of Grounding Made Simpler. As the author recommends I began with Part one and took them in order comparing and studying the drawings along with the descriptions, further researching anything that wasn't sure about. It was so worth it. I doubt a video will ever be made that even comes close to the depths this written series has in clarifying this topic of electrical grounding. As I said, it took me a full day to read and digest this, but then I'm pretty thick. Still, I can only imagine the time it took FilterGuy to organize, write, illustrate, and publish these papers. Many, many thanks, it is such a gift for the those of us that need this knowledge.

To FilterGuy: I'm rebuilding a 29' Airstream travel trailer. An 800W PV array and a large 24V LiFePO4 battery bank are two of the big additions I'm incorporating. I had to tear the trailer all the way down to the frame so I'm also completely rewiring the trailer electrical, but I do plan on restoring the shore AC power to 120V and 30A, more seems unnecessary since I'm building it for boondocking and I'll have the hybrid inverter and a 24V battery bank with 560Ahs. I've been thinking a lot about, and searching for answers for the proper / safe way to ground everything. I'll feel so much more confidence now about making my solar charge controller and hybrid inverter selections. Admittedly, I'm a serious researcher and I take working with electricity very seriously. Up until now the majority of my experience has been basic residential split phase wiring, so, it's been necessary to learn a great deal considering PV and LiFePO4. DIY SPF, has been a godsend and your articles and papers are a perfect compliment to Will's videos and the great thread and Resourse shares by others! If you have any suggestions of information I should pursue I will gratefully receive it.
Thanks,
Pete
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