Loadshedding affordable battery setup?

leon.davibe said:
Reading the post and yes so far it is doing a great job of not getting to technical or just keep it in a way of explaining that makes sense often with too much info a person can get lost

Some constructive criticism
The cycles

one part that nobody mentions is that when they talk about cycles on lithium

the claim is that after said cycles you would still be left with 80% capacity if you had a 5kw battery you would now essentially have a 4kw battery but still usable
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Thanks. I'm trying to avoid getting into the weeds... This is aimed at laymen.

The thing is, some batteries will state 500 cycles to 80% capacity but they did not mention the DOD that they used with these tests and others will state 2000 cycles at 80% DOD but they do not mention the capacity after the 2000 cycles. I'm trying to be as broad and factual as I can.
 
Park@82 said:
Ill be using this part "LFP are also often marketed as "lead acid replacements" as their voltage is similar to lead acid." but I am not saying that people can use lead acid chargers because I am still not 100% certain about how pulsing would affect them...
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Just say 3 stage charger will work.
 
Park@82 said:
hey @wingnut771

I asked chatrgpt to "combine the following into one coherent paragraph: Note that the life expectancy in terms of cycles can be affected by how deep you discharge a battery. The less deeply you discharge it, the more cycles you can expect to get from them. For this reason, it is a good idea to make sure that the power station that you opt for has more watt hours (Wh) of available power than the amount you would be using, so that you don't deplete it all the way to 0% before recharging it. With lithium batteries it is a good idea to aim to have around 20% battery left after you have used it. It would also be good practice not to charge it all the way to 100% but that may be too cumbersome for most users, and I won't discuss that here. This is more applicable to NCM than LFP because LFP has way more cycles.

It gave me this:

When considering the life expectancy of a battery in terms of cycles, it's important to keep in mind that the depth of discharge can have an impact. The less deeply a battery is discharged, the more cycles can be expected from it. To ensure a longer lifespan, it's a good idea to select a power station with more watt hours of available power than what you typically use, so that you avoid completely depleting it before recharging. With lithium batteries, it's recommended to aim for having around 20% battery left after use. While it's also good practice not to charge the battery all the way to 100% (when dealing with lithium, lead acid needs to be 100% charged), this may be inconvenient for most users, and it's not discussed here. This advice is especially relevant to NCM batteries, as LFP batteries have a significantly higher number of cycles.

Seems better. Thoughts?
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Is easier on the eye lol

I would add in the part in bold.
 
leon.davibe said:
By living a normal lifestyle on a battery that is just enough ah for your needs

ie i cycle about 80dod on 7.5kwh
In 4hrs stint

So can just imagine someone with a 5kw can easily do it if lifestyle isn't adjusted for load shedding
especially with stage 6
Without panels ie only battery backup
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Sure, then you cycle 3 times a day. What's the problem?
 
Park@82 said:
Thanks. I'm trying to avoid getting into the weeds... This is aimed at laymen.

The thing is, some batteries will state 500 cycles to 80% capacity but they did not mention the DOD that they used with these tests and others will state 2000 cycles at 80% DOD but they do not mention the capacity after the 2000 cycles. I'm trying to be as broad and factual as I can.
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Oooh and then there is also the Class A,B or C vs 1st and Second life rabbit hole.

EG: https://evreporter.com/lithium-ion-cells-a-grade-vs-b-grade/
 
Park@82 said:
Ill be using this part "LFP are also often marketed as "lead acid replacements" as their voltage is similar to lead acid." but I am not saying that people can use lead acid chargers because I am still not 100% certain about how pulsing would affect them...
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imo
It's all about the voltage

Lithium can accept varying amps no problem

As long as voltage isn't over the 3.65v per cell ideally. And 3.75 recommended max by many cells spec sheets

Though the bms would happily cut the charging off

I would not use it long term as if the bms ever fails recipe for disaster

ie if you quickly want to top up a lithium i would do it without stress

But would not connect and forget it
 
wingnut771 said:
Sure, then you cycle 3 times a day. What's the problem?
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It's not a problem

The problem is a blanket statement of 10 years to deplete the 3000cycles

But yea that's common sense and nut picking sorry
 
Park@82 said:
Thanks. I'm trying to avoid getting into the weeds... This is aimed at laymen.

The thing is, some batteries will state 500 cycles to 80% capacity but they did not mention the DOD that they used with these tests and others will state 2000 cycles at 80% DOD but they do not mention the capacity after the 2000 cycles. I'm trying to be as broad and factual as I can.
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Yea from what i have seen most try and use the 80% but some don't to fudge the numbers

ie to have the same cycles as another manufacturer

But the dod of 70% is somewhere in the small print
 
AlphaJohn said:
Not once its build no, you can test for it when you have individual cell's and see how they hold V under high load.

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Sure, that is the only way to know is to do your own tests. If they fail then you just hope for the best if the supplier will sort it out.

I guess you learn which suppliers are more trustworthy than others.

YMMV
 
so how many extension cords are everyone using? It's making me nuts at the moment with the cables running all over the house
 
wingnut771 said:
Sure, that is the only way to know is to do your own tests. If they fail then you just hope for the best if the supplier will sort it out.

I guess you learn which suppliers are more trustworthy than others.

YMMV
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Thats why its better to stick with Name brands ie: "Hubble" than some "Secure Battery" brand.

Not saying Hubble is legit as I have seen negative reports on them but far less than say CFE.
 
imo this only matters for diy batteries, that guy is gonna find the weeds himself

Manufacturers will match cells
To limit warranty claims
 
AlphaJohn said:
Thats why its better to stick with Name brands ie: "Hubble" than some "Secure Battery" brand.

Not saying Hubble is legit as I have seen negative reports on them but far less than say CFE.
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I would be comfortable with any brand with a warranty.
 
wingnut771 said:
Is easier on the eye lol

I would add in the part in bold.
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I don't know if a person should mention it

But if you do the 20-80 bms will most likely not do any balancing
As you may not meet balance voltage criteria

So from time to time could do a full charge to allow the pack to balance internally

Won't add my vitriol about the pathetic balance current and explain why i think it's better to always fully charge here
 
leon.davibe said:
I don't know if a person should mention it

But if you do the 20-80 bms will most likely not do any balancing
As you may not meet balance voltage criteria

So from time to time could do a full charge to allow the pack to balance internally

Won't add my vitriol about the pathetic balance current and explain why i think it's better to always fully charge here
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Also a non issue imho.
 
wingnut771 said:
Also a non issue imho.
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You don't have enough data/statistics to say that

Cells drift =fact

If you don't exceed 3.4-3.45v per cell on certain balancers they don't balance and balancing at a lower voltage is problematic for obvious reasons

So if you do 20-80
The shunt will tell you that you are in that range

If one cell drifts apart it can be 10% or even lower

ie that cell gets overworked
And you only noticed that you have lost capacity once you dip below the 60% capacity that you actually use

By that time the cell is toast

Sure if you look at the battery regularly it should show an alarm

On cell low voltage when you get that one or more cells drifted low enough
And can then charge to try and balance the cells if you don't or it's in a position that you cannot see the lights, you will happily abuse cells and be none the wiser
 
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