Battery use for best longevity

[williet]

Hi All

 

I have a Deye inverter 8kw with 12 x 370w panels and a 2.4 kw Dyness battery.

I use the panels to reduce the cost of my Crypto mining farm and have two circuits one non - critical and one critical. 

Critical runs lights and plug points in lounge and rooms. and draw is generally 200 -300w.

 

I have the Dyness as a backup for loadshedding and believe that is enough. At the moment I do not discharge and reading on the net I cannot get a clear answer

Do you need to cycle (discharge) the battery daily to keep it in good health or is it fine just floating and keeping the charge up ?

 

Would really love some input/recommendations on this.

[Buyeye]

General rule for lithium batteries is cycling is good for your pocket and for the batteries.

[williet]

5 minutes ago, Buyeye said:

General rule for lithium batteries is cycling is good for your pocket and for the batteries.

Thanks a mil!

[Speedster]

2 hours ago, williet said:

Thanks a mil!

Once a week to 50% should do very nicely.

[Buyeye]

That is vague terrible advice. Why once a week? Why 50%? 

 

Guys you have to actually read before commenting. It's a lithium battery you can cycle it everyday down to 80%(I mean you can use 80% with 20% remaining)and still get minimum 6000 cycles.

 

Cycling it everyday will give an idea of how far you are from self sufficient,  you could be 2 batteries from self sufficient depending on your load in the evening. 

Edited April 9, 2021 by Buyeye

[Yellow Measure]

@williet, if I were you I would direct the question to the manufacturer, who is responsible for the batteries' warranty.

[GreenFields]

Just a half-thought. Will your battery only ever be supplying the critical loads of 200-300W? It should be no issue to drain the battery every evening for 7-10 hours to supply the critical loads. But will it ever be supplying the crypto mining rig in the evenings in the circumstances where you have no solar power, but no power outage?

If so, I would just look at the power demand of the mining rig compared to the power that the single battery can supply. You don't say how much power the rig draws, but the panel capacity of 4440W to supply the crypto rig is probably more than the single battery can match.

[Sc00bs]

Dyness is recommended discharge at 0.5C and burst at 1c, on a 2.4kw/hr battery that gives you a recommended continuous discharge rate of of 1.2Kw.

Most mining rig power supplies are +2400Watts so that isn't going to work.

 

 

 

[Speedster]

4 hours ago, Buyeye said:

That is vague terrible advice. Why once a week? Why 50%? 

 

Guys you have to actually read before commenting. It's a lithium battery you can cycle it everyday down to 80%(I mean you can use 80% with 20% remaining)and still get minimum 6000 cycles.

 

Cycling it everyday will give an idea of how far you are from self sufficient,  you could be 2 batteries from self sufficient depending on your load in the evening. 

Did you even read OPs question?

[Speedster]

3 hours ago, GreenFields said:

Just a half-thought. Will your battery only ever be supplying the critical loads of 200-300W? It should be no issue to drain the battery every evening for 7-10 hours to supply the critical loads. But will it ever be supplying the crypto mining rig in the evenings in the circumstances where you have no solar power, but no power outage?

If so, I would just look at the power demand of the mining rig compared to the power that the single battery can supply. You don't say how much power the rig draws, but the panel capacity of 4440W to supply the crypto rig is probably more than the single battery can match.

 

Edited April 9, 2021 by Speedster

[FixAMess]

Generally, For best longevity, for LiPo chemistry,  never discharge to Lower than 20% State of charge (some can go to 90% DoD)or charge above 90% and keep at 60% for long term storage...Otherwise charge, discharge as much as you like.

Heat and high charge 90-100% kills the battery...Saying that my pylontechs always charge to 100% as per the BMS.

Also keep charge, discharge rates (Amps),DoD, max voltage etc  in line with battery specs.

Go to batteryuniversity.com to read further.

Edited April 9, 2021 by FixAMess

[Sc00bs]

11 hours ago, Speedster said:

Did you even read OPs question?

Fair point, got sidetracked on the C rating on the battery 

[williet]

On 2021/04/09 at 4:43 PM, GreenFields said:

Just a half-thought. Will your battery only ever be supplying the critical loads of 200-300W? It should be no issue to drain the battery every evening for 7-10 hours to supply the critical loads. But will it ever be supplying the crypto mining rig in the evenings in the circumstances where you have no solar power, but no power outage?

If so, I would just look at the power demand of the mining rig compared to the power that the single battery can supply. You don't say how much power the rig draws, but the panel capacity of 4440W to supply the crypto rig is probably more than the single battery can match.

Crypto mining on nonessential grid as I export PV to CT and no futher excess Solar is pushed to my mining equipment. I must admit I need more panels but have run out on my north Northwest  facing roof. So I will have to add panels on the East facing roof. just not sure if it is worth it. 

[Bernardf]

Slightly off topic, but related to crypto mining. If the only thing on battery backup is the crypto mining rig, it could be justified to deduct the depreciation of the inverter and battery from the income declared to SARS, because the power system's costs relate directly to the generation of the taxable income, therefore reducing your income tax payable. But if the whole house is on backup, it is a bit of a grey area what portion of the expenses you could deduct. What are you guys' thoughts?

[williet]

3 minutes ago, Bernardf said:

Slightly off topic, but related to crypto mining. If the only thing on battery backup is the crypto mining rig, it could be justified to deduct the depreciation of the inverter and battery from the income declared to SARS, because the power system's costs relate directly to the generation of the taxable income, therefore reducing your income tax payable. But if the whole house is on backup, it is a bit of a grey area what portion of the expenses you could deduct. What are you guys' thoughts?

Very simple. U have a separate dedicated circuit with a usage meter on there that you use during declaration 

btw using Crypto rigs on battery not feasible but solar definitely.