Selecting a solar lithium battery

[BOBBEJAANKLIMDIEBERG]

Sunsynk SUNBAT 5.32 kWh battery claims the following warranty conditions: 6000 Cycles @ 80% DOD / 25ºC / 0.5C, 60% EOL.
Does this mean that under ideal laboratory conditions, they measures 6000 cycles under these specific parameters, at a constant rate of discharge of 50% (2.66 kW)?
Does it mean that every time I discharge it faster than at 0.5C, the number of 'guaranteed' cycles drops further below 6000?

Please correct me if I am making any wrong conclusions.

I am aware it is all relative because actual battery discharge rate and depth varies every day, within the limits of the BMS.
However I am trying to compare this battery to the HUBBLE AM-5, which has an even more vague warranty of 'unlimited' cycles for 10 years.
Different manufacturers also state different End Of Life capacity percentages, which makes it even harder to compare a Sunsynk 5.32 with a Hubble-AM5 5.12 or with Volta Stage 1 (5.12 kWh) battery.

From the discharge curves supplied in the VOLTA STAGE 1 guarantee, I conclude the following is true for all batteries, even within the limits set by the BMS:
1.Higher discharge rates greatly reduces long term life (number of cycles).
2.Greater discharge depth up to 80% DOD reduces long term life.
3. Higher ambient temperatures means the battery's own working temperature rises more rapidly to a level that reduces the battery 'effectiveness'. This leads to the battery being 'laboured' more, leading to a shorter long term life.

Neither Sunsynk nor Hubble AM-5 supplied discharge curves.

[Isetech]

To give you an idea, I downloaded the data for a Sunsynk 5.3 kwh battery, the battery was installed mid November 2022. It indicates that it has cycled 43 times. Lets say 50 cycles per 6 months, that would mean 100 cycles per year.

A quick calculation 6000 cycles/ 100 per year = 60 years.

I have 8 (left) Makita 18 VDC batteries, used on site literally everyday. The batteries are old (cant say the exact date of purchase) years. Had then tested, no faults, SOH 100% 80 % charged at the time of test. Cycles ranging between 450 and 500, which indicated that we are alternating the batteires often.

2 other batteries purchased at around the same time, used with a makita tool which is not star rated and ran flat, both indicated faulty when I attempted to charge them. I stripped then and recovered the cells, still being used for site torches. I should have done the bridge charge, because I beleive it was a BMS cutout issue (you live and learn). I think the manager at Makita was even surprised at how long the batteires have lasted.

I dont understand why the HIlti 36 VDC batteries dont last, I have both 22 VDC and 36 VDC Hilti batteires, the 22 VDC we used everday, the 36 VDC batteries have very few cycles yet they no longer charge, I took them to the hilti store, they indicated they dont ahve a tester for the batteires. Dont try strip a Hilti battery. I am going to rather take it as is, to Hilti and let them dispose of them.

[Isetech]

I dont beleive the cells are going to be the issue, I beleive the BMS will fail long before the cells, I could be wrong, only time will tell.

[GCE]

Sunsynk SUNBAT 5.32 kWh battery claims the following warranty conditions: 6000 Cycles @ 80% DOD / 25ºC / 0.5C, 60% EOL.
Does this mean that under ideal laboratory conditions, they measures 6000 cycles under these specific parameters, at a constant rate of discharge of 50% (2.66 kW)?
Does it mean that every time I discharge it faster than at 0.5C, the number of 'guaranteed' cycles drops further below 6000?

Please correct me if I am making any wrong conclusions.

I am aware it is all relative because actual battery discharge rate and depth varies every day, within the limits of the BMS.
However I am trying to compare this battery to the HUBBLE AM-5, which has an even more vague warranty of 'unlimited' cycles for 10 years.
Different manufacturers also state different End Of Life capacity percentages, which makes it even harder to compare a Sunsynk 5.32 with a Hubble-AM5 5.12 or with Volta Stage 1 (5.12 kWh) battery.

From the discharge curves supplied in the VOLTA STAGE 1 guarantee, I conclude the following is true for all batteries, even within the limits set by the BMS:
1.Higher discharge rates greatly reduces long term life (number of cycles).
2.Greater discharge depth up to 80% DOD reduces long term life.
3. Higher ambient temperatures means the battery's own working temperature rises more rapidly to a level that reduces the battery 'effectiveness'. This leads to the battery being 'laboured' more, leading to a shorter long term life.

Neither Sunsynk nor Hubble AM-5 supplied discharge curves.

You are correct - The warranty conditions pretty much make it impossible to be able to claim

Besides what you mention above there is also the if battery has been short circuit then it falls away , if battery has overload trips it falls away .

There is a battery that the warranty says only if the battery performs below 50% does the possible warranty kick in

So batteries are a minefield and you need to check and rather purchase batteries where the manufacturers have been around the block a couple of times

[jennyzhang]

What is C rating?
A C rating is a rating of how quickly a battery can release energy. This rating is combined with the capacity of the battery to determine the maximum discharge.

This is very important when you are considering battery selection for your solar electric system. Especially if you have some high power heating type appliances, they tend to pull a lot of current from the battery side the moment they are turned on.

How do you calculate the C rating?
Let’s take the EVE 3.2V 280Ah LFP battery cell as an example.


In the specification, the charge/discharge current is 1C and the maximum charge/discharge current pulse is 2C (3s).

So,
Continuous charge/discharge current = 280Ah x 1C = 280A.

Maximum charge/discharge pulse current = 280Ah x 2C = 560A.

[HGTesla]

When selecting solar panels, the key focus is on the power of the solar cells. Generally, the power of a solar panel is directly proportional to the area of the solar photovoltaic (PV) cells. The area of the solar PV cells does not necessarily equate to the area of the solar panel's packaging because some solar panels may be large but have wide gaps between individual solar cells. In such cases, the solar panel's power output may not necessarily be high.

[HGTesla]

When selecting solar lithium batteries, it is important to determine the battery capacity required for your system to meet the energy needs of your home or business, ensuring the efficient and reliable operation of your solar energy system. You should also understand the battery's cycle life, which refers to the number of charge and discharge cycles it can undergo, typically measured in charge-discharge cycles. A higher cycle life typically implies a longer battery lifespan.