Selecting a solar lithium battery

[Isetech]

I am trying to figue out how one manufacturer sells a battery with a 0.5C and another a 1C, but they are both 5 kwh and both use BYD cells?

From the little knowledge I have acquired about lithium batteries, the only way I can see that you could achieve a higher C rating is if you have a cooling system in place.

The one has increased the warranty to 10 years and the other has reduced the cycles to 3000 but indicates a 15 year life design.

How do you cut through all the bullshit and get the apples to compare apples with apples or 5 kwh with 5 kwh?

Deep cycle batteries had thicker platers and bases, what makes a lithium battery a good battery, what a the key point to identify when selecting a good quality lithium battery?

If I have ever had to deal with an industry that tries to baffle customers with bullshit, this solar industry certainly takes the cake with the cherry on top.

What do we know about lithium batteries, the harder they work the lower the cycle life. Can we agree that if a battery is advertised at 1C with 3000 cycles, then a 0.5 C battery advertised at 0.5C at 6000 cycles, would also be capable of 1C rating if advertised at a max of 100 amps (for a 100 amp hour battery) if we reduce the cycles to 3000 cycles?

[Isetech]

I hear chatter about, lithium batteries being sold which are not off the production line, how could you verify if the cells in your battery pack are off the production line or if they repurposed?

A QR code on the cells maybe, considering a seal would be fitted to all batteries, how would you verify the origin of the cells used in your battery?

This could become a huge problem as older batteries are decommissioned.

[Justloadit]

There are also many poor quality and incorrectly marked cells.
If they sound cheap then there is something wrong!
Keep to the known name brands, they will not compromise their quality for a cheap battery, the investment is just too high.

[Isetech]

Its seems the challenge to get credible information out of battery manufacturers and suppliers is a lot more difficult than I thought.

You get to listen to a lot of "please hold your call is important to us" or "please hold why I redirect your call" or some tune while the technical person you are speaking to has to find a technical person who can relay the information to the technical person who has very basic technical knowledge.

Now I know why we are sitting with really badly designed R150 000.00 solar systems

[Isetech]

Cycle life: determined by the depth

Sunsynk: 6000 Cycles @ 80% DOD

Hubble: 3000 cycles @ 100% DOD and 6000 cycles @50% DOD

Other than the 10 year warranty if used in combination with the inverter, the sunsynk just doesn't seem to stand achance against the Hubble.

Even the price, I can get a Hubble battery R2000 cheaper than the Sunsynk.

The question: will the Hubble battery communicate with the new Sunsynk data logger and software?

[Isetech]

Then I found this hidden away in small print at the bottom of the Sunsynk data sheet.

1. Test conditions: 100% depth of discharge (DoD), 0.2C rate charge & discharge at 25℃

2. Charge/discharge derating occurs when the operating temperature from -10℃ to 5 ℃.& 45 ℃ to 55 ℃.3. Condition apply.

Refer to SUN-BATT-5.12 Warranty Letter

[Isetech]

As I keep scratching and become more knowledgeable about this topic, the more I realise how much bullshit there is being rattled out there

[Isetech]

This has become quite a challenge.

Too many variables, too little technical support.

It seems everyone has the downloaded check sheet, anything past the check list you are on your own.

[Isetech]

Why is selecting the correct battery so important? Load shedding, as the levels of load shedding go up, so the demand for higher discharge rate and fast charging.

Why lead acid batteries just dont cut it anymore, they may seem like a cheaper viable option, but as soon as you throw in a stage 4 or above schedule, those batteries become lead weights.

Waiting 10 hours for a 100 amp/hr to charge at the recommended 10% charge rate is going to leave you sitting in the dark with candles. Yes they are more affordable and practical for stage 1 load shedding, anything past that , with cable theft and sub station fires and explosions, or a couples days of cloudy weather if you are fortunate enough to have solar panels, you will soon be wishing you had put a little more thought into the system.

[Isetech]

Today we learnt a little more.

I founds a battery which looked like it had exactly the same product information, 52VDC-100amp/hr and even 5.12 kwh written on the battery. The batteries look the same, and even the the same manufacturer.

So makes the one different from the other?

The voltage - no

The kwh rating - no

The amp/hr rating - no

The BMS - no

The temperature rating - no

Ok so what makes the one R5000 more expensive than the other.

The cells look the same, they are both lithium ion lifePO4 so what makes one better than the other, apparently the cells.

the questions you need to be asking:

How long is the battery warranty, it should be at least 10 years.

The cycle life of the battery under daily use, not just as a backup battery, it should be at least 6000 cycles at 80 % DOD.

What grading of life PO4 cells are being used, and seems to be the big question. what grade lifePO 4 cells are being used.

It seems any battery with a 3000 life cycle can be rated at 1C with a 5 year or less warranty.

If you spending around R25000 on a lithium battery, with a 5 year warranty and 3000 cycles the cells could be B or C
grade cells.

The sad part we will only know in the next 5 to 10 years.

As for battery support, I am sure those who have tried to get more technical data will know what a joke that has become.

I have been reading technical data and features advertised and comparing to the actual data sheets downloaded from the manufacturer, it gets quite interesting.

It seems lithium batteries and Nike shoes have a lot in common