Selecting a solar lithium battery

**Isetech** · 09-Jul-22, 08:10 AM

Lets take a closer look at the questions you should be asking your battery supplier when purchasing a 52 VDC - 100 amp/hr - 5 kwh lithium lifePO4 (not just the sale talk used by most suppliers with check sheet)

We are talking about the same battery a 52VDC - 100 Amp/hr - 5kwh lithium, one of the most common sold at this point.

1/ Is you battery designed for backup or daily use?

2/ What power can the battery sustain for a standard load shedding period and can it sustain this value for multiple power cuts per a single day and for how many days?

3/ Are the cells in the battery "new generation cells" ?

4/ Can the cells in the battery be used for high currents?

5/ Are the cells in the battery repurposed (seconds) or brand new (off the production line) and what grade of cells being used, not all LifePO4 cells are equal

6/ What is the designed life, there is a good chance the replay will be the same as all the batteries 15 years.

7/ What is the cycle life of the battery at 80% DOD, dont get confused with 50% and 100 % ?

8/ What is the C rating of the battery is charged and discharged at 50% and 100 %?

There is a lot more to batteries and I am only scratching the surface. Because this industry is still too new, we will only know the true facts in years to come as the batteries start to fail and warranty claims are put to the test.

Which brings me to a very very important part of your purchase, did person who sold you the battery inform you about the warranty registration, because without it you are a fish out of water flapping your gums trying to get your battery repaired or replaced.

Copied directly from a warranty form

"2.2 It is the duty of the Customer to obtain confirmation from the installer that the product had been duly registered."

This is the important stuff.

5.1 In respect of the Lithium Iron Phosphate (LiFePO4) cells (hereinafter “the Cells”), the duration of
the warranty shall be 10 years or five thousand (5000) cycles (whichever comes first),
commencing on the date of sale.
5.2 For purposes of paragraph 5.1 a single cycle for the BR (Battery Rack) range is defined as a
discharge to maximum 80% depth of discharge of the battery’s capacity at >C/2 (capacity at a 2
hour discharge rate or more) followed by a recharge to 100% state-of-charge at >C/2 (capacity at
a 2 hr recharge rate or more).

Do yourself a favour and make sure you understand who carries the warranty, it is passed on to you or will the person who sold the battery to you handle the claim. If you are responsible for handling the claim, best you try contact the company distributing the batteries in South Africa. Many people think that the batteries are manufactured in SA. I would verify that statement before you purchase. I am yet to find one which doesn't arrive her from the far afar away. They may designed in an office in SA, but actually built here, well show us the production line.

Once again please feel free to set the record straight if any of this information is incorrect. I am trying to find my way through a maze of bullshit.

**Isetech** · 10-Jul-22, 05:53 AM

You need to read the warranty forms, the features and all that sales jargon is just that, sales jargon

Warranty Exclusions & Terms and Conditions:

The battery has a 15 year intended design life, however the battery cells should achieve at least 5 years’ service life or deliver at least 3000 charge, discharge cycles as counted by the BMS, which ever event is achieved first.

however a standard 3 year warranty is provided for the BMS

9. If placed in storage then the ambient temperature should be no higher than 25 degrees Celsius.

24. Any damage to the battery caused by peripheral electrical equipment.
The integrated BMS module is designed to last over 15 years, however a standard 3 year warranty is provided for the BMS and all related probes and sensors.
The operating temperature for the battery is designed to be 0 to 55 degrees Celsius, however it is recommended to keep the battery below 25 degrees Celsius to maximise the design life and life cycle of the battery. The cycle life is negatively affected by temperatures above 25 degrees and cannot be guaranteed if the battery is operated in temperatures exceeding 25 degrees Celsius.

**Isetech** · 10-Jul-22, 06:29 AM

This extended warranty indicates that the cells have a 10 year warranty or 6000 cycles, but also indicated a reduced period for the BMS only 5 years.

So the next question you need to ask : How are the cycles recorded, per charge and discharge no matter how short or only once a full cycle has been reached?

Something else to note it seems all the supplier exclude labour charges and shipping.

Another thing to consider is the total cycles per year.

https://www.sunsynk.org/_files/ugd/50e58b_28402ba46c08406c8eb8e6bd2e141efb.pdf

**Isetech** · 10-Jul-22, 06:32 AM

3.1 In respect of the Lithium Iron Phosphate (LiFePO4) cells (hereinafter “the Cells”), the duration ofthe warranty shall be 10 years or five thousand (5000) cycles (whichever comes first),commencing on the date of sale.

3.2 For purposes of paragraph

3.1 a single cycle for the NG (New Generation) range is defined as adischarge to maximum 80% depth of discharge of the battery’s capacity at >C/10 (capacity at a10 hour discharge rate or more) followed by a recharge to 100% state-of-charge, and a singlecycle for the HC (High Current) range is defined as a discharge to maximum 80% depth ofdischarge of the battery’s capacity at >C/2 (capacity at a 2 hour discharge rate or more) followedby a recharge to 100% state-of-charge at >C/2 (capacity at a 2 hour recharge rate or more).

**Isetech** · 10-Jul-22, 06:48 AM

What would you offer your customer a battery featuring 15 year life span with only a 3 year warranty on the BMS, a 5 year warranty on the cells and 3000 cycle life, which requires different software to remote view, special cables and dip settings etc?

Or would you buy a battery which offers a 10 year warranty and 6000 cycles on the cells, a 5 year warranty on the BMS and links directly to the inverter and communicates without additional software and firmware glitches all on one app.

It was down to the Sunsynk battery and the Blue Nova daily use battery, pretty much matched on price, but it just makes more sense to buy the battery that comes from the same supplier, has a decent warranty and communicates with the inverter.

I think I have just made my decision, it looks like it is going to be the Sunsynk battery. Best I get those payment made so that I can get my demo model setup in my workshop.

It might be a better option to get the customer to transfer the money directly to the supplier so they can benefit if they are VAT registered and I dont have to worry about warranty claims, then can also charge the customer for any callouts and shipping for any warranty claims

Once I know the products work, by then I will be Vat registered again, its a win win.

**Isetech** · 10-Jul-22, 07:06 AM

Would the warranty of the battery not indicate the grade of the battery?

If the cell has a 10 year warranty with 6000 cycles would that indicate a grade A battery compared to one only offering a 5 year warranty with only 3000 cycles being a grade C cell?

From all time I have wasted doing research, I would go with credible data being featured for a 5kwh battery. A battery offering the following:

5 year BMS warranty.

10 year cell warranty or 6000 cycles

Discharge and charge rate of 50 amps continuous and 100 amp max

Limited to 700 cycle per year.

I would say this would be a fair way to compare apples with apples.

If you feel I am way out the park on this, feel free to correct me supported with the technical data and warranty specs, not some bullshit feature for sales.

Done forget to include a technical support contact number for people to contact to verify your information

No matter how good a product in sale pitch, without technical support it is pretty useless.

**Isetech** · 10-Jul-22, 07:28 AM

I should be ready to offer to supply and install products which will carry my personal stamp of approval, within the next 4 months, with a demo unit setup in my workshop to simulate any software or technical queries.

Now to figue out which panels will best suit the inverter.

I have already started installing prewired essential and non essential 3 tier surface and flush DB,s with enough space to add any future EV requirements and automation using devices like the ASC's for geysers, pool timers, security lights or any other automation.

All the automation, an be triggered by the alarm app we install and manual switching.

The alarm system can also trigger the automation using the alarm app or alarm keypad.

Alarm PIRs can also trigger the security light in that specific area and send pre recorded notification to your phone from the camera linked to the PIR.

We also link the 12 VDC equipment like the CCTV, alarm, router and even 12 VDC flood lights to an independent backup systemin case everything else falls or the batteries on the main inverter backup cutout.

**Justloadit** · 11-Jul-22, 06:49 AM

Just a question, with respect to this 10/15 year warranty.
What are the requirements to make the warranty claim? - Original invoice and original packaging, certificate of installation of qualified installer I suppose

Are the companies even going to be in business?

All these claims made in my opinion are lip movement, the proof is in the actions when it goes south.

**Isetech** · 11-Jul-22, 07:40 AM

Originally Posted by Justloadit

Just a question, with respect to this 10/15 year warranty.
What are the requirements to make the warranty claim? - Original invoice and original packaging, certificate of installation of qualified installer I suppose

Are the companies even going to be in business?

All these claims made in my opinion are lip movement, the proof is in the actions when it goes south.

100%, that is the reason I still havent decided which battery yet.

I would love to hear a top 3 batteries in SA, comparing spec's and battery type and grade, new or old generation, the real information not the sales check list and features.

Would you be getting what you pay if you spend R30 k on a battery battery compared to R25K or would a 5 year warranty be a better choice than a 3 year warranty.

Buying light fittings is just as bad, you get a 10 watt flood light with a 1 year warranty and one with a 2 year warranty, why would you pay R100 more for a light with a 2 year warranty, the lights breaks after 6 months and they indicate that there is no warranty because of the power issues in SA

People are desperate and have money to waste, so in most case you can throw any crap at them and get away with it. They whine about the petrol price then go piss R150 000 against the wall on some crap system that not suitable for their application, then expect everyone else to do it right and replace the system as a fraction of the cost.

**Isetech** · 14-Jul-22, 01:59 PM

Here is an example of a company which displays the reality of selecting a lithium battery and the same size and voltage, just different cell grading.

Note!

The warranty period

The cycles at 80% DoD

Daily use or backup.

We are going through an absolute stupid phase again. People going nuts, similar to when a message did the rounds that there was going to shortage.

The same thing happened when load shedding started, people went crazy buying generators, we had container loads of generators arriving, then suddenly the load shedding stopped, those containers arrived and people withdrew their orders and so a lot of people went bang, companies disappeared as fast as they arrived.

Make sure all your orders are paid up front and the money has cleared before you order and pay for the shipment and hope that your container doesnt arrive full of sand.

https://www.bluenova.co.za/rac-power/