Which 48 volt lithium battery is the best

[Isetech]

This seems to be a more difficult task than I could have imagined.

What do you consider when choosing a backup battery for your inverter or solar system?

1/ The type of cells used?

2/ The type of BMS used?

3/ Temperature monitoring?

3/ How the battery temperature is managed during charge and discharge cycles?

4/ Compatibility with the inverter you choose.

5/ Charge and discharge rate, this seems to be trick question, normal, max or advisable

6/ Life cycles? how many time it can be charged and discharged

7/ Designed life expectancy, 10 or 20 years?

8/ Firmware and software compatibility with inverters?

9/ Type of BMS of communication?

10/ parallel connections, how many etc?

Those days of talking about a the thickness of the lead cells or the battery case base and battery amperage only is a thing of the past.

Batteries have become complex little power houses.

what I thought would be a simple question, who makes the best bang for your buck with all the frills.

Which battery is the best and why? Can anyone supply credible data comparing lithium batteries with lithium batteries.

I bought a blue nova battery and cut it up to see what it looks like inside. It was assembled better than I expected.

Maybe I should buy each battery sold in SA and strip it, check things like the QR on the cells to verify the information on the data sheet, do capacity checks and show everyone how they are built.

[Isetech]

I do realise my warranty would no longer be valid I am not sure that there would be any legal implications, I see guys doing it on youtube all the time.

[Isetech]

Lets start with the cells.

BYD prismatic cells seem to be the preferred ones. They advertise -

The cell has a larger surface area than regular prismatic cells, allowing for better heat dissipation. The cells also allow for slow heat release, lower heat generation, high starting temperature for exothermic reactions, and do not release oxygen during thermal runaway.


It looks like I will be spending the next few weeks doing research into lithium batteries.

[Isetech]

I still cant find someone to answer what I thought would be a very simple question, how to determine the C rating of a battery in manner which can be used to compare information published on data sheets.

[Isetech]

I see Sunsynk have 2 types of batteries


CATL Battery SSLB1

BYD Battery

[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.

[Justloadit]

BU-402: What Is C-rate?

The C is usually provided by the battery manufacturer.

[Isetech]

The protective device controls the C rate?

If one battery has the same capacity and cell type, then the manufacturer would control the charge and discharge rate protection?

Buying a 0.5C or 1C battery cycle life would perform the same and the life cycle would be the same if both charged and discharged at the same rate at the same temperature?

The 0.5C would have internal protection to prevent the battery being "hammered" with high charge and discharge rates, hence a higher life cycle advertised?

A 1C battery protection would be toned down, allowing the battery to be "hammered" thus reducing the life cycle?

All just question it seems impossible to find out from any of the suppliers. I have tried contacting numerous outlets and manufacturers, either "we are experiencing high call volumes please be patient" or I have left messages and nobody returns my calls. It seems the call centre are manned by operators with a spec sheet with just enough info to answer most common questions, most of us know already.

I will just keep scratching until I understand.


"While lead- and nickel-based batteries can be discharged at a high rate, the protection circuit prevents the Li-ion Energy Cell from discharging above 1C. The Power Cell with nickel, manganese and/or phosphate active material can tolerate discharge rates of up to 10C and the current threshold is set higher accordingly."

[Isetech]

From my experience installing batteries, my first choice is an IP 56 Susnsynk battery.

The reasons:

10 year warranty

All the battery data is visible on the inverter screen, including cycles.

They are IP 65 rated , ideal for the coast were I do most installations.

[Isetech]

I think its time to buy a few different batteries and open them, check if they have QR codes on the cells, then see how they are assembled.

I have already popped open a blue nova battery ( yip warranty out the window), I am going to have to cut the plastic off, then get a blow torch to remove the resin.

Any legal experts know if it will be ok for me to post pics of the battery in pieces? I see the youtubers do it all the time, so I am assuming there will be no issues?