itareanlnotani
Executive Member
Due to Eskom's unreliability, I think its time for me to go completely offgrid.
I'm going be bringing in Lithium Iron Phosphate Batteries from China to do so.
Pricing will be similar to premium Lead Acid pricing in SA.
I've talked about this a few times in a couple of threads, and a few people have expressed interest in doing a group buy.
Before we start -
There are some caveats if you want to buy and use these batteries.
1) You need a charger that explicitly supports Lithium.
Voltages for Lithium are higher than for Lead Acid, and Lithium charging is a lot different to Lead Acid charging.
Lithium is a lot easier to charge than lead acid, as you just feed in till you reach the required voltage, then stop charging.
There is no peukerts law/curve to worry about, and Lithium is a lot safer to deal with - no hydrogen / explosion issues.
2) You'll need a disconnect relay for low voltage and high voltage to protect the batteries.
Lithium will be damaged if you discharge too low, and will be damaged if you charge too high. Adding extra protection to prevent this is excellent insurance to prevent chargers killing the batteries.
Example disconnect circuit - http://zeva.com.au/index.php?product=101
(also needs relays)
3) Lithium batteries need to be balanced.
I will be ordering battery balancing circuits for the batteries, this will be an extra cost.
Guesstimate roughly 5% of the battery cost, exact pricing to be determined still.
Balancing is essentially making sure that all the batteries in a pack get charged equally. Some batteries will charge faster, some slower. Balancing circuits ensure that all batteries reach the same charge.
Example balancers - http://www.ev-power.com.au/-Thundersky-Battery-Balancing-System-.html
4) I will need to know what voltage you require for charge/discharge.
The CALB Batteries I'm pricing, are 3.2V / 100Ah or 3.2V / 180Ah each.
You'll need to buy enough batteries for your KW required, and inverter charge rate.
48V inverters will require a minimum of 16 batteries.
36V inverters will require a minimum of 12 batteries.
24V inverters will require a minimum of 8 batteries.
12V inverters will require a minimum of 4 batteries.
5) I will need to know what sort of KW size you require.
Lithium Iron Phosphate works best at 20% - 80% usage from the data sheet DoD curves.
This means that you will only have 60% usable capacity if you wish to treat the batteries nicely, and have them last.
You can go higher or lower, but you will reduce cycles. 60%* appears to be the best bang for buck on the lifetime / usage according to my calculations.
This effectively means that you will need to buy 160% of the capacity you actually need.
This compares nicely to Lead Acid where best lifespan is in the 30% range, (and you need 300% of capacity required).
To cut a long explanation short - if you need 10KW of Lithium storage, you will need 16KW of battery*
*You can probably go another 10% extra to 15-85% for 70% usable capacity without too much issue, but I need to test in real life before I can recommend that.
6) I am not offering a plug and play solution (yet).
I am ordering batteries + copper connectors + battery balancers for the pack size you / I require.
- This is not an off the shelf solution.
- You will need to understand how to integrate these with your existing system.
- You will need Items #1, #3, and I strongly recommend #2 above
(I will be sourcing these as part of my install)
- You'll probably need monitoring for voltage, temp etc. eg a Victron BMS or similar product.
- If it works well, I will be looking at bringing in a complete solution (charger / batteries / bms), but this won't be until I have my own system running properly.
7) Shipping will be to Cape Town
You will need to arrange your own collection/ shipping from Cape Town if you are in other parts of the country, and are still interested, despite all my dire warnings above!
Timeframe will be for arrival mid-late August.
I strongly suggest that you read the ENTIRE thread here - https://forums.energymatters.com.au/solar-wind-gear/topic6186.html as it discusses the issues you'll be dealing with. Bonus points if you can guess who I am in the thread there
This is a good overview also - http://www.pbase.com/mainecruising/lifepo4_on_boats
If you have read the above, understand and are still interested, then reply in the thread below with an indication of voltage and wattage required.
FAQ
Why only 100Ah / 180Ah?
Purely due to price. Higher capacity is substantially more at current pricing.
What charger do I need?
Suitable chargers are ones that can change the charge voltage, float values etc to appropriate values.
As a rule of thumb, the more expensive chargers support this, the cheaper ones do not.
eg Victron, Outback..
What batteries are they?
CALB 100Ah or 180Ah in blue plastic shell packaging.
http://en.calb.cn/product/show/?id-627 CALB 100Ah
http://en.calb.cn/product/show/?id-629 CALB 180Ah
Note that the batteries will have a *blue* shell casing.
Whats the expected pricing
Ballpark figures _excluding_ shipping/taxes/duties are about R1000 per 180Ah battery. I guesstimate this to roughly double when landed with costs, so R2000 per 180Ah / 3.2v battery. Final figures will likely be within R1500-R2000 depending on volume.
More units == cheaper overall pricing per unit. This also relies on the rand not taking a huge dive. Guesstimate values are calculated at R2 = RMB1
But thats still expensive!
You need roughly half the total battery capacity for Lithium than you do for Lead Acid, so its comparable per KW usable.
Lead Acid = 30% DoD = 3 x capacity required for usable storage requirements.
Lithum = 60% DoD = 1.6 x capacity required for usable storage requirements.
eg
You need 10KW of usable capacity.
You'd need 16KW of Lithium, or 30KW of Lead Acid..
I'm going be bringing in Lithium Iron Phosphate Batteries from China to do so.
Pricing will be similar to premium Lead Acid pricing in SA.
I've talked about this a few times in a couple of threads, and a few people have expressed interest in doing a group buy.
Before we start -
There are some caveats if you want to buy and use these batteries.
1) You need a charger that explicitly supports Lithium.
Voltages for Lithium are higher than for Lead Acid, and Lithium charging is a lot different to Lead Acid charging.
Lithium is a lot easier to charge than lead acid, as you just feed in till you reach the required voltage, then stop charging.
There is no peukerts law/curve to worry about, and Lithium is a lot safer to deal with - no hydrogen / explosion issues.
2) You'll need a disconnect relay for low voltage and high voltage to protect the batteries.
Lithium will be damaged if you discharge too low, and will be damaged if you charge too high. Adding extra protection to prevent this is excellent insurance to prevent chargers killing the batteries.
Example disconnect circuit - http://zeva.com.au/index.php?product=101
(also needs relays)
3) Lithium batteries need to be balanced.
I will be ordering battery balancing circuits for the batteries, this will be an extra cost.
Guesstimate roughly 5% of the battery cost, exact pricing to be determined still.
Balancing is essentially making sure that all the batteries in a pack get charged equally. Some batteries will charge faster, some slower. Balancing circuits ensure that all batteries reach the same charge.
Example balancers - http://www.ev-power.com.au/-Thundersky-Battery-Balancing-System-.html
4) I will need to know what voltage you require for charge/discharge.
The CALB Batteries I'm pricing, are 3.2V / 100Ah or 3.2V / 180Ah each.
You'll need to buy enough batteries for your KW required, and inverter charge rate.
48V inverters will require a minimum of 16 batteries.
36V inverters will require a minimum of 12 batteries.
24V inverters will require a minimum of 8 batteries.
12V inverters will require a minimum of 4 batteries.
5) I will need to know what sort of KW size you require.
Lithium Iron Phosphate works best at 20% - 80% usage from the data sheet DoD curves.
This means that you will only have 60% usable capacity if you wish to treat the batteries nicely, and have them last.
You can go higher or lower, but you will reduce cycles. 60%* appears to be the best bang for buck on the lifetime / usage according to my calculations.
This effectively means that you will need to buy 160% of the capacity you actually need.
This compares nicely to Lead Acid where best lifespan is in the 30% range, (and you need 300% of capacity required).
To cut a long explanation short - if you need 10KW of Lithium storage, you will need 16KW of battery*
*You can probably go another 10% extra to 15-85% for 70% usable capacity without too much issue, but I need to test in real life before I can recommend that.
6) I am not offering a plug and play solution (yet).
I am ordering batteries + copper connectors + battery balancers for the pack size you / I require.
- This is not an off the shelf solution.
- You will need to understand how to integrate these with your existing system.
- You will need Items #1, #3, and I strongly recommend #2 above
(I will be sourcing these as part of my install)
- You'll probably need monitoring for voltage, temp etc. eg a Victron BMS or similar product.
- If it works well, I will be looking at bringing in a complete solution (charger / batteries / bms), but this won't be until I have my own system running properly.
7) Shipping will be to Cape Town
You will need to arrange your own collection/ shipping from Cape Town if you are in other parts of the country, and are still interested, despite all my dire warnings above!
Timeframe will be for arrival mid-late August.
I strongly suggest that you read the ENTIRE thread here - https://forums.energymatters.com.au/solar-wind-gear/topic6186.html as it discusses the issues you'll be dealing with. Bonus points if you can guess who I am in the thread there
This is a good overview also - http://www.pbase.com/mainecruising/lifepo4_on_boats
If you have read the above, understand and are still interested, then reply in the thread below with an indication of voltage and wattage required.
FAQ
Why only 100Ah / 180Ah?
Purely due to price. Higher capacity is substantially more at current pricing.
What charger do I need?
Suitable chargers are ones that can change the charge voltage, float values etc to appropriate values.
As a rule of thumb, the more expensive chargers support this, the cheaper ones do not.
eg Victron, Outback..
What batteries are they?
CALB 100Ah or 180Ah in blue plastic shell packaging.
http://en.calb.cn/product/show/?id-627 CALB 100Ah
http://en.calb.cn/product/show/?id-629 CALB 180Ah
Note that the batteries will have a *blue* shell casing.
Whats the expected pricing
Ballpark figures _excluding_ shipping/taxes/duties are about R1000 per 180Ah battery. I guesstimate this to roughly double when landed with costs, so R2000 per 180Ah / 3.2v battery. Final figures will likely be within R1500-R2000 depending on volume.
More units == cheaper overall pricing per unit. This also relies on the rand not taking a huge dive. Guesstimate values are calculated at R2 = RMB1
But thats still expensive!
You need roughly half the total battery capacity for Lithium than you do for Lead Acid, so its comparable per KW usable.
Lead Acid = 30% DoD = 3 x capacity required for usable storage requirements.
Lithum = 60% DoD = 1.6 x capacity required for usable storage requirements.
eg
You need 10KW of usable capacity.
You'd need 16KW of Lithium, or 30KW of Lead Acid..
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