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Looking for some Advice and Insight - LiFePo4 System

JacquesC

New Member
Joined
Dec 15, 2020
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Gooday :)

I have recently ordered these: https://www.aliexpress.com/item/100...092dd5a7d55a5e741-1623357609562-09154-_9fYkO3 I've ordered 8 and the plan is to set them up in a 24v system (unless anyone can give me a good reason that isn't advisable)
Really I'm looking for recommendations on suitable and affordable inverter and charger or inverter/charger, I have some experience with Victron and know they are good bits of kit, but I'm wondering if anyone has any other recommendations or experience with these batteries. Price is an important factor but I want to make the system last as long as I can, so quality is also important.

Also I have very little experience with LiFePo4, so any advice is appreciated :) Will I need a seperate BMS? Or is that dependant on the Inverter/Charger I decide on?

TIA

J
 
Will I need a seperate BMS?

Yes. You also want to do a top balance on these cells once you have them - so you will need a power supply. Parallel the cells, set the power supply to 3.6V, then hook it up and be patient. Search the forum!

What is your load going to be? It's hard to suggest an inverter without knowing your power requirements.
 
Thank you :)
I have been reading that I will need to do that, I will check some resources and make sure I know what I'm doing there.
Regarding loads, it will be nothing too major tbh, I will probably only use about 1000W at any one time, but I would rather have a slightly larger inverter, 2000/3000W incase of emergencies or expansion, I'm in southern Spain
 
Please download this resource, many of your questions are answered in this PDF.

We cannot suggest any Inverter/Charger without knowing what Country and what voltage you want. No point in suggesting a European Model if you are in the USA and vice a versa.

Every Battery Pack (assembled collection of cells) has to have a BMS and a Fuse.
The BMS is the Cell Guardian & Manager, the emergency brake if anything goes awry, like over/under voltage or out of operational temperature range. The Solar Charge Controller (SCC) and Inverter/Charger still have to control the Charging & Discharging as well as cutoff points which should occur before the BMS is forced to (that is not the BMS' job).

BTW: The general unwritten rule is to not draw more than 250A from a battery bank (excepting surge handling). Stackable inverters and such are another matter handled differently.
12V@250A=3000W (25A AC),
24V@250A=6000W (50A AC),
48V@250A=12,000W (100A AC)
-- for quick reference. The (50A AC) can be 120V/50A out to panel or 240V/25A split phase to panel.
In simple terms. -- AC 120V/15A=1800W, 240V/15A=3600W uncorrected
? 250A. Because it's recommended to be the MAX draw limit for a standard"single" system. Single, meaning non-stacked inverters and similar.
! Inverter Wattage has to support the watts required plus surge capacity. Should never be run at the limit for an extended period of time (that's undersized).

I run a 24V system, with a Samlex EVO-4024 4000W Pure Sine Low Frequency inverter that can handle 12,000W surge.
As I sit here writing this I am using 10.2A, turn on coffee maker add 70A for 6 minutes while brewing (no warmer has thermal carafe). Turn on Microware (1200W Panasonic Inverter type) and there's 72A. IF I was running 12V that would be Double the amps drawn, if 48V then it would be Half the amps drawn. I turn on my compressor and get a surge of 200A and then 75A while running (2.5HP, 20gal).

Hope it helps, Good Luck.
PS, also download the LFP Voltage Chart from my signature, the PDF in the resource is Hi Rez and will help you on your path.
 
Thank you for the help and resources :) Will check them out
 
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