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DIY Lithium/LifePo4 battery build


Gerlach

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I spotted some of the guys on the group have build there own lithium/LifePo4 battery setups. I'm busy looking down this rabbit hall to do my own setup to and looks really nice because there is a lot of options. The guys that have played with this sort of stuff, share a bit of your knowledge and findings/experience and DIY photos please and what sort of BMS you using. I Spotted that @Coulomb actually have build his own BMS with someone a few years ago. 

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3 hours ago, Gerlach said:

I Spotted that @Coulomb actually have build his own BMS with someone a few years ago. 

It's kind of died now. But if you're interested, the thread is here:

https://forums.aeva.asn.au/viewtopic.php?f=17&t=4302

The licensing to Lithium Battery Systems didn't work out either; they're moved on to some other system.

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7 minutes ago, Coulomb said:

It's kind of died now. But if you're interested, the thread is here:

https://forums.aeva.asn.au/viewtopic.php?f=17&t=4302

The licensing to Lithium Battery Systems didn't work out either; they're moved on to some other system.

Thanks @Coulomb I founded this post yesterday. You guys did a great job there. Do you still have some of the boards and stuff? 

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My order of 16 x 120amp Lifepo4 batteries have arrived the morning in Cape Town, just need to go collect it. Waiting for my BMS's to arrive from overseas. Order balancers that can do top end ballancing and a BMS that got Over voltage and under voltage cutoff with it's own balancing to. 

I'm waiting on a price for a Orion jr BMS.

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19 hours ago, Richard Mackay said:

Let me answer what I would want:

On all cell banks:

1) over voltage cutout

2) under voltage cutout

3) balancing

 

That's the bare minimum a BMS should do. Dry relay contacs to indicate that you should stop charge/discharge (allow the inverter/charger to avoid a disconnection event by warning first) is the next thing. Next up is a built-in SOC meter and all the nice comms stuff.

Edited by plonkster
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  • 1 month later...
On 2019/12/04 at 6:38 AM, Gerlach said:

My order of 16 x 120amp Lifepo4 batteries have arrived the morning in Cape Town, just need to go collect it. Waiting for my BMS's to arrive from overseas. Order balancers that can do top end ballancing and a BMS that got Over voltage and under voltage cutoff with it's own balancing to. 

I'm waiting on a price for a Orion jr BMS.

What brand are your Lifepo4 cells and where did you order them from at what cost and freight charges. I have been looking at the Youtube site of Will Prowse in Las Vegas and it has a wealth of information on the subject. It would seem to me that to connect a suitable BMS to say 100AH or larger cells would give one the same as the complete units like Pylontech etc. and hopefully at a lower outlay. There just does not seem to be a local source which means ordering from China. Any infromation will be much appreciated.

https://www.youtube.com/user/errolprowse/featured

 

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@ebrsa i got my lifepo4s from Lithium south africa. Local guy up in JHB that imports 120amp cells. Cost met R15500 for 16 cells with shipping to cape town. His new shipping of cells is landing middel of this month. 

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The bms with screen and bluetooth was $93.00 with shipping on BlackFriday, that landed in SA last week so just waiting to arrive in Cape Town side, top end Balancers was $16.60. Waiting for that. 

ACDC enclosure was R1250 for 600x600x270. Rack i build out of steel that i had. Going to add welding speed connectors to make it easy to connect and disconnecting the unit. The copper bars i made out of old 3mm copper plate i had from a othet project. 

My solar instellation not finish in this photo, waiting for stuff that i order and stuff that bought on holliday that i will add when I'm back home. 

Planning to build one more or two if this one works out nicely. 

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@Gerlach  thank a great deal for your information. The Lifepo4 cel price is really great and from the photos on the website it would appear that the BMS is a Daly which is what Will Prowse recommended on his website with the reservation that it does not have low temperature charge cut-off. Also please advise if the barcodes on your cells have been blanked out or not. According to a test by Will Prowse (Cheap 120Ah LiFePO4 Al Cased Aliexpress Cells: Are these Grade B?) some of the cells sold have the bar-code blanked out which would indicate that they are used cells. Does yours have the bar-codes intact. If your cells are new, one would be able to build your own Lifepo4 battery at a considerable saving and with some confidence that they will last for a long time.

He also has a test of the Daly BMS latest model. See this video. If you click on the first link after the video, there are links to a new BMS that he is going to test as well as links to cells and the Daly BMS.

 

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@Gerlach just another question. You mentioned balancers in the equipment you purchased. From what I think I have learned from Will Prowse's Youtube site is that the BMS does balancing between cells. That would imply that you do not need balancers, or am I missing something.

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@ebrsa i know Will. I'm on his forum following all the stuff there. 

On the batteries, the person that i bought mine from in SA imports them from an manufacture and tested. He tested them before sending them off to me and he founded that they actually takes more then 120 amps when charging. They have black tape over so cant see whats on top.

On the BMS part. I didn't like the Daly one's because the don't have bluetooth or coms and they only have fix settings, i want to change stuff on mine. On the temp stuff, we don't get snow weather or go - temp like in the states side.

The one i took is this one ZAR 749.72 25%OFF | Smart Bluetooth 7S-20S CELL Lifepo4 li-ion Battery protection Board BMS 400A 320A 300A 100A 80A PHONE APP 8S 10S 12S 13S 14S 16S https://s.click.aliexpress.com/e/DVWllBBQb

Will did a test on this one and was really impress with it. 

On the extra balancer i took was because the bms units only bleeds low m/amps like 100ma, thats to low for me and will take really long to get your batteries level out. The balancers i took can run at 1.5amps and is top end ballancers.

Active ballancers is super expensive when you buy the propper DIY one's. 

I did a lot of reading and info about bms and stuff. 

So this setup will be my test setup to see how it runs and performs.

There is already a 48v diy setup running on a Axpert 5kv and so far it's running good. 

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15 minutes ago, Gerlach said:

On the extra balancer i took was because the bms units only bleeds low m/amps like 100ma, thats to low for me and will take really long to get your batteries level out. The balancers i took can run at 1.5amps and is top end ballancers.

Once the cells are balanced you never need more than a couple hundred milliamps to restore balance. The larger balancers only help you get there faster and in many cases the only time their full capacity is used is in the first week after commissioning the battery. After that the fancy balancer is a bit of a white elephant 🙂

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17 minutes ago, plonkster said:

Once the cells are balanced you never need more than a couple hundred milliamps to restore balance. The larger balancers only help you get there faster and in many cases the only time their full capacity is used is in the first week after commissioning the battery. After that the fancy balancer is a bit of a white elephant 🙂

We will not talk about the price of the fancy balancers. Eina!!!! 

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@Gerlach thanks again for all the information. As I live in Yzerfontein on the West Coast, freezing temperatures is not an issue but perhaps for folks on the Rand or Free State etc. I also saw the test by Will of the BMS that you purchased and he was quite enthusiastic about it. The Lifepo4 cells appear to be used ones but as long as they work reliably, it is a bargain. When one looks at the prices of new Calb or Sinopoly cells from China, you end up pretty close to prices for Pylontech for instance and then there is the warrantee consideration. The Chinese are used to shipping containers full at a time and our market is probably too small for such volumes not to talk about the capital outlay.

However your setup is most impressive and innovative and I for one hope you will keep the forum updated on performance as time passes.

My whole house runs off 2 x 4KW Axperts in parallel with 450AH of Trojan T105's which are mostly not drained much below 80% DOD. An evacuated tube heater does the hot water supply and that dramatically limits electricity demand from the grid with total grid usage for the geyser at 189 KWh for the 2019.

I look forward to information on the forum about performance of your test setup once it is operational.

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