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DIY LIFePO4 Battery bank


Warlok
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Hi again.

Explored allot of options, but getting a reliable battery bank is very expensive. So this is what I found on the internet.

This is a result of my AGM battery bank going south. Did not expect this so soon, so $$$ is a big deciding factor.

batteries.thumb.JPG.6fe49a1bde88c61eca7f69425b35e3c6.JPG353976973_batteriesspecs.JPG.62301d06578c52cf0faf97975f0dd739.JPG

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Option #1 (R10400,00)

Looks like I need 16 of these to get to 51.2v and they are rated @ 160wh.

Please help me if I'm wrong with what I'll be getting.

160wh x16 = 2560wh

So, if I draw a constant 500w they should last about 5 hours until 0% SOC? Right?

Or should it be 50ah? Draw 10 amps an hour and this also comes to 5 hours? This looks like it's the same thing.

Realistically, how many cycles should I expect to get if I discharge them to 50%? This will only happen when the grid goes down.

 

Option #2 (R16400,00)

Same setup, but with 120ah batteries

10amp draw for 6 hours= 50% SOC?

 

How does the 2.4kw Pylontech battery (R15000.00) compare to option #1 and #2 performance and price wise?

I have a raspberry pi connected to the inverter running solpiplog

This is quite urgent because the run time on my agm batteries are only 10 minutes now at 70% SOC (500w draw) and load-shedding usually lasts for about 2-2.5 hours.

 

Thanks to @Coulomb for his advice to try and save my battery bank. I will try different ways to try and revive it. And in the meantime lets hope load-shedding only happens during the day when the sun is shining.

Thank you and good night.

 

 

 

 

 

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I’ll be the first to admit I’d prefer to DIY than to buy ready made. And I’ve been keen to sink my teeth into a DIY battery project for a while. Thing is, DIY needs to be a LOT less expensive in terms of parts, to justify the time spent getting it going to a reliable point vs commercial options. In the numbers above, I would seriously just get the Pylons; the DIY route isn’t saving you much vs the reliability and features you get with the Pylons. 
 

If you want to save with DIY, you need to go for a bigger pack and batteries from LithiumBattery SA.

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2 hours ago, gbyleveldt said:

I would seriously just get the Pylons

Thanks for the input. Could you perhaps tell me what warranty we are getting?. I see there's anadditional3 year warranty upon registering. But I would like to know about the initial warranty as well.

 

You can now register the Pylon US2000 for an additional 3 years of manufacturer warranty for free. Go to http://www.pylontech.com.cn/service/support and complete the information in the 'sign up battery' page.

Found this at the Bundu Power website.

warranty.thumb.JPG.532199ec8ca8d73ffee087c0d3ff04f9.JPG

Looks like 7years + 3 years if I register. That alone could be worth the R5000 in savings vs. DIY

 

Sorry, just maybe answered my own question. Correct me if I'm wrong

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6 minutes ago, Calvin said:

Totally agree with @gbyleveldt.  DIY is fun but needs to be cost effective.

You will probably find Pylon 3.5kWh on November specials for under R20k - same sort of cost per kWh, 10 year warranty, integrates with all sort of inverters, no hassles.

Thanks Calvin. As I posted the above reply, yours came in. Now where did I put my balaclava again? 🙂

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4 minutes ago, Gelo said:

Agree with the guys above regarding DIY, but buying ready made just seems easier and quicker and looking at prices you quoted not far off from the diy route. Have a look at the pylons and dyness range from solar advice.

Thanks. The Dyness looks pretty good right now.

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@Warlok I am also busy with a DIY battery build with 2nd life cells and an ANT BMS from Litiumbatteries. I have and am still spending many hours researching this forum and the Internet, particularly YouTube. @Coulomb has 16 cells driving his 2 Axperts. I have bought 32 cells and will put blocks of 2 cells in parallel to give 16 cell units which will be connected in series. Therefore I need one BMS and the ANT gives more Information than the Daly BMS. Mine is a slow process as I will ensure that all cells are first connected in parallel and carefully balanced before connecting them in series. I had to buy an adjustable bench power supply for the purpose.

Since the cells are 120AH each and I am putting 2 in parallel, I end up with 240AH. Cycling the bank between sy 25% and 85% is 60% of total or 144AH which will take me through the night and mostly off the grid. Since my base load is also about 500W, same as yours, we are in a similar situation. 500W divided by 48V  conservative voltage of the batteries gives 10.42A or 11A rounded off. 

If you build a  50AH battery and use perhaps 70% of capacity it will give you 50 x 0.7 / 11 = 3.18 hrs backup. The Pylontech at 2.4KWh is also a 50AH unit of you use 48V to calculate. A DIY battery of 120AH will give you 6.36 hrs and so forth. I hope this helps in making your decision. 

What I have learned is:

1. LiFePO4 should preferably not be  charged to 100% in a solar setup and never discharged below 2.5V per cell or above 3.65V. 

2. @___  ( Plonkster I guess) said don't charge over 3.45V per cell.

3. Find @Coulomb 's post with his Axpert settings. In my view he and @weber knows more about Axpert inverters than the rest of us collectively.

4. Take a look at Will Prowse's YouTube channel. Much information there about LiFePO4 and DIY. 

Good luck with finding the right solution to your battery problems. I hope my own DIY will solve mine in replacing my aging Trojans. 

Edited by ebrsa
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42 minutes ago, ebrsa said:

@Warlok I am also busy with a DIY battery build with 2nd life cells and an ANT BMS from Litiumbatteries. I have and am still spending many hours researching this forum and the Internet, particularly YouTube. @Coulomb has 16 cells driving his 2 Axperts. I have bought 32 cells and will put blocks of 2 cells in parallel to give 16 cell units which will be connected in series. Therefore I need one BMS and the ANT gives more Information than the Daly BMS. Mine is a slow process as I will ensure that all cells are first connected in parallel and carefully balanced before connecting them in series. I had to buy an adjustable bench power supply for the purpose.

Since the cells are 120AH each and I am putting 2 in parallel, I end up with 240AH. Cycling the bank between sy 25% and 85% is 60% of total or 144AH which will take me through the night and mostly off the grid. Since my base load is also about 500W, same as yours, we are in a similar situation. 500W divided by 48V  conservative voltage of the batteries gives 10.42A or 11A rounded off. 

If you build a  50AH battery and use perhaps 70% of capacity it will give you 50 x 0.7 / 11 = 3.18 hrs backup. The Pylontech at 2.4KWh is also a 50AH unit of you use 48V to calculate. A DIY battery of 120AH will give you 6.36 hrs and so forth. I hope this helps in making your decision. 

What I have learned is:

1. LiFePO4 should preferably not be  charged to 100% in a solar setup and never discharged below 2.5V per cell or above 3.65V. 

2. @___  ( Plonkster I guess) said don't charge over 3.45V per cell.

3. Find @Coulomb 's post with his Axpert settings. In my view he and @weber knows more about Axpert inverters than the rest of us collectively.

4. Take a look at Will Prowse's YouTube channel. Much information there about LiFePO4 and DIY. 

Good luck with finding the right solution to your battery problems. I hope my own DIY will solve mine in replacing my aging Trojans. 

Thanks allot. Will take a look at all the info. Would love to run all night without grid, but that's way to expensive right now

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Is the diy route feasible tho? When taking to account the cost of ready to go out the box lithiums eg pylons,dyness ect?

Would you mind sharing the cost on a diy setup @ebrsa.

I also suffer from tinker finger syndrome but worry a diy setup is way out of my technical league.

 

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Hi all,

DIY is not for everybody but I've taken the DIY plunge.

I have 2 x 16s, 120ah banks in parallel for approx 12KWh.  This setup has cost around R36k including bits and pieces to get it setup and LOTS of research and reading!

I have my inverter set to use down to 15% SOC at night and that provides 10KWh through the night

The ready made units have come down in price but when I priced Pylontech's a year ago, the above setup would have set me back in the region of R70k, very close to twice the price of my DIY setup so for me, DIY has worked out well and has saved me a bunch of cash.

At today's prices, I would need 3 x 3.5KWh Pylontech's to get close to the capacity of my setup and that will cost in the region of R58k, still about R22k more than the cost of my setup. 

Based on my setup and experiences so far, I have to say DIY is more cost effective than off the shelf

If you're not scared to get your hands dirty, i'd say go for it. There are a few other chaps on this forum who have gone the DIY route and are generous and always very willing to share their experiences.
 

Edited by smurfdbn
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@Gelo  I do not believe the DIY route requires a great deal of technical skills. Have a look at Will Prowse's YouTube videos as there is much to show you how he did it. He even has a video of building a 24V battery bank with an ANT BMS and connecting it to Axpert rebranded inverters.

Regarding costs, just take a look at Lithiumbatteriessa website and decide on the cells you want to use. I connected my 32 120AH cells in pairs of parallel cells giving me 16 120AH cell blocks. As a result I need only one BMS and I liked the features of the ANT at R2500 from Lithiumbatteriessa. For busbars I flattened 12mm copper pipe and drilled holes to connect 4 terminals together.

There is a very nice control program for Android called VBMS on Google Playstore to set up and read information down to cell charge level for the ANT BMS for about R80.00. Or you can just use the one supplied which is free.

As @smurfdbn shows in his post above, you will save around 40% or more compared to commercial batteries. I also purchased a adjustable bench power supply which can deliver 10A at 30V which is fine as I will use it to balance the cells with all connected in parallel when voltage should not exceed 3.65V prior to connecting the cells in pairs and then the 16 pairs in series. This I purchased from DIY Electronics on the Internet for R1449.95.

@smurfdbn Perhaps you would be so kind and post some photos of your final DIY battery.

 

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3 hours ago, ebrsa said:

Have a look at Will Prowse's YouTube videos

@Gelo - A great resource for learning the ropes and to get a feel of the process...   https://www.youtube.com/user/errolprowse

I got a Daly BMS with my 1st bank.  2nd bank I got an ANT Smart BMS.  While the Daly does work, I would highly recommend the ANT BMS- being able to see what the battery is doing down to the individual Cell level is worth every cent of the extra R500 for the ANT BMS.

Another tip I would offer from my almost sad experience, if you buy the Cells with ports that connect with bolts, not easy but check the threads before you assemble.  The Cells have Aluminium connection ports and though I was super cautious in assembling the bank, the thread on 1 Cell crumbled a few weeks after assembly (all by itself) - managed to salvage the Cell by removing a few washers allowing the bolt to purchase on what was left of the thread lower down.  The only other solution to this situation would be to have an engineering friend re-thread the port or buy a replacement Cell - either way, the bank is unusable until you can resolve the issue.

 

3 hours ago, ebrsa said:

Perhaps you would be so kind and post some photos of your final DIY battery.


Confession ☺️  - still all a work in progress, looks 10 times worse than Will Prowes's workbench 🥴  Will post some photo's once I am a little further down the road... 

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@Wildebees I suppose the connection method between 6 battery banks depends on the maximum load or charge current. Even though the banks will be in parallel, I would  connect the positive load/charge cable to bank 1 and negative to bank 6. It may prove interesting to keep the banks balanced too. If you  parallel connect blocks of say six cells in parallel and then the blocks in series, you will only need one BMS. But then it is a question whether the BMS can handle your load/charge current. Perhaps one  can overcome this with large relays. There has not been much discussion or clarity on parallel banks yet although Will Prowse recommended connecting cells in parallel.

 

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@Wildebees Still learning so no expert at this...

A parallel setup will certainly work as @ebrsa and others are doing but I'm a "divide and conquer" type of chap so I have opted for individual banks each with it's own ANT BMS

It does add to the cost per bank but this route has allowed me to add a bank as and when the wallet allows. The setup for a single bank is quite straight forward and I can manage each bank individually from a charge/conditioning point of view - the BMS is incredibly flexible with a range of settings that made my head spin when I first opened the App.  Also, with a single large bank, if there is an issue with any Cell/s and the BMS shuts down, the lights go off.

For 6 x 48v as a single battery, you would have to choose a BMS that can handle adequate charge/discharge current.  Eg. if you look at the ANT BMS, charge current is rated at 50A so it could take quite a while to charge a single large bank using the ANT.  Fuses, cable sizing etc. will also require careful consideration for a bank this size.

An option could be to look at a combination of parallel Cells and multiple banks eg. 2 banks of 3 parallel Cells or 3 banks of 2 Cells in parallel.

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If you do go the DIY option, I would suggest you look at a BMS that do have some sort of communication options (the normal Daly does not, but they do have a Smart Daly version. Or the ANT, or Smart LTT/DJB BMS). 

If you do have comms then there is always the option to link it to your inverter in some way like the driver I did for the Victron system. 
https://github.com/Louisvdw/dbus-serialbattery

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I am also in the process for my DIY. I went with 16 x 120ah. I have made up the battery busbars. So this weekend will be Drilling them out and connecting. 

Then making some angle iron brackets to fit the battery. I went with the ANT smart BMS. I think Sunsynk need to do some work to build comms with this BMS, there might be a market for it.

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This is getting interesting. Who wouldn't want a BIG battery bank for half the price. (Give or take).

As most of you know, there are diy kits available like the following....

diy.thumb.JPG.9e82c4df38264c4dedd8433a9e9329ca.JPG

Now add this and this and this and a bit of common sense......

box.thumb.JPG.978f98e62caf336b4bba90dba249b0c9.JPGdisplay.thumb.JPG.28c65be6f12659cf86607114b3595a69.JPGcb.JPG.07475e017c76f4eba44ae81b9887a302.JPG

..... and you have a 6 kWH battery for R19800.00 inc. (check my math), excluding shipping.

 

As before, I'm in two minds. I said I should go for a ready built Pylon or Dyness. The warranty is flippen awesome (10 years).

On the other hand, we have the power to actually build something that's more reliable than our favorite power supplier, EKSDOM.

Sorry, I'm trying to correct the spelling there, but my pc absolutely refuses to.

 

As @Coulomb has a diy battery, I would appreciate his input (again). If he says build it, that's what I'll do.  (1 767,74AUD)

 

@Wildebees What do you want to do with that battery bank? (24kWH?) Run a small town? :)

 

(Most of the time these items are out of stock, but at least we know they exist)

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited by Warlok
Out of stock
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17 hours ago, Warlok said:

As @Coulomb has a diy battery, I would appreciate his input (again).

A friend and I built our own BMS together. We had some crazy idea about selling them, but realised there is so much effort in supporting them, that we didn't want the headache.

It's really hard to advise what others should do. DIY is a lot of work, but you know what's in there and have the ability to change things if required. But if you get a quality factory made system, you should not need to change anything. The trick, of course, is to figure out what factory parts are good quality. And of course, you pay for that quality (and sometimes you pay for a lemon).

One thing that irks me about my setup is the noise on the current sensing. I don't have the final PCB (used a prototype board to save pennies). It means I get about ±2 A of noise on the reading. Not fatal, but really annoying. That's just one example of what can happen if you go DIY.

Sorry if you were looking for a simple yes/no answer.

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1 hour ago, Coulomb said:

One thing that irks me about my setup is the noise on the current sensing. I don't have the final PCB (used a prototype board to save pennies). It means I get about ±2 A of noise on the reading. Not fatal, but really annoying. That's just one example of what can happen if you go DIY.

Thanks Coulomb,

I love DIY. I remember my first.....(Sorry, nearly went off topic there) DIY. It was a crystal radio. No more than 4 parts. But when it actually worked, It felt very, very good. I was very young then. In a strange way you actually convinced me to go DIY. If Nikola Tesla, born in 1856 could do what he did, surely we can slap 16 batteries and a bms together. And don't worry. I will not blame you if something explodes. (That's what my wife is for :) )

If anybody else has built his own battery, please share your experience with us, good and bad, so we can learn and pass the knowledge on to our children, so when they ask you for the Iphone 35xs+/holographic display and 26 zettabytes of ram, you can simply say, "build your own, it's much more fun"

 

 

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Still going to build my own battery, but would like to know if anybody has experience with the following batteries...

They seem pretty much the same, but I'll rather take advice from the people that actually use them than a salesperson.

Capture.JPG.6768a6ec8150e75773b7eac09ceadee1.JPG

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