My new 3S-17P DIY li-ion battery pack is working! Off grid in my yurt ;+)

in ecoTrain4 years ago (edited)

battery5.jpg

Hey everyone! Some of you may have spotted a video and some posts a while back about me making a lithium ion battery back. Think of it like a small Tesla power-wall! Thinking back to the very start of this idea, it has been a huge journey of research. learning, and finally doing it! Let me say that at times this has been one of most scary things i have done in a Very long time. It is SO easy to cause these packs to catch fire or even explode if you make any kind of mistake whilst you make them. Even just fumbling and dropping a bit of metal in the wrong spot can be a fatal move! In fact i did have a few sparks on one occasion which definitely caught my attention!

Safety was always the #1 priority and i made sure to watch many hours of YouTube videos to make sure i really understood the whole process. Everything had to be right, and im not a trained electrician by any means! I have learned on the job, as always, and by the end of my research i was pretty confidant that i had done everything to a decent level of safety! IT is working now and powering my laptop and fan and that is amazing to see!

You may ask, why make a battery pack like this instead of just using normal lead acid batteries that have been the normal for off gridders for many years. The simple answer is that they are terrible, expensive, have a short life and if you drain them too much (which always happens somehow), they can get badly damaged beyond repair. They are also huge and heavy and a real challenge to move about.

If you are technical minded then here are a few details about this battery pack.

Battery Cells: NCR18650GA 10 AMP 3500mAh
3 Cells in series, 17 cells in parallel.
Nominal Voltage of pack: 11.V
Capacity: 700 Watts Apx

There are different ways to configure these batteries. I chose to connect them in a series of 3 rather than 4. This means that the overall voltage is quite low compared to normal 12V off grid solar powered systems. To compensate for this i have also chosen a solar charge controller and inverter that will run even at very low voltages of 9Volt. I have also configured my charge controller to stop charging at 12.4 volts rather than 12.6. By charging the pack 10% less than completely full it should prolong their lifespan by a factor of 2. Therefore i hope that this pack should last around 8 years, and even then it will still have 80% of its capacity. Who knows how long it will really last, and right now im more concerned with how much power they really can deliver, and how many hours my fan and laptop will last on one charge! Lets see, so far so good and no explosions! ;-) In theory it can hold 700 watts, which is enough to power them for many many hours!

So this mission is accomplished. I am thinking about making more of these, but i have to say that the stress of making them and having to absolutely sure they are perfect is a bit heavy Making a battery fire anywhere is bad enough, but doing it in my location where fire risk is a big issue for the entire area!

Once ive seen it run for a few days, and kept an eye on it, I will isolate it in a small tyre walled battery room just outside the yurt. That should be enough to contain anything if it should happen, without burning the Yurt down!

SO thanks for stopping by. If you have any questions about this please do let me know. You can of course buy lithium ion power packs, but they do cost quite a lot.

 

 

Here's some pics of the battery as I was building it

battery2.jpg

battery5.jpg

battery6.jpg

battery3.jpg



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Awesome. We will be doing a lithium set up for our new #overland vehicle. Gone are the days we used to get old car batteries for pennies from scrap yard and run them dry to charge stuff.

 4 years ago  

oh cool! im curious how much you are paying for them.. do u know what size they are?

We aren't at that stage yet.. but will let you know. They ARE pricey but they last so much longer so a good investment right???

Looks awesome - impressive that it can run a fan.

I'd probably be more inclined to invest in a regular lithium larger lithium battery and put some kind of discharge protection cut off in place if that's even possible!

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 4 years ago  

yeah,. actually the laptop uses twice what the fan does.. the inverter is 500 watts peak so theres a natural limit on the load.. but ive also got a 60amp fuse to assist in any strange surges..

those larger batteries are Expensive .. and i can make mine bigger.. its easy to make two in series with 24 volt inverter.. i would LOVE a proper 3Kw powerwall from tesla.. maybe one day! ;-)

I'm absolutely fascinated by solar tech, especially the DIY versions, expect lots of questions in the coming months!

I've got a smaller 250 WH Lithium ion arriving today, that was pricey, but I've got to start somewhere. I'm hoping it will at least give me a couple of rounds on the laptop and phone every day, plus a few small battery charges for lights.

Congrats Alex, I see you're making progress with your projects. How are you these days? How's life without substances?

 4 years ago  

thanks erikah! I am making progress every day now.. THanjs for checking in on the smoking! i did well for 5 days.. then i had some big stressy events and i started a little bit again.. Now i am sort of in the middle.. trying to find the right balance for me.. i definatley overdid it today though! <3

I hope you can find that balance and be able to keep it. Good luck and do a post about it from time to time. Maybe it can encourage others.

Impressive and salute your hard-work that you have completed this, Same field person will learn from it.

Interesting, I can imagine how expensive those batteries are in the market, that is the idea to put our knowledge into practice to innovate. We invent or we fail but we always have to try! 👍

 4 years ago  

thanks! yeah they cost a lot on the market.. and they arent as good either.. i used the best batteries, and components so that helps a lot.. so far im very happy!!

What a great job, super inspiring and educational ... I admire your effort and dedication.

wao !! Sustainable energy ... interesting article !!!

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