Let's design our own UPS

Throw in one of these and it can function as a ups

It will impact cost tho. I kinda have the same small setup but with a victron inverter. So i can set at what volts the inverter must switch off to prolong battery life.
Great find, pity they out of stock, cant find anywhere else,.....
 
Great find, pity they out of stock, cant find anywhere else,.....
Search outomatic transfer switch or automatic change over switch on takealot or geewiz. Not sure how to wire them but with enough time I'm sure you will figure the wiring out :)
 
I am adding a fuse to each cell so no I am going to be using Peter Matthews method (Youtuber)
I would not recommend soldering 2nd life batteries. For 999 out of a 1,000 I'm sure it will be fine... but it just takes one to really mess up your day. Have a safety protocol in place while you build your pack, Lithium fires are difficult to put out if it starts with a cell in the middle of a 100P battery. Etc, etc

Consider spot-welding with fusable nickel
1676543727412.png

Question: when you where testing your cells, did you cycle them at 0.5A or 1A and did you track and remove cells that started to overheat ?
 
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I would not recommend soldering 2nd life batteries. For 999 out of a 1,000 I'm sure it will be fine... but it just takes one to really mess up your day. Have a safety protocol in place while you build you place.

Consider spot-welding with fusable nickel
View attachment 1477079

Question: when you where testing your cells, did you cycle them at 0.5A or 1A and did you track and remove cells that started to overheat ?
500mA test
No heat issues
Very good cells
 
Getting there on my project
Free salvaged 18650's
My 7S100P is almost complete
Taken over 3 months to test each cell
Average 2200mA each
This will be a 24v array (4.2v x 7 = 29.4 volts actually)
1540 amps @4.2volts
= busload
But the curve drops quickly to settle at 3.7v nominal so on this number we can calculate my power wall will be 5698Wh on average

Basically a 5killowatt battery bank

View attachment 1476677


Li-ion Voltage Analysis

Let us know how this works out.
I want to build a custom battery for my electric dirt bike one day and this is the kind of skills needed.
It would basically end up looking something like this:

1676546844488.png

I'm s**t scared of building one though, seems like one neesd to really know what you're doing.
 
That fit on the trolley is perfect and looks nicely balanced too. :thumbsup:

That is going to work so nicely.

Yeah, still blows my mind that all the components line up like this.
I even ordered my own battery terminal crimp tool and some cables and lugs so I can create custom cables so the build can be as clean as possible.

It's starting to make sense at this point to maybe build one or two more of these and see if people would be interested in buying them. No idea if there's a market though.
The closest competitor in terms of price/performance that I've seem would be something like this:

1676547210254.png

But honestly, those things are ugly and the batteries seem to be made using second life cells.
I think the Growatt inverter is also nicer if someone wanted to disassemble the trolley in future and turn the components into a wall-mounted home hybrid solution with a decent sized solar array and WiFi monitoring included.
 
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I have a spot welder
****ing difficult getting it right
Looks so easy on youtube
You have to choose the right current for the thickness plate
And then you also have to use the right downforce pressure as well
Not easy

Then again, practice makes perfect
 
I have a spot welder
****ing difficult getting it right
Looks so easy on youtube
You have to choose the right current for the thickness plate
And then you also have to use the right downforce pressure as well
Not easy

Then again, practice makes perfect
Split second too quick and the contact is ****ed and a split second to long and the contact is ****ed. :ROFL:
 
Oh, didnt know that, my cells were all at 4.2v each LOL
I guess you can have a slightly smaller fire if something goes wrong.

On a serious note - if you get this down, I'd pay for a custom battery pack or 3. Always worried about diy'ers not fusing their cells cos I'm paranoid. (That's a lotta energy); so you're the first one I've found who is / will do that.
Oh wait, are you in CT?
 
I guess you can have a slightly smaller fire if something goes wrong.

On a serious note - if you get this down, I'd pay for a custom battery pack or 3. Always worried about diy'ers not fusing their cells cos I'm paranoid. (That's a lotta energy); so you're the first one I've found who is / will do that.
Oh wait, are you in CT?
Hold my beer.

Haha yup in Somerset West
But you want a pack made up just go to this place.
I used them last year to repack my robotic vacuum cleaners and a friends one
Prices were pretty good, in Milnerton

 
Hold my beer.

Haha yup in Somerset West
But you want a pack made up just go to this place.
I used them last year to repack my robotic vacuum cleaners and a friends one
Prices were pretty good, in Milnerton

Thanks, will have a look.
 
Thanks to someone in china sleeping at the job I ended up having to tear apart my trolley build this weekend and do some of the cabling again.

Brand new multiplug, but the neutral rail wasn't secured in one of the little pegs.
So I'm testing my new inverter & battery build, thought I'd plug in the watt-meter and get some capacity readings as I'm discharging it.... next thing you know it's just sparks and explosions as the live and neutral become one.

So yeah if you're in the market for a multiplug I'd stay away from these.
Awful quality... from now on I'll just stick to Ellies multiplugs.

What I still don't understand is how it's possible for a person with one anus to leave behind three parallell brown stripes on the floor.

1676877347655.png

1676877367218.png
 
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