Quick and irelevent update. Isn’t that what this forum is used to?
Got all my packs welded done today. I used 47ms and the welds seem pretty good. Think I shorted a cell really quick cause it made a spark. I put a lot of pressure on a nickel strip to see how strong the weld was and there came a spark. Measured the volts and no damage was made.
Okaaaaaay… I’ve made very little progress but it’s time for an update!
UPDATE #46
Glued my pack together, put some tape around it and cut some nickel
My old 340A car battery was not strong enough to make good welds so I had to get a new one. Got this for free but turned out it lost too much power after each weld. The welds was also not strong enough.
Okay. Got a new big 700A car battery! NOW WE’RE WELDING! right? Well, turns out the battery had a lower output than 700A. Great! I have sent it to repair and I am currently waiting to get the battery back or a new one. They said a week, but it’s now been 8 days and no battery. Enjoy the pictures
My original plan for the series connections looked like that
They were pain in the ass to get perfect but I found a solution. Just lay them like this instead. Much easier!
Ohh yea… Also shorted my battery. Think everything is fine. The nickel strip acted like a fuse. Just some burn marks.
To avoid the same thing happening to you always insulate positive and negative. If it had been the main leads it would probably had started a fire. I was lucky. Learn from other peoples mistakes and when you think “it’s not gonna happend to me” it is going to. As good old friend Crazy Russian Hacker says “Safety is number one priority”
Finally got answer from where I bought the car battery. It got denied and they told me nothing is wrong with the battery. Great… Can’t get my money back from the car battery and it dosen’t work properly.
What im going to try and do now is see if the spot welder is broken. I don’t think so but it’s worth it trying. I’ve messaged a couple of guys on the forum about their car battery specs to contradict the shops claim that the battery is fine and to have some kind of proof.
Luckily I still have my old 340A battery and im pretty sure I measured the amps to be 380A. Which is 40A over the rated. Which means that if thats still the case, the 700A battery is broken and the spot welder works fine. Great!
Thanks for reading and remember to never let the challenges stop you.
Time for an update! Only 25 days since last and no progress made on the skateboard!
So what has been going on?
Well I placed an order on Amazon for a new car battery and it said “Usually dispatched within 2 to 3 days” and me be like "great! I get a battery from a well known source and I will have it in a few days. Two weeks later without the battery has been dispatched I contact them and gets told “we have some problems with our system so the item is not actually in stock and we don’t know when it will be again”. GREAT AMAZON! THANKS FOR WASTING 2 WEEKS WITHOUT EVEN TELLING ME ABOUT IT!
Then I needed to find another place to buy the battery. Luckily the place I bought my 340A battery (Tayna Batteries) had it in stock and shipping time was only a few days. On October 24. I bought the battery and I received it today. It was well packaged and had no acid in the bag. Voltage was 12.56V.
Got my vesc set up and WOW! It’s much more powerful!
(Not even close to full power )
Got my BMS connected but can’t charge the battery yet. The charger outputs 42.4V and pretty sure that’s too much. I’ve sent an email to Alberto and will hopefully will get an answer tomorrow.
Wait… Just realized one thing. When the charger outputs 42.4V each cell will be at 4.24v fully charged, correct?
Standard charge: CCCV, 1.50A, 4.20 ± 0.05 V, 150mA cut-off
That means each cell potentially can be at 4.25V safely?
Which means the conclusion would be that the charge output is correct and the battery pack won’t be overcharged?
edit:
The BMS has a overcharge voltage detection of 4.28V. That means the charging will be interrupted when the voltage of a cell exceeds 4.28V. The 30Q max charge is 4.25V, doesn’t that mean the cell will be damaged before the bms turns off?
It will be fine, it most likely won’t even reach that voltage once under load. I would expect it to reach 41.9-42.1v. I know that my adjustable charger I set to 50.5v and my 12s gets balance perfectly to 50.4 once removing the charger
European building seems to be a lot more expensive than in the USA. I’m in the UK and these extra taxes and shipping fees look prohibitively expensive!
I did the math recently and on my first build, after making a few mistakes and ordering most items from overseas I ended up spending over £700 on shipping, import taxes and fees.
There are some pretty decent builds on the forum for £700 haha. We get abused.
Definitely also need a new charger. 5 hours since I plugged it in and only at 39.3V so far.
Just don’t know which one of these two to get. Any suggestions?
For the same price or cheaper you could buy a cc/cv boost converter and watt meter giving you a fully adjustable charger able to charge any voltage batteries up to 80v and all you need is a 12-24v input supply for powering it. @skatardude10 is using the same thing as me and I think he’s using it for a portable charger.
Here’s a pic of it currently powering a bt speaker im making