A third hand helps also.
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I didn’t grow up in chernobyl though.
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I’ve seen somewhere, I don’t know if it was in an Esk8 build. That you wrap thin copper wire around the solder joint to bind the wires together
I like this too. Get good end to end contact. 
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Yeah I wasn’t born that lucky 
more like an 11th finger
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Solder session coming in Feb…
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Looking for some help with one of these constant current load testers. Never used one before, looked it over and watched a few videos. Pretty sure there’s something wrong with mine.
Brand new. Powered in back with included 9v1a power supply.
So started off connecting a 10S3p battery pack to the inputs on the left. Yes I double checked polarity. Yes the current control knobs are all the way counter clockwise. Got a spark— yea a 10S spark. Replaced the XT60 that charred the negative pin.
Tried again, this time with an XT90S and I put a 15amp fuse inline. Smoked the fuse right away when i connected. Hmmm
So now I’ve connected something smaller (included usb A to alligators) to either end of a single 25R battery and it immediately shows 1V and 11amps. The battery and cables got warm and control knobs still at minimum. The cell dropped to 3.05 V when I tested it after it was disconnected.
Here’s the 25R connected
Fan spun when it was plugged in. Never saw correct voltage on screen 3V or 42v on the prior test.
I tried to test a portable battery pack and got no readings. I tried plugging a 10S 2A charger into the input 5.5 jack and get nothing.
Seems like it’s trying to pull max amps. Any way to test it? No burn marks underneath
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And with livestream…
Guys.
Which version of the dickyho bms doni get for 10s?
Charge only.
Will bypass for discharge.
Going to build a 10s4p 30q pack.
Load/charge same port 15A should be more than enough for a charge only BMS.
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that looks awful, mainly because you’ve obviously put a LOT of heat into those two cells putting a solder blob that big onto them, and the solder isn’t wetting out properly on the nickel.
You need a more aggressive flux for soldering to nickel strip than you do for soldering copper wire. I swear by “Ruby Fluid” liquid flux.
For soldering ANYWHERE near batteries, lat alone right on them, you want absolutely the smallest amount of heat input possible. Too much heat for too long will damage the cells, and in extreme cases can result in an immediate thermal runaway and/or explosion. The technique that I’ve found best is to have your iron set very hot, and go really fast. It’s better to go hot and fast than cool and slow. A fat tip with lots of thermal mass is also helpful.
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I guess I will have do better next time. I am not going to put more heat on that thing anymore. Lesson learned.
But @MysticalDork don’t get me wrong I am grateful for you guys taking the time to rate my work or should I say my failure 
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I have no direct experience, but everything I’ve read says caution… If it works for you carry on.
Don’t see anyone talking about this site maybe its new on the PGroup block
https://www.bulkbattery.com/batteries/21700/
$150 min order and free shipping over $500
so If me and a friend go in on 200 Samsung 50E together it would only be $432 each
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It’s not a good idea if you have access to a spot welder, but I’ve built three packs that way and so far so good.
My technique, combined with an excellent soldering iron with great thermal performance, means I can complete a solder joint on the bottom of a cell is less than ~1.5 seconds, and can hold my hand on the joint immediately thereafter. That flux also helps a TON - Tinning the cell with it is super quick compared to regular flux.
@b264 has one of my packs, and may be able to give some lifespan info, as he rides more than I do.
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I don’t mind soldering, but that flux is corrosive… Might not be a big deal on chunky wire and nickel?
It is, but I only use a tiny, tiny drop, like <2mm diameter, and it’s mostly water. It doesn’t take much.
From the manufacturer’s description: “General purpose flux. Easy-to-use. Produces strong, durable joints without corrosion or dangerous fumes.”
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Yeah, if you have been soldering for 30 years and are a professional then it’s possible but I generally won’t recommend it because folks underestimate the “if you have been soldering for 30 years” part and think they can do it anyway when you mention that it’s possible.
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Yow. From the spec sheet
SAFETY AND PRECAUTIONS Superior RubyFluid is a corrosive product and should be handled with care and the normal precautions taken when working with chemical products
The MSDS says zinc chloride.
Links are from https://superiorflux.com/rubyfluid-flux/, which does not mention electronics.
https://www.lifewire.com/types-of-solder-flux-818849 says:
Inorganic acid flux works better with stronger metals such as copper, brass, and stainless steel. It’s a blend of stronger acids like hydrochloric acid, zinc chloride, and ammonium chloride. Inorganic acid flux requires complete cleaning after use to remove all of the corrosive residues from the surfaces, which will weaken or destroy the solder joint if left in place. Inorganic acid flux should not be used for electronic assembly work or electrical work.
And https://www.quora.com/How-do-I-use-zinc-chloride-on-electronics says:
Zinc chloride is an aggressive flux. I would not use it on electronics, although you can if you have nothing else. It’s more suitable for soldering and brazing copper and brass with a gas flame, and you may find your soldering iron isn’t hot enough to activate it; but if you were told to use it, then at least try. When you are done, wash it well with copious amounts of hot water and a stiff brush, since traces of corrosive zinc chloride left in crannies between the pins will cause no end of trouble in future. It eats copper and conducts electricity.
For electronics, a resin flux is always preferable. If what’s provided in the solder core isn’t enough, you can buy it in handy tubes for not much money. It says “no clean” because it isn’t corrosive like a chloride so you don’t have to clean it off, but it washes away in alcohol.
Again, I have no personal experience.
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I agree, and if I build another pack, I’ll take more care in cleaning the cells after tinning. Basically I tin the cells with ruby fluid, then all the rest of the soldering (tinning the copper braid and combining the two) I use regular rosin flux.
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I kinda wanna try it 