Pro tips when DIY'ing - Post all your pro tips or just tips

[Legend27]

Hey everyone!

Starting this thread to gather all tips that might be handy when DIY'ing in a single thread (if someone made a thread like this before, I'm sorry...). 

Everything is welcome, even the things that you might think is really obvious. I'll start off with one of those lol.

 

Whenever you are moving connectors or something completely different on the control board, MAKE SURE YOU DISCONNECT POWER!

 

It seems really obvious or you might think "I just have to move this wire", but things can and probably will go wrong. Just disconnect power, it takes 3 seconds instead of days waiting for replacement parts...

Everything on the control board is exposed so you might do like me and short the phase wire with something and make a whole lot of sparks and a bang. 

 

Thanks for reading till the end and have a great day

[Tinkererboi]

15 hours ago, Legend27 said:

MAKE SURE YOU DISCONNECT POWER!

Also, always drain the capacitors by holding the power button for a few seconds. There's still enough power left in there to mess up your wheel real bad if you slip.

Edited October 6, 2019 by Tinkererboi

[EUCGUY]

8 minutes ago, Tinkererboi said:

Also, always drain the capacitors by holding the power button for a few seconds. There's still enough power left in there to mess up your wheel real bad if you slip.

yup. this is the most important part, the small resistors between the caps dont drain them fast enough

 

[EUCGUY]

For my old msuper v3, i sprayed the capasitor legs with sealant for electrical contacts. it would be smart for anyone who rider where its a lot of moisture. 

[yuweng]

i've upgraded most of the internal power cabling to 12 awg & the differences is very obvious, better feel on acceleration, braking & also the battery less voltage sag. Nowadays EUCs mostly are almost double the voltage & power, i believe if you upgrade to 10 awg or better 8 awg silicone cable & XT90 connectors, the differences will be huge. 

[mrelwood]

55 minutes ago, yuweng said:

i've upgraded most of the internal power cabling to 12 awg & the differences is very obvious, better feel on acceleration, braking & also the battery less voltage sag. Nowadays EUCs mostly are almost double the voltage & power, i believe if you upgrade to 10 awg or better 8 awg silicone cable & XT90 connectors, the differences will be huge. 

Not sure about the XT90, but most if not all XT60 will not fit AWG12 or thicker cables inside the attachment point, which would compromise safety in a big way. Solder by itself is not anywhere near strong enough to sustain the stress and vibrations that are enforced upon the connectors.

[yuweng]

Soldering a 12 awg to XT60 is actually a breeze when you know how to do it. You can actually even solder a 10 awg ! The trick i found out is that you must have a very hot soldering iron, strip about 5mm, twist the copper wire first, tinned it, cut the excessive, tinned the XT60 connector, have a holder holding the connector with both ends plug-in, it will act as a heat sink transferring excessive heat. With a very hot soldering iron, it will be done in a snap ! Most of it i learn from youtube videos 

i was a little shock when i found out that silicone wires use on EUCs is 14 awg & less. On the outside, the cable looks thick but the copper conductor inside is actually less than 2 mm in diameter ! Here is the maximum current load test for XT60 & XT90. As said for 84/ 100 volt EUCs, i believe will benefit with 8/ 10 awg upgrade 

[ir_fuel]

1 hour ago, yuweng said:

Soldering a 12 awg to XT60 is actually a breeze when you know how to do it. You can actually even solder a 10 awg ! The trick i found out is that you must have a very hot soldering iron, strip about 5mm, twist the copper wire first, tinned it, cut the excessive, tinned the XT60 connector, have a holder holding the connector with both ends plug-in, it will act as a heat sink transferring excessive heat. With a very hot soldering iron, it will be done in a snap ! Most of it i learn from youtube videos 

i was a little shock when i found out that silicone wires use on EUCs is 14 awg & less. On the outside, the cable looks thick but the copper conductor inside is actually less than 2 mm in diameter ! Here is the maximum current load test for XT60 & XT90. As said for 84/ 100 volt EUCs, i believe will benefit with 8/ 10 awg upgrade 

That video really is a bad example, what a messy way of doing it 

Just tin the inside of the XT60, tin the end of the wire and use a very big soldering tip and an iron that can produce a lot of watt (not to be confused with a lot of heat. More watts for the same temperature = an iron that will dissipate that heat better over a bigger surface. No need to go higher than 400C.), and just flow them together. 

And yes, keeping them plugged in is a good idea.

[mrelwood]

That’s exactly how I do it, but the issue is that the cable doesn’t fit inside the tube shaped soldering connector of the XT60. I soldered a few XT60s recently, and I used the AWG 16 and AWG 12 cables since I had them at hand. AWG 12 didn’t fit even close, and I had to cut a third of the strands off before twisting to make it fit in a way that was acceptable for me.

I seem to recall that the AWG sizes are not standardized by the conductor thickness, which would make some cables with the same AWG size to be different in diameter. I guess some AWG 12 could fit.

[Tinkererboi]

Always verify polarities with a multimeter when working with cheap chinese products. Finally noticed that the polarity info on my GT16 charger was backwards. Could have ended really badly.

[mrelwood]

1 hour ago, Tinkererboi said:

Always verify polarities with a multimeter when working with cheap chinese products. Finally noticed that the polarity info on my GT16 charger was backwards. Could have ended really badly.

Great reminder! A local rider toasted his 18XL mainboard with a 3rd party fast charger and a Lenovo adapter. The 18XL uses inverted polarity on the charging connector.

[Elder Meat]

DIY tips?

1. Photos are free. Take lots as you disassemble stuff so you can see how it's supposed to go back together.
2. If you have the space, lay the screws and parts you take off around the device approximately where it came from. Sorta like an exploded diagram view. That makes it easier to know where it should go back.
3. It's better to have too many screws/materials/whatever than be short just one. It also helps you build up stock over time which makes future DIY projects easier.
4. Good tools are important, but more tools are better. One tactic is to buy cheap stuff first and when it breaks upgrade. That way you don't spend money on expensive stuff you don't use often. You also have a better idea of what you want when you buy the replacement as well.
5. Put your tools and everything back neatly once you're done using them. Leave them lying around and you will waste more time looking for them the next time than it would have taken to put them away. Neatness does count.
6. Wear safety glasses and other safety gear as appropriate when using power tools. It's easy to skip. It's also easy to injure yourself.

[Tinkererboi]

Here's a new one. Locktite eats plastic.

Have seen disassembly videos and posts commenting that manufacturers did not use locktite and thus screws were working themselves loose over time so using some locktite when putting their wheels back together is a good idea. 

It isnt. Even the fumes alone can turn plastic brittle and shatter the surrounding area in as little as a day. 

[Elder Meat]

Liquid Loctite eats plastic because it's designed to penetrate. Paste is different. https://www.amazon.com/Loctite-506166-Medium-Strength-Threadlocker/dp/B0053ZNMDE

[Jacky Heshi]

On 10/6/2019 at 9:58 PM, yuweng said:

i've upgraded most of the internal power cabling to 12 awg & the differences is very obvious, better feel on acceleration, braking & also the battery less voltage sag. Nowadays EUCs mostly are almost double the voltage & power, i believe if you upgrade to 10 awg or better 8 awg silicone cable & XT90 connectors, the differences will be huge. 

When you say "the differences will be huge" I did notice the cabling for the Gotway Tesla were quite thin for its power output. 

[esaj]

Check that your multimeter probes are connected correctly (current vs. voltage measurement) before measuring. The power spike before the BMS cuts the power / meter fuse blows is enough to vaporize your probes if you plug them in the battery connector with the meter set up for current measuring... guess how I know?  

Acetone can be used to "weld" plastic, it liquifies the plastic, which then hardens again once the acetone evaporates. Use small amounts at a time and be careful, the plastic starts to melt pretty quickly. Also inhaling the fumes a lot isn't exactly healthy, so good ventilation isn't a bad idea. Never had more than a slight headache though 

Mixing plastic (such as Lego-blocks, which are ABS, or something like 3d-printer filaments probably would work nicely too) with acetone creates a "slurry" which can be used to fill in small holes or cracks, or create new threads for screws in plastic (fill the hole to re-thread with the slurry, insert the screw, maybe move it a little bit up and down to ensure the liquid plastic settles in the threads and leave it there until the acetone has evaporated and the plastic has hardened). Easiest way to make small amounts is to take a small glass jar (preferably with a lid), pour some acetone in there and drop the blocks or 3d-printer filament or whatever there, close the lid and swish it around for some time until it has even consistency (the time it takes depends on plastic, sizes of blocks, amount and purity of acetone... if you just leave it sitting it will take a long time, but twirling it around makes it much faster). More acetone vs. plastic makes it more runny and vice versa. Somebody with more understanding of chemistry once said that using solvent-based "gluing" is far superior to "normal" glues, because the bonds occur at molecular levels, ie. basically the parts melt together instead of being held together by a layer of other substance.

Draining the caps is a good idea before touching anything on the mainboard, probably pressing the power button is enough, or just place a small resistor across the cap legs and wait a bit (careful not to short anything else with the resistor legs!). But when plugging back in, the discharged caps will pull a high current spike when they recharge and can cause sparking, people have destroyed the connectors this way and in at least one case, the MCU fried (Rehab1's ACM). Either use a XT-90 with "spark arrestor" or use small resistors (if you don't know what I mean or how, then don't try it, I don't have the time to draw a diagram right now ) between the battery and mainboard connectors first to recharge the caps, then connect normally.

Edited November 19, 2019 by esaj

[hyperair]

Some things I picked up while working on battery packs:

• You can't turn off a battery, so be very careful with exposed leads -- shorting a battery pack can spray vapourized metal
• 84V DC can shock you pretty hard, so think twice before picking up a fully-assembled battery pack with exposed leads (I picked up an assembled V8 battery pack with left hand over the B- connection and right hand over the B+ connection -- fun times). Consider adopting the one-hand rule wherever possible, and being extra careful when you need to bring both hands in.
• Watch where your solder wire goes -- if it drags over another part of a battery pack, you can short it while soldering a joint.
• Silicone wires have fragile insulation. The insulation can crack easily if kinked and get scraped off if pulled through a small hole.