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by neptronix
Apr 20 2021 8:54pm
Forum: Battery Technology
Topic: Maximum charging amps for these ( RC Lipo ) cells
Replies: 30
Views: 342

Re: Maximum charging amps for these ( RC Lipo ) cells

An 18650 is in compression all the time but never has the chance to show a warning sign. I've owned 48 RC Lipo packs over my lifetime. They puff when stressed, dropped, or improperly constructed. It can be a sign of an imminent explosion. It was a sign of an imminent off-gas once. Another which was ...
by neptronix
Apr 20 2021 8:06pm
Forum: Battery Technology
Topic: Maximum charging amps for these ( RC Lipo ) cells
Replies: 30
Views: 342

Re: Maximum charging amps for these ( RC Lipo ) cells

I always thought increasing compression ( beyond the pack's compressive wrap ) was a very bad idea because it removes a safety / warning mechanism. I've never seen any good information showing that it improves safety. I imagine it does the opposite.
by neptronix
Apr 20 2021 7:20pm
Forum: Battery Technology
Topic: Maximum charging amps for these ( RC Lipo ) cells
Replies: 30
Views: 342

Re: Maximum charging amps for these ( RC Lipo ) cells

Sure, 18650's are a bit more puncture resistant, but when pushed over the edge they react the same way as pouch cells. I've dropped lipo packs on the floor a very short distance multiple times and after a 3 month cool off-period for those packs, continued to use them with no noticeable loss of capac...
by neptronix
Apr 20 2021 6:59pm
Forum: Battery Technology
Topic: Maximum charging amps for these ( RC Lipo ) cells
Replies: 30
Views: 342

Re: Maximum charging amps for these ( RC Lipo ) cells

ps: 18650 is safer simply because they hold less energy, is encased in a steel shell and any "exitement" is directed into 1 direction. with pouches the stored energy can be 10x or more so a simple needle against a pouch like that is a much larger issue then actually needing a hammer and a...
by neptronix
Apr 20 2021 6:33pm
Forum: Motor Technology
Topic: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?
Replies: 46
Views: 1423

Re: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?

Easy to test for me. I have an eZee in a 20" wheel that nobody wants, nor do i. I also have a thermal camera. I also live next to some insane prolonged hills. The eZee is not hard to get hot on them, lol. No hoverboard needed. I'd like to sacrifice the motor in the name of science sometime soon...
by neptronix
Apr 20 2021 5:27pm
Forum: Battery Technology
Topic: Maximum charging amps for these ( RC Lipo ) cells
Replies: 30
Views: 342

Re: Maximum charging amps for these cells

I wrote the manual for assessing and doing second party quality control of RC Lipos but can't defend usage of them anymore because a majority of people haven't taken the memo. I will say that number of cells in series is not inherently dangerous. Not minding the balance of the pack, not assessing fo...
by neptronix
Apr 20 2021 4:13pm
Forum: General Discussion
Topic: 2 thumbs up for mankind
Replies: 8
Views: 94

Re: 2 thumbs up for mankind

It's a step in the right direction to even find a way to make it to an uninhabitable planet. Eventually, large scale geo-engineering could also be figured out.

Would be nice to live on a planet where only the most intelligent inhabit and leave this one behind.
by neptronix
Apr 20 2021 3:36pm
Forum: Battery Technology
Topic: Maximum charging amps for these ( RC Lipo ) cells
Replies: 30
Views: 342

Re: Maximum charging amps for these cells

Hobbyking states either 1C or 5C as an ideal charging rate for their lipos, depending on the model. 1C on a 30AH pack would translate to 30 amps. 5C would translate to 30A x 5C = 250 amps. that is the ideal current.... for hobbyking..... to keep selling you new batteries. I charged my 20C turnigy p...
by neptronix
Apr 20 2021 3:34pm
Forum: Battery Technology
Topic: Maximum charging amps for these ( RC Lipo ) cells
Replies: 30
Views: 342

Re: Maximum charging amps for these cells

Hobbyking states either 1C or 5C as an ideal charging rate for their lipos, depending on the model. 1C on a 30AH pack would translate to 30 amps. 5C would translate to 30A x 5C = 250 amps. that is the ideal current.... for hobbyking..... to keep selling you new batteries. I charged my 20C turnigy p...
by neptronix
Apr 20 2021 3:29pm
Forum: Motor Technology
Topic: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?
Replies: 46
Views: 1423

Re: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?

Excluding the special properties of ferrofluid, opticool is better at conducting heat as a fluid, and more of it can effectively be used per volume of motor. It also does not rely on transferring heat to magnets, which are sensitive to heat, therefore i suspect it's better at transferring heat overa...
by neptronix
Apr 20 2021 2:17pm
Forum: Stand-up EScooter/ESkateboards
Topic: ‼️ LOOSE AXLES ON SMALL SCOOTERS ‼️
Replies: 1
Views: 43

Re: ‼️ LOOSE AXLES ON SMALL SCOOTERS ‼️

Did it have a nylon washer embedded? because that can help out a lot. As well as proper washers and such.

Always question Chinese engineering. :)
by neptronix
Apr 20 2021 2:11pm
Forum: Motor Technology
Topic: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?
Replies: 46
Views: 1423

Re: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?

Justin proved that oil cooling is far superior to air cooling long ago. Air cooling only works well when you have oil cooling also. The big challenge with geared hub motors is transferring heat to the case. They have exceptionally poor thermal transfer from the windings and magnets to the case as a ...
by neptronix
Apr 20 2021 1:57pm
Forum: General Discussion
Topic: Lightweighting and aerodynamic optimization of a subcompact car.
Replies: 72
Views: 1159

Re: Lightweighting and aerodynamic optimization of a subcompact car.

Not going to go down the road of looking through a service manual. I have a modified electrical system to a non-stock state and the best course of action would be to revert it to a stock state before diagnosing it.
by neptronix
Apr 20 2021 11:40am
Forum: Battery Technology
Topic: Maximum charging amps for these ( RC Lipo ) cells
Replies: 30
Views: 342

Re: Maximum charging amps for these cells

Hobbyking states either 1C or 5C as an ideal charging rate for their lipos, depending on the model.

1C on a 30AH pack would translate to 30 amps. 5C would translate to 30A x 5C = 250 amps.
by neptronix
Apr 20 2021 11:34am
Forum: Motor Technology
Topic: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?
Replies: 46
Views: 1423

Re: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?

Grin's thru axle motor has an extremely low mass of metal ( hence the exceptionally low weight ) and would benefit from some kind of oil fill and heatsinks extremely well. I haven't tried one since they do not have a rear motor version. The one notable efficiency booster in the motor is the N40 magn...
by neptronix
Apr 20 2021 11:28am
Forum: Motor Technology
Topic: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?
Replies: 46
Views: 1423

Re: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?

Do you have shares in Opticool? :) He's not claiming it would work, just cheerleading for people to try testing it No, i just have a particular interest in high energy density and efficiency motors. And see that people have been using ATF on this forum for a decade.. a fluid that is not compatible ...
by neptronix
Apr 20 2021 10:50am
Forum: General Discussion
Topic: Lightweighting and aerodynamic optimization of a subcompact car.
Replies: 72
Views: 1159

Re: Lightweighting and aerodynamic optimization of a subcompact car.

That was a good lead. They have metric nylon nuts or nothing. And ship super fast. Their aluminum bolts are expensive..i found a race car fasteners site that sold them for a bit less, then read that aluminum screws won't work properly in steel. That's a bummer and a half. I did find shorter metric s...
by neptronix
Apr 19 2021 4:10pm
Forum: General Discussion
Topic: Lightweighting and aerodynamic optimization of a subcompact car.
Replies: 72
Views: 1159

Re: Lightweighting and aerodynamic optimization of a subcompact car.

Some progress... It's been dry as a bone out here in Utah and i believe i touched something with a static charge..my car would not turn off until wires were unplugged.. and the infotainment screen that i hate isn't operating properly anymore either. However the car is turning off and on normally now...
by neptronix
Apr 19 2021 1:54pm
Forum: EBike Technical
Topic: Modifying a Hub Motor
Replies: 38
Views: 975

Re: Modifying a Hub Motor

You can't rewind a motor to make it able to make more torque at any voltage. A rewind accomplishes nothing that you can't accomplish by changing the voltage and current, unless you are able to fit more total copper around the stator teeth than the factory. If you want better performance from the sa...
by neptronix
Apr 19 2021 1:40pm
Forum: EBike Technical
Topic: Modifying a Hub Motor
Replies: 38
Views: 975

Re: Modifying a Hub Motor

You want more torque, why not set the controller for higher amps? what is your current maximum amperage?
by neptronix
Apr 19 2021 1:09pm
Forum: Motor Technology
Topic: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?
Replies: 46
Views: 1423

Re: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?

A liquid cooled motor would be very expensive to design, produce prototypes for, figure out how to manufacture, find suppliers for, etc.. why do that when $5 worth of opticool could get you awfully close with an existing motor design?
by neptronix
Apr 19 2021 12:23pm
Forum: EBike Build Threads
Topic: leaning trike cargo bike front end kit
Replies: 178
Views: 32367

Re: leaning trike cargo bike front end kit

I think your idea is great, and would even love to adapt one to one of my semi recumbent bikes. But why would it be so expensive?
by neptronix
Apr 19 2021 11:37am
Forum: EBike Technical
Topic: best shock type for rear hubs?
Replies: 12
Views: 253

Re: best shock type for rear hubs?

Back to OP's question. A heavy hub motor will always make any type of suspension you put on the bike perform poorly due to the extreme amount of unsprung weight. Very expensive rear suspension can help counter this, but it's impossible for a bike to have the floaty feel it should with a hub motor. Q...
by neptronix
Apr 19 2021 11:27am
Forum: EBike Technical
Topic: best shock type for rear hubs?
Replies: 12
Views: 253

Re: best shock type for rear hubs?

Proper spring coils offer superior suspension performance to air shocks -- not just on a heavish rear hub, but on any hub. Air shocks are only used for weight and cost reasons. When was the last time you looked for rear shocks? even the most high end ones typically use air, and are also the most ex...
by neptronix
Apr 18 2021 11:00am
Forum: Motor Technology
Topic: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?
Replies: 46
Views: 1423

Re: Oil cooling a motor with transformer oil/dielectric fluid - the next frontier?

I'm surprised that nobody has played with this stuff still. I tipped Justin off to the existrance of isoparaffin oils and as far as i know, he hasn't gotten down and dirty into it. It may be suitable to add a lubricant additive which is compatible with the materials. A few drops of PTFE ( teflon ) c...