Recent content by Smoke

Nickel is almost free so use as much as you can. Go for the thickest your welder can handle and as wide as you can fit. Instead of amps, I like to think about discharge rates measured in C. I'm building a 20Ah 48V pack for a 1,800 watt motor but I intend to cruise at around 500 watt output...

I can pretty safely say those stats are BS. What I hear is that most motorcycle accidents are alcohol related and most of the motorcycle accidents reported as not alcohol related are just cops and emergency responders trying not to give a gravely injured rider legal problems too. What I know...

Compared to an XT90, yes but if you can't fit a connector the size of a Speakon, connector quality probably isn't your biggest issue.

I'm glad to hear that is working for you. I know Speakon connectors are designed to handle some current, but I have never really tested them at high current. Now I'll have to think about them for other things.

I think I have found a source of paraffin wax to use for phase change cooling. I'm going to try it out. I can't say who it is until I ask him if he would like to sell wax a few pounds at a time. He's being very kind helping me out but may want to focus on bigger markets than homebrew ebike...

I think your 20A number is right at 14 watts heating. 1/2 the heating with 4x the mass equals 1/8 the temperature rise. Instead of a my 30° rise, yours is probably 4° over the same amount of time. With the size of your trike, a 40 lb battery does sound appropriate. If it would fit and the...

Yeah, 40C would be great but my ambient is about 30C as I speak, 10° rise is probably about what my cells at 0.2C in the charger do. If I add insulation on top of that (heat shrink) and pack them more densely, it's got no chance. When my ambient gets to 40°, which happens, I'm doubly screwed...

Yes, new LG M50T 21700s. The Opus says around 4,800mAh and between about 60 and 120 mili-ohms. I would prefer lower internal resistance but it's not too bad. I'm going to do some statistics to see if any of the slots are giving results that differ too much from the other slots because I was...

Yep, big problems are coming and sooner than people think. I know Microsoft has a serious cold computing program that is aiming to make quantum computers with hundreds and thousands of q-bits, that will make most encryption vulnerable overnight. I'm sure Microsoft isn't the only one trying...

With typical heat shrink insulation on a battery pack, what you can feel on the outside is not indicative of the temperature on the inside. Also, there are not multiple definitions of heat. There just is not. I am currently testing my cells so I can sort them and place them in my pack for the...

Heat in the battery is unavoidable. The question is how much power can you pull out of your cells before the temperature exceeds what you are comfortable with or what the cells will tolerate gracefully over its expected lifetime?

I hear bitcoin is very popular in Venezuela so I think it is more like entity's forcing people on to their monetary system and cryptocurrency's popularity is a function of distrust in those governments. Trust in fiat currency is just big brother telling you what to believe when you think about...

A little more calculation, it looks like 1,100 watts is required to attain maximum speed at 27.3mph and with an 1,800 watt motor, I should be able to maintain that riding in to a 10mph head wind or up a 4% grade. A 7% grade drops the speed to about 21mph, not terrible. I probably should have...

So far, my cells seem to be testing out at around 4,800mAh according to my Opus charger and the 1A charge rate seems to give similar results to 500mA charge rate. This tells me that 0.1C and 0.2C rates are nothing for these 21700 cells. A power calculator says I should be able to cruise at...

The thing about air is you can get convection or forced air cooling, that can be much more effective than the thermal conductivity of potting compound. On the other hand, if your pack is covered in heat shrink with no air flow, that is when the air does nothing for you. Unless you have an...