.
So why the US still uses the English system is simple. It is too embedded and can only switch gradually over time.
Products made in English are difficult to switch to metric, it is better to design in metric. So as companies make new products in metric and older products in English wear out and replacement parts are no longer needed, then the metric system will gradually become more prominent.
.
Funny I worked at a small machine shop yrs ago that rebuilt nail making machines. They were made in China, everything was metric. I just switched the parameter in the CNC Mill to metric and typed in the metric values and out popped metric parts.
.
Neither one is more or less accurate than the other as far as linear measurement goes from a machining perspective. I work in both worlds and I see more simplification in the metric system.
.
How many times have you seen an article that goes something along the lines of
The police followed the suspect 3.2km (1.98838781516mi) down the road...
Preheat your oven to 425°F (218.333333°C) before putting in the roast.
(instead of “2mi” and “220°C”, respectively) so they think by “going metric” they’ll have to carry around calculators and figure out things to 10 significant digits.
Actually, the only system I have found useful is nautical miles. It is not based on some arbitrary value, but on the approximate circumference of the earth. It is about one minute of latitude along any line of longitude and a minute of longitude on the equator. Really close for most uses.
On an icebreaker headed north for New Zealand from Antarctica, the captain asked, “About how far is Wellington.” I looked at the chart and subtracted Wellington’s latitude from ours in my head and converted each degree to 60 minutes plus the remaining minutes. Gave him the nautical mile answer in about 10 seconds. He looked surprised and measured the distance with dividers based on the scale printed on the chart and got the same answer. Took him a minute or so. You can do the same on a trip from Los Angeles to Seattle or New York to Burlington as long as your map has latitude in the margin and approximate is good enough. A statute mile is about 1.14 nautical miles for another easy mental conversion. 6000 feet divided by 5280 feet is about 1.14 so add 10% or so and round up.
It works for east west as well if you know a little trig. At 45 degree latitude multiply longitude change by .7, close enough to .707, etc. Keep it simple and approximate. Those more into math can easily calculate trips at 45, 30, and 60 degrees from a cardinal direction without any trouble.
Other than this, all systems are fairly arbitrary IMHO. Anyone of average intelligence can use whatever they are taught. These days people just use mapping programs anyway. Of course, you might not agree, and I am fine with that. Sail on!
The basis for metric units and the conversions between are at least as elegant, practical and well thought-out as nautical miles. Imperial system units are truly nutty, and decimals are so much easier to work with vs fractions in most cases.
So I’ve been doing some research on the Olight Warrior Mini and noticed a warning in its manual that says:
“Do not short-circuit the tail switch cap with the ring surrounding it. the short circuit in this case will result in an electrical discharge of below 3mA between them, and may lead to a complete battery drain if its in this state too long.”
Can anyone explain this in laymans terms to someone who understands nothing about electricity?
Will it just drain the battery and will need to be recharged?
Or will this damage the battery?
I don’t see this same warning in the manual for my Olight S2R II baton, but am wondering if it does have the same risk.
With both flashlights ends being a magnet, I would think your always at risk of making this contact just by sticking it to magnetic surfaces?
Or even just change in my pocket sticking to it.
Also, is there somewhere more appropriate to be asking this question?
Fenix and Nitecore have more costs involved and have to charge a higher price to make profit. You can ignore their batteries.
Pretty much everyone on this form that is actually enjoying flashlight has a battery charger or several battery chargers and just regular OEM type batteries.
I’m going to ask around see if I can find a good place for you to buy a couple basic batteries and basic charger.
Lithium ion batteries can be ruined if their voltage should ever drop below 2.5 volts. The chemical structure breaks down. So any type of small drain on the battery can be a concern. A 3mA drain on a fully charged 3,000mah battery would take over a month to drain down. So it’s not too big a concern as you might think. Just don’t leave it stuck to a bare metal object for several days.
When people test flashlights they always test them for parasitic drain. Most people also will give the battery caps a twist in order to break the connection and eliminate parasitic drain when they’re storing their flashlights. If you’re really concerned about it you can get a protected battery.
There’s a lot of trade-offs with protected cells, so if a protected cell will fit in your light and it’s reduced amperage is not an issue, you might consider getting a protected cell. It’s a battery with a little added on circuit that shuts off power if the battery voltage gets too high, too low or draws too much power/short circuits. Some might even shut off if the battery gets too hot.
Protected cells tend to cost a lot more, are longer than normal and have a maximum amperage output typically around 5A to 7A, but some are higher.
Since you need at least a 10A cell it means you need a protection circuit of at least 10A. There are very few choices. One a company in the US. They offer a 20A circuit on a good OEM high capacity cell. LG MJ1 Protected
Its fairly cheap, but you need to make sure your light can fit a 70mm long battery.
Another is this Imalent 3000mah cell with a 15A protection circuit for $20. It is also 70mm long.
I see Manker makes a 18650 cell with built in charging. You should ask them if it will fit the MC13 and if you can buy it separately.
Nitecore and Fenix do make some protected 18650 with built in charging and they are really expensive. Maybe these are what you were referring to earlier. The problem I see with these 2 brands is they don’t say how much current will trip the protection circuit. Is it 5A, 10A, 15A? I don’t know. If you can find out, they might be worth buying.
Thanks for taking the time to type that all up to explain to me.
Its occurring to me that this might just be a little too advanced for me. I dont think i’m going to be able to understand a lot of what might need to be understood to own and operate these flashlights.
I just had my second OlightS2RBatonII crap out on me today…
Olight has good warrantees. Contact them to get it fixed or replaced.
For people who are not into lights, like my family members, I usually get them a light like the Eagle Eye X2R and put a protected battery in it. It has a mechanical switch so when it’s off there is no drain on the battery. You plug a usb cable into the light to recharge. It’s pretty simple.
Sorry about the bad luck, having two S2R going out seems really unlucky.
What’s the maximum amount of current I could run through the FET in a BLF A6 driver? I’m building an S21A with triple LH351D LEDs powered by a high drain 21700 cell. If I’ve understood the relevant graphs, its likely to be drawing around 15A on full blast. Is this going to melt the driver?
I use short piece of 8 ga as that’s what I had handy. You don’t want it to be too long or too skinny because it’ll just add resistance. Being that thick though, does make it a little hard to bend and work with. So if I’m doing an amp draw on a smaller light where the amperage is fairly weak, I have a second wire that’s like 14 ga and a little longer that’s a lot easier to bend around and hold into place. When it comes to lower amperages a little extra resistance is no big deal.
What would the application be for this good alternative? Are you talkin about from the driver to the LED or do you mean for taking amp draws?
Thanks for your reply Jason! :+1:
I was also thinking that 8AWG would be a good “thickness”, despite the thoughness when bending it!
My use will be to check the draw in my lights, I don’t have many “hot rods” so maybe I can use a thinner (12AWG) wire? Or that would be too less?
The alternative I was referring to was using a different kind of wire, like “single core electric wire”, in copper of course. The purpose would be the same, measuring battery drain.
Wait, are you going to be measuring high amp draws or super low parasitic drain?
All of the stuff I talked about above concerns the higher amp draws. If you’re going to be measuring very low currents such as parasitic drain I would not recommend the clamp style ammeter. For that I use test leads on my DMM. The clamp style meters are great four typical amp draws but when it comes to super low amperage it just doesn’t have enough accuracy.
I don’t think single-core or any type of solid copper wire is a good choice for amp draws because you really need to get a good connection on both the battery and on the edge of the battery tube. Having the soft copper strands spread out helps to make a better electrical connection.
