Photo quality is back

... After just one more pic, I swear! I mean, this pic wouldn't be possible with anything other than my cell cam. It'll be obvious, don't worry.

Before, this blog has had a maximum of 2 confirmed (by comments) readers at any given time, with previous picture quality. There hasn't been a comment since the poor picture quality began. Anyone remember this failed attempt at fixing my good ol' Konica Minolta X50? Tried to charge using the external DC jack, but then realized it doesn't charge from that jack, then tried to power from that jack ~5 volts from USB. Then I found out the USB supply current was too low for the camera to actually operate on.

Now, I had this idea a few months ago, but then forgot about it until now. It's so simple.

Yep. Just 4 AA's, NiMH, rated at a total of 4.8 volts, while the dc jack on the camera is asking for 4.7 volts. Close enough, even alkalines worked, which provided nearly 6 volts. I measured current draw, and it was only a little over the USB 100 mA at 340 mA. Okay, it's more than three times as much, but its still very low.
I'll probably re-do it with a longer cable, as this will get cumbersome when I try to use a tripod, but it worked. Also, yes that is the 4-AA holder that I also used as a receiver pack on the last post.

10 Cells

On Saturday, after the old Ni-Cads had been cycled a few times with my discharger, I headed out to a nice little spot (in fact the only spot with flat dirt here in Berkeley) west of here to finally see what 10 cells could do-at least with my 20 turn Stinger/Flash hybrid.

It just so happened there were a bunch of guys running nitro RCs! As I was setting up for some fun and getting ready to challenge their Losi XXX-NT (I think) to a drag race, since I was feeling confident with the 10-cell setup, I pulled the trigger (throttle) ever so slightly, it moved a little and--death. It died right there. The ESC had died. It had run on 10 cells before.

I inspected it later that night, nothing seemed wrong, and it was rated for up to 10 cells. I went back on Sunday with the very old and weak (but dependable) Elektra, rated at 6 cells and only handling down to 20-turn motors.

It was still fun, but I felt it could have been a lot more fun. I still went and got it a bit dirty though :D Enjoy

That little red thing in the back is a ghetto (but effective) air intake to cool the motor.









Where the intake leads to


And another shot









My favorite shot








The Elektra, the purple heatsinks match the rear purple shocks lol.

The failed ESC - Duratrax Streak.
I don't know if you can blame it, I was pretty bad at soldering when I replaced the 14 gauge with 12 gauge. But it was working fine this entire time. Also, why on EARTH would you release an ESC rated up to 10 cells and down to 12 turns with 14 gauge wire, a tamiya plug and bullet connectors? Where are the solder posts? It was very cheap though, so I'm not too sad.

I kind of messed up that motor mount that I described a few posts ago, so it'll be a while before I get the time and money to work on it again, but I figured by then I might as well go brushless :D

Also, for when I get back into this, I picked up a disposable camera that can be used as a battery zapper, for the next time I decide to bring out the old NiCads. I think I'll document it and everything, recording down charge cycle statistics before and after the treatment, and I'll try on the entire pack, and per cell as well. Hopefully there will be graphs.

Funny story about how I got this also. So, all i really went to Walgreens for was a bag of chips, I had a 6" sub for lunch and was feeling a bit hungry again, and then I passed by the disposable cameras and remembered the whole zapping thing, although I had intended to focus more on school and not RC again for a while. Anyway, I ask the clerk if I can have one of their old disposables, she asks the manager, and I'm denied. Then, as a stroke of luck, some girl happened to be there, ready to develop, and offered me hers. This was all in front of the clerks and manager too. Okay, I'm sorry, that wasn't funny at all.

MORE POWAH

Well, the Knex truck has been put on hold for now. I got tired of not being able to go very... off-road.

The motor I rewound was FAST. When it worked. My crappy solder-joints kept coming off and ruining everything. So I bought a stock Losi Mini-T motor ($15, GASP!) and all is good.

I've been meaning to get the Rustler back in operational condition, and so I said, what the heck, I'll go straight for the 10-cell setup I've been wanting to try for so long. 6-cell is standard.

There are a total of 14 cells in this pic! Because 12 volts is too much for the receiver to receive power from the ESC, I needed a separate battery-pack to power it. Luckily I had a 4-AA holder left over from my electrical engineering course.
For the main battery pack, basically I just wired a cheap 6-cell 1500 stick pack with a 4-cell 1500 stick pack. The 4-cell is a chopped-up 6-cell, and that was the only soldering I had to do for the entire thing :D

I use Duratrax/Andersen Powerpole connectors, which have a low resistance compared to the typical "tamiya" connector, but they're very unpopular nowadays compared to deans and traxxas connectors. However, you can't do this with deans or traxxas:

I just turned two battery packs into one! And its reversible! This is made possible because the Powerpole plug is modular, and more importantly, has no gender (or is it hermaphroditic? who cares). I don't know about the current carrying characteristics (o.o alliteration) when comparing the three types of plugs, because the Traxxas one is relatively new and I've seen the contact plates, they're pretty big, but for my brushed-motor, NiCd application the 'poles are super. I'm glad I switched so many years ago.

How did it run? Extremely poorly D: My comm has breathed its last breath, as I had overworn it, and the NiCd's haven't been run in years, so it's understandable they were slower than my 6-cell-matched NiMH packs.
The badly worn comm. It's hard to see but much of the copper is missing.

For the battery packs, I read around about zapping them with a high voltage to revive them and loosen the internal crystals killing their performance, but a tip from a guy at my local electronics shop made me reconsider. He told me to beat the packs. It made sense! However, now, after a few charge/discharge cycles it doesn't seem to help that much. I haven't tried it in the truck yet, and because of the comm's condition, it looks like it will be quite a while before I get to see 10-cells and 13-turns come alive.

Speaking of batteries, I finally made a discharger so I could perform battery maintenance better. The local electronics shop had the standard automotive 1157 bulbs for $1 for two. I bought out their 6, and made a 6-bulb, 12-amp discharger. The closest automotive parts store wanted $2 each, so I didn't opt for the full, standard 10-bulb discharger. So the total cost was pretty much the $3.50 for the 6 bulbs, since I had some old 12-gauge laying around, and I have a bunch of the powerpole plugs.
construction
The finished discharger.
The discharger in action (it got a LOT brighter with my 6-cell sidexside NiMHs, saying a lot about the performance of shotgun-style construction, which is shown in the picture).

The bulbs get blindingly-bright (with the NiMHs) and really hot. Each one draws 2 amps at 7 volts! This seems terribly inefficient, I've seen LEDs on lots of the newer cars (for everything but headlights) but why don't they put them on all cars now? I wonder if the prius and other hybrids use more efficient lamps.

Hmmm... What else was there? Oh yeah. I spotted a 9.6 volt battery charger and battery on clearance at Radioshack the other day for $4. Those batteries for crappy RC cars are pretty much 8 AA batteries, like my transmitter, and I already had 8 NiMH AAs for my transmitter, and a plug that would work with my 18R transmitter (it doesn't matter I can still take out the AAs and use them with my traxxas TQ), so now I have an easy solution for charging my transmitter batteries (previously I would have to charge 4 at a time).


As for the Rustler, I've had the 20-turn armature from my Stinger motor for quite a while now just sitting in my toolbox, with its comm in relatively good condition. I went out to my local park with my NiMH packs, and while it was impressive for what it was (A "frankenstinger", a stinger armature from the old traxxas electric vehicle standard in my Reedy Flash BB can with stiff brush springs and quad magnets) the enjoyment I had from the raw power of the 13-turn was gone. It sounded underpowered. It did go pretty fast though, and I managed to completely screw over my ESC D:

The Stinger. Apparently they gave it a makeover in recent years

Since traxxas electrics were (and are) extremely popular RC vehicles, I wonder if this could be like the standard "small block" that everyone has and is familiar with. Nah, that's probably where competition stock motors would lie.

So I think I'm going to put away the RC for a while. I really miss my old small town, living in the city, I couldn't RC just anywhere. I've gone far and wide just searching for places to have this kind of fun. Looks like I'll have to start getting into microcontrollers finally...