the RC (radio control) and electric rideables thread

[Gibson99]

Didn't know about A979B, just order a A959 (non B) version for my 2 year old kid so that when we go out he can have his own car

even without the B upgrades, the 959 will still be pretty fast for a kid. my 4 year old son (will be 5 in july) has two 2.4ghz RC cars but they are slow and simple - no proportional controls, no suspension, maybe goes about 2 mph... very basic. but that's fine since he's still learning and these are his first RC cars. they probably have a little 1S battery inside since they charge via USB and run for about 20-30 minutes.

depending on where you shop, the 9x9B version costs almost 2x as much as the non-B. i went ahead with the B to get the upgraded metal driveline parts (center driveshaft, diff cups, dogbones/axles, hub cups, some gears, and obviously upgraded motor and gearset (different tooth count on reduction gear and motor gear), possibly the ESC (not real clear on that, but it does use a 1400mAh battery with deans/T-plug instead of 1200mAh with JST), and whatever else they upgraded. almost all parts are interchangeable on the A949/959/969/979, and there's lots of spares and other metal upgrades too, so that was a big driving factor for me picking this one. will be good to know that when (not if) i break something, i can easily get parts, and even upgrade it quite a bit if i want to.

they make a metal parts kit, but it seems to be made for the non-B version, since it includes a lot of the parts that are already metal on the B, and the reduction/motor gears have the wrong tooth count for the B. whatever... the full metal kit costs as much as the car itself, so i won't be buying it any time soon. sure does look pretty tho:

basically with the metal kit, (which doesn't include adjustable tie rods/control rods, shocks or the bottom plate - they're sold separately) you just move the receiver/ESC, motor, steering servo, differentials, wheels, and shell (and rear wing if you have 959) from the original kit. i posted on the banggood forum asking if they plan to make a kit for the B versions since there's so much overlap. no reply yet, but not really expecting one either.

tracking says it should arrive monday. strangely, tracking info shows that on Wednesday, it was in Missouri City (just outside Houston, about 20 miles from me), but later that day it was in Hutchins, just outside Dallas... which is about 200 (yes, two hundred) miles to the north. I guess their automated shipping system isn't as smart as they'd like to think.

 

[Gibson99]

well that wasn't much fun... received the car on saturday evening, charged up and got it ready... tried driving it sunday, and it turns out the steering gear has a ton of slack, is bent, and is not adjustable on the car, so it has way too much toe out. as a result, it can't drive straight (no matter how much you try to trim it at the remote) and is completely undriveable at anything more than 50% throttle. any faster, and it just spins out, flips and crashes. so what's the point?


and as if that wasn't enough, sometimes reverse just doesn't do anything at all - i have to push the trigger multiple times before it reacts... and then when it does, it's at full throttle, which results in an instant crash.

now i get to find out how much "fun" returning something to tmart will be.

 

[Gibson99]

So I started the return process. They asked for a video showing the problem... Ok, done. They did ask good questions like whether it made any sound when trying to reverse (it doesn't) but then said something about the gears not being connected or something (hard to tell, bad translation I guess), which doesn't apply here.

Then they offered me store points towards a future purchase. Uh, no. Starting to look like I might need to start a PayPal dispute.

 

[Gibson99]

On a more positive note:

 

[abarth]

So I started the return process. They asked for a video showing the problem... Ok, done. They did ask good questions like whether it made any sound when trying to reverse (it doesn't) but then said something about the gears not being connected or something (hard to tell, bad translation I guess), which doesn't apply here.

Then they offered me store points towards a future purchase. Uh, no. Starting to look like I might need to start a PayPal dispute.

that stinks. the situation sounds like something gearbest would put a customer through. fight the good battle sir.

 

[SawMaster]

Based on what some of my flashlight friends have spoken of, T-Mart may be problematic with getting a refund or replacement. They were once quite good to do business with so maybe your luck will be better- I certainly hope so.

Phil

 

[Gibson99]

Well tonight I received a return shipping label from them! About to print the label and box it back up, then have UPS pick it up tomorrow.

 

[kamkar]

Regarding anti drone measures, i do prefer this one, though i am not sure on how much range you get out of it.

But it is nifty you can get it in both a 12 gauge and the throaty 40 mm, and who wouldn't like to have a grenade launcher in the house,,,,just in case.

 

[Gibson99]

So I opened up my son's little toy RC car to see if I could find out why it doesn't work in reverse. I expected to see a little 1s lipo inside, and according to the label, I did... But this looks like a big capacitor to me. You guys ever seen a "battery" like this?

 

[abarth]

that looks like an 18650 battery that's wrapped and soldered down. some of my flashlights use them. puts out good power.

 

[kamkar]

I have a tendencies to agree, after all the whole end and casing of the cell is negative, and then it look like it have a on-board charge/discharge circuitry.

You can find the physical size of 18650 cells online.

This cell i have off a battery for a HID torch, so its the kind meant for connecting together, so i had to put a little solder on the + end so i can use them in my LED torch.
You will find similar style batteries in a wide range of batteries, for laptops and what not.

If you go looking for new ones or maybe spare ones, just be advised these like dashcams and memory-cards are also susceptible for fakes and smaller batteries relabeled as larger MAH batteries.
I have seen some marked as large as 8000 MAH, i an not quite sure how true that is.
The 6000 MAH ones i have for my torch i doubt they are actually 6000 MAH, im more inclined to think they are 2500 or 2800 MAH.

 

[Gibson99]

the thing that makes me think it's a cap is the cross stamped into the top, the 2 thin wire leads coming out the bottom (through what appears to be cardboard/paperboard), as well as the "ring" stamped around the bottom. in @kamkar1 's pic above, the ring looks to be raised, not pressed in like a capacitor. the body is held down to the board with foam tape. and when i googled images of the 18650, it looks like a AA battery, complete with the little "button" for the positive. This doesn't have the button.

it does run for at least 20-25 minutes in this car, but then again it's a VERY simple/basic car that only goes about 2-3 mph and doesn't have proportional controls. dunno what freq the radio runs on, but the transmitter doesn't have a power switch. the LED only comes on when you're holding one of the control sticks down. it can steer while not using throttle, but that doesn't mean much, really. the tx doesn't have an external antenna, and the car only has about 3 inches of 16ga insulated wire coming off the board for an antenna.

didn't see anything weird in the car to indicate why reverse isn't working. probably should have looked at the TX first anyway. thing is though, the TX led comes on when you press down on the left stick, so that tells me the button is working, it's just not transmitting or something. or maybe it's actually 2 buttons and only one is being pressed.

 

[jokiin]

it does run for at least 20-25 minutes in this car, .

would run 20 to 25 seconds if it was a capacitor

 

[kamkar]

Try take its physical measurements as good as you can without having sparks flying, and see how they stack up to the 18650 standard, though i do think there is a little wiggle room in the 18650 standard.

The battery in my pic also have something going on in the end, this is leftovers from the connectors that was connecting the batteries in the power pack for the HIS torch.
Some sort of thin metal that appear to be spot welded to the battery. ( 3 tiny spots )

18650 is also what is in Tesla batteries, on the other hand the new mega factory will be making batteries a bit larger, not sure if its to a existing standard or Tesla pulling a apple on us.
But the new Tesla batteries should be 30% larger, but i am not sure if thats in capacity or physical size.

The button in the ? end of lipo batteries like the 18650 depend on the type, there is both with and without, and there is also with ot without charge protection circuitry, i think both yours and mine are with charge protection, seem like similar batteries without safety PCB look a little different in the + end.

A 18650 with protection circuit is a little longer than one without, similar the types with the knob in the + end meaning they are for use like regular batteries where you put one or more in a devise.
And then there is my type in the pic that dont have the knob in the + end as they are supposed to be welded/soldered together to make up lager battery packs ( my HID torch was made up of 3 "sticks" with 3 of these batteries in each, making 3 X 12 V or in this assembly 3 X whatever MAH these battteries are )

This is the type i have.

Often assembled to make up a power pack like this.

The common type with the knob on the + end just look like a amped op AA battery.

Here is a pic that clearly have both ends of my type of 18650 in view, as you can see the + end sort of have a knob too, but its too large and not knobby enought to be used in say a LED torch.
Thats whu i had to add a blob of solder to that end to make it work in my LED torch.

Here you can see protected battery Vs no protected and sizes

Lipos is a science too

 

[SawMaster]

There's more than a "little" wiggle room with 18650's; they vary wildly Protected versions are too fat or too long for many flashlights and even unprotected cells vary a lot on length so don't always fit. Some expensive lights can only fit a few specific cells and nothing else because they are machined too tightly Unless there's a significant change in technology, 18650's can't get to more than about 4200 mA actual capacity and anybody who says their 18650's deliver more than that are simply lying But we've come to expect those lies from most of the Chinese cell makers and suppliers- 5800 is widely quoted and even 8000 has been claimed. That's technically impossible to do.

All eyes are on the new "Tesla" cell which is a 20700 size, able to deliver about 1.5X of what 18650's can do and more than the best larger 26650's now do Whether it becomes a 'standard size' in other applications is the big unknown right now, but with it's performance it's likely to displace the 26650 in many applications. Tesla developed it specifically to get the most power possible when assembled into packs with limited outside dimensions- before this they used 18650's which is why that size cell has been so well developed compared to the other sizes

The incised "X" is found on several LiIon cells meant for permanent installation. Like with capacitor's it's there to prevent over-pressure conditions. Most LiIon cells do this with a thin metal disk and holes at the positive end; each manufacturer used a slightly different system there so that you can identity the manufacturer even with re-wraps and unsleeved cells by studying the venting system. Protection circuits on cells are always an aftermarket add-on; none of the big name cell manufacturers makes protected cells. Indeed, none of them actually intends their cells to be sold individually or at retail- they're supposed to be used only by device manufacturers to make battery packs but none of them are complaining about the massive numbers of their cells being sold on the open market to vapers and flashlight nuts like myself

Phil

 

[Gibson99]

learn something new every day!

 

[jokiin]

I've seen a lot of the 18650 cells that are fake capacity with a smaller battery inside, to make matters worse they're often marked with even larger capacity than what fits anyway

 

[kamkar]

Yeah it is a market with a lot of shady stuff on too.

 

[SawMaster]

Same as with dashcams, you gotta stick with reputable sellers and stay with the top brands (Panasonic, Samsung,LG, and Sony are the best). Efest is a re-wrapper but has good cells. Shipping has become quite an issue with numerous Chinese discount sites no longer shipping to many different countries and if they do the costs have skyrocketed from just a few months ago. While we all hate price increases, this has helped eliminate some of the fake cells since the shipping is the bigger part of the overall cost now when purchasing 1 or a few cells.

If you've got a really hot soldering iron, you can solder to these cells and swap out crappy cells sometimes found in cheap equipment with ones having better-suited qualities for the job. Right now the Sony VT-6 and the Samsung 30Q cells are the front-runners in the power game. If you're new to LiIon cells, for safety's sake read this http://budgetlightforum.com/node/45314 before doing any soldering, welding, or charging with LiIon cells.

Still hoping to get a drone this summer. It looks like my work will be good enough to do that if something doesn't 'go boom' and wipe out the piggy bank.

Phil

 

[Gibson99]

I'm not new to lipos since I have several for my quads. But they're the "bag" type of cells, not hard ones like this. Have had to get rid of a few that got real puffy due to crashes that damaged them.