Slim LiPos ???

[atcttge]

I'm looking to get slim LiPos for my tank because I need two batteries to power two boards.

1) Compared to normal size LiPos, are slim ones have a shorter running life? I mean do they have smaller capacity than regular sized ones?

2) Any recommendations for slim/small LiPos that can power your first or second gen HL MFU? The HL MFU board will only power two small motors that will run an accessory, not the whole tank.

3) Any recommendations for slim/small LiPos that can power the IBU2 Pro or IBU3? This is the main board of the tank.

Thanks.

[MichaelC]

If you go onto the HobbyKing website, you can specific the battery size you need and they will give you a list of lipos that will fit that size. 2S for Heng Long, 2S or 3S for IBUs. If you don't need much output then pick a lower discharge rate and it will run for a real long time (i.e. 1C/5C vs 25C/40C).

[Jay-Em]

The hobbyking zippies and Turnigy small sized packs are as good as any other brand.
The "compact" moniker just means that the manufacturer has put the LiPo-slush in somewhat different shaped bags.

I use the yellow 25c 2200mah in almost all tanks and vintage cars. They always fit, however odd the battery compartiment is, and they are light, which is a boon in already heavy, metal-equipped tanks.

Afa high loads go, My Chally 2 weighs-in at a cool 5kg, and runs 2 Motraxx 390's. Turning on carpet, or grass made the Clark TK-22 brown-out and restart with NiMh's, even high-quality ones. Zippy's? The Clark just keeps running, lights don't dim with cannon fire (a sure-"fire" -forgive the pun- way to determine if a battery has enough oomph to power a tank. Suffice to say that Heng-Long's 2000mah's are a joke in that regard..) Don't underestimate the peak-power that tanks use with all their motors and gizmo's. They are by no means "low power appliances"

[Rad_Schuhart]

Humn, you are going to fit a HL board and a IBU. You know you need two transmitters for that, right? The stock heng long and a hobbygrade for the IBU. It might be better to control that motors with spare channels in your transmitter.

In case you already knew that, why just not to take a solder iron and just solder two plugs in a wire (one for each board) and save tons of space in your tank?

[atcttge]

Humn, you are going to fit a HL board and a IBU. You know you need two transmitters for that, right? The stock heng long and a hobbygrade for the IBU. It might be better to control that motors with spare channels in your transmitter.

In case you already knew that, why just not to take a solder iron and just solder two plugs in a wire (one for each board) and save tons of space in your tank?

Did that already. See viewtopic.php?f=195&t=20145, especially wibblywobbly's post at the bottom.

Yes, will be using two Txs. The stock HL Tx will be modified (i.e., opened, cut up, etc) to have a smaller form factor.

[Jay-Em]

I still believe that getting a small esc to power the mine plow, is a better solution, just take out the red wire in the ESC plug (to prevent it from cooking the BEC in the IBU2), and use the channel 6 rotary dial or something. That way the ESC can have its own power, yet be switched from the same transmitter. In snowcats (one of my other hobbies) it's usual multiple esc's for the tracks, and tiller drum, and high torque servo's to raise & lower blade & tiller. (Take a look at rcsnowcats . Com for ideas and solutions for accessories)

2 differend tx's just to power an accessory is an un necessary complex solution to a rather simple problem that quite possibly can be fixed with a small ESC and /or a remote switch..

Hobby King sells a small 10amp forw/rev car Speed controller that will run the motor on a tiller/mine plow pretty easy.

Could You elaborate on what the mine-plow (at least I gather by "accessories" you mean a mineplow and drum?) should be doing exactly? Is it just to raise and drop it, or is it a plow with whip-chains that should rotate? If it's just raising & dropping You should be looking at a servo-based solution, pissibly with a small UBEC if it's a really powerful servo. The bec on the IBU is a tad anemic tbh. I bet You have at least one spare channel left on the tx.

I f.i. Use the channel-5 3-way switch on the Kyosho Blizzard's blade servo. Works great. 3 steps: up high, medium height, so the driver can look out of tha cabin, so to speak, and fully lowered.

For realism, I added a landing-gear module that regulates servo-speed, so that lowering and raising doesn't "snap" but gently raises and lowers the blade.

[atcttge]

The mine plow is detachable. The plow arms are raised and lowered like the real plow, using motors that are in the tube housings up front which drives the lifting pulleys. Servos are too big, so I use two geared motors.

viewtopic.php?f=41&t=17727&start=500

[Jay-Em]

I see.

Well, If You have the extra channel available, it seems to me that 1 small esc will do the trick. put the motors in parallel .They seem like those smallish geared motors used in ships to make radar dishes rotate and such. They hardly use any amps at all, so a fwd/rev 10, or 12 amp ESC will do just fine. Like the one HobbyKing offers.

[atcttge]

How do I do the 1 ESC trick? I'm still new to this hobby, and I how I'd do this with the IBU2 Pro.

[Jay-Em]

How do I do the 1 ESC trick? I'm still new to this hobby, and I how I'd do this with the IBU2 Pro.

Well.

My suggestion is basically completely by-passing the IBU, and set the plow-control on its own channel on Your Transmitter.

All of this depends on You having at least a 6-channel transmitter and receiver!!

It dòes get somewhat complex, but less of a fuss than Your inital 2-receivers idea.

Let's assume You have 2 smaller motors that drive the pullies that raise/lower the plow. (I hope it's clear that the tank itself should be powered-up, since the esc's control will be powered by the IBU's BEC, but the pully motors by their ówn battery! )

1) if both motors control the same function, wire them inparallel, ie. red wire to bridge both + on the motor, and black wire bridge the - Make sure they lower/raise the plow the same.

2) choose which channel should control the motors, center its stick/rotary/switch (preferably the rotary dial, to prevent trouble with switching the esc to full-fwd/bck when using a 3-way switch. The Turnigy and flysky only have 2-way switches, so that would't work anyways on them, only on the R-dials. I don't know the brand of Transmitter You will use? )

3) put the esc servo-lead in that channel's bus on the receiver, but take-out the middle wire in the servo-lead.(!!!!!!!! If You don't, You'll fry the BEC-unit in the IBU!! )

4) attach a battery to the esc, and check if the esc gives its beeps, and led blinks (depends on the type)

5) connect an old motor to the esc, I bet You have some laying about. Check where the "neutral" is. Mark that on the Transmitter.

6) check if flipping the switch, or rotating the R-knob (on aflysky, or turnigy) makes the motor, indeed run, and check if it runs fwd ànd bck. With a 3-way switch, it might be neccessary to "double-clutch the switch backwards to get the motor to run reverse.

If that all checks out, connect the pully motors to the ESC's + and - and check it's workings when the rest of the tank is powered by its own battery. Connect the battery for the plow-esc and see where the plow is at its end of movement. Keep that in mind, because rigging a separate end-point switch (to switch-off the pully motors when at the end of their throw) is a whole new bag of headaches.

That's one of the reasons I would prefer to use a high-torque servo and a long piece of piano-wire, or even cables, to do the raising/lowering of the plow, because You'll be able to use a brake-link style linkage as used on rc fuel cars. Or flight-surface linkages/bowden cables. That way the end-point doesn't matter too much. The servo linkage would run through the plow-linkage, and just move "in the free" the stopper on the cable/linkage would mean that gravity keeps all of it connected, with the added bonus that the blade/plow will be free to move in the vertical, able to follow the terrain, but that's an aside.
Have a look at fuel-powered rc-cars. The principle will become pretty clear when looking at the way drivers link-up their disk-brakes.

The only disadvantage of the servo-method, is the cost. A good, 6kg + high torque servo is more expensive than a simple 10 or 20 amp brushed ESC

By manipulating the switch/rotary You can manipulate the raising and lowering fairly precise.

It's the way scale-crawler guys run their winches.

If You want a servo-powerd raise/lowering,(yes. I'll kéep pushing that solution :p ) it might be interesting to have a look at how Kyosho did it on their "Blizzard". A simple, but effective linkage-system. (Just google "Kyosho Blizzard" or "Kyosho Blizzard blade mechanism" and all will become clear) only drawback will be that You'll have to ditch the interesting motor/pully construction You came-up with.

I hope this is somewhat clear, because You are about to start a journey in the deep bowels of multi-function scale-models, where things can get really complex, and all is just limited by the amount of channels that can be controlled.