My custom Rx hump pack
 

Well I was looking for a good/powerful hump pack to power the new servos I will be putting in my truck soon and couldn't find much beyond 1400mAh. I bought an Airtronics steering servo that's 200oz-in and .07 speed @ 6v. The 1200mAh Venom pack was fine for the stock servos no doubt...lasted a good long time too...but I wanted more. hehe :D

So I set out to build my own high-current hump pack. Start off with Energizer 2500mAh AA cells and off we go! I've used these cells for about 2yrs now in a wide range of equipment and love them. I've had them in cameras, a high-speed Mini-T, in my DX3.0 transmitter (9 cells to make up for the voltage loss @ 1.2v), MP3 players, etc. (5) of these cells in a hump configuration fits pretty darn snug with only minimal trimming of the radio box lid. A support on the inside needs to be removed to clear the top cell.

So here's what I ended up with...BTW there's also a picture of my solder/de-solder station as well. I haven't checked pricing for a pack of this capability, but I'd imagine $30+ and I've only got $12.50 in the (5) cells. They're $10 for (4) at Wal-Mart.

http://i4.photobucket.com/albums/y12...5/DSCF3869.jpg


http://i4.photobucket.com/albums/y12...5/DSCF3868.jpg


http://i4.photobucket.com/albums/y12...5/DSCF3871.jpg


http://i4.photobucket.com/albums/y12...5/DSCF3872.jpg


http://i4.photobucket.com/albums/y12...5/DSCF3873.jpg

RE: My custom Rx hump pack
 

hey how is the rear of the second pic soldered up i cant exactly see whats going on there ? can you make a better pic of this , i dont understand how the top batt is being connected and i want to see how and where you soldered the rear of the batts

RE: My custom Rx hump pack
 

are you still able to charge them with a rc charger? I think you could have made your own from 1/3 size cells I think I saw some 2200 mAh ones once that were loose.

RE: My custom Rx hump pack
 

I have a Duratrax ICE charger so I can choose (5) cells, the capacity, charge rate, etc. So yeah no problem there.

RE: My custom Rx hump pack
 

If you know a little about electronics it's *real* easy. You must alternate connection positive to negative and make a complete path to flow through each battery. Here's the side where the connector is soldered.

http://www.sciencebuddies.org/mentor...lec_img053.jpg


http://i4.photobucket.com/albums/y12...5/DSCF3870.jpg

RE: My custom Rx hump pack
 

Wooo baby this pack is strong!! Woke up that crap Futaba S3003 even over the 6v Venom hump pack.

RE: My custom Rx hump pack
 

ok sir i fully understand how its done now , i have these energizer packs too and i use them in my DX3R and led torches they really are the best rechargeable batts you can get , and i have 5 of these AA batts lying around so im gonna make this pack and HELL YEAH its powerfull nothing like it on the market with this many miiliamps lol isnt when its done like this it becomes 12,500 milliamps lol , one things forsure is that i never have to waste money on useless weak hump packs sold at the local hobby shops lol , thaknyou very much for this usefull tip indeed [sm=thumbup.gif][sm=thumbup.gif][sm=thumbup.gif]

RE: My custom Rx hump pack
 

No sir, the max capacity is still the same as the individual cell (2500mAh).

The 6volts will give enough power to get some good torque and speeds out of your servos...the 2500mAh cells will last a good long time!!

RE: My custom Rx hump pack
 

yep, the only way you'd get 12,500 mAh out of it would be at 1.2V and if you lashed all of the positives to one positive plug, and all of the negatives to one negative plug.....though, I do have the urge to make a pair of these, and then use a Y cable to double the run time.....

RE: My custom Rx hump pack
 

so could you still do this using AAA batterys and make two seperate packs then join them together at the charge plug , like this it will be smaller and still pack some punch . and isnt it too dangerouse to run extremely high mah , would it kill the reciever

RE: My custom Rx hump pack
 

The highest rating I've found in a AAA was 900mAh. I wouldn't bother...that's worse than the hump packs that are already out there.

The high current ratings won't kill the receiver.

RE: My custom Rx hump pack
 

yep, in a AAA you'd have to use 10 cells just to hit 6V and get the milliamp hours rating high enough to beat regular 5 cell hump packs now.

I was talking about taking a pair of 5 AA packs, running 2500mah, 6V each, and setting them in a parallel Y cable so that I had 6V @ 5000mah, and also could carry two spares and have them ready to interchange on the fly, but, if I were going to waste that much space, I'd be better off just getting some sub-C cells and making a 4200 or 4600mah 5 cell hump or stick pack....depending on how I configure stuff when I do the new TVP's a sub-C hump might actually work, since I'll be putting the reverse servo directly against the transmission, and the steering will be all the way forward, so, I'll have plenty of room beside them to work with.....and fit that all UNDER the fuel tank )

RE: My custom Rx hump pack
 

im really good at welding and soldering and been doing it for over ten years now, but have ZERO idea of how to do battery configurations and little understanding of intricate small electronics lol , thats why i need you guys help , if you do end up making a 6volt hump pack capable of making 5000 mah plus dont forget to show me some pics so that i can replicate it for my self to make .

RE: My custom Rx hump pack
 

6V Hump @ 5000mah = 2 x 6V hump packs @ 2500mah wired to be on one connector in PARALLEL not series (tie both reds together, not a red to a black) and there you have it.

RE: My custom Rx hump pack
 

what do you get if you only use four of the aa's Mah and cell wise? this looks to be an interesting idea.

RE: My custom Rx hump pack
 

4.8volts @ 2500mAh.

RE: My custom Rx hump pack
 

I understand how too build a hump pac..But what solder are you using?Rosin core will not stick to batt.How about silver or acid core?
Only thing I have for iron is a small butane torch with solder tip..Should I get a 60 watt elect gun?
Thanks for any replies

RE: My custom Rx hump pack
 

I use a standard 60/40 low temp. solder. And it's Rosin core BTW. You may need to rough the surface slightly to get it to stick. Also you may not be concentrating your heat properly. You need a good soldering iron...not a gun.

RE: My custom Rx hump pack
 

I would definitely do that if I could solder worth a crap! My soldering looks like the iron puked up solder. I need a higher watt iron, that's my main problem. Looks very professional, good job. From what I have used those same batteries in, they should last a long time in there. No need for a recharge during the day.

Oh, BTW, does everything still fit ok in the box, I got an X rad. box, what do you have?

RE: My custom Rx hump pack
 

Yes sir you need the proper tip/iron with the proper heat levels for it to look that nice. [)] Thanks for the compliments BTW.

I have an X radio box in my S-25 where this is installed. I had to trim out a little plastic from the lid for it to close. Nothing that will take away from the function or support of the radio box lid.

There are (2) triangular shaped supports in the lid that need to be cut out for the pack to fit. Otherwise it is a perfect fit with the servo tape holding it securely in place. :D Need a picture?

RE: My custom Rx hump pack
 

I think I'm gonna try this since this is my last week of classes, and I think I see what you're talking about with the lid. I doesn't come through to the outside of the lid does it, only a change inside? I'll be heading to the hardware store looking for a good iron. Can you show me the style tip that you used. Thanks!

RE: My custom Rx hump pack
 

Sure here are some pictures of everything.



http://i4.photobucket.com/albums/y12...5/DSCF3894.jpg


http://i4.photobucket.com/albums/y12...5/DSCF3895.jpg

RE: My custom Rx hump pack
 

Well, I made my pack today. Man the joints look like garbage compared to yours. I gave each a good tug and their solid though. It looks as nice as yours now with the tape all over it. Thirty seconds with the dremel and the box lid went right on.

RE: My custom Rx hump pack
 

[sm=shades_smile.gif][sm=thumbs_up.gif]

We can't all have 20yrs soldering experience. If they hold you're golden! Welcome to the club BTW. hehehe

RE: My custom Rx hump pack
 

Soldering battery cells works best if you use a heavy tip on your soldering iron: it stores more heat than a small tip.
The faster you can solder, the better for the cell: batteries don't like excessive heat. That means a big iron.
Properly sand the battery terminals: they're likely to be nickel plated against corrosion.
Use an etching compound, this really helps, but you have to wash the remains off afterwards.
First tin the battery terminals and the wire seperately, solder them together afterwards.

That about sums it up.