PDA

View Full Version : 8 NiMH AA Powered



CableMan
06-01-2005, 01:46 AM
I was able to put 8 AA batteries into my H8. Runs really great!!

I am using the Energizer AA NiMH batteries (about 5 amps continuous discharge) at 9.6V. At least Energizer claims they will give 5A/2C for 20-25 minutes, but voltage will drop to about 8V.

Here is the technical data and you can look at the bottom left chart:
http://data.energizer.com/PDFs/nh15.pdf

Of course they don't compare to LiPo batteries!

Oh, it only cost me $2 at Radio Shack to get the additional battery holders.
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F011%5F002%5F001%5F000&product%5Fid=270%2D401

Does anyone have any idea about how many amps the stock motor draws?

How about the x-speed?

.5x8
06-01-2005, 03:56 AM
how much were the batteries

CableMan
06-01-2005, 01:40 PM
You can get them at Wal-Mart, Target or Wal-Greens for cheap. I paid $17.87 + tax for a pack of 8 of them at Wal-Mart. They come in packs of 4 or 8.

You know, the downside to using these is the weight, but I love getting 25-30 minutes of run time.

The cool thing is that these batteries work in many other devices that take AA.

plain_simple
06-01-2005, 02:24 PM
Can you post some pics on how it fits in the H8?

CableMan
06-01-2005, 04:52 PM
Please excuse my crude wiring, but it works for testing. I still need to solder and heat-shrink the wires. I plan on getting either strong double-sided tape or vecro to connect the battery holders to the car. They fit fine in the windshield, but that probably throws of the center of gravity, although I didn't notice it when driving. The car does drift a lot (even on pavement) with the extra weight, which is kinda' fun. Just make sure the wires do not get in the drive train and tangle everything up!

Here is a picture of the battery configuration:

http://halfeight.com/gallery/uploads/131/IMG_0500b.JPG

Here is a picture of the battery holders on the car:

http://halfeight.com/gallery/uploads/131/IMG_0498b.JPG

Here is a picture of the battery holders through the windshield:

http://halfeight.com/gallery/uploads/131/IMG_0499b.JPG

nslv
06-01-2005, 07:10 PM
Hey this is my custom pack, is easy for made.
http://img194.echo.cx/img194/1481/pilas29yx.th.jpg (http://img194.echo.cx/my.php?image=pilas29yx.jpg)
http://img194.echo.cx/img194/8708/pilas38iu.th.jpg (http://img194.echo.cx/my.php?image=pilas38iu.jpg)
http://img194.echo.cx/img194/2720/pilas45sj.th.jpg (http://img194.echo.cx/my.php?image=pilas45sj.jpg)

nslv
06-01-2005, 07:11 PM
http://img194.echo.cx/img194/5163/pilas51rp.th.jpg (http://img194.echo.cx/my.php?image=pilas51rp.jpg)
http://img194.echo.cx/img194/2170/pilas0os.th.jpg (http://img194.echo.cx/my.php?image=pilas0os.jpg)
http://img194.echo.cx/img194/5987/pilas12sp.th.jpg (http://img194.echo.cx/my.php?image=pilas12sp.jpg)

navydochalf8
06-01-2005, 07:26 PM
i think those are both great designs if you only wanna throw a few dollars in to her and 20 bucks worth of power. if you all have a battery shop in town take the battery holder to them and ask if they can make you a rechargable 8 cell pack the same size for cheap. :D

CableMan
06-01-2005, 07:57 PM
Zenislev,

I thought about doing the same thing, but I would have to remove the hinged battery doors. Not sure if I want to do that yet.

CableMan
06-01-2005, 08:12 PM
navydochalf8,

That doesn't sound like any fun. I would also have to buy a charger as well and I can't reuse my batteries in my kids' rc cars, my digital cameras and mp3 player.

Anyway, I have ordered 8 of these:

CBP1650AA
info
CELL SPECIFICATIONS
AA
Chemistry: NIMH
Capacity: 1650mah
Length: 1.95in. 49.53mm
Diameter: 0.56in. 14.22mm
Weight: 1oz. 28.33gm
Available (0) PRODUCT DESCRIPTION

New NIMH cell. True 1600+ mah performane in high output use. 15-20amps no problem. This is a great replacement for KR-1400 or KR-1700 nicad packs. Perfect for Unicorn flying wings. This cell will outperform KAN1300/1400 and CBP-1400.

$2 each = $16 total

nslv
06-01-2005, 08:26 PM
I use de Sanyo Idustrial grade 2500 mha, of www.ripvan100.com, the best cells of the AA size, of course.

.5x8
06-02-2005, 01:51 AM
why wont u just get a set of URC packs? and for ur kids, jsut change the plugs to deans or watever you use! then you could just attach it to the top of their car! i did tat with my stick packs when i used tamiya plugs..and my little cuzin wanted to try so i stuck em on my old tyco! it was a bit faster and it ran for a long time! but if you wanted to use AAs for all those things..thats cool..its just that the 8 cell AA charger i ahve...takes FOREVER to charge! i rather use my REAL r/c packs charging on my real r/c charger! but what you like is what you like! nice setups guys!

CableMan
06-02-2005, 01:53 PM
Zenislev -
I couldn't find specs on those batteries. What is the maximum sustainable discharge rate and you can still get most of the capacity of the battery? (Not just burst or peak.)

CableMan
06-02-2005, 02:56 PM
.5X8 -

Energizer AA NiMH batteries only take 15 minutes to charge (but as with any NiMH batteries, the quick charge does not allow you to get the maximum capacity of your battery). If you want to get the maximum capacity of any NiMH battery, you should charge for at least 10-12 hours at a low amperage (trickle charge). Also, the quick charge shortens the life of a NIMH battery.

Here is the link to the charger:
http://www.energizer.com/products/rechargeables/sizes.aspx
(Select the first charger to view details.)

I am not that concerned with speed, since I have a nitro car that goes over 50MPH, so if I want speed, I can just run that car and get infinite run times (about 4-5 seconds to fill while the engine is running, so not really any stopping).

I bought my H8 to have fun with my kids. I can't go too fast, or they just won't be able to handle it. They aren't allowed to run my nitro cars, so this is the best bet for them. We can take the H8 and my 1/8 buggy to the track and have a blast. I don't have to keep changing their batteries out each time while I am trying to drive my car. This gives me 30 minutes of peace or should I say 30 minutes of loud nitro action.

OneTimeCRX
06-02-2005, 11:24 PM
For around a month now I've been using a similar AA setup, but with only 7 cells. When I tried 8 the ESC would simply die as soon as I touched the throttle. Luckily no permanent damage was done, and I could revert back to 7 cells just fine. I use velcro to hold the extra battery clip down, just above the servo plate.

CableMan
06-03-2005, 01:15 PM
Were you using 1.2V batteries or 1.5V batteries? I think the esc is only setup to handle about 10-11V Max.

8 X 1.5V = 12 V (too much)
8 X 1.2V = 9.6V (ahh, just right)

.5x8
06-03-2005, 02:34 PM
well, cable man you've made a good point, since the car is for your kids, it doesnt need to be like gp1100s...but for me..ill take batt packs! lol. well the most important is, that you have fun and ur kids have fun!

OneTimeCRX
06-03-2005, 07:02 PM
Cableman, I was using 1.2v NiMH cells. Measured with a voltmeter, the actual voltage was 10.8v unloaded. I thought that once you add a load to the cells it would drop below 9.6v, but apparently the ESC still couldn't handle it.

What happened with 8 cells was that after turning the car on, I could use the steering servo just fine. But as soon as I touch the throttle, everything would shut down - no steering or throttle. And this would happen before the car got a chance to move, though the motor would give a small buzzing sound just before shutting down. Once the electronics shut down, I'd have to unplug the batteries from the ESC for a minute or two before I could try again.

.5x8
06-04-2005, 04:58 AM
thats weird...it should work if you were using 1.2v...maybe theres something different about ur esc...

CableMan
06-04-2005, 04:20 PM
Mine hasn't had a problem running 8 X 1.2v cells. Yes, it will drop below 9.6v with a load. Are your batteries OK (can they handle the amperage?) Were they fully charged? When my batteries get really low they act like that, but I don't have to unplug them to get them to work again. Are you running the x-speed motor or stock motor? (x-speed will require more amps)

Other than that, maybe your esc is bad? The car is designed for either 9.6v 8-cell NiMH batteries or 7.2v 6-cell NiMH batteries.

.5x8
06-04-2005, 05:03 PM
hey CRX, if ur putting too much power into ur esc....try using a resistor on both sides on the wire (the one that connects to the battery pack). a few 100 ohms should do it.

OneTimeCRX
06-04-2005, 06:54 PM
Cableman, I think it's a fault of the ESC. With 7 cells everything runs fine. One of these days if I can get my hands on a 8-cell 2/3AA saddle pack I'll give it a try (kinda hard to find in Sweden though). I use an x-speed btw.

I don't think it's a problem with current draw through the batteries, since the ESC will shut down at the slightest touch of the throttle (where the current draw isn't very high, please correct me if I'm wrong).

It doesn't matter though, since 7 cells is good enough until I completely replace all the electronics.

.5x8, thanks for the suggestion but I don't want to add any resistors. Adding resistors will simply leech electricity from the batteries (and turn it into heat), so it's just a waste of power.

.5x8
06-06-2005, 12:35 AM
or use a BPU (batt. protection unit) might work....suit urself....just run 7 cell until u get different electronics anyways. best way right there.

NitroSpazzz
06-06-2005, 12:56 AM
Kind of off the AA idea but .5x8 you mentioned the BPU thing. When I ordered my 8 cell pack from here it came with that. Do I really need that thing taking up space, adding weight and making heat? I would like to remove it but if the ESC will fry itself without I could leave it on ;)

.5x8
06-06-2005, 01:20 AM
no you dont need it.....the esc works perfectly fine without it..