650 mAh rechargeable Tx batteries

[LBRC]

I’ve been putting in a lot of Epoch track time, approx. 2 hours a day, and have started to feel the battery strain. Especially since I’m mostly working on multiple cars at one time comparing different versions of the same mod and find it easiest if each car has it’s own Tx, also because I want to stick to the Epoch Tx for true evaluation since that’s what others will mostly use.

Anyway after my wife realigned my priorities, I don’t think I would have actually taken the batteries out of the smoke detector I was just looking :o . I had to do something, 9 volt rechargeables where out at only 150mAh they would be more annoying than useful besides for $12 each I decided I could certainly do much better.

So here’s my solution, two 650 mAh 14430 lithium-ion’s, for 7.4 volts compaired to a 9 volt rechargeable’s 7.2 volts. They are just a hair wider than a 9 volt but otherwise fit perfectly, all you have to do is solder one side of the batteries together, cut through the corners on the positive side of the battery compartment so that the wall presses/swings in slightly at the bottom, then pull the tabs out to make contact, and make sure you put them in + to + and – to -. Simple, quick, works great, and best of all you can revert back to a 9 volt at any time.

http://lbspd.com/v-web/gallery/albums/album61/Tx_Li_Ion.jpg

Warning: Lithium batteries can be dangerous, they must be used responsibly and require a degree of intelligence.

• You must use a lithium battery charger
• You must read and understand the directions
• You must absolutely never charge them other than at the rated voltage
• And never over the rated current, usually 1C (i.e. 650 milliamps for 650 mAh cells)
• You must never discharge them below 2.9 volts per cell.

If you don’t understand you have no business playing with lithiums. Just like a car or lawnmower they can and are used safely every day, but also just like a car or lawnmower someone will fail to use common since and injure them selves or worse someone else usually though pure stupidity. If this warning sounds harsh to you I don’t recommend cars, lawnmowers, or lithiums.

One bad weekend: Yesterday a 15 year old neighbor kid put his brothers eye out pushing a lawnmower over a gravel driveway, then to top that last night a young man decided he didn’t need to slow down when driving on fresh gravel and oil rolling his truck right in front of my house, he wasn’t even scratched but the 16 year old girl in the seat beside him has at least 6 years of plastic surgery to look forward to before anyone will look at her without flinching. Then not to be outdone by someone else’s stupidity I actually considered borrowing batteries from a smoke detector, until my wife brought me to my senses in a far kinder way than I disserved.

[cdog4w]

Interesting idea. Any good sources on those batteries? Also to comment that the battery will peak at 8.4V so its closer to the 9V than you would think. Not to mention with an epoch you will never be all that far from it, so pefect conditions aren't a neccisity.

http://batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1337

has the 600mAh ones for $4 each. This place has the best pricing I've seen so far. One time shipping charge of ~$5 so be ready to buy a bunch of stuff to offset the shipping cost.

Its shocking to me that people online charge ~$20 for the xmod lithium kits when the batteries can be purchased RETAIL for $3.50 each...

[LBRC]

With the lithium batteries the Tx works great, if anything the range is increased (current not voltage), the electronics don’t actually run off of 9 volts.

The BS cells would work just fine, I have purchased batteries from them, both lithium and NiMH, the cells arived promptly, but I do have to tell you that you get exactly what you pay for though, which is not to say you get anything better buying from someone selling an Xmod kit either, especially since most Xmod fans are relatively uninformed and so are the closet Xmod internet shops (there are notable exceptions), I have no doubt that most of the people selling kits are buying cells directly from BS or similar sources.

Lithium batteries, just like milk at a grocery store, have very distinct shelf lives when you buy from a discount store it is usually because they are over the expiration date and can no longer be sold to a manufacturer. It doesn’t mean that the battery doesn’t work it just means that like milk with an expired “sell by date” it won’t last near as long. I do like the BS introduction, and had to read it several times but finally decided that the whole thing actually states that they don’t sell used batteries they are “new” (you know not used) and that the batteries are made in a factory (duh), it implies something entirely different though if you just scan it quickly it implies that they make their batteries at a facility they own and that you are receiving cells fresh off the assembly line, not. It doesn’t mean that you aren’t going to get a good deal it just means you get what you pay for, which is not always true either, since you also have to know exactly what you are buying and purchase it from a reputable source.

[cdog4w]

Good post, you'd get rep points if this forum used it. Come to think of it one18 is the only place I've seen it used. Still, I think the ones from BS will last long enough for most of our needs. Even if you cut the recharge cycles from 500 to 300 for it not being shelf fresh, it's still half the price of competing vendors. Ordered from them before (just nimh) and had a good experience. Will probably again once I figure out my next set of battery needs. Need to cover my epochs, an airlark heli (bladerunner clone), perhaps my custom xmod, and hopefully my wireless cam. Maybe some small lipos to fart around with too :)

Anyway, I'm hoping a better current source will work well on the wireless cam I got too, same principle that you mentioned for the epoch Tx. The 9V its designed to work with doesn't even put out the spec current listed on the "instruction" sheet. So a slight undervolt but better current should provide a more stable transmit frequency, or so I hope :)

[epoch1-43]

Sorry for OT post, but cdog4w, what cam are you using? Got pics? :)

[cdog4w]

Using this cam:
http://www.geeks.com/details.asp?invtid=203C-50MW-N&cat=VID

Got it for $34 shipped :)

Sample video:
http://cstanleyw4.home.comcast.net/rc/cam_on_car.avi

Haven't tried at home, but hopefully will have less interferance. Offices are supposed to be nasty (fluauro lighting etc.)

If you want detail pics I can take some.

I have plans to improve upon the signal, such as using a lipo or other power source since the 9V its designed for doesn't provide enough current and the transmitter isn't very stable on it. There is also a cheap home-made antenna I would like to make for it too. Kinda useless except for home use until I can get a usb cap card to use on a laptop or some other device that will record off an RCA input.

[arfin]

Hey Cdog! Watching that video was awesome, i bet the office peoples are jealous! Can you show a pic of where you mounted it?