garyo1954

Picked up an 8 pack this afternoon, thinking I might try making my own battery pack. But I'm wondering if a NiCD charger will charge them.
The package says they are great for delicate electronic equipment. I haven't weighed them yet, but they feel the same as the NiCDs.

Anybody tried these batteries? (Or do I get to be the crash dummy this time?)


Here's a link, not much information there though:


http://www.energizer.com/products/re...les/sizes.aspx







edited to add link by Kaptain Kangaroo.

RCKen

My Feedback: (9)

garyo1954,
The biggest problems with batteries like this isn't the chemistry of the battery, but rather the battery form factor. Batteries like this without solder tabs on them can be VERY difficult to solder into a battery pack without damaging the batteries. Nimh batteries have a small plastic seal the seals the entire cell. If it gets too hot from soldering the seal will melt and then the battery will be ruined. It may still charge and give voltage, but it's now unreliable as it can fail at anytime like this. How much heat is too much. I can't give you the exact temperature, but I can tell you that 2-5 seconds of heat from a soldering iron can be too much for it. I'm not saying that it's impossible to solder batteries like this, but unless you can make a perfect (and quick) solder connection you're going to run a real risk of damaging the battery cell.

For those that want to build their own packs I recommend that they get batteries with solder tabs on them so that can avoid a lot of the problems I've listed above.

Ken

garyo1954

Excellent point Ken. We've seen it numerous posts right here that heat will destroy batteries. Even the tutorials on pack building state it.
A few suggest such batteries (2500MaH) would not provide the current necessary for electric flight, or not a long flight.

All in all, it appears, if you choose to try:

The majority use an iron 50 watts or above.
The iron should not be on the batter longer than 3-5 seconds to make the connection.
Holding the bar/wire down on the post with a screwdriver helps drain off excess heat (like a heatsink.)
Flux can be used, and tinning the battery and the wire or attaching bar is often suggested.
Also cleaning the battery posts with alcohol, or light scuff the terminals with sandpaper.

I've never tried it. But I'm curious. (And you know what curious gets you?)
I would hope no one would rush to do it without some checking, and satisfying their own concerns.

I have to agree with you Ken. 100% reliability is what we are seeking. And the best chance we have is professionally built packs.
(Still there is that 1% percent stupidity factor in me that says, "Watch this!"

LOL

luis_hac

My Feedback: (4)

You don't have to solder them. If I remember right there is a "battery holder", holds 4 AA batteries and looks like a square pack with a universal connector you can get. You'll have to make sure you wrap it in foam for extra shake protection but I believe it will work. I have one of them a while back, don't remember what happened to it.

RCKen

My Feedback: (9)

This is very bad advice for an airplane application. Putting foam around it won't be enough to isolate it completely from vibrations. The vibrations can cause the battery cells to lose contact in the pack which can cause loss of control of the plane. Any battery that goes in a plane needs to have the connections to the cells properly soldered or spot welded.

Ken

sscherin

My Feedback: (1)

Radio Shack sells these battery holders.. $2 PN 270-407

It's not exactly high current but it'll make up a 9.6v pack for testing.

you'll prob melt it trying to run an motor on it.

It's to bad MEC doesn't make solderless power tubes for AA size cells

toobadtwo

I use a battery holder and 4 alkiline batteries with I want to fly and have forgot to charge my rx battery. so far (10 to 12 flights later)it`s worked fine.

RCKen

My Feedback: (9)

Even in Russian Roulette you can go five times before the gun goes off. I'm not trying to be a smart allec, but rather trying to make a point here. So far you have been lucky, but you're playing around with something that could go bad in a hurry. In all honesty, the receiver battery is probably THE most critical piece of equipment in your plane. It would a shame to lose a plane just because you tried the cheap way out. I can't see risking hundreds of dollars of a plane on something this simple. And it's not just the plane. What if you lose control and the plane hits and injures somebody, or worse yet kills them? All because you took a shortcut? This might have worked for you so far, but you're really asking for trouble doing this. And it's really bad advice to be giving here in this forum.

Ken

bruce88123

Different NiMH batteries have various charging/discharging and internal resistances. This makes some of them VERY unacceptable for RC use. I would also never use a battery holder in anything other than an electric plane due to the trouble the vibration could cause in a nitro/gas plane.
Soldering on regular cells is also a bad idea as it can cause thermal damage to the cells very easily.

More battery info:
http://www.rcbatteryclinic.com/

garyo1954

So far the batteries are safe from any soldering. And with the grandkids coming Saturday I'll probably charge them and use them in one of those Zip Zap Micros.
I did take disassemble one of my packs to see how they were put together. And to see why it wouldn't maintain 9.6. The answer was two bad cells.

If I get any of this done, it won't be until next week. There is no rush in killing a perfectly good battery.

Deadeye

I've built probably 12 RX packs with the Energizer Nimh in the last four years. Never had one fail. I am an expert at soldering, though, so i wouldn't recommend it to anybody. I use 100 grit sandpaper to rough up the ends, clean with iso, and apply solder paste with a toothpick. Once the cells are tinned, I use braided copper to link them. After the pack is built, I form charge them at 50 ma for however long they need. Then I discharge them with my Triton to see their capacity. I do this 3 times. What's amazing to me, is that they will take EXACTLY what they are rated on the cell. The last three 2500 ma packs I built discharged at EXACTLY 2500 ma, and charge back up the same. I've saved about $250 over the years doing them myself.

But again, I'm not going to suggest this to anybody.

rcuman

Be careful when soldering anything to a battery because if you get it too hot the battery will explode. I used to solder batteries to motherboards so that they will keep there BIOS settings. I got one too hot one time and it exploded in my face. Thank goodness I was wearing glasses at the time. It was a quarter sized watch battery though not a AA.

RevGQ

I build packs using these batteries, usually buying them on sale during the Xmas holidays. I simply put paste flux on solder braid [bought from Radio Shack] and the battery ends. I then tin the braid, and by getting a nice drop of solder on the end of the iron, I place a drop of solder onto the end of the battery. To attach soldered braid to battery end, I first heat the soldered braid and place it onto the drop of solder at the battery's end. My packs have never failed, and I have been using some packs for three seasons.

garyo1954

Speaking of stupid things I have done in my life:

Many, many moons ago when I was working R&D, I was given the task of high voltage power supplies for a certain flight simulator; the kind that trained the pilots to fly the machine. I was handed a set of drawing which I followed carefully, and was quite pleased with the final product. It went to final checkup where they hooked it up......and immediately blew a two by four ceiling tile out.

Seems in all the zest and zeal to get the job done on time, somehow we forgot to check the polarity of one 1000uf electrolytic capacitor.

Anyway....

Thanks Deadeye! I was wondering if the batteries were reliable. 12 packs/4 years/no failure. That's good enough for me. I do agree with everybody. If you don't have some soldering experience, it'd best not to learn by trying to make battery packs.

J-3

Over the years I have accunulated about 1000 flights on 4 Lazy Bee's powered by the same Magnum 15 engine and the same radio gear HiTec Focus AM 3CH powered by 4 alkaline batteries. I get about 46 flights that are 12 minutes in length and I have never experienced battery failure or problems. I use alkalines as I can go flying in a moments notice and do not have to worry about charging batteries. I believe this has worked for me because I use a lot of foam to wrap the batteries in and I replace the 4 cell holder each year as the plastic wears out and breaks from the spring tension. For me it has worked well.
Thanks for your time....Brian