747

My Feedback: (1)

I wanna buy the smaller a123 cells(1100mah).
Pls tell me:

1)Where can I get the B&D 1100ma A123 cells (2 cells per pack) cant find in HD . Anywhere online or in WM maybe?

2) Where is the best place to buy loose cells?

3) Will I save $ if I rip open a B&D 1100ma pack?

TIA
747

rlmcnii

My Feedback: (3)

747,

Just bought a VPX pack at WM for $12. Just make sure to remove the resistor (thermistor??) at the end of the third wire nearest the end of the cells.

747

My Feedback: (1)

Wow..Does it say anywhere that its a123? Can I chrg it using my Astro109 a123 chrger( I use it for chrgin the 2300 mah currently), Will Astro109 behave the same way for the 1100 mah too? (LVC, Full V etc)

Also do we have to balance these 1100 mah cells? THANKS

rlmcnii

My Feedback: (3)

747,

No, as a matter of fact, it does not. Perhaps all the info here on RCU is incorrect. I don't really know. The VPX packs are B&D.

I charge mine with and FMA Cell-Pro 4 on the A123 setting and it has always worked fine. I have no first-hand experience with any other charger for these cells.

Walt Thyng

My Feedback: (9)

Menard's has the B&D VPX battery packs on sale for 7.99 thru October 5th.
Walt

747

My Feedback: (1)

Maybe the cells will have text as 'a123'...so leme open it! Did you open yours? Theres a disassembly post in RCG in case ...

My Walmart had them today for $17.98 each wonder why - will they PM other WMs? I got 2 from WM....Tks

Walt Thyng

My Feedback: (9)

I now have purchase 10 of the VPX packs and they were all A123s.

Thank you RincnII for the alert about the electronic device on the white wire. I had been using that wire as one of the balancing leads and was having problems with my two previous packs - very low capacity. Cut them out and the packs perform as expected.

Walt

747

My Feedback: (1)

I am about to cut open , can I use this thread for info about dissasembly?
http://www.rcgroups.com/forums/showt...76#post8502776

Or is there another?

Snipin_Willy

I made thread for building a pack for mini's, shouldn't be much different if you wanted to change the config.
http://www.rcuniverse.com/forum/m_7825636/tm.htm

OldRookie

My Feedback: (13)

How do you plan to balance your pack?

Greg

Snipin_Willy

For the most part the 2 cells stay within balance reasonably well as long as you discharge them down to their cut-off voltage. A few weeks ago I added balancing tabs to two of my packs. One of the packs didn't take 30 seconds for the balancer to quit, the other took less than 5 minutes. This was using a blinky 123.

747

My Feedback: (1)

I already use 2300 mah a123s for bigger plane and I balance using the astro-a123 blinky. Can I use the same for the smaller 1100 mah cells? I plan to make a 3s or 4s!

Snipin_Willy

The blinky-123 will work fine with either 1100mah or 2300 form factor batteries.

747

My Feedback: (1)

But do I HAVE TO balance , some people dont even balance...Do Ihave to balance even if I am only making a 3S pack? which is ~10v

helishack

You don't "have" to balance your batteries (Lipo & A123), but it is recommended if you want to get the maximum life out of them. I have been building battery packs for years - including A123 (1100 & 2300 mAh batts) and can tell you without pause that A123 batts stay balanced much better than lipos. That being said, I have watched my (personal use) A123 packs, over time, come out of balance.

Balancing ensures that you get the most "bang" from your packs. With unbalanced packs you might have one or more cells that are either higher or lower voltage than the others. This leads to having your charger top off too soon or too late - leaving the other cells over or under-charged (or your low-voltage cut-off (LVC) might kick in too soon). Over time this imbalance can get to the point where you think your pack is simply a poor quality pack (or that it simply can't hold a charge too well anymore) and that it's time to "retire" a perfectly good pack.

I don't balance at every charge, but I do like to start my day flying (helis and planes) with freshly charged and balanced packs - especially since I time my flights based on style and application (this keeps you from coming down unexpectedly). It's the same for my 1/8th scale vehicles - they draw a lot of voltage and current so I need all cells balanced and delivering peak performance.

Btw, all of the packs I build have balance adapters wired into them. Speaking of which, I'm down to 30 VPX packs... TIme to source out some more!

Cheers,

Jeff

747

My Feedback: (1)

Jeff, Nice answer , yes that makes sense....Have you converted park flyers/foamies into a123?

Also where so I buy balance pins and deans connector for cheap?...Tks!

nikg

Is balancing lipo and A123 the same as balancing NIMH and NICD? By that I mean is balancing just an equalizing of charge among the cells. If the cells had exposed ends like a flat race NIMH pack, then you could charge them individually, right. Is that what the whole balance plug does? Gives you access to each cell individually in order to balance the charges?
Sorry, I'm a lithium newb. I know a good deal about NIMH but not the new lithium chemistries.

Snipin_Willy

That's the idea behind it. But there are different methods of doing so, it all involves some sort of current flow from individual cells. My charger equalizes all cells as the start of the charge and then charges them up together and stops when the pack is full and balanced. Stand alone balancers are generally used after you charge at pack, draining the higher voltage cells of a few mah to bring them to the level of the lowest cell.

helishack

Thanks - just hanging around to contribute to the thread You can typically buy balance leads in lots of 10 on eBay for very few $$$ (same for Deans connectors).



Nikg, as Snipin_Willy confirmed, that's really it in a nutshell - balance leads provide your charger the ability to monitor each cell independently. There are, indeed, numerous ways to charge and balance cells - but balancing while charging provides a great means of bringing low voltage cells up to the level of the other cells. Balancers like the Blinkys are good, but they simply discharge to the point where are cells are pretty much equal. Some chargers capable of charging A123s, like the a few Hyperion models, come with balancers that allow them to charge and balance at the same time. There are more than a few chargers that charge and balance today, and more companies are supporting LiFePo4 (Lithium Iron Phosphate - e.g. A123) so your choices will continue to expand.

Jeff

SU29

My Feedback: (20)

I purchased about 15 of these at WM for $11 each. I use heavy duty servo leads utilizing the signal wire to turn the servo lead into a balance lead. I use the HD type switches with the charge jack built in. I then made up two adapters, one by soldiering another servo lead to a MFA balance lead so I can use with my 10s to balance charge when needed and another lead with out the signal wire to charge them with my Ion Cube charger from Fromeco.

Simple and works great both ways. I also remove the signal wire from the receiver side of the switch to avoid any issue with one cell feeding voltage into the receiver due to the fact that I'm using the signal wire to balance with.

Jeff

JLB

My Feedback: (2)

I've been looking for a place to buy some A123 cells or packs but they seem to be getting scarce. I have purchased a few packs from SinCity but they, along
with most folks that sell A123 packs, are out of stock and have been for a while now. I have a few VPX packs but looking for 2300's. Any suggestions
for a good place to look ? Thanks.

Snipin_Willy

Dewalt 36v or Nano-Lithiums batteries, only if you are interested in making your own packs.

chadr

http://www.cheapbatterypacks.com (if the address gets removed by rcuniverse it is cheap battery packs dot com). I buy my hyperion balance leads for for 1.50 each with only 3.50 shipping charge. I had no luck finding what I needed on ebay.

sirrom

My Feedback: (4)

I bought two packs from electrodynamics. Great service and the packs were to me very quickly.

Patrick

JLB

My Feedback: (2)

Appreciate the replies. Guess I forgot a couple of obvious places. Thanks.