canopy2k

My Feedback: (1)

Last year, I purchased 3 battery packs all about the same time. One Futaba 600 mah flat (16.99) , One Futaba 1500 mah flat (29.99), and one Tower Hobbies 500 mah square pack (12.99). All have seen pretty equal use in different planes. The Tower square has seen the most abuse. (3 crashes) Having been in use pretty consistently for a year, I decided it was time to cycle them. To my surprise, the most abused and cheapest pack performed the best. I used a Hobbico Accucycle (and yes, I calibrated it first)

The Tower pack held the following. Cycle 1 436 mah, Cycle 2 529 mah, Cycle 3 523 mah. Holding more than the rated capacity. Not bad for an abused pack.

The Futaba 600 mah pack held the following. Cycle 1 506 mah, Cycle 2 524 mah, Cycle 3 518 mah. Not even rated capacity, but still well within the 80% limit.

The Futaba 1500 mah pack held the following. Cycle 1 1342 mah, Cycle 2 1404 mah, Cycle 3 1416 mah. Again, within limits.

I just found it curious that the cheapest pack held up the best, performing better in fact than a higher rated pack. Anyone else ever seen anything like that? One question I did have, in the instruction manual it says that the drain in minutes shown on the accucycle should give you a good idea of flight times available on a pack. But realistically, event the 500 mah pack took just over 2 hours to drain at 250mah load. I know theres no way im getting 2 hours of flight time out of it. What is is better way to determine the flight capacity of a pack??
Thanks!
Brice

Gringo Flyer

My Feedback: (18)

I dont really have any experience with the packs you are mentioning but if you really are wanting top quality packs I wouldnt buy from Tower or Futaba. The packs are fine, but they are way overpriced.

Check out NOBS batteries http://www.hangtimes.com/

You can get a 1650 pack for $23 and they have a deal now that if you buy 2 of the same pack you get a 25% discount on the second pack.

The quality of the cells, construction, etc is first rate and they are always quick to help you out. (a cell went bad on one of my packs, without receipt, explanation, anything, they just said send it back for a new one or a credit towards another pack)

Also, if you have any questions about the packs (like these questions about your tower and futaba packs) their customer service is great.

phat23

To guesstimate flight time you need to know how many amps your setup is using and at what throttle setting. A bench test will give you static amps, but props usually (not always, depending on dia x pitch ratio) unload somewhat in flight. You can get a ballpark flight time by doing a static bench test at the throttle setting you use most. Say you throttle back to 1/2 after takeoff and fly the entire flight lke that, then do the bench test at 1/2 throttle.

Example:
500 mAh pack
8A @ 1/2 Throttle

.5Ah (500mAh) / 8A = .0625 Hours

.0625 Hours X 60 min = 3.75 minutes

Again, your prop will probably unload in flight which will extend your actual time in the air.

For good prices and excellent service, try the following sites. They are THE places for e-flight cells and packs.

(in no particular order)
http://www.unipros.com/cbpsite/packs...sion_id=261157
http://www.maxamps.com/index.html?la...d=38405.062442
http://www.battlepack.com/index.asp

piper_chuck

My Feedback: (12)

I agree the Futaba packs are overpriced, but I've been quite happy with the Hobbico packs from Tower.
I recently got 2 1650 nimh packs for $37.40 from Tower. By the way, these were 5 cell, not the 4 cell ones for $23 from NOBS. They use Sanyo cells.

I've yet to buy into the hype that the NOBS batteries are THAT much better than those from other sources (except the generic no-name ones offered by auction). I have not found the prices at NOBS to be so good. I'm not saying there's anything wrong with them, but I wonder how much of a premium people pay for the perception that their product is better.

canopy2k

My Feedback: (1)

Actually, these are receiver packs. So, Im looking at servo run time, not motor run time. I wonder how much 6 servos draw? Anybody ever figured that out? As far as new packs go, I learned to buy from other sources now. I was first starting out when I bought these and didnt know there were better prices out there.

Gringo Flyer

My Feedback: (18)

I like NOBS bc you can get more specialized packs. 4.8 volt 6 volt etc. They have nicd nimh and even different type cells. I am aobut to place an order for some packs with 2/3 A cells. And the customer service.

But to each his own.

JPMacG

My Feedback: (2)

I've noticed the same thing. My Tower 500 mAh pack cycles above its capacity while Futaba and other packs of various brands cycle just under their capacity. I'm guessing that Tower under-rates their pack. They may build the pack from 600 mAh cells and label the pack 500 mAh for some reason - maybe marketing.

I've heard that Tower and Futaba both use Sanyo cells. The Tower 500 and Futaba 600 packs may be exactly the same cells.

By the way, in order to achieve the rated 600 mAh you may need to discharge at a slower rate. If I discharge at 100 mA I get the rated capacity but if I discharge at 300 mA they come up short.