Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Mar 06, 2004, 01:25 PM
Artillery! King of Battle!
Brill 1's Avatar
USA, KS, Scammon
Joined Mar 2002
4,431 Posts
Do I need a Bigger Power Supply?

I just purchased a 12amp Pyramid power supply to provide the current for my Great Planes Triton charger. The power supply is working great, but I can only get a 3.8amp charge rate out of it while charging a 20-cell 3300NiMH pack.

Do I need a power supply that can supply more amps? Also what type of battery should I be looking at for field charging?

Thanks

Brian
Brill 1 is offline Find More Posts by Brill 1
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 06, 2004, 01:49 PM
Castle Tech
Joe Ford's Avatar
Olathe, KS
Joined Aug 2003
4,889 Posts
For field charging you want a deep cycle marine battery. I got a 95Ah one at Auto Zone for $55...if you're charging 20 cell packs on it though, you might wanna buy 2...those packs really suck the juice out of deep cycle batteries. Sorry dont know about the power supply...never used one.
Joe Ford is offline Find More Posts by Joe Ford
Reply With Quote
Old Mar 06, 2004, 11:46 PM
Right Honorable Member
flatfour's Avatar
Chicago Midway, Illinois, United States
Joined Jul 2003
517 Posts
A bigger power supply will not help. There is a page in the manual "Operating characteristics of the Triton Charger"
At any voltage over 18, the max current starts to drop from 5A
flatfour is offline Find More Posts by flatfour
Reply With Quote
Old Mar 07, 2004, 08:52 AM
Crash Master
Gene Bond's Avatar
Indianapolis, IN
Joined Sep 2001
16,632 Posts
Probably a maximum watt limitation... As the output voltage goes up, the current capability decreases... Same thing with a lot of the dischargers.
Gene Bond is offline Find More Posts by Gene Bond
Reply With Quote
Old Mar 07, 2004, 09:41 AM
Registered User
Bill Glover's Avatar
United Kingdom, Bracknell
Joined Nov 2000
11,492 Posts
You need a fairly expensive charger to do 20 cells at 5A. Most of the Schulzes above the isl 6-330 will do it, the isl 8-936 will charge 20 cells at 9A on outlet 1 and (at the same time) another 20 cell pack at 5A on outlet 2. That charger needs a 40A power supply!

I wouldn't try charging 3300 nimhs at 9A though ...
Bill Glover is offline Find More Posts by Bill Glover
Reply With Quote
Old Mar 07, 2004, 09:49 AM
Artillery! King of Battle!
Brill 1's Avatar
USA, KS, Scammon
Joined Mar 2002
4,431 Posts
Thanks for all the replies. My Ohms Law knowledge is way rusty!!

Would the AstoFlight 112D charge 20-cells at 5amps from a 12amp charger, or do I need to look at getting a Schulzes?

Later

Brian
Brill 1 is offline Find More Posts by Brill 1
Reply With Quote
Old Mar 07, 2004, 10:19 AM
Registered User
Bill Glover's Avatar
United Kingdom, Bracknell
Joined Nov 2000
11,492 Posts
Quote:
Originally posted by bwillhite
Would the AstoFlight 112D charge 20-cells at 5amps from a 12amp charger
The datasheet for the 112 is on the Astro website, yes it will charge 20 cells at 5A no problem.

Will your 12A power supply handle that? Probably not, Astro say on the website that the 112 can pull up to 18A.

If you know what voltage you need to apply to a cell to charge it at 5A then the sums are quite easy. Let's guess at 1.8V per cell. So 1.8V times 20 cells times 5A = 180 watts of energy required to do the charging. Divide 180 watts by 13V (assumed voltage of your power supply) gives 13.8A required from the power supply. In reality the charger isn't 100% efficient (it consumes some energy itself), so it would pull more current than that. 10% overhead? That would be 15A in total.

Lots of guesses in there, but you get the idea.
Bill Glover is offline Find More Posts by Bill Glover
Reply With Quote
Old Mar 07, 2004, 11:46 AM
Convert!
rroback's Avatar
Los Angeles, CA (UCLA)
Joined Nov 2002
3,889 Posts
power supplies are usually underestimated so as not to damage one. I have the astroflight one and I've pulled 15 amps, although it gets hot, I just put a small computer fan on top of it, and that does the job.

Rhett
rroback is offline Find More Posts by rroback
Reply With Quote
Old Mar 07, 2004, 12:08 PM
1,1,2,3,5,8,13,21,34
Shortman's Avatar
United States, OR, Portland
Joined Nov 2003
2,116 Posts
Ive heard the Pyramid power supplys are junk. Get a Cosel power supply from www.lightflightrc.com and they are much better. They are also just as good as the $80 power supply from Astroflight.


Steven
Shortman is offline Find More Posts by Shortman
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Help! I need a cheap power supply for my parkzone lipo charger!!! SwissBoy Batteries and Chargers 5 Feb 16, 2007 10:52 AM
Wanted need a cheap power supply trashmanf Aircraft - Electric - Batteries & Chargers (FS/W) 11 Aug 25, 2006 12:41 PM
Found need a 12volt power supply brianb10 Aircraft - Electric - Batteries & Chargers (FS/W) 5 Jan 22, 2006 10:53 AM
Do I need a new power supply? Brian Courtice Slope 10 Feb 24, 2005 04:02 PM
You mean to say I need to buy a power supply to power the Triton at home!! Canada Goose Batteries and Chargers 19 Dec 26, 2004 01:18 PM