RC-Monster Forums  
RC Monster

Go Back   RC-Monster Forums > Support Forums > General Electric

Reply
 
Thread Tools Rate Thread Display Modes
Hyperion 7i Wiring
Old
  (#1)
BrianG
RC-Monster Admin
 
BrianG's Avatar
 
Offline
Posts: 14,609
Join Date: Nov 2005
Location: Des Moines, IA
Hyperion 7i Wiring - 09.02.2006, 09:53 PM

I was charging my 14 cell GP pack at 5A earlier today and happened to notice that the wires going from the 12v power supply to the charger were warm. So, I opened the charger and measured the voltage across the positive wire. At ~9A draw on the power supply, there was a 0.27v drop on both the positive and negative wires. That is a total of over 1/2 a volt, so the charger was getting only 11ish volts even though the power supply was outputting 11.8v. The wires alone were dissipating ~5W.

So, I replaced the approximately 6 feet of 20ish gauge wire with 2 feet of 14 gauge wire and ran the test again. Much better. No voltage drop on the wire and now I can charge almost to 7A, when I couldn't charge even 6A before because the charger would shut down due to inadequate supply voltage. Now, the limit is the 120W power limitation on the charger itself. This also causes the switching power supply in the charger to not work so hard.

Anyway, just thought I'd share for those who have this charger. I suppose I could have simply shortened the present wire, but when I saw how thin it was, I decided just to replace it.
  Send a message via Yahoo to BrianG Send a message via MSN to BrianG  
Reply With Quote
Old
  (#2)
MetalMan
RC-Monster Mod
 
MetalMan's Avatar
 
Offline
Posts: 5,297
Join Date: Mar 2005
Location: SoCal
09.03.2006, 12:21 PM

I think this is something for all people to know that use a computer PS. When I used to use a PC PS I would have the same problem, which I'm sure was partially due to a load on the 5v line that wasn't enough (10ohm, 10watts).


SH Z-Car, Custom Crawler, 8s Savage, 12s XTM XLB 1/7 buggy, 4wd 4-link rear/IFS Pro4 truck, Custom Hyper 10 Short Course, Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz
   
Reply With Quote
Old
  (#3)
neweuser
RC Monster, the Final Frontier
 
neweuser's Avatar
 
Offline
Posts: 3,379
Join Date: Feb 2006
Location: Minnesota
09.07.2006, 06:49 PM

I'll have to throw you guys a pm when i get my PS so you can help me. Is that ok?


"if you've got something to say, say it peacefully"
  Send a message via MSN to neweuser  
Reply With Quote
Old
  (#4)
BrianG
RC-Monster Admin
 
BrianG's Avatar
 
Offline
Posts: 14,609
Join Date: Nov 2005
Location: Des Moines, IA
09.07.2006, 09:40 PM

Of course! We might not answer, but you can ask. ;) :005: J/K
  Send a message via Yahoo to BrianG Send a message via MSN to BrianG  
Reply With Quote
Old
  (#5)
coolhandcountry
RC-Monster Mod
 
coolhandcountry's Avatar
 
Offline
Posts: 6,739
Join Date: Jul 2005
Location: VA in the US
09.07.2006, 10:14 PM

Well some power supplies has more than one 12v wire coming out. Couldn't you just wire them together? That would cut resistance.


Peace!
Country
Help support the
Rc-Monster
Buy here


My pics and videos
   
Reply With Quote
Old
  (#6)
BrianG
RC-Monster Admin
 
BrianG's Avatar
 
Offline
Posts: 14,609
Join Date: Nov 2005
Location: Des Moines, IA
09.07.2006, 10:56 PM

I don't know if I would just tie them together. I tried it on one of mine and I noticed that one of the 12v supply output FETs got quite warm. If one of the supplies is even a little higher voltage than the other, there will be current flow and cause the slightly higher voltage one to work harder. It's not like batteries where the slightly higher one will drain down until they match.

Also, many of the dual 12v supplies have 12v rails that don't match current-wise. One will be rated for say 15A, while the other will be rated for 17A. I don't know why and it doesn't make much sense.

A supply with a single 12v supply has a higher current capacity than either 12v rail on a dual supply. The single supplies are still made, it's just a matter of looking at the specs, or better yet, the label on the side of the power supply itself. If there are two 12v supplies, then there will be the max current ratings for each. Pretty easy to tell.

Newegg.com has good prices, great return policy (although if the wires are cut, that will void the warranty), and have good pictures usually showing the label on the PS. Plus, you can read the user reviews to see if one is prone to problems.
  Send a message via Yahoo to BrianG Send a message via MSN to BrianG  
Reply With Quote
Old
  (#7)
neweuser
RC Monster, the Final Frontier
 
neweuser's Avatar
 
Offline
Posts: 3,379
Join Date: Feb 2006
Location: Minnesota
09.10.2006, 08:53 PM

So with my Hyperion, the 6 feet that go from the power supply to the charger(stock wires for the charger that come with bananas) should be cut and changed to like say 14 or even 12 gauge? and shorten to only 2 feet?


"if you've got something to say, say it peacefully"
  Send a message via MSN to neweuser  
Reply With Quote
Old
  (#8)
BrianG
RC-Monster Admin
 
BrianG's Avatar
 
Offline
Posts: 14,609
Join Date: Nov 2005
Location: Des Moines, IA
09.10.2006, 11:10 PM

That helped quite a bit for me. No more warm wires and the input voltage at the charger was higher.

However, this will require opening the charger and desoldering/resoldering on the circuit board. I am sure this will void any warranty, so be warned.

Another way to go about it would be to shorten the existing wire to about 2 or 3 feet. This obviously won't change the gauge, but will still reduce the voltage drop, if not as much as replacing the wire altogether.
  Send a message via Yahoo to BrianG Send a message via MSN to BrianG  
Reply With Quote
Old
  (#9)
neweuser
RC Monster, the Final Frontier
 
neweuser's Avatar
 
Offline
Posts: 3,379
Join Date: Feb 2006
Location: Minnesota
09.11.2006, 12:48 AM

Thanks Brian!


"if you've got something to say, say it peacefully"
  Send a message via MSN to neweuser  
Reply With Quote
Old
  (#10)
BrianG
RC-Monster Admin
 
BrianG's Avatar
 
Offline
Posts: 14,609
Join Date: Nov 2005
Location: Des Moines, IA
09.11.2006, 01:28 AM

Np. :)
  Send a message via Yahoo to BrianG Send a message via MSN to BrianG  
Reply With Quote
Old
  (#11)
BrianG
RC-Monster Admin
 
BrianG's Avatar
 
Offline
Posts: 14,609
Join Date: Nov 2005
Location: Des Moines, IA
09.17.2006, 05:48 AM

A little more data on the 7i:

When maxed out to 120w output, the 7i draws 151 watts. The extra power (31w) is simply dissipated as heat on the heatsink.

I charged a 14 cell NiMH pack I have at 7A (or tried to), and easily hit the 120w mark. Once there, the pack voltage slowly increased, but the charge current steadily decreased to meet the 120w limit. Actually, the 7i was outputting 121w, but close enough. I measured the current on the input at 12.5A with a supply voltage of 12.07v.

So, it looks like you need a minimum of a 150w power supply to run the 7i to its max rating. Personally, I'd choose a 170w-200w supply because it's never good to run things to their max ratings.
  Send a message via Yahoo to BrianG Send a message via MSN to BrianG  
Reply With Quote
Old
  (#12)
coolhandcountry
RC-Monster Mod
 
coolhandcountry's Avatar
 
Offline
Posts: 6,739
Join Date: Jul 2005
Location: VA in the US
09.17.2006, 11:19 AM

Is the 31 watts gone to heat? You do have the electronics in the charger to
draw a little. That is some good info.


Peace!
Country
Help support the
Rc-Monster
Buy here


My pics and videos
   
Reply With Quote
Old
  (#13)
BrianG
RC-Monster Admin
 
BrianG's Avatar
 
Offline
Posts: 14,609
Join Date: Nov 2005
Location: Des Moines, IA
09.17.2006, 01:45 PM

Quote:
Originally Posted by coolhandcountry
Is the 31 watts gone to heat? You do have the electronics in the charger to
draw a little. That is some good info.
Yup, if the charger is drawing 151w, but only delivering 121w of that to the battery, the rest has to go somewhere - the heatsink.

However, when not charging anything, the charger only draws 87mA (0.087A), which equates to a measly 1.1w. That's just with the charger "on".

I just thought it was interesting to test worst-case power draw so people could judge their supplies accordingly. At least it shows that there is in fact losses and about how much, in this case about 20.5% at full capacity, which makes the charger 79.5% efficient. This really isn't bad and much of that high efficiency is attributed to the DC-DC switching supply in the charger.

Once I finish building my linear power supply (just for basic electronics projects), which can hold a steady 11v-16v up to 40A, I'll probably try this again with a higher input voltage (~15v). This will cause the charger to draw less current and also increase its efficiency.
  Send a message via Yahoo to BrianG Send a message via MSN to BrianG  
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump



RC Monster




Powered by vBulletin® Version 3.8.1
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
vBulletin Skin developed by: vBStyles.com