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Old Aug 03, 2010, 04:32 AM
ancora imparo
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Melbourne, Australia
Joined Jul 2005
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Just checked the HobbyCity LiPo monitor. When power is applied it defaults to 60C temperature alarm setting. Sounds about right for the air flow in a PS. I'll have a go at fitting one of these to my 1300W HP PS at the weekend with a 5V regulator on the fans and see how it works as it is loaded up. If I can remember how I got it apart in the first place.
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Old Aug 03, 2010, 05:45 AM
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Son, Norway
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Sounds like a plan. Are the alarm settings not saved permanently? What are the pins on the unit used for? Keep us posted (even if that means I have to order three of those ).

Fred
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Old Aug 03, 2010, 07:27 AM
ancora imparo
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Melbourne, Australia
Joined Jul 2005
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Fred, no settings are saved as it has no memory.

The pins are to connect the temperature sensor which uses a standard servo plug. The wires to the battery are permanently soldered to the LiPo monitor - you add your own plug normally.

For the price they are a good buy. Handy to use as an add-on temp alarm when you are charging if the charger does not have a probe of its own.

John
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Originally Posted by flarssen View Post
Sounds like a plan. Are the alarm settings not saved permanently? What are the pins on the unit used for? Keep us posted (even if that means I have to order three of those ).

Fred
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Old Aug 03, 2010, 02:49 PM
Use the 4S Luke
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USA, TX, Euless
Joined Aug 2003
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I just carry around several extra supplies.
Per your comment on regulation, the 42A models I sell seem to have a very slightly positive voltage to load coefficient. That is, as the amp load increases so does the voltage by a few 0.01 Volts. Pretty easy to do with the digital circuitry.

I was testing some new ones the other day at the flying field and noticed that even the unloaded one was 114degF on the case. I measured the wood table and it was also 114. Finally I pointed the IR thermometer at the (metal) shade roof. 142degF! No wonder. Like standing in an easy bake oven.
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Old Aug 03, 2010, 04:17 PM
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Wellington, NZ
Joined Aug 2006
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Those temps are certainly not a problem here! Not even in summer. Not even close!!

I've decided not to be a worry wort over temp rises in these PSUs in our climate, even when I slow down the 747 jetstream.

I think I am turning into a 'feather' as I have now bought six of these treasures!! Seems I can't stand seeing them neglected and possibly ending up being scrapped!

I've given one to my instructor who still gives me great advice and one is destined to go to a club member at cost but that still leaves four. I've no doubt I will be able to find other takers, though. Thanks to the power of RCGroups, though, I have, or will have, them all 'cracked' and able to be turned on. Can't imagine what we used to do (or not do) before the Internet. So, thanks guys for your help and friendship.
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Old Aug 03, 2010, 05:23 PM
ancora imparo
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Melbourne, Australia
Joined Jul 2005
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Fred, just looking back at your post, I assume these are not regulators but straight MOSFETS since you took them out of a dead ESC? As such they presumably are just acting as a dropper really. What values of resistor did you use to make them run in linear mode?

Lindsay's comments about using these with slower fans and ambient temperatures make sense. For most of us, unless we are really pushing them to deliver the full output I suspect a slower air flow is entirely adequate and the PS will be protected against overtemp I'm sure. In summer it can get over 40C /140F here like in the Southern US though and I think I will investigate the switched fan option just for the hell of it. Most of the effort is in taking the PS apart and you have to do that anyway. Running two wires to add a relay and one of these temp sensors across the dropping resistors is not much extra effort (and you could just have a manual switch to short out the dropping resistor for a two speed fan if you wanted real simple).

Agree with others - this has been a nice thread. Almost no noise and self importance, just information. How often does that happen!

John
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I have now done the mod on all three PSU's. All parts were taken from a fried 18A ESC that had four regulators in total, so basically free.

Fred
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Old Aug 04, 2010, 12:07 AM
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Son, Norway
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Quote:
Originally Posted by jj604 View Post
Fred, just looking back at your post, I assume these are not regulators but straight MOSFETS since you took them out of a dead ESC? As such they presumably are just acting as a dropper really. What values of resistor did you use to make them run in linear mode?

John
Sorry John, I should have stated the BEC part of the ESC. They are 5V regulators good for around 1A with proper cooling. There were two stacks in parallel, and two in each stack. Without capacitors, the (noload) output was just above 10V, so the capacitors were needed to get proper regulation. I'm not sure these fancy to be bypassed (having 12V on the input), so a double-throw relay is probably needed to select either 5V or 12V.

Fred
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Old Aug 04, 2010, 12:28 AM
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Wellington, NZ
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One series resistor with a switch across it sounds easier!
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Old Aug 04, 2010, 03:49 AM
ancora imparo
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Melbourne, Australia
Joined Jul 2005
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Well that's what I'll be trying first.

From memory most of these fans normally only draw about 300-500mA. Even the frantic little beasts in these supplies ought be an Amp or less so 5W is probably what we need to lose max.
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One series resistor with a switch across it sounds easier!
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Old Aug 04, 2010, 03:55 AM
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Wellington, NZ
Joined Aug 2006
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I think my 747 one (AKA PS4060) drew 800mA!! Anyway, the 10W 6.8ohm I had here did enough to make it tolerable out in the garage. Moved that one on to someone else's garage so 'problem' has gone away (literally!).

My DL380 G3 and G4 ones should arrive tomorrow. Interesting to see (hear?) how noisy they are.

Love my DL360 460W ones as they can't be heard at all!

Lindsay.
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Old Aug 04, 2010, 02:15 PM
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Son, Norway
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Quote:
Originally Posted by jj604 View Post
When power is applied it defaults to 60C temperature alarm setting. Sounds about right for the air flow in a PS.
I did some measurements today, charging a 10S A123 pack. Problem was that it goes so fast that I only get readings for 10 minutes.
Outside in the sun, intake air 26C (yes it's summer here ). After 10 minutes at 37-38A, exhaust temperature was 44C and still rising slowly. Did another one and reduced the current to 30A after 7-8 minutes. Temperature went to 43C, then dropped to 41.5C when current was reduced.

Fred
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Old Aug 04, 2010, 04:17 PM
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Wellington, NZ
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26C sounds good to me, Fred. It's about 10C here with a cold wind.

The temp rise you see doesn't sound excessive to me.

That is a serious bty with 10S. What is it driving?
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Old Aug 04, 2010, 11:38 PM
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Son, Norway
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No it seems OK, so I'll just leave the fans at 5V and enjoy the silence .
The pack is not driving anything yet, but two of them in parallel will hopefully be in an old 1/4 scale Zlin 226AS some day.

Fred
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Old Aug 05, 2010, 04:54 AM
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Wellington, NZ
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That's an interesting looking plane - had to google it as had no idea what it was! Hope you get to complete the project.

Lindsay.
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Old Aug 05, 2010, 04:59 AM
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Wellington, NZ
Joined Aug 2006
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Both my new unused PSUs arrived today and the 'cracks' helpfully provided got them working in minutes. One has been moved on to a good home so will seek other buyers for another couple here. Like I said before, to me they are a work of art and have to be rescued from the tip or dusty shelves!
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