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Forum Index : Electronics : Fuse indicatior
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Wombat Regular Member  Joined: 27/05/2011 Location: AustraliaPosts: 72 |
I'm looking to improve my bank by having fuse indicators on by battery's. 2 led's, 1 red, 1 green to show working or blown. Probably need to take power from the battery itself? Gizmo has a nice little fuse holder gadget without indicators. Something like that "with" would be ideal. I'll be using them for both 24V and 48V. A simple circuit from the guru's out there would be great as I've been out of the electronic hobby game for a long time now.. 
All thoughts and ideas welcomed! Russ  |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
A "blown fuse" indicator would be easy enough, just a LED and resistor in series, across the fuse. Of course, it will only light if the fuse has blown, and, there is still a load on the battery bank, enough to draw current through the LED/resistor. For a 12v battery, a 1k resistor would be fine. A OK/blown fuse indicator would be a bit more involved. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Wombat Regular Member Joined: 27/05/2011 Location: AustraliaPosts: 72 |
Hi Glenn. Yes, I'm actually looking for indication for easy reference at a glance as I'll need about 24 off @ 24V and 16 @ 48V. My walls will look like a christmas tree! I don't allow my battery's to get below 11.8V (each), so the question is how to force current though an led in parallel with a 'good' fuse, and to stop current flow when a fuse is 'bad'. AND/OR, NAND/NOR? It's all a little beyond me now I'm afraid... I feel a headache coming on... 
If a 1K resister is okay @ 12V, would it then be true that 2K @24V & 4K @48V be true? Russ |
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Tinker Guru  Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
What size fuse are you talking about? If its 30Amp or thereabouts you can get automotive in line fuse holders with a blown fuse light incorporated. Just requires to clip in the appropriate size blade fuse and keep a few spares  .
A 'good' fuse means the light (usually red) is off, it comes on to indicate which one of your fuses has blown. I think the red/greed LED idea is a bit over the top unless you like to complicate things  .Klaus |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
I suppose you could connect a red Led and resistor directly across the fuse, and a green Led and another resistor after the fuse between supply and common to indicate there is power there. That would probably be about as good as you can do with something fairly simple. One thing is for sure, a single illuminated red Led among a sea of glowing green Leds really stands out. Cheers, Tony. |
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| Wombat Regular Member Joined: 27/05/2011 Location: AustraliaPosts: 72 |
Giday Klaus. I am using car type blade fuses and did consider fuse holders like Jacar have. But at a few bucks each and with only about 2mm cable on them, find them inadequate. I think you are right about over complicating things abit... As Glen said, resister and led across the fuse would be the easy. Tony, Your idea is so simple! I don't believe I didn't think of putting something in series with the fuse to indicate a good condition.. My brain must be a sieve! 
This would mean using a shunt and personally, I don't like them. 1 loss X 24? I still like the sea of colour idea, but now don't think it practical. Now here is a kicker! (my brain just got in gear)
If I used 'The Almighty Maximite', this should be able to give me a blinking LED when a fuse is blown.. yes? I've 2 Color Maximites on order, so one of these could cover 2 banks! 
24 X 15A fuses on 26Ah X 2 for 24V and 16 X 30A fuses on 55Ah X 4 for 48V. Mmmm... Long runs of small wires... Maybe a 'stick' on each bank is the go. Well! This is all good.  Thanks guys!
Stepping forwards. Russ |
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| Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Russ, there are blade fuse holders around with more than adequate wires, perhaps Jaycar sells the el cheapo model. I think I got mine from a marine store like Withworths. Anyway,the wire is heavy duty IMO, requiring yellow crimp connectors and at least good for the maximum blade fuse size available. The only con is the wire comes in a loop (for easy manufacturing) and needs to be cut in the middle. This might leave wire tails too short for your application. Good luck with the LED idea but using a microprocessor to drive them is definitely over the top in my book . Or is blowing fuses a regular event at your place? 
Finding the cause for that might be a good idea too. Klaus |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
I think Gizmos idea was the most practical and can be wired to a fuse indicator board. Why the hell do you need a green led when a single red led for a failed fuse will tell you all you need to know. I have used what Gizmo suggested in many fuse board designs and it works well, as you only need to know when something fails and not when its working, if it aint failed then its working! The more complicated the indicator system becomes, the more prone to a fault in the indicator circuit is possible, then becomes a chase me, chatch me, situation. Keep it simple s.......? Sometimes it just works |
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| Wombat Regular Member Joined: 27/05/2011 Location: AustraliaPosts: 72 |
Thanks Klaus, I'll check Withworths out. Haven't been there for almost a decade. It will be good to see whats available no I have a bunch of crimp lugs already so I'll go with the Gizmo idea with LED. And 'NO' I don't blow fuses. Except in multimeters.
Giday Downwind. I just like to cover my butt. The 'what if' scenario. "If it ain't failed then its working" is an assumption the LED is working. If it's not working, then I won't know that I've lost a string... 
I'd like to use a maximite only to 'sense' that all is okay. This would only need 1 indicator for all inputs. Then they can compliment the other.
Besides, I can't play space invaders all day! 
Russ |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
[quote] And 'NO' I don't blow fuses. Except in multimeter's. [/quote] You mean multimeter's have fuses?? i tend to find they have fusible tracks indicated well by the little puff of smoke that escapes the housing, and as a added indicator should you have missed the smoke indicator, there is that disgraceful pungent smell to inform you the last test made, might be well the last test the meter will ever make.
Depending on the number of fuses needing to be monitored a cheaper solution to the maximite might be a Picaxe chip, the maximite would seem like using a sledge hammer to kill an ant for this application. Perhaps consider using tri coloured leds (red and green leds in the one package)then it keeps the panel less cluttered, and i think looks more professional, as xmas lights for panels always look as though someone had more parts then they knew what to do with, or no idea what they should be doing with them. Then thats just my opinion. Pete. Sometimes it just works |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
You could use Flashing LEDs instead of normal ones. JayCar sell a range of them. Search their web site for ZD-0240. Len |
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| phase Newbie  Joined: 16/09/2012 Location: AustraliaPosts: 7 |
honestly if you want to have constant voltage recognition of your batteries then go with an lm .3914."cct it will tell you about your batteries ..24/7/ but besides this go with an ..ETI 324 kit pcb cct,...either way you go there will be current drain on your supply... |
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| phase Newbie Joined: 16/09/2012 Location: AustraliaPosts: 7 |
the lm 3914 can be figured to a single led dot display using approx 20-40 Ma or go with the bar graph display...read the application notes and look it up on the ..web...,,,... |
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| phase Newbie Joined: 16/09/2012 Location: AustraliaPosts: 7 |
a blown fuse indicator would have to indicate that the current was no longer flowing through the cct ,,the.. cct that shows this occurrence..drop in current flow would have to measure the abstinence of current therefore reporting this to some kind of semiconductor to allow it to display a fall in current thus tripping a digital switch showing a positive / or negative..output ..turning a cct detection signal on...to display a fault.or..to an indicating light....that would of coarse have to be electrically isolated...pretty simple really current falls the device trips whether the device is current stable or current dropping either way the semiconductor can be tripped..capacitive assisted... |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Because a red led across a fuse will not show if there is no power on the hot side of the fuse. It will also not show if there is zero down stream load. Where you have a very large and complex power distribution system, and fuses supplying other fuses, it is possible to have some very strange failure modes where the root cause of a major power outage may not be immediately obvious. Sometimes it can be fairly important to diagnose and fix faults very quickly, and knowing that various nodes in the whole system are actually "alive" can be a very big help in gaining a fast overall picture of what happened. Cheers, Tony. |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Tony, Perhaps you should read post one, its a simple battery system not some concocked system of nodes or a complex power distribution system. And for simple application the more complicated a simple indicator is, the likely it is for a failure of the indicator, which can be worst than no indicator at all. Sometimes it just works |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
I agree that a very simple system often requires only a very simple solution. But to say that the green Led alternative display backup idea would NEVER be worth the trouble would simply not be true. It is also not true that a simple system will always be more reliable than a much more complex system. Backup systems, self testing, and built in redundancy all add to cost and complexity, but also definitely add to reliability. If you had ever worked in aviation, medical life support, mission critical military, or the nuclear industry, you would understand where I am coming from. Cheers, Tony. |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
[quote]If you had ever worked in aviation, medical life support, mission critical military, or the nuclear industry, you would understand where I am coming from. [/quote] No, only worked in other fields that use redundancy systems. But crikey its a battery fuse board indicator asked about here, not rocket science or space stations. Reality check.............101. Sometimes it just works |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Hehehe, I certainly agree. Cheers, Tony. |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
Phase, you mean mA not Ma. m = milli, M = Meg. And the convention for units that are named after a person employ a capital letter. In this case it was Ampere. The same applies to Watt, Volt, Gauss, etc. but not units such as metre. Hence mm = millimetre, km = kilometre, Mm = megametre. Len |
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