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AU3 Falcon XR8 Ute (auto)
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Discussion Starter #1
G'day guys.

I just bought a Matson standard-duty AntiZap surge/spike protector today (it's a permanent mount one - wires to the terminals of your battery). Buying one first and asking questions later is rather illogical, but Im gonna do it anyway.... :)

So; what do you guys reckon of...
--The specific unit that I bought
--Surge protectors in general
(are they necessary/good/bad, any negative aspects to 'em, some better than others, any thoughts opinions on the matter at all)

I personally figure that (jump-starting excluded), you should never really have surges/spikes in your electrical system, but I also figure that they are still possible, and it'd only take one to maybe wreck your ECU. I also see no negative aspects to the device I bought, so I figure overall it's worth having.

That's my opinion at the moment, I'd love to hear some others.

Thanks guys.
 

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Steve,

I suppose it depends on how many ECU's have died from voltage spikes. Maybe we have an auto electrician on here that can answer.

How much did it cost? If it safely allows jump starting, it may be worth the money. And the sureity of "no dramas" in car battery charging would be good also.


cheers:beer:
 

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AU3 Falcon XR8 Ute (auto)
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Discussion Starter #3
Cost $24.95 usually (I got it 20% off @ Supercheap though).

Yeah, I think jump starting is the main idea. They have models which just clip on your jumper leads to protect while starting, but I figured the permenant model has the added advantage of protection all the time which might be good for (like you say) when changing batteries etc. and general protection.
 

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Thanks for that, didn't even know they existed.

cheers:beer:
 

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Hi Guys,
Well for that price I think its a good idea.
I recently bought a XR6 El manual ecu and stuffed it !
I was repairing my clutch bracket as it had split and as I was putting it back and tightening the nuts up with my ratchet, the ratchet touched the only piece of bare wire that was probably 1cm wide and spiked it ! So bye bye ECU......
Anyway its a good idea if it works.

Regards
Shane
 

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AU3 Falcon XR8 Ute (auto)
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357 Posts
Discussion Starter #7
G'day Shane,

Bugger about the ECU mate! They wouldn't be cheap either.

As I've said, I too think they are a good idea but I guess it's the sort of thing that you never really know if it works - only if it doesn't! :) Matson seem to have the best reputation for these sorta things though, so I'm pretty confident (and a mysterious flashing light under the bonnet at night is pretty cool :cool:. Next time I get some spare cash I may buy another one and just pull it apart to see how it works - looking at the type of circuit would be the easiest way of telling if they're effective.

Steve.
 

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do YOU have rubber?
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I've got a cheap "spike protector" that came with my jumper cables. It only has very small gauge cables and has LEDs that indicate the charge state of the battery. Personally (and this is only an opinion formed from visually inspecting the things) I don't think it would do much - but what do you expect from a freebie I guess. Nevertheless considering they are so cheap... why not. Even if the unit fails and shorts the battery terminals (hopefully it is fused anyway - but you could externally fues it) you're not likely to damage other equipment on the 12v rail, just stress the battery a little :s5
 

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AU3 Falcon XR8 Ute (auto)
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357 Posts
Discussion Starter #10 (Edited)
G'day !Gn|T|0n,

As I understand it, spikes in an electrical system are actually voltage spikes, not current spikes, which means you shouldn't need heavy cables to carry them (the heavier cable, the more current it can handle, but small wires like on the spike protectors can still carry ten's of thousands of volts if it's at bugger-all current), so the light gauge wires shouldn't be an issue. I don't think the physical size of the unit should matter either really, based on my theory as follows...

In 240VAC spike protectors, the best units out there use MOVs (Metal Oxide Varistors). These are only very small devices, but are effective at absorbing quite large spikes/surges. (NB. any spike protector is a self-sacrificing device - if it absorbs too big a spike/surge, it will be destroyed, but will still usually save the circuit it's protecting in doing so - this is why I like unit's like the Matson ones which have a flashing light to indicate it is working. If the light stops flashing, you know it's absorded too many/too big a spike/surge and needs to be replaced (or your battery's too flat :) - without the light, you never know if you still have protection). I think they can be so small because it's simply just a variable resistor basically.

I think how they work is; As the voltage goes up, the resistance goes down, so when you get a sudden increase in voltage, the resistance across the terminals decreases enough that the amount of current being used goes up and therefore pulls the voltage back down. This usually happens very quickly and breifly, so large current usage/heat dissipation is insignificant.

Your point about the unit shorting the battery terminals if it fails is a good one. I dunno if they're fused internally (I think they pretty much are due to the nature of the circuit being able to act the same way as a fuse (?)) but I muy put an external fuse on anyway like you suggest. Have to find out what fuse wouldn't affect the unit's operation, but you could just go a pretty big fuse anyway.

Sorry for rambling on :) I just like sharing opinions and figuring out how this stuff works. Please note: all of the above opinions/theory of mine is pretty much a guess and may be in no way accurate. I won't really know until I pull the units apart I spose. ;)

Steve.
 

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I don't think they worth having. I have personally welded a car with the battery hooked up (efi too). I actually have done an electrical eng degree and any properly made and designed device which had no form of protection should be illegal to sell in Australia. In addition to that basically all DC electronic devices usually have capacitors on them to prevent voltage spikes. If you shove 100's of Amps into something of course it will blow up.
 

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do YOU have rubber?
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Hey guys,
It is very cheap and easy for manufacturers to install transorbs or zener diodes into the front end of the power stage of a device. As not ford said, it would be lunacy not to incorporate such into all electrical devices but as to the legislative side of things, I'm not sure. "Spikes" refer purely to high gradient quantities large in magnitude. You can get current and voltage spikes and they may not occur at similar times in a circuit depending on the reactance of the system.

Steve_T, the behaviour you are describing is best matched by that of a semiconductor. Essentially you can use these as voltage or current controlled resistors. A zener for instance when operating in reverse breakdown is designed to safely clamp the voltage across it and conduct as much current by virtue of a variable conductive channel inside the device to keep it clamped. Within limits, this is not destructive and in fact is normal operation for a zener.

My advise would be to go for it! Although (especially in automotive environments) electronics should be more than adequately designed for protection, extra protection is not a bad thing and at $20 or so it sounds like a goer ;) Try an external fuse just for the sake of paranoia.

p.s. Hey not ford, fellow EE here :s5
 

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AU3 Falcon XR8 Ute (auto)
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Discussion Starter #13 (Edited)
Didn't know you guys were electrical engineers. It's great to get some input from a couple of guys qualified in the area.

I've installed the device, and necessary or not, I think I'll be happy to keep it on there (I agree that extra protection can't hurt) - as long as there are no negative aspects to it, which it doesn't sound like yet.

I'll still chuck a fuse on there I think, like you said !Gn|T|0n, just to be sure.

EDIT: The wires look like pretty standard (3mm-ish) auto cable, so I'm guessing they're good for maybe 10A. So, if I put a 16A fuse in, that should be high enough not to interfere with normal operation of the surge protector, but obviously should still blow in a short circuit before the battery fries and in time to stop the wire catching on fire I'd hope. I realise, as has been said, the surge protector may be of no real use anyway, but I'm assuming for the sake of figuring out what size fuse that it would work as claimed. What you guys think - 16A ok?

Thanks.

Steve.
 
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