Reply With Quotebetween 300 and 400 amps (theres lots of things that vary it, temperature, condition of batteries voltage on batteries)
the draw can go as high as 700 Amps.
I work my cable runs (positive and earth) for diesel starters on 500amps petrols around 250A
YarnMaster
SubscriberI've been searching around, but i can't find any details for the standard 12v one. After a short recently I'm thinking of fitting a large marine circuit breaker, but I'm not sure how many amps are needed when it cranks..
I found a post by Dougal mentioning between 300-500 Amps, but that seems way to much??
Hercules: 1986 110 Isuzu 3.9 (4BD1-T)
Brutus: 1969 109 ExMil 2a FFT (loved and lost)
RoverLord
between 300 and 400 amps (theres lots of things that vary it, temperature, condition of batteries voltage on batteries)
the draw can go as high as 700 Amps.
I work my cable runs (positive and earth) for diesel starters on 500amps petrols around 250A
Dave
"In a Landrover the other vehicle is your crumple zone."
For spelling call Rogets, for mechanicing call me.
Fozzy, 2.25D SIII Ex DCA Ute
TdiautoManual d1 (gave it to the Mupion)
Archaeoptersix 1990 6x6 dual cab(This things staying)
If you've benefited from one or more of my posts please remember, your taxes paid for my skill sets, I'm just trying to make sure you get your monies worth.
If you think you're in front on the deal, pay it forwards.
YarnMaster
SubscriberThanks.. The highest amp rating breaker I can find is 350. Maybe this wont work..
Hercules: 1986 110 Isuzu 3.9 (4BD1-T)
Brutus: 1969 109 ExMil 2a FFT (loved and lost)
TopicToaster
SubscriberAre you after a circuit breaker or a disconnect switch?Originally Posted by flagg
Steve
1985 County - Isuzu 4bd1 with HX30W turbo, LT95, 255/85-16 KM2's
1988 120 with rust and potential
1999 300tdi 130 single cab - "stock as bro"
2003 D2a Td5 - the boss's daily drive
YarnMaster
SubscriberI was hoping for a breaker that I could push a button to trip, effectively having a switch too. Reason being my old battery switch had a plastic leaver which melted when I needed it most. If I can't bet a breaker ill go for a proper truck style isolator that is all metal, with a removable 'key'. (Wont get hot)
Hercules: 1986 110 Isuzu 3.9 (4BD1-T)
Brutus: 1969 109 ExMil 2a FFT (loved and lost)
TopicToaster
SubscriberWas your old switch one of the black plastic ones with the small red key? If so then I've got a similar one fitted to the County as a main disconnect switch. Might need to review that in light of your experience with them.
I can't help with circuit breakers, but some of the Blue Sea battery switches on eBay have pretty hefty current capacity - like this one: m-Series Battery Switch, Single Circuit ON-OFF - PN 6006 - Blue Sea Systems
I've got one as my dual battery "link" switch and its a nice piece of gear. Probably complete overkill but the shape and mounting arrangement suited me.
I'm wondering if a circuit breaker is actually going to give you the protection you intend it to. As far as I know, an eg 20A circuit breaker doesn't trigger instantly as soon as it sees 20A - it will pass more than that for a while until it triggers. If it sees 40A it should probably go instantly.
You'd have to select one that would handle cranking current for a short time but still trigger below what the wiring can handle continuously or its going to make smoke if anything big shorts out.
If you achieve that balance with say a 350A breaker, then what happens next? How long can batteries handle a few hundred amps?
Apart from the cost perspective, I wonder if that's why you don't find circuit breakers on starter motor circuits?
Steve
1985 County - Isuzu 4bd1 with HX30W turbo, LT95, 255/85-16 KM2's
1988 120 with rust and potential
1999 300tdi 130 single cab - "stock as bro"
2003 D2a Td5 - the boss's daily drive
Master
The fact that the starter motor can draw such a varied current makes me think that a breaker (if one rated high enough even exists) would be a bad idea. Breakers are good for circuits that have a constant load - anything above the ordinary will trip it.
The current to the starter motor will vary, sometimes to large degrees, depending on battery condition, engine condition, starter condition, put a little more than normal load on the starter and the current draw will spike by quite a bit. I'm imagining a scenario where you need that little bit more cranking power to start, and right as it's about to turn over, the breaker clicks in.
Like Steve, I use a dual battery marine breaker bolted to the passenger side seat box. Allows me to kill everything at a twist of a switch, or I can link up the batteries for a cold start if it's needed. They're pretty bulletproof - can't imagine mine melting anytime soon.
Posting Permissions
| Search AULRO.com ONLY! |
Search All the Web! |
|---|
|
|
|
Bookmarks