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35 minutes ago, cletus said:

Electrical question.

 if I'm using fused relays, do I need to run circuits through a fuse box first? Would prefer this for simplicity. 

 

Or is it better to use regular relays and a separate fuse box? 

Will use relays for fuel pump/fans/ignition box /etc  

In my opinion...

If you're running fused relays and the wire from your positive feed is capable of handling the current and any over current conditions and isn't at risk of rubbing through the insulation to the conductors, then go for it.

It it's a nice short run from power source to relay you should be fine. I like to fuse as close to the battery as possible though.

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My plan is to have the battery in the boot, cable runs up to a plate mounted under the dash with all the relays , coil, and ignition box mounted to it, with a insulated terminal that I can bolt the main cable, starter feed, and alternator wire to. 

 

I have heard that the alternator wire should go directly back to the battery , but not sure if that's an old wives tale or a real thing?  

 

Can probably fit one of those big 200amp? circuit breaker /fuse things at the battery in the boot if thats safer as well   

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My only issue with having everything off the battery fused means that in an, albeit rare, occasion where you might just need to move the car in an emergency using the starter alone it could then trip that circuit breaker.  Thinking situations like when you get stuck in a ford/on railway line etc ( yeah I know, rare as) 

But I guess you can't do that trick with an auto equipped car anyway? 

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Is the starter motor ever fused on any vehicle? I thought they are always pretty much just a big honking cable capable of delivering many hundreds of amps at a direct short.

 

Should always run the alternator sense wire directly to battery by itself, you can put a small fuse (like 1 amp) for this wire.  There will be effectively zero current through this wire and it is essential there is no load on this wire or your output voltages will be wrong.

 

The output of the alternator can just feed into the general 12 Volt network wherever you want, but you will still want a fuse on that.

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17 minutes ago, ajg193 said:

Is the starter motor ever fused on any vehicle? I thought they are always pretty much just a big honking cable capable of delivering many hundreds of amps at a direct short.

 

 

Most vehicles that have factory battery in the boot seem to have some sort of fuse, battery in engine bay is such a short run its not worth it

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I'm literally in the throes of doing this right now.  Auto sparky mate said those fusable link wires aren't a thing anymore. Gave me a nice 80A plastic fuse. I'm also running an isolator switch between the battery, and the starter. Ain't nothing worse than when the smoke escapes from the wires, and you cant easily unhook the battery.

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  • 2 weeks later...

Speaking of battery stuff. I have a battery (was 10.8V) I'm trying to save (just for interest). My 2.2A charger wasn't doing the biz, and @RUNAMUCKhas been kind enough to loan me his 3 or 4A "Pulse charger" (MSPaint graphs coming later). It's slowly clawing the peak voltage up, which looks promising.

My Q is: what happens if I invert the battery and slosh it around to try and loosen the crystals / acid-salts/whatever while it's charging. Does it short through the electrolyte and explode, or go flat real fast or some nonsense? ( @ajg193, Autosparkies?)

Anyone with experience with flooded lead acid batteries from roll-overs etc? Thanks team.

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3 minutes ago, ajg193 said:

You can borrow my 5A ctek charger and use it on rejuvenate mode. It hasn't failed to save a battery yet

I haven't had much luck with agm motorcycle batteries with mine. They are probably worse case scenario tho. Maybe 2/10 come back

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Safety squints

 

Batteries are pretty hardy, built for vibrations, so smacking them around a bit doesn't hurt them. I have one I have rolled down a hill and left sitting on its side till I went and got it. no acid even came out

 

Watch those guys in Pakistan refurbish the plates, there's hardly anything to go wrong

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On 14/03/2022 at 11:39, ajg193 said:

You can borrow my 5A ctek charger and use it on rejuvenate mode. It hasn't failed to save a battery yet

Mine has failed to save the Aqua battery (AGM) but it is 9 years old, so meh. Worked mint for a week but now it’s running low again.

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I'm actually keen to try the blast it with a welder trick. 

Totally not keen to get splattered with scalding hot acid though.

[Sharn]

My brother was once involved in a laboratory explosion, and was very very lucky to only get a few minor burns on his leg. Emergency services were amazed he wasnt killed.

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On 14/03/2022 at 20:47, RUNAMUCK said:

I saw a video on you tube (uncle Tony's garage) where he blasted a fucked battery with a big shot of juice from a welder. 

Came up mint.

Have watched similar videos of starting bulldozers in the Canadian winter. Build fire under engine to pre heat it and hit battery with welder for extra cranking juice 

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17 hours ago, RUNAMUCK said:

I'm actually keen to try the blast it with a welder trick. 

Totally not keen to get splattered with scalding hot acid though.

[Sharn]

My brother was once involved in a laboratory explosion, and was very very lucky to only get a few minor burns on his leg. Emergency services were amazed he wasnt killed.

Well, your charger is no longer making progress on it. I'll gratefully try one from @ajg193, and if no joy we can try that when I come to borrow your mig for a minute (please).

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