Fuse for trunk battery

[badazz81z28]

Do any of you PT trunk battery users have a fuse at the battery terminal? If so, what are you using?

Thanks

[1989GTA]

I do. It is a Littlefuse Mega but I forget the amperage. Maybe 300? I have other fuses to, like between the alternator and the distribution block. Here is a link.

http://www.delcity.net/store/MEGA%C2%AE-Fuses/p_800374.h_800375.t_1.r_IF1003?mkwid=se6pKVrgO&crid=38094426869&mp_kw=&mp_mt=&gclid=CIKhwu-jm8gCFUhufgod6lgCbg

[slofut]

I'm thinking about putting a constant duty solenoid at the battery with a 3 amp or so fuse in parallel. Wired to the ign switch ...it's on when the switch is on, but the big ass cable is disconnected when the switch is off ...like at night, while I'm asleep.

[badazz81z28]

I'm thinking about putting a constant duty solenoid at the battery with a 3 amp or so fuse in parallel. Wired to the ign switch ...it's on when the switch is on, but the big ass cable is disconnected when the switch is off ...like at night, while I'm asleep.






I have seen that all over the net, but too many wires to try and route through my cab. I think the chance of my Quick Car cable chafing through it's shielding is not likely, but by chance a fuse would blow if it did. A fuse just seems like a similar effective method without all the additional wires.

[obengston]

I don't have a fuse, but I do have a remote (keychain) selonoid mounted on the battery box so I can just hit the button and it kills all power coming from the battery (except the alarm). When I'm ready to go for a ride I just hit the key chain and all power is instantly back on. The only thing it kills the power to the radio so no channels stay programmed. I could easily fix that by wiring like I did my alarm, but really don't listen to the radio just the iPod that connects to the radio.

[slofut]

I have seen that all over the net, but too many wires to try and route through my cab. I think the chance of my Quick Car cable chafing through it's shielding is not likely, but by chance a fuse would blow if it did. A fuse just seems like a similar effective method without all the additional wires.

You'd have to use a large fuse like you said, and I've been tossing this back and forth on my car between a fuse or solenoid without a final decision. I've seen a lot of cars burned up because of wiring issues so I'm with you on fusing the battery cable. My car is a '71 vette and the batt cable is run under the driveshaft tunnel, lots of close tolerances under there. In my case, having only a 3 amp circuit connected when the car is unattended feels a bit more comfortable. Plastic burns easily! I'm subbed, would love to know which fuse/holder you settle on.

[slofut]

I don't have a fuse, but I do have a remote (keychain) selonoid mounted on the battery box so I can just hit the button and it kills all power coming from the battery (except the alarm). When I'm ready to go for a ride I just hit the key chain and all power is instantly back on. The only thing it kills the power to the radio so no channels stay programmed. I could easily fix that by wiring like I did my alarm, but really don't listen to the radio just the iPod that connects to the radio.


Do you have a pic of how you mounted the solenoid? Is your battery in front or back?

[ErikLS2]

I have seen that all over the net, but too many wires to try and route through my cab. I think the chance of my Quick Car cable chafing through it's shielding is not likely, but by chance a fuse would blow if it did. A fuse just seems like a similar effective method without all the additional wires.

A 300 amp fuse will blow on a direct short (assuming your battery is healthy enough to output that)but 290 amps can still do a lot of damage which is why a starter solenoid at the battery is the best option IMHO.

[badazz81z28]

Gotcha, I think the BUS site I was looking at suggested 200amps for my wire gauge.

[Vegas 69]

I run trunk mount battery with a Ford Solenoid to the large starter cable. Only hot while cranking. Then from the bat to power the car with #10 wire and fusible link.

[Kenova]

Ford solenoid in the trunk so starter cable is live only when cranking. I have a 4 gauge cable taking power up to the engine compartment with a 140 amp circuit breaker at each end and an 8 gauge wire from the alternator to the front circuit breaker.

Ken

[ErikLS2]

It's not hurting anything to have 2 circuit breakers but it doesn't help anything, just one right off the battery protects the whole circuit

[badazz81z28]

Just to ensure I'm comprehending here. What's really the difference between a 10 GA running live versus a 2 GA battery cable?

If the fusible link or fuse rather is closer to the engine, you still have wire from that point to the battery. So in a Chafing condition, you will still have raw battery power shorting to ground. Since AMPs will be high and the cable is small (#10), your chance of overheating and fire is higher right?

So in theory, my fuse at the battery is safer than a 10ga with a fusible link at the alternator?

[swicke69]

Did the mad electrical route few months back. Works great. First time doing electrical wiring on a car. Helps to read and talk to someone who knows what they're doing. So you can understand it well. Hiding everything and making things as clean as possible was the main challenge for me.

[ErikLS2]

Just to ensure I'm comprehending here. What's really the difference between a 10 GA running live versus a 2 GA battery cable?

If the fusible link or fuse rather is closer to the engine, you still have wire from that point to the battery. So in a Chafing condition, you will still have raw battery power shorting to ground. Since AMPs will be high and the cable is small (#10), your chance of overheating and fire is higher right?

So in theory, my fuse at the battery is safer than a 10ga with a fusible link at the alternator?

A 10 GA wire will burn up under much less amperage than a 2 GA wire will, is that what you mean?

The fusible link closer to the engine, with the battery in the trunk, leaves a large portion of wire unprotected and is not how it should be done. Just put an appropriate fuse right at the battery with the correct gauge wire for the length it's going to run and it will be fine. Every wire coming off the battery, except for the large one going to the starter motor, should be fused right at the battery, or as close to it as possible so that only a short wire exists between it and the battery. Now, you can have one larger gauge wire, fused right at the battery, running to your main fuse block mounted somewhere else in the car. To answer your question, yes, a fuse at the battery is the safest.

[1989GTA]

Dittos to the above post.

[badazz81z28]

I’d like to bring up this topic again. What’s changed in 10 years?


What I’m concerned about is a short to ground. I get proper routing and shielding is key, but that is not fool proof. I feel I need a breaker or a fuse.

[Vimes]

How much wire is where does not matter. Put the power interrupt at the power source. This means at the battery and at the alternator. No matter where a short is in the car, you want it to interrupt the source of power. Wire with no power running through it is just dead weight.

If chafing is a concern, use welding cable for the primary wiring inside plastic split tube conduit, with a retaining device every foot or so. The retainers will keep the wiring from moving much, the split tube conduit will wear through first so will be found during regular inspections. The welding cable is designed to be dragged around in a horrible environment for years, being walked on, sitting in various chemicals with sparks flying around landing on it. The environment under a car is way, way easier than a worksite so it'll last forever under there.

[DreKoushRanada]

Awesome thread! Does the same rules apply when using things like a Terminator X Max?

[badazz81z28]

What about these??


https://www.amazon.com/GENUINE-18980-08110-1898008110-1898008300-SPORTAGE/dp/B087BB4FDB

[badazz81z28]

What about these??


https://www.amazon.com/GENUINE-18980-08110-1898008110-1898008300-SPORTAGE/dp/B087BB4FDB



Looking at this too.


32V 400A Car Quick Release Fused Battery Distribution Terminal Clamps Connector | eBay (https://www.ebay.com/itm/354912185777)

[Vimes]

Either one would do the job. Whatever you use to should be able to pass an overcurrent for a short time like the second one states. Otherwise, it's going to pop every time you start as the starter pulls hundreds of amps for a short time.

There really is no need for a fuse right on the battery though. The OEMs don't use one on the primary cabling and they don't really even do anything to protect it from chafing anywhere. Split loom and tie downs will keep the primary wiring from moving enough to chafe. I've never done more than use wire loom with proper tiedowns, and have never had an issue with it.

When I relocate the battery on my project to the bed, I won't be doing anything more than I've done in the past. Welding cable, wire loom, tie it down every so often. Only, I'll be running the alternator to the starter lug, then using the wire from the starter to the battery to charge the battery. Welding cable sheathing is nearly indestructible.

[Y-TRY]

I went with this relocation set up from CE Auto Electric Supply. This runs from the top battery post to a bulkhead at the firewall to power everything except the efi. The Terminator X power harness is by itself on the side posts.
https://ceautoelectricsupply.com/battery-relocation-kits/deluxe-single-battery-relocation-kits-with-complete-electrical-protection-10-awg-and-2-awg/

215181

This is the side of the box. There’s a short cable connecting that top lug to the battery post. A long cable is attached at the bottom and runs up to the firewall.

[srode]

There really is no need for a fuse right on the battery though. The OEMs don't use one on the primary cabling and they don't really even do anything to protect it from chafing anywhere. Are you sure? I think these distribution blocks are fused, and are used in most of the newer GM vehicles
https://www.amazon.com/Distribution-Chevrolet-Colorado-Canyon2015-2021-23270100/dp/B0DCBVL6KZ

[badazz81z28]

Like I mentioned, I think we have neglected to see what’s being done today in modern cars. It seems many cars now are fused at the battery.

[Vimes]

Interesting. Here is a nice discussion about it.

https://electronics.stackexchange.com/questions/355936/why-arent-starter-circuits-protected

I then looked at the size of the battery cable on a Colorado and it looks like they've been put on a diet, which may be why they now use a fuse. Battery cables used to be a 0GA or 2GA, but (going by a picture) it looks like they're now more like or 8 gauge. So, what it boils down to here is while there's no real reason to run one, there's no real reason not to. You might also consider a circuit breaker, which blows like a fuse but can easily be reset.

https://www.amazon.com/12V-24V-80-300A-Marine-Circuit-Breaker/dp/B074FGT36D

[badazz81z28]

The way I see it, most cases of a rare fault or short to ground happens it will burn down a disposable car. Not a big deal right? It’s insured, just collect the payout and move on.

It’s a different game when it’s your classic car. In a way you want to accept the minimal risk as possible.

[srode]

So, what it boils down to here is while there's no real reason to run one, there's no real reason not to.
https://www.amazon.com/12V-24V-80-300A-Marine-Circuit-Breaker/dp/B074FGT36D

Read this post
https://www.camaros.net/threads/more-starter-troubles.488545/?post_id=1783368631#post-1783368631

[Vimes]

That's a good way of putting it. Never let it be said I can't change my mind mid-stream. :rotfl:

[badazz81z28]

I’m putting something in line with the main cable like it or not….its just a gamble hoping you don’t chafe it!

I just need to figure out what…I might also get the CB just to see how it likes the starts amp draw.

[Vimes]

No worries. But, a fuse and a circuit breaker will do the same job, so you only need one or the other. You can use a clamp on ammeter to find out what your starter draw is and size the fuse or circuit breaker accordingly.

[srode]

This is a nice breaker used in marine applications if you want a breaker instead of a fuse so you can reset it. The time+load to trip curves are available for each size and available up to 200amp. If you look at the curves, you should never be in a situation where you exceed 200amp trip time+load limit without a dead short. Easy to make a panel to install this in for a nice finished result too.

https://www.invertersupply.com/index.php?main_page=product_info&cPath=620_627&products_id=185310

[Vimes]

Nice looking. Question, does anyone know if there is an amperage difference on what a circuit breaker rated for 48V will pass on a 12V circuit? Math says the circuit breaker should handle 4 times more amperage on 12V as 48V, since the wattage would be the same, but I don't know if a circuit breaker only looks at amperage or voltage, or both. My google-fu indicates that the amperage may be the same regardless of voltage, but that doesn't seem right.

[dhutton]

Nice looking. Question, does anyone know if there is an amperage difference on what a circuit breaker rated for 48V will pass on a 12V circuit? Math says the circuit breaker should handle 4 times more amperage on 12V as 48V, since the wattage would be the same, but I don't know if a circuit breaker only looks at amperage or voltage, or both. My google-fu indicates that the amperage may be the same regardless of voltage, but that doesn't seem right.
It’s strictly based on current. It does not vary with voltage. The circuit breaker doesn’t have a ground connection so it has no way to sense the voltage.

[BBPanel]

How about a shutoff via Bluetooth. That way the shutoff could be located a little more remote (or hidden). Use a key fob to turn it on or off.

[badazz81z28]

How about a shutoff via Bluetooth. That way the shutoff could be located a little more remote (or hidden). Use a key fob to turn it on or off.

Nice feature, but the intent would be for an immediate disconnection rather on demand.

[Vimes]

It’s strictly based on current. It does not vary with voltage. The circuit breaker doesn’t have a ground connection so it has no way to sense the voltage.

Appreciate it.

[badazz81z28]

This is a nice breaker used in marine applications if you want a breaker instead of a fuse so you can reset it. The time+load to trip curves are available for each size and available up to 200amp. If you look at the curves, you should never be in a situation where you exceed 200amp trip time+load limit without a dead short. Easy to make a panel to install this in for a nice finished result too.

https://www.invertersupply.com/index.php?main_page=product_info&cPath=620_627&products_id=185310


How do you read the time-load chart? It seems it takes about 1.5 sec to start my car hot, about a 1.25 cold. How many amps can it handle for that amount of time?

[srode]

In the chart at the bottom of this page for the 200amp breaker, the red zone is the trip zone with the time to trip across the bottom of the graph and the % rated load on the side. As an example, on this model it takes between 10 and 40 seconds to trip at 200% of the rated load, which would be 400amps drawn.
https://www.bluesea.com/products/7049/187-Series_Circuit_Breaker_-_Panel_Mount_200A
So you want to calculate your max load and max continuous load and and use the larger of the 2 to decide on which size you need. A starter isn't likely going to trip the breaker unless there's something wrong with it it most cars because the start cycle is so short and most people aren't going to let a starter spin for longer than 10 seconds anyway and will let it cool before trying again. Big cooling fans+AC+ECM+lights+Stereos and amp draws in some cars are going to make a continuous load that will determine the breaker load rating.

[badazz81z28]

I went ahead and bought a 200 amp breaker. I’m confident it will work…will report back.

[badazz81z28]

Got the thermal breaker installed, mocked up rather…initial test was good. Started the car and no issues. Now time to mount it and wire it with the 2ga and do more testing .

[badazz81z28]

Well, the 200amp has been working flawlessly so far. Even cranked it over a little more than normal today and still issue free. Thermal is the way to go…considering people are saying a 300 AMP breaker would pop for others.215415

[srode]

Nice installation job, looks great.

[rallystyle]

I have started to look into this as well. with everything needing to hook directly to the battery. looking at the list of things that say they need to go to the battery

starter / alt
body harness -fuse block or pdm
stereo amplifier
holley ecu
vintage air
vaporworx controller

i looked at what the oem is doing and i see the 6th gen camaro and the c7 corvette or using a z fuse type of set up. stuff like gm 23173653, gm 84081785. the only thing i see about them is that they are not individual replaceable if you have a problem.
i found littelfuse 0FHZ0005Z or FHZ00863.
any thoughts on this or other suggestions? is there anything that is on the list that does not need to go directly to the battery?

[Steve68]

Your worried to much about chafing

securing the wires with the correct clamps, tucked and routed out of the way, sharp edge protection, using Teflon tape or wrapping, even the wire split covering is adequate,

I worked on the Space Shuttle wiring for years and we didn't worry about it that much, we did the necessary precautions, and were mindful of were and how the wires and harness were routed, I have also built rockets and worked on satellites and missiles, I build Executive jets now, it's about protection, correct routing and should I say common sense, dangerous term now days,

[thedugan]

Well I'm another one now doing this.. Makes sense to have it with all that we have into our cars. Can't tell in the picture where you wired the vaporworx controller to. If you have any more pictures please post.
Thxs
Doug

[ULTM8Z]

Your worried to much about chafing

securing the wires with the correct clamps, tucked and routed out of the way, sharp edge protection, using Teflon tape or wrapping, even the wire split covering is adequate,

I worked on the Space Shuttle wiring for years and we didn't worry about it that much, we did the necessary precautions, and were mindful of were and how the wires and harness were routed, I have also built rockets and worked on satellites and missiles, I build Executive jets now, it's about protection, correct routing and should I say common sense, dangerous term now days,

Exactly. Make a failure essentially non-credible, with good routing practices, double insulation where necessary, heat shielding where necessary, etc.

The only thing I did was put in a starter solenoid at the battery so the overall cable running the length of the car is only live during starting. If I get into an accident or something, then at least that can't cause the short either.

[badazz81z28]

I’ve worked on military aircraft my whole adult life and I can tell you even with the best routing and best protection, the vibrations, bumps etc can cause the slightest issue. I don’t mind replacing a burned wire harness, burned up component or fuse box on something that ain’t mine…but the car has too much into it to take that chance or beat the odds.


Btw, my vaporwork controller is right behind the breaker.217113217114

[AUTODYNAMICS]

217149
217150
This is what I did

[Y-TRY]

I like how you arranged your double breakers, but I can’t figure out if/how you have them bridged. Is the bottom one just open for now?

[AUTODYNAMICS]

Bottom at the time of this picture the break it wasn’t populated yet

[Cdog]

Anyone using this solid state switch from race wire? They advertise the sheeit out of my FB. 30% off right now. 2 or 300 amp?

https://racewiresolutions.godaddysites.com/shop/ols/products/racewire-solid-state-kill-switch-kit