Welcome to the MacNN Forums.

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

You are here: MacNN Forums > Community > MacNN Lounge > Crazy Car Question

Crazy Car Question
Thread Tools
subego
Clinically Insane
Join Date: Jun 2001
Location: Chicago, Bang! Bang!
Status: Offline
Reply With Quote
Mar 19, 2018, 06:59 AM
 
Is there a safe and reasonable way to install battery terminals inside a car?

The idea is to be able to clamp a heavy duty power inverter to it without popping the hood.

My original plan was to hardwire the inverter somewhere, but I like the idea of being able to put it away if I’m not using it.
     
P
Moderator
Join Date: Apr 2000
Location: Gothenburg, Sweden
Status: Offline
Reply With Quote
Mar 19, 2018, 12:39 PM
 
Connect it to the lighter outlet? I mean, it will be limited to whatever current that outlet is fused to, and it may or may not be disconnected when the ignition is off (it varies between models), but it should work.
The new Mac Pro has up to 30 MB of cache inside the processor itself. That's more than the HD in my first Mac. Somehow I'm still running out of space.
     
Laminar
Posting Junkie
Join Date: Apr 2007
Location: Iowa, how long can this be? Does it really ruin the left column spacing?
Status: Offline
Reply With Quote
Mar 19, 2018, 01:05 PM
 
Look into how to wire up a subwoofer amp. They even sell installation kits complete with 4GA wire, which is typically good for up to 1000W (83A @ 12V) or more. You can go thicker or thinner as needed.

You need a big ol' fuse as close to the battery as possible for the positive terminal. The negative terminal gets grounded to the car's body with as short of a lead as is possible.

Something like this: Amazon

You could couple it up with a shutoff switch like this one.

12V car stuff is typically cake compared to high(er) voltage AC home wiring.
     
subego  (op)
Clinically Insane
Join Date: Jun 2001
Location: Chicago, Bang! Bang!
Status: Offline
Reply With Quote
Mar 19, 2018, 04:34 PM
 
Originally Posted by P View Post
Connect it to the lighter outlet? I mean, it will be limited to whatever current that outlet is fused to, and it may or may not be disconnected when the ignition is off (it varies between models), but it should work.
I’ve got to run 300 watts, which is way too much for a lighter outlet.
     
subego  (op)
Clinically Insane
Join Date: Jun 2001
Location: Chicago, Bang! Bang!
Status: Offline
Reply With Quote
Mar 19, 2018, 04:38 PM
 
Originally Posted by Laminar View Post
Look into how to wire up a subwoofer amp. They even sell installation kits complete with 4GA wire, which is typically good for up to 1000W (83A @ 12V) or more. You can go thicker or thinner as needed.

You need a big ol' fuse as close to the battery as possible for the positive terminal. The negative terminal gets grounded to the car's body with as short of a lead as is possible.

Something like this: Amazon

You could couple it up with a shutoff switch like this one.

12V car stuff is typically cake compared to high(er) voltage AC home wiring.
Good deal! Thanks!

The one problem which prompted the question is the positive lug needs to get mounted to the body, which is the negative lug.

Seems like a recipe for a short.
     
reader50
Administrator
Join Date: Jun 2000
Location: California
Status: Offline
Reply With Quote
Mar 19, 2018, 06:36 PM
 
Get a 50A socket and plug from a hardware store. It'll be for AC, but that won't hurt anything. Permanent-mount (and wire) the socket. In a standard box, if you like for safety. Add an inline fuse near the battery, and optionally, a disconnect.

Wire the plug to your inverter. This would be good up to 600W. If plug or socket wears out, you can replace easily with standard components.

I think they make high-amp plugs & sockets for DC, but I'm not finding them with simple-minded searches.
     
BLAZE_MkIV
Professional Poster
Join Date: Feb 2000
Location: Nashua NH, USA
Status: Offline
Reply With Quote
Mar 19, 2018, 07:15 PM
 
except now you have a dc source in an AC socket.
     
andi*pandi
Moderator
Join Date: Jun 2000
Location: inside 128, north of 90
Status: Offline
Reply With Quote
Mar 19, 2018, 07:17 PM
 
I don't think we should be helping him build a car bomb.
     
P
Moderator
Join Date: Apr 2000
Location: Gothenburg, Sweden
Status: Offline
Reply With Quote
Mar 19, 2018, 07:38 PM
 
You can use the plugs meant for PCIe power supplies. The biggest one, the 8-pin, is meant for 150W DC@12V. Wire up two of them in parallel. That is how high-power DC works in computers, lots of pins for each of the 12V and ground.
     
subego  (op)
Clinically Insane
Join Date: Jun 2001
Location: Chicago, Bang! Bang!
Status: Offline
Reply With Quote
Mar 19, 2018, 11:17 PM
 
Originally Posted by andi*pandi View Post
I don't think we should be helping him build a car bomb.
ProTip: this will ruin your inverter.
     
subego  (op)
Clinically Insane
Join Date: Jun 2001
Location: Chicago, Bang! Bang!
Status: Offline
Reply With Quote
Mar 19, 2018, 11:18 PM
 
Originally Posted by reader50 View Post
Get a 50A socket and plug from a hardware store. It'll be for AC, but that won't hurt anything. Permanent-mount (and wire) the socket. In a standard box, if you like for safety. Add an inline fuse near the battery, and optionally, a disconnect.

Wire the plug to your inverter. This would be good up to 600W. If plug or socket wears out, you can replace easily with standard components.

I think they make high-amp plugs & sockets for DC, but I'm not finding them with simple-minded searches.
It took me a second to wrap my brain around it, but this is brilliant.
     
subego  (op)
Clinically Insane
Join Date: Jun 2001
Location: Chicago, Bang! Bang!
Status: Offline
Reply With Quote
Mar 19, 2018, 11:53 PM
 
For the curious, this is for an air compressor.

I normally just use it in the garage to top off tires, but it would be good to have one in the car to fill up the spare if I catch a flat.

Seems silly to have two compressors, so I’m going AC compressor + inverter to rule them all. Inverter’s useful on its own, anyway.
     
subego  (op)
Clinically Insane
Join Date: Jun 2001
Location: Chicago, Bang! Bang!
Status: Offline
Reply With Quote
Mar 20, 2018, 12:02 AM
 
Originally Posted by BLAZE_MkIV View Post
except now you have a dc source in an AC socket.
But the AC socket is providing DC service, which is what my inverter needs. Rather than have battery clamps come off the inverter’s terminals, I have an AC plug come off the terminals.

That’s theoretically bad, because plugging the inverter into AC lets out the magic smoke, but only if it’s plugged into a live, 50A socket, which takes effort to find.
     
reader50
Administrator
Join Date: Jun 2000
Location: California
Status: Offline
Reply With Quote
Mar 20, 2018, 12:44 AM
 
I like Viair compressors for car/truck use. I've got this one. Way better than the cheapo plastic 12V compressors that poop out after a couple uses. Probably more compact than your existing one (B&D Air Station?), plus you don't have to carry a 2nd device (inverter) or do wiring.
     
subego  (op)
Clinically Insane
Join Date: Jun 2001
Location: Chicago, Bang! Bang!
Status: Offline
Reply With Quote
Mar 20, 2018, 02:15 AM
 
Originally Posted by reader50 View Post
I like Viair compressors for car/truck use. I've got this one. Way better than the cheapo plastic 12V compressors that poop out after a couple uses. Probably more compact than your existing one (B&D Air Station?), plus you don't have to carry a 2nd device (inverter) or do wiring.
That’s... tempting enough to make me rethink everything. I was put off of 12v compressors altogether because of the crappy reputation.

Also, it’s actually the exact same size as the AC compressor I have, so I know it’ll fit perfectly under my seat (blocked from the airbag wiring, as per P ).

I still want the honkin’ inverter (for whatever), and I still like the idea of it being “plug and play”, but this takes care of the horror scenario where I need to inflate a tire in a torrential downpour.
     
iMOTOR
Mac Elite
Join Date: Jan 2003
Location: San Diego
Status: Offline
Reply With Quote
Mar 22, 2018, 07:06 PM
 
I'm not sure how the inverter hooks up, but it seems like a quick connect jumper kit would work great:

https://www.amazon.com/Energizer-1-G.../dp/B01GU4O3GG

Just mount the quick connect inside the car. If the inverter hooks up with alligator clamps, you could just cut the alligator clamps off both the inverter and the kit then splice both ends together.
     
ghporter
Administrator
Join Date: Apr 2001
Location: San Antonio TX USA
Status: Offline
Reply With Quote
Mar 22, 2018, 07:10 PM
 
You want to basically follow Laminar’s idea of basing your project on wiring a subwoofer. And you REALLY want to use a connector rather than terminals and so on. It’s safer, it’s easier, and it’s less likely to give you problems.

Glenn -----OTR/L, MOT, Tx
     
Laminar
Posting Junkie
Join Date: Apr 2007
Location: Iowa, how long can this be? Does it really ruin the left column spacing?
Status: Offline
Reply With Quote
Mar 23, 2018, 11:48 AM
 
Originally Posted by iMOTOR View Post
I'm not sure how the inverter hooks up, but it seems like a quick connect jumper kit would work great:

https://www.amazon.com/Energizer-1-G.../dp/B01GU4O3GG

Just mount the quick connect inside the car. If the inverter hooks up with alligator clamps, you could just cut the alligator clamps off both the inverter and the kit then splice both ends together.
That would be great as long as there's a fuse close to the battery.
     
ghporter
Administrator
Join Date: Apr 2001
Location: San Antonio TX USA
Status: Offline
Reply With Quote
Mar 24, 2018, 04:49 PM
 
Anything connected directly TO the battery needs a fuse RIGHT THERE AT the battery. This isn’t a “nice to have” thing. It is absolutely essential. Nobody wants to burn down their car, or to explode their battery, right? Those can happen if you don’t fuse everything that comes straight off the battery.

Glenn -----OTR/L, MOT, Tx
     
   
Thread Tools
 
Forum Links
Forum Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Top
Privacy Policy
All times are GMT -4. The time now is 12:14 AM.
All contents of these forums © 1995-2017 MacNN. All rights reserved.
Branding + Design: www.gesamtbild.com
vBulletin v.3.8.8 © 2000-2017, Jelsoft Enterprises Ltd.,