battery and alternator connections
 

guys,

I have some questions.

I replaced all my ground-wires today, because I thought I had a bad ground problem.

In that proces I took a look at my positive connections at the battery and around the engine bay too...got some questions.

1 - when I check the Chilton and Haynes, they both show the battery directly connected to the alternator +. is that how it is hooked up with you guys?

2 - I followed the thick red from the alternator to the battery and it goes like this:
alternator --> connector on firewall --> some strange device on right side above the fender --> connector on the chassis --> to the battery +

this is what that strange device looks like:
https://lh3.googleusercontent.com/-c...0/accu_2-1.JPG
https://lh5.googleusercontent.com/-L...0/accu_2-2.JPG

this strange device has no numbers on it and it also has a connection to the ground on the chassis.

picture of the connection on the firewall:
https://lh3.googleusercontent.com/-k...640/accu_3.JPG

can anybody tell me what that strange device is?

how are your rides hooked up?

and I think the red wires are far to thin? arent they?

the wire in this picture that goes to the left (thin one) is the wire that is supposed to charge my battery? isnt that way too thin?
https://lh4.googleusercontent.com/--...512/accu_1.JPG

Re: battery and alternator connections
 

ow man! did I find a very nice and well written article on alternator, battery and accessory setup...

there are a couple of VERY NICE articles here:

http://www.madelectrical.com/electri...evymain1.shtml
http://www.madelectrical.com/electri...esensing.shtml
http://www.madelectrical.com/electri...witworks.shtml

they all come from this page:
http://www.madelectrical.com/electrical-tech.shtml

I thin I now have found out that:

1. this is my junction at the firewall:
https://lh3.googleusercontent.com/-k...640/accu_3.JPG

2. and this is probably my horn relay, with also a small junction next to it:
https://lh5.googleusercontent.com/-L...0/accu_2-2.JPG

I now know that I have to do some major reconnecting stuff in my engine compartment...and taking connections I had made a the battery to these junctions where the voltage is kept at the perfect level...

learned a lot again...

Re: battery and alternator connections
 

Yes that appears to be a relay, a 75A one at that. As for your alternator it should be connected to the battery using some heavy gauge wire like #4 or #2. On my 85 Burb with a 6.2L Diesel my alternator connects directly to the factory side mount on the side hand battery.

As for the junction on the firewall, it is simply an isolated 12v+ junction terminal, my truck has one as well, i have simp0le things like my horn and trailer plug 12v charge line attached to it by factory, and i have used it for things like my CB as well. The wires coming to and from it are DEFINITELY TO THIN for an alternator.

I noticed that your battery connections are not the factory side mounts that were originally covered in plastic. It appears to be an aftermarket connector crimped on with a standard crimper. Did you make that change?

Re: battery and alternator connections
 

The red wire with the fuse goes to your trailer connector on the back bumper as a charge line as i refereed to in my last post.

Re: battery and alternator connections
 

zaccaglin: he man, thanks for the answers. The wires are so thin, because that is why the engineers from GM setup the system like this. To save on copper. Got a few question still though.

This article says that a three wire setup alternator the big plus and the voltage sensing wire should both be connected to the junction at the firewall. so how is your alternator connected if you connect it directly to your battery?

If the big silver thing is a relay, then what does it relay? In my case a wire from the firewall junction runs to it and the other side of the relay connects to the small junction and this small junction connects through 8# wire to the battery. this made me wonder. Because if its a auxilery relay and both my battery's are now connected by a big 4# wire, then this relay has absolutely no function...or does it?

Re: battery and alternator connections
 

okay, did some more research and I have draw up a schematic of how things are hooked up right now:
https://lh4.googleusercontent.com/-E...520battery.jpg

I used this online service to draw this. Pretty cool website.
http://www.dz863.com/

currently my alternator BAT is hooked up to the JF1 firewal junction.
I cant see where the two other wires go, but if I read the information from the above website right then the nr2 wire goes to the junction JF too and the nr1 wire goes to the IGN in the dashboard.

Currently I have the following stuff hooked up to the various points:
JF2: MSD 6AL ignition box
JF3: HID ballasts (2x35W) and cooling e-fan (10A, 120W)

the problem I see with my setup is that the main battery is directly connected to the Auxiliary battery. This way the main battery (intended for starting the engine) is drained together with the Auxiliary battery.

I found this topic and schematic and I think the last post makes sense.:
to hook it up to ACC (like it is right now) and connect it like in this topic is shonw:
http://67-72chevytrucks.com/vboard/s...d.php?t=500732
https://lh6.googleusercontent.com/-z...Large%2529.jpg

Re: battery and alternator connections
 

I guess what I need to do is cut the thick wire that is connecting my two batteries positives and connect a wire from my main battery positive terminal to the junction on the firewall. That way:
- both batteries are allways charged when the engine is running
- the main battery isnt drained when in ACC mode

Re: battery and alternator connections
 

another question I got is if the auxiliary junction will be able to handle the connected accessories:
- electric cooling fan, 120W, 10A
- 2 ballasts for Xenon headlights, 2x35W, 2x 3~8A (8A is for starting the bulbs and 3A is for normal operation)
- and the stereo is also hooked up to this connection. regular car stereo 4x50W rms

Re: battery and alternator connections
 

Thanks for the link for the drawing site.

Before I make any comments on how its is wired I need to know what the blower motor is above the main battery in your drawing and the drawing shows that it is not switched, is that correct?

Re: battery and alternator connections
 

Other than the radio or an amp I would supply all accessories from JF1 where the alternator output and voltage sense wires are connected.

Re: battery and alternator connections
 

sorry, blowermotor is de blower from the cabinheating and indeed it is controlled by a relay I didnt draw. My bad.

for your second answer. thanks.

one question for me left then, would you also cut the line between the positive terminals of my battery's and replace it by a line from the junction JF1? from what I read a long wire from the junction to the battery is a good thing, as long as that junction is the junction where the voltage sensing is also connected.

hope you can help me.

Re: battery and alternator connections
 

I removed the blower motor for clarity, if you wire it like this it will isolate the aux battery from the main.

http://i1176.photobucket.com/albums/...ualbattery.jpg

With the charge wire I would try to keep it as close to original as possible. The diagram below shows a regulator just ignore it and look at the charge wire. Don't forget the fusible links at each battery.

http://i1176.photobucket.com/albums/...metershunt.jpg

Re: battery and alternator connections
 

hi fixit-p,

the aux seems isolated, but isnt, because of the relay, but the relay is closed in ON and ACC mode of the ignition key.

your drawing only shows one battery. How do you hookup a main (starter) and aux battery?

Re: battery and alternator connections
 

The top drawing I posted was yours that I modified, the aux battery in this system was designed to be isolated from the main battery with the key off would sometimes be used to power a camper. The relay connects both batteries when in the run position so it can charge with the engine running. When in the aux position both batteries are available to power the aux circuits with the engine off. The acc circuit should drop out once the key is turned to the start position again isolating the batteries preventing excess current draw though the relay while cranking.

The second diagram I posted was just to illustrate the charge wire, the feed from the second battery relay would connect to the buss on the alternator side in your drawing it is JF1.