voltage drop / battery & ground cable

[AC439]

(1) Out of curiosity, I put a pair of alligator clips across the seal beam's low beam bulb element, I measured around 10.2 volts. At the same time, the voltage measured at the battery terminal is 11.9v. I have some significant voltage drop. So, I pulled out the schematic and started measuring the voltage of the headlight circuit from the battery terminal.

At the battery terminal -11.9v
At 40A fuse under the hood - 11.8v
At the big white wire under the steering column and above the fuse box - 11.4v (this is before the headlight switch)
At the red/ble wire (after the headlight switch at the steering column) 10.9v.
At the light - 10.2v

Which items should I look at first? Should I just forget it and run a relay and pull power for the lights directly from the battery?

(2) I'd like to replace the stock battery terminal clamps. I found a direct fit one from Autozone for the -ve bat terminal to the transmission. But how do you do the +ve (red) side? There are two large wires connecting to the clamp on the +ve side. But new clamp only have one large wire coming out of it. How do you connect two large wires there?

(3) There is a piece of cable connected between one of the nuts on the valve cover to the body of the car. Where do you find a good replacement? I found some 19" lawn mower bat cable but the pre-drilled holes seems to be too big.

(4) Am I wasting my time trying to fix all these?

Thanks for insights !

[bobafett]

not sure if this will help you, but some members have hooked up 'heavy duty' wiring harness if they use really brigh H4 bulbs or HID's.

from my understanding you hook the stock connectors up into a relay, which gets its power direct from the battery and u can use nice wire and that way you ensure the wire can hold up to the load of the higher end lighting solution.

this would help you because you would be getting clean power right from the battery. unfortunatly i have never installed one of these, so i dont have details on how they work.

good luck

[AC439]

Thanks. I have wired this way for the fog light (with relay). I'm getting a set of diamond conversion kit and will be using standard H4 bulbs. If my standard stock seal beam at 35w low beam creates a 1.7v drop, the 55w H4 will surely creates a bigger voltage drop due to higher current through the wires. I know I can run a new relay for the H4 conversion, but I'm only bypassing problems. I think if I have poor battery cable / clamps, I should fix them because other electrical systems pull juice through the main battery cables too. I know fixing electrical problems can be tricky. - AC

[bobafett]

yes thats true. the headlight relay is only circumventing the problem...
you could run new battery cable to your fuse box from your battery using a nice gauge wire and good connectors.

i have too much shit hooked up to mine ATM but i think battery + only goes to the starter and to the fuse box on the left side of the engine bay. it would be pretty simple to replace those lines.

also, im not sure how many grounds a 3g is 'supposed' to have, but i only had my valve cover grounding to the chassis, and the negative terminal on the battery grounding to the tranny and maybe the starter? but there could definetly be more grounds installed, like to the intake manifold and such.

[Oldblueaccord]

Just wrote this in the other thread. Battery should be 12.7 v at rest fully charged and the car running should be 14v .


wp

[AC439]

Yes, I know my bat is a little on the weak side too and I'm also looking into that. But I believe the voltage drop is not due to a weak battery but to some bad wirings.

As for the battery grounding to chassis, I have also only noticed that the -ve side connects to the trans, then the valve cover to the chassis. So, the electron path has to go through the transmission/engine junction, then to the top of the engine through the valve cover nut to the chassis. To me this is an indirect path. I am thinking adding a cable from the -ve terminal to the chassis directly.

[Blkblurr]

the highest voltage drop is what you should focus on first. You can of course use a relay to power your lights. Just use the 12 volt source from your headlight switch to turn the relay on then run 12 volts from your battery to a fuse or circuit breaker (short run between battery and fuse) then to the relay and of course then the headlights. I don't remember if the fuse box under the hood has a spare space in it for a fuse but if it does, use it because the wire from the battery to the fuse box is protected by a large fuse and won't cause a fire if it shorts out.