dumdumgreg

iTrader: (5)

What the best places to mount grounding wires for a trunk mounted battery???

Tammy

As you neglected to state what auto or year, you'll need to run a large grounding cable to the engine... along with a large positive cable to the starter.

Trunk mounted batteries don't charge or perform well, since the electric load is at the engine and alternator. The large wiring required acts as an additional load in itself, as does the body metal if you ground thru it.. This is why battery cables are cored with copper wiring. Changing battery locations could damage the voltage regulator in the alternator, as this change creates the need for additional output and exceeding design.

Not a very practical idea.

motorheaddown

I have just performed this mod to make room for IC piping that passes through the battery platform.

There is a dedicated ground point right in the center of the main trunk lip; you can't miss it. It sits between the two taillights.

Also keep in mind, you need to run at least a 2 gauge cable (I used 0 gauge) to the engine compartment from the positive battery terminal. You'll also have to splice the starter power into the positive cable from the battery. Since the ground point from the negative battery post to the engine has been removed, make sure the engine grounding cable is attached to a frame of the car.

-scott

dumdumgreg

iTrader: (5)

thanks. I'll look for the dedicated center gound point
yeap I have to Moroso trunk mount kit with 2guage wire.
I was thinking of adding a multiple wire grounding in the trunk (like the grounding kits in the engine bay)
any other good ground points in the trunk area?

also how did you attached the stock neg cable thats under the hood to the frame, did you just cut off the terminal(that was attached to the battery) and add a flat connecter/terminal?

thanks

VJ RC51

I will also soon be adding my battery to the trunk, to make room for IC piping. This is all good info!! Keep it comming

vipsoarer

for the original ground cable, just remove it since it is not necessary any more. also having multiple ground points in the trunk is useless. the reason for them under the hood is to ground vital operation electrical components to allow them to perform at their max ability without electrical noise and unequal powering of compenents from using common grounds. in the trunk you would only be grounding the antenna and lights which wont yield benefits worth the money. if you are looking for perfomance, reducing the distance from the electrical component wire paths will lead better results. this means use the least amount of wire possible and the shortest ground point from the battery to the chassis.

VJ RC51

Also if your 1JZGTE, use the 2JZGE alternator, its a higher amp

JTJerryls400

I grounded my trunk battery in 3 points:
1. rear shock absorber mounting bolt
2. upper fuel tank bolt to chasis
3. lower fuel tank bolt to chasis

that two last are really big bolts so thinking good ground points.

vipsoarer

be cautious of those gas tank bolts, if you are connecting the battery and somehow the bolt has come lose you can get a spark and blow yourself up!
the shock mount isnt great either, your best bet is to make your own by drilling and tapping a spot in the trunk well.

JTJerryls400

thanks
so I will tap it in different point, somewhere cd charger/amp unit neighbour.
Jerry

xirforever

Ive done this mod to another lexus before, and plan to do it to my newest one as well (SC400). I wont go below a 0 guage cable and make sure is of good quality, also its good to get a higher amp rated battery when you do this, im using/ will be using a optima blue top. Worked great in my last aplicaiton. I ran two 4 guage grounding spots and it worked great. Just make sure that where you ground it, the wire has metal to metal contact and no paint or rust between, obviously this makes for a bad connection as resistance goes through the roof.

i think your wrong, its great for achieving better weight distribution, dont be such a negative nancy

xirforever

So your saing (hypethically speaking) if i used one 4 guage cable to connect my battery + to the pickup in the engine bay there will be less resistance than if i used two 4 guage wires? (or a thicker wire)

Ill give you the shortest part of course, but not sure about the thinner part....

vipsoarer

you could use either the single or dual 4 gauge, its the length of the wire that we are looking to deminish. so lets say you could run a ground wire that is 4 foot or a ground that is 1 foot, we would want the 1 foot long ground wire for optimum performance. xirforever has his set up the correct way.

REMEMBER: you dont have to use a stock bolt to ground these parts, its actually a better idea to find the thickest body panel closest to the battery and drill and tap OR use a self tapping stainless screw. like said above you will want to scrape off any surface oxidation (rust) and paint to get a bare metal contact point.