Moarpower

Hi guys, Im looking to relocate the battery to the trunk in my 1990 Celsior. Anyone know what size battery I will need to crank and run properly once this is done? Just trying to make a little more room so I dont have to low or rear mount FI

YODAONE

Should not require a different size battery if you use correct gauge wire.

Consider conduit path from trunk back to engine compartment for postive and negative battery cables.

Also conside how you will vent battery and drain or retain any acid overflow (some even with sealed lead acid battery).

Finally contemplate battery mounting hardware, in the event of a rear end collision or head on front collision and the heavy 50 pound battery momentum is forward....

I think the LS430 placed battery just in front of passenger side engine firewalll (as did Mercedes) and have seen batteries mounting in lower trunk well, but not at or near a trajectory to the gas tank.

Not sure why Toyota reasoned a 50 pound battery positioned forward of front wheels...bad weight distribution and sitting in hot engine compartment.

They should have followed Mercedes Benz example with battery positioned between a sound barrier and firewall on passenger side.

The spare tire well might work...but then no room for the spare tire.

Yamae

A good advice.
It would the best if the surge problem and the countermeasure were added. A long cable causes a big fly back pulse when the starter is turned off and this damages semiconductors very often. Mercedes cars have an additional capacitor as a countermeasure.

Moarpower

Yamae, Any more advice you could give with details on this ?

Yamae

The link below would give you some more ideas about the capacitor used among Mercedes W140 models.
http://www.benzworld.org/forums/w140...l-lines-8.html
You can find the photo of the capacitor here.
http://www.benzworld.org/forums/11422961-post69.html

Moarpower

Ok thanks guys. Much appreciated. As for mounting hardware and venting and drainage, there are several relocation kits that I am looking at. I will place it over on the rear left, opposite to the filler cap.

The reason I asked about the size of the battery or the CCA rating is because I have seen some people relocate a battery, only to find it wouold no longer crank to to greater resistance with the added wire.

fixmiester

Added cable length results in higher path resistance; higher CCA cannot remedy this. The only way to overcome this is with larger cable diameter, restoring original path resistance. The reason Mercedes adds a cap has nothing to do with current spikes, since a linear conductor has very little inductance. The real reason is because a long cable without shielding travelling the length of the car picks up all kinds of electronic noise, from every digital device and car network, to motors operating nearby. Shielded large cabling is much more expensive than a simple noise trap circuit, but is is something you need to consider.

Moarpower

Thanks Fix. Ill do some more research.