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i bought a optima yellow top battery about 2 weeks ago. i bought a civic version of the battery so i could lie it on its side under my intake. well as it turns out its still too big so i re-located it to the trunk.


what i did was i ran a 4 gauge power wire from the trunk to the + that attached to the battery under the hood, i then grounded my battery in the hatch section. it started up mint for the first bit, then i noticed the engine turning slower and slower. sometimes it would go so slow i was amazed that it actually started.

so i thought that maybe i should run a wire from the original negative that connected to the battery. i ran a 8 gauge negative wire from the hatch to under the hood and connected it too the original negative.


so all i have done is lengthen the original pos and neg about 10 feet. using 4 gauge for pos and 8 gauge for neg. and today i stalled it (mixture of grabby clutch, engine mounts and a terrible terrible driver ) and it wouldnt start. it just turned so slow and i was PISSED!!!

so should i keep it the way i have it set up and just add a ground to the trunk again? do you guys think my wiring is too thin? are optima yellow top batteries s---? are civic batterys too weak?

ive searched a lot about relocating batteries and all i could come up with was "battery relocation causes speaker interference" so DAMN i have that problem as well but its so quiet i cant hear it at all really.

I don't know to much about battery stuff.... But it makes sence if you are laying it on it's side to get an Optima... But I always say stick to OEM if you are going upright, I find it is the best! I have let my Mazda battery run for 8 hours at shows with music bumping and it starts just fine! Never died on me ever had it for 2 yrs and plenty of shows!

I guess I will bring booster cables to the meet... ehehe

My guess, you've got 2 things working against you:
1) Battery Size
2) Deep Cycle

The problem with deep cycle batteries is, because of their design, they give out less cranking amps than a regular starting battery. You've also went with a smaller battery, which further decreases it's starting potential. I think this is where your problem lies. Your battery is typically used to start small 4cyl cars, not a V6, those 2 extra cylinders are extra areas of compression that the starter needs the power it needs to fight against.

I thought you could mount optimas in any direction because of their spiral gel-cell design?

One thing I highly recommend if to increase the wire size when relocating to the trunk. With a longer wire you create more resistance. Of course, an impecible ground point needs to be used too. But if you try your battery in the engine bay and you're still having that problem, I wouldn't attribute it to the relocation.

I got the normal stock (Optima D35) battery for our cars a few weeks ago and it's been running perfect since I got it. I went to a drive-in theater and ran the whole Fast and Furious movie at full blast (2 12" Kickers, 1600 watt [900 watt RMS] Kenwood amp, and a separate amp for the tweeters/mids) without the car on and it started just fine. I think your option to use the civic battery screwed you over. My best advice would be to use the D35.