View Single Post
Old 08-11-2013, 04:38 PM   #2 (permalink)
Master EcoModder
cbaber's Avatar
Join Date: Feb 2012
Location: Missouri
Posts: 540

Lean and Mean - '98 Honda Civic HX
Team Honda
90 day: 46.69 mpg (US)
Thanks: 30
Thanked 190 Times in 110 Posts
Alternator Delete Project

Alternator Delete Project

As many of you have found out, deleting parasitic accessories reduces the load on the engine, which can increase fuel economy. The alternator is another one of those parasitic systems that can be replaced with an alternative power system.

With the guidance of California98Civic and his DIY thread, I wanted to be able to switch off the alternator when I didn't need it and on when I needed a charge.

I decided to replace my starting battery with a marine deep cycle battery. This would allow the car to run without alternator assistance. Doing the same with a car starting battery would kill it very quickly. Marine deep cycles are meant to cycle many times, and a group 24 can provide about 100 Ah. Due to the size of these batteries I had to relocate the battery to the trunk. I'll need to see what kind of distance I can get out of a full charge to see if one battery will be sufficient. I'm hoping to only use 50% capacity in 100 miles of driving. If I can do that, I only need to charge the battery overnight at home.

Charging the battery will occur overnight with a battery charger. I haven't decided to permanently install it in the car or not. For now I will just use my regular battery charger on the lowest setting that will allow it to fully charge in about 9 hours.

Parts and Accessories Used
- Marine Battery Box (fits group 24-31) - $8 @ Menards
- 15' 2-gauge welding cable - $30 @ eBay
- Inline fuse holder - $7 @ eBay
- Misc. connectors and parts - $10
- Fuses - $14 @ Best Buy
- Group 27 marine deep cycle battery - $70 @ Wal Mart

Inline fuse holder with 150 A anl fuse. 2 gauge welding cable is routed through the passenger compartment up through the firewall to the distribution box.

Ground is connected to the mounting bolt on the shock tower. 4 gauge ground cable.

*Updated* Instead of previous distribution block, I simply bolted together the positive leads for the starter, fuse box, and battery together with copper lugs and a bolt. The bolt is connected to a plastic mounting tab, which is secured with double sided tape to the fuse box.

I don't actually have the deep cycle battery yet. I'm waiting on this 7 year old car battery to finally die!!! But it still fits nicely with the included spacer.

This thing takes up quite a bit of room...

Here is my alternator switch. Just a simple toggle switch that I mounted in a spare pop-out plug on the left side of the dash. Labels were made with a label maker.

So far I have tested the switch and it works. You can't turn the alternator off while the car is running. The switch does nothing. I have to turn the motor off and then I can switch the alternator off. However I can turn the alternator on while the car is running.

Just waiting for the new battery. This mod would not make financial sense unless you needed a new battery anyway (like I do). I figure that despite the cost of relocating the battery, my cost is still going to come out at about the price of a nice quality battery. I'm not sure what to expect to gain in fuel economy. Some have reported as much as 10%, another 2%. I'm hoping for at least 7% but only time and gas will tell. Stay tuned.
1998 Honda Civic HX - My Project Thread

Last edited by cbaber; 08-28-2013 at 01:50 AM..
  Reply With Quote