How To: Alternator delete

[sully06]

If I get a battery big enough to last me 3-4 of driving can I just hook the alternator back up for a day to charge it back up and avoid using a battery charger?

[redpoint5]

Originally Posted by sully06

If I get a battery big enough to last me 3-4 of driving can I just hook the alternator back up for a day to charge it back up and avoid using a battery charger?

You could do that, but it defeats the purpose of running without the alternator.

Also be aware that the belt and pulley are very efficient and don't put much drag on the engine. For this reason, many people keep the alternator belt on and just disable the alternator electrically with a switch. This makes it easier to go back to normal charging mode for longer trips.

[oil pan 4]

Its not an alt delete if the belt is still turning the alternator. Most of the parasitic losses are from just turning the alternator at 3 time crankshaft speed.

Solar panels don't work very well on vehicles because:
1 you don't get 8 hours of useable light (8hrs was mentioned in an earlier post)
2 useable solar panel light is limited to 5 hours a day in the best areas, make that 0 hours a day up north, in winter, clouded over, with panels covered with ice and snow.
3 On the roof of a vehicle your solar panels will virtually always pointed far from the optimum solar panel angle for your location and season. So your 5 watt panel becomes a 2 watt panel when pointed almost straight up with the sun 60 to 70 degrees off orthogonal.
4 charging losses, it take about 2 amps just to raise a fully charged large truck batteries voltage up normal resting voltage of 12.8 to 14.4v. The problem then is to fully charge a lead acid battery you need to bring it up to 14.8 to 15 volts and hold for a short time depending on temperature and last depth of discharge (and maybe a few other factors).

[Cobb]

One reason to use a smaller battery or one of a different chemistry is so you could take it in the office or place of employment and charge it at your desk unless you can plug in outside.

With my 30 amp regulated setup I see a 9 mpg improvement. Its only good for 150 miles with the 70 amp capacity battery I have.

[Daox]

Well, my starting battery gave up the ghost yesterday in the cold of winter. So, in goes the new deep cycle.

Next up, I'll figure out how to disconnect the alternator on the Metro. Sadly, I believe its self exciting, so I can't just cut some logic level wire to kill it. I think I'm going to have to cut the main power line to the battery and put in a large relay.

[synergy]

Originally Posted by redpoint5

A 5 watt panel in direct sunlight for 8hrs will produce 40 watts of energy assuming no charging losses. My car requires a minimum of 163 watts to run, so 8hrs of charging will get me 15 minutes of run time if I run absolutely no accessories.

Just wondering. What if you had a Solar panel in the Trunk of say 50-100W that folded? and mounted to the trunk?

What if you mounted that on your cars roof while stopped at work or home.
Or heck what if you were to mount it on your hood.

I think that will be one of the next advancements. With solar power dropping to .50cents a w imagine in a few years.

The new focus EV I think has this coming out this year. A roof deployed solar collector.

[Daox]

Time to get this alternator disabled!

I did a bunch of digging on this one. The Metro uses a 'self exciting' regulator. So, you can't just cut power to a logic or low power wire. Instead, you have to cut the main power connection between the alternator and the battery.





To do this, I got a beefy relay. The Metro alternator is rated at (I think) 55A. I happen to have a 70A relay kicking around. Here is a link to the one I used. Its for automotive use, works directly off of 12V, perfect for this project. The only issue with it, is it uses 3/8" wide blade connectors... which nobody carries. The solution? Bolt it together. So, I drilled out the large connectors for a #10 screw.





I had a ~12" section of 6ga wire laying around as well. I bought some ring connectors at the local hardware store and crimped one on the end. This bolts up to the relay, and the other end will bolt up to the alternator. The original wire that goes to the alternator was bolted to the other terminal on the relay.





I then installed the relay into the engine bay. Unfortunately, my 12" piece wasn't long enough to mount the relay up higher (out of water's way more), so I had to mount it on the brake distribution block. I'll figure out some way to waterproof if later on.

I have not hooked up the coil wiring to the relay yet, so I can't actually turn the alternator on. I'll get to that sooner or later.






A while back, I needed a new battery, so I got a group 24 deep cycle battery. This is necessary anytime you want to drive around for extended periods with the alternator disabled. A regular starting battery will not hold up to the deep cycling at all and will die a fast death. Also, this battery was actually cheaper than a new starting battery for the Metro, so win-win!






With the alternator disabled, you also need a way to charge the battery. For this, I am reusing a Soneil 5A charger that I had used for an alternator disable mod on my previous car. Its fully automatic, just plug it in and it charges. Once its done, it goes into a low level float mode which uses very little energy. So, I plug in once I get home, and the next time I leave I unplug and go. The wires aren't run all nice and pretty yet, but I'll get to that too.

I've made just a few trips with the car since the mod. I can definitely tell a difference. First off, when I use my kill switch, my engine idles down much slower. I've actually not held the kill switch long enough once or twice and its restarted on me because the rpms weren't low enough. Second, I do seem to have a little more oomph. I hit my target speeds on roads a little earlier than before. Lastly, the mpg is hard to say, but I did hit 60.0 mpg for the first time this year on my morning commute. That is pretty darn good considering I nailed a couple red lights pretty bad and it was only 35F out. My previous best was 58.9 and not hitting as many red lights. Of course all of this is anecdotal, so take it with a grain of salt.

[oil pan 4]

An easy way to charge the battery with out lifting the hood is to put a repurposed trailer wire connector at the front or back of the car wired into the battery. Then have the corresponding connector on your battery charger.
I use my suburbans 7 pin RV connector for this since it already has a 12 volt power source for charging a trailers emergency break away braking battery. Its wired straight to the battery with 8ga wire and a 35 amp fuse. I have an RV plug battery charger attachment with the ground and 12 volt source hooked up. It back feeds battery charging power through that circuit to the vehicle battery.
Most of the time when I start the suburban it doesn't leave the yard. It gets started to move it, hook or unhook from a trailer and I am not going to leave it running just to charge the battery.

[Daox]

Thats a nice option. I've just left the charger in the cabin of the car. This allows me to park outside and still plug in. I just close the door on the cord.

I really do like the RV plugs though. I had one on my Matrix for the block heater and it was wonderful.

[oil pan 4]

The next big push is going to be to add high voltage external power to them for running block heaters and space heaters during winter.
I am going to put the L14-30 version of something like that plug/cover on my vehicles.