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| 92 Silver Geo Metro LSi; Modding my newest geo for high MPG | |
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| Topic Started: Nov 9 2009, 01:11 AM (1,296 Views) | |
| Metro Fanatic | Nov 9 2009, 01:11 AM Post #1 |
 
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I'll be using this Project Forum to share my new of my project to fixing up my 'Bullet'. I'd like to get her looking great and go from average MPG to hopefully stellar MPG. I bought bullet in July of 2008 from a very nice hippie lady who lived near Manoa Falls on Oahu. Plans for modding this car aren't extreme but I do plan on trying to use a combination of small modifications coupled with smart driving techniques. I'll take suggestions and inputs as I go. I've been reading for several weeks now about a Fuel Efficiency (FE) Mod that involves deleting the alternator drag from my mighty 3 cylinder. Some fairly empirical tests have shown about a 10% increase in MPG from simply taking the altenator out of the system. 10% seems like about the single, biggest gain I've seen in improving MPGs and I was interested in trying it. But, like most of you, my car is not just a hobby, it's a daily driving vehicle so removing the alternator seemed a bit risky. Afterall, I work late into the evening sometimes, I'll need those headlights! What I've come up with is a switch I'll mount in the central console (where my radio used to be) that will disconnect the alternator when I think I can get away with it. This will typically be at cruise (45-60 mph) or down long hills where I'll be coasting anyway and can afford to divert some horsepower to electricity generation. From reading, I knew that our regular starting batteries aren't designed for this type of cyclical deep draining so I wanted to come up with a clean, easy way to supplement the battery to slow its run down. What I came up with was a solar charger coupled with a charge controller. I found a SUNFORCE 15 Watt Photvoltaic (PV) cell that would fit nicely in the back cargo cover tray area of 'Bullet'. When I bought this car, it came with the high side rear speaker mounts behind the rear seats that also doubled as the support for the option cargo lid that was supposed to deter theft by keeping valuables out of site. Bullet didn't come with the cover so I decided to fabricate my own. I used some fairly thin plywood that I cut to fit and after a few coats of primer I found a good gray paint that would closely match the interior of my car. I used some excess weather stripping to provide padding under the glass PV cell and under the wood mount to keep this modification silent (no squeaky or loose fittings).  Plywood cut to shape.  Primed white and black.  Painted gray to match the interior.  Installed with weatherstrip pads added.  PV Cell in place! Before I had everthing locked up and screwed down I was able to take the unit out for a test drive. Under driving conditions with the cell mounted high behind the rear seat. I drove several places around the island with the PV hooked up to my Multimeter set to Voltmeter mode. I was supprised to see that even on a rare overcast day I was generating between 17 and 19 watts. That's good considering it's a 15W panel. I found out later that the company underrates their PV cells to ensure people get enough juice. The 15W panel can actually deliver up to 26W under peak conditions. I hooked the PV cell up to the battery with a 7AMP charge controller in between. This will ensure the battery doesn't get fried. The charge controller feeds the battery anytime it's less that 13 volts and cuts out whenever the battery is >14.2 volts.  Close up of charge controller, I'll put this near the instrument cluster. The first step of removing my alternator via controlled switch is complete. Now I'm waiting for a few voltmeters I purchased from Singapore. They'll be part of a electical load monitoring station I want to put in the 5 x 8 inch hole where my stock radio used to be. I want 3 voltmeters there. - The first will tell me what my solar PV cell is delivering (just for kicks) - The second will show me the current auto battery voltage - The third will show me what the alternator is providing. - If there's room in the panel I'll try to squeeze in a digital clock / inside outside thermometer gadget and a MPGuino. - It should also have an alternator cut out switch and an overall power switch that will enable me to bypass everything. The control panel will be subject to another post. I realize the PV cell, even under ideal conditions of providing 26W won't be anywhere near what my basic load requirement is (I think somewhere aournd 175W for my ECM and to fire my plugs). What I hope to do is be able to smartly disengage the draw my alternator puts on my engine and squeeze out 5 or 6 more MPGs. 75MPGs here I come! What do you guys think? Edited by Metro Fanatic, Nov 14 2009, 02:10 PM.
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| Johnny Mullet | Nov 12 2009, 08:58 PM Post #2 |
"Mullet of Ox"
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I truly think you are on to something. I closely monitor the fuel mileage on my 1998 Metro and with the econo cam from 3Tech and my driving style and other improvements, I have learned that every bit counts when it comes to ultimate savings. Having a really good battery with a full charge is essential for the car, but being able to eliminate the power usage or at least minimize it's use, will net in considerable savings. Kudos to you man! I hope some others can join in and elaborate their opinions. |
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| john. | Nov 12 2009, 10:06 PM Post #3 |
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Member
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Great idea! Can't wait for the results! john |
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| tmaxmetro | Nov 12 2009, 10:29 PM Post #4 |
Advanced Member
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I hate being the gloomy kid in class.... but I wouldn't put a PV panel inside my vehicle - too dangerous in the event of an accident. |
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| iamgeo | Nov 12 2009, 10:33 PM Post #5 |
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Well written and interesting post. Can you please post the prices of the various items you have listed. |
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| nerys | Nov 13 2009, 12:21 AM Post #6 |
Grr
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considering all the other projectiles I typically have in my car a PV panel would be very low on my radar of dangerous. a nice thin film solar roof would be cool though you might even get 70+ watts from something like that. as for battery. these are TINY cars with TINY engines and TINY starters. Just put a deep cycle battery in it and be done with it. I hope to one day eliminate both the water pump and the alternator. Use an electric pump instead (these run really cool so I probably would not even need a very powerful pump) I figure i will LEAVE the water pump and alternator in the car so I can "pop" on the belt in an emergency or if the need somehow arrises (really long drive for example) I think your measurements are off though. either thatof my 94 xfi uses a LOT less power. 175 is 12.5 amps. NO WAY it takes that much power. I ran my battery SO DEAD (alternator died did not know it) that the battery was nearly depleted even with the alternators minimal output the engine would stutter and die if I even turned on the turn signals. I find it VERY hard to believe these consume 12.5 amps just SITTING their doing nothing but running. Did you verify this number? I LOVE how you mounted the PV. I really want to do something like that! I love that shelf so much I am going to build one (it seems it was only available 95 and up would the 95 shelf FIT my 94 or are they just too different?) Convert all but headlights to LED. that will drop a massive number of watts at night. Don't forget your dome light. pick the right fixtures and you should be able to keep it just as bright as the incan. I plan to try it this weekend if I can find some warm white arrays (I hate the cold blue white) I am also considering high power LED or lower power headlights in TANDEM to my regular headlights so when I am city driving where there really is plenty of ambient light I can turn off the high power headlights and use the low power secondaries to meet the legal requirements and be safe :-) Edited by nerys, Nov 13 2009, 12:24 AM.
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| Metro Fanatic | Nov 13 2009, 02:24 AM Post #7 |
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I appreciate the safety facet to this issue but in the case of Geo Metro, especially the pre Supplemental Inflatable Restraint Gen II models (89-94), I think we can worry ourselves to death. Any additional 'anything' within the occupant compartment of course is another potential projectile when large, rapid changes of momentum occur. I've tried to mitigate this somewhat by using the 4, 2" stainless steel screws that came with the panel to mount it to the cargo cover supports. It's also velcro'ed down along the left and right sides. The PV unit weighs in at 9.8 pounds and that is something to be concerned about...no doubt about it. SUNFORCE also makes a 2 pound, foldable PV cell that has more Watts. I wasn't able to figure out how to get that in place effectively and still have some aestethic appeal of this PV. Your point is well taken. Any home mod has a lot of unknown and untested safety consequences. Wish me luck! Metro Fanatic Edited by Metro Fanatic, Nov 13 2009, 11:40 AM.
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| Metro Fanatic | Nov 13 2009, 02:46 AM Post #8 |
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IAMGEO, Thanks for the complement. Prices weren't as bad as you may think. If you assume you have to buy everything, the mod will run you about $125. When this total mod is complete (voltmeters installed/alternator cutout in place) and assuming an optimistic 10% increase in mileage, it will still take about 50 gas tanks to realize any savings. The good side to this is that there really are no consummables to this set up. By that I mean that unlike new tires or a fresh crank case full of high end synthetic oil that begin to lose their effectiveness almost immediately after implementation, the solid state / plug and play attributes of this set up can be moved to another metro without too much adieu. With this outlook, the ROI is a little more achievble (see Ma, my MBA isn't totally useless!). Here are the #s. PV Cell & Charge Controller ($90) 14 gauge wire ($5) 11/32 plywood (2 x 4 sheet) ($5)...got this 50% off because of a cracked corner (always ask for discounts) Alligator Clips for battery hook up ($3) 1 x 2 x 8 for spacers and legs ($2) Spacers required to let air flow under the PV cell to keep it cool...they're more efficient when cooler. Velcro ($4) Weather Strip ($4) Killz Primer ($8) Gray Paint ($3). Small Hinges (that allow the support legs to fold up when I need the cargo space ($3) This list assumes you have no supplies around the house. Cheaper if you can improvise. Hope the details didn't bore you. |
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| Woodie | Nov 13 2009, 08:24 AM Post #9 |
 
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No way 10%. It takes about 12 hp to keep a car rolling at 60 mph. 10% of that is 1.2 hp or around 900 watts. The maximum output of our alternator (which it almost never puts out) is less than 700 watts. So in the unlikely event that your running along at a constant 60 mph and your alternator is charging just as hard as it can, then it's approaching 10%. The other 99.9% of the time, it's far, far less than that. Good idea and nice work, but it's not worth 10%. |
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| nerys | Nov 13 2009, 09:08 AM Post #10 |
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Grr
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sometimes its JUST FUN to do and any gains are cream on top :-) |
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| Manny | Nov 13 2009, 10:48 AM Post #11 |
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Definitely one of the greatest ideas around fuel economy, most likely when sun these days is too hot, by doing that are you able to fully disconnect the alternator from the system then? will be interesting to establish a kind of priority, where solar cell acts first and if no sun, engage the alternator automatically. Just an idea because the alternator don't create that drag all the time, it does not use to work 100% of the time at full workload. Edited by Manny, Nov 13 2009, 10:52 AM.
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| Metro Fanatic | Nov 13 2009, 11:11 PM Post #12 |
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Nerys, Inputs like yours are what I love about these forums. They give me other ideas and let me reexamine my assumptions. The whole idea behind a switchable alternator gives me the freedom to use as I go...without having to pop the belt back on. Time will tell if it works...still waiting for components to arrive in the mail. I'm curious, how did you come up with your minimum power consumption figures? Did you have a tool to measure the amperage out of the alternator while the battery was disconnected and the engine running? I'd use my multimeter but I'm pretty sure that would fry it. I'm a bit hesitant at this point to tap into the rotor field control wire anyway. I still have to figure out the correct gauge of wire to use and if I want to step it down at all with intermediate switches between the alternator and the control panel in the passenger compartment. Not sure how reliable a switch is with all the juice running through it (switch dependant I guess). Do you know of a non-intrusive amp type meter? The cargo lid option was available on all LSi models of the Gen II Metros (89-94). It will definity fit your 94. Appreciate the LED idea but I'm ahead of you on that one. I've already done the math and figuring on night driving I can roughly save around 1/2 a HP worth of watts. Can't wait for real LED headlights though. Oahu however is a poor place to buy OTS parts. Our auto stores are fairly small and lack selection. I will experiment with some high vis LED running lights that I can embedd in my plexiglass air dam project of the future some time. Thanks for the input and great ideas. Hope you can help with my questions. Other techies feel free to jump in! Dan (Metro Fanatic) |
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| Metro Fanatic | Nov 14 2009, 12:20 PM Post #13 |
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Manny, I won't fully disconnect the alternator. It will still be hooked up via the pulley and belt. Essentially a free turning wheel. I know there is still turning resistance to overcome but much less so if the alternator is not under load. I chose to do it this way for simplicity...I didn't want to have to go under the hood to move belts. The completed project will have control panel inside with the driver being the 'smart chip' that will adjust the priority you speak of. With full sun and max wattage, I can switch off the alternator and monitor the battery voltage. When I think it needs charging I'll engage the alternator again. From an efficiency standpoint, it's best "ON" when decelerating or descending a grade - the same times regeneration is active in hybrids. Look back for future progress and more pix. Thanks for the comment. Metro Fanatic (Dan) |
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| iamgeo | Nov 14 2009, 12:33 PM Post #14 |
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Please take plenty of pics and make a technical "How to Guide" on implementing the various items. I'm all for getting as many MPG's as possible. |
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| Coche Blanco | Nov 15 2009, 01:15 PM Post #15 |
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Captain Slow
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http://ecomodder.com/forum/showthread.php/test-alternator-vs-no-alternator-10-gain-70-a-98.html |
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