Civic VX MPG project (Delete Alternator, add solar)

[VxonFumes]

California98Civic: thanks for the reply. Actually I ran WAI on my 98 odyssey several years ago for a couple years, and had results from that too, although my problem at that time was my EGR valve was almost completely plugged and I didn't know it then, and so I got lean burn stumbles, etc. By the time I figured it out I had ditched the WAI. lol. I was able to get 930 kms on a 60 liter tank on the van once (over 36mpg) using other tricks, but WAI wasn't one of them then. Perhaps I should revisit that.

I am very curious to hear anything from anyone (esp. VXmpgRacer) who knows about a stock VX ecu from England, or any other info on ECU's for the VX, as that is one the part that rules all other mods, "and in the darkness binds them."

[cRiPpLe_rOoStEr]

I actually like the idea of solar assist, but I wouldn't want to get totally rid of the alternator. I'd consider to at least work around a motorcycle-type stator to be crankshaft-driven.

[Mr. Previa]

Awesome! I have added solar to several of my vehicles with good results. Not mind blowing, but good. Especially in the van I had.

[paulgato]

What a great thread! That's a MASSIVE battery, and a MASSIVE solar panel. I once calculated that if I had about 200w of solar panel then that would pretty much negate the need for an alternator, assuming a large enough storage battery.

The aerodynamic hit from having a large, square panel on the roof worries me though. I came to the conclusion for myself that at some point I would build some raw solar cells into the paint layer, maintaining the original profile and covering them with a smooth layer of resin, feeding all the wires through the roof and fitting all the connectors, diodes, etc. inside the car, ...but life is short. That is though what I believe manufacturers could be doing at a relatively modest cost. Solar cells will last the life of a vehicle and would look pretty cool. Roof panels (and bonnets) rarely get significant minor accident damage in day-to-day driving, so those (hypothetical) factory panels should keep on working til the car is scrapped.

I am less worried about the effect of the extra weight. An additional 50kg (your battery must weigh at least that!) is only 3% of the weight of a 1500kg car, and so the maximum possible mpg hit from that is 3% - and that is if you are using all your fuel to climb hills slowly, never coming downhill again, and at speeds at which air resistance is negligeable, which as far as I know would mean well below 30mph, although that will depend on the shape of the car. As far as additional rolling resistance goes, I think that if the tyres are pumped up nice and hard to account for the extra weight (as per manufacturer's instructions, by the way, although I guess we all run tyre pressures way higher around here anyway) then rolling resistance shouldn't be affected too much at all, especially if the weight distribution is arranged so that no one tyre or pair of tyres is overloaded.

As for adjusting alternator output to accomodate AGM batteries' higher voltages, well I just fried my alternator by trying to fit a switch to turn it off with the engine still running (by grounding the field current) so perhaps you should be wary of anything I say, but I've heard, and I believe, that a simple diode inline with the alternator's VOLTAGE SENSE wire (teh one that goes direct to the battery, bypassing the larger high current wire) would fool the alternator into 'thinking' the battery was half a volt (or less or more - choose your diode carefully) lower in voltage than it really is, and so it would put out a half volt more. (Schottky diodes have a lower forward voltage drop than standard ones.) Getting an alternator to put out a LOWER voltage is difficult but a slightly higher voltage should be pretty easy. Having said that, I run an AGM battery and my preference would be to run the alternator at a lower voltage, so that it runs the car's electrics when the battery is low but doesn't 'waste fuel' trying to fully recharge a partially discharged battery. I would rather recharge the battery fully at my destination using mains power.

[TexasCotton]

I am thinking the battery used by the op of this thread the battery weight is about 62-60 lbs weight spec....I am also thinking that additional weight means a tradeoff needs to come about .....
I have seen vehicle modification that used additional battery capacity/ and or alternators
mainly to increase amperage,,,
Lead acid battery can be solar trickle charged/charge controller........

[jakoken]

Have you looked into flexible self adhesive solar panels like this one.http://www.amazon.com/Unisolar-Flexi...pr_product_top
My thought is that you could put them on the roof and hood and just cut them to fit and reseal them.

[California98Civic]

Originally Posted by jakoken

Have you looked into flexible self adhesive solar panels like this one.Amazon.com: Unisolar 128 Watt Flexible Solar Panel PV Laminate - Simple & Easy Installation - Peel & Stick: Patio, Lawn & Garden
My thought is that you could put them on the roof and hood and just cut them to fit and reseal them.

I don't know about others, but I have considered these many times. Depending on how I crowd and minorly modify my Civic's roof, i figured I could get as much as 120w up there (during peak operation). I would be careful about the hood though (engine heat). EDIT: this was not the specific product I was considering, though.

[jakoken]

Originally Posted by California98Civic

I don't know about others, but I have considered these many times. Depending on how I crowd and minorly modify my Civic's roof, i figured I could get as much as 120w up there (during peak operation). I would be careful about the hood though (engine heat). EDIT: this was not the specific product I was considering, though.

The one thing to test is how hot the hood gets. The hood might be hotter if the upper grill is blocked. If it is below 150F or so it won't cause breakdown of the cells but the question is if the adhesive. The power would reduced by the heat of the hood tho.

[elhigh]

It shouldn't be a big deal to insulate the hood. Lots of vehicle hoods/bonnets are already insulated.

Do we have any idea just how warm the hood is while the vehicle is in motion? I know mine is warm because I touch it with my hand, but it's hard to run along at 45mph and do that.

[paulgato]

Most of the time the vehicle is not in motion, so most of the charging will happen while parked up. My guess is that heat from the sun while parked is likely to heat the panels more than heat from the engine while driving, as when driving you have the wind blowing over them.

I've looked into these flexible panels in the past and always decided they are good but too expensive for any reasonable output. Car body panels are compound curves, so I would also want to know whether they can bend in two planes at once. The fact that they are (some of them) long and thin does mean that rows of them could deal with compound curves OK.

One problem with mounting potentially expensive kit on your roof is that someone might come along and try to steal it. Flexible panels could be bonded down, but there still may be a tempatation to try, and when thieves are frustrated they can get aggressive (and break things in revenge for someone making their job harder than they thought it was going to be.) That's one reason I thought that actually building the cells into the body panel - into the paint layer in effect - might be the best way to go, as it would then be 100% obvious that they couldn't be removed.

A bonnet, in that case, might be preferable, as one could get a spare bonnet (hood) panel from a breakers' yard and build the solar panel into it indoors, and then when it's complete, swap it over with the original bonnet panel. That's a bit more difficult to achieve on a roof panel, although one could perhaps make a thin (3mm?) fibreglass 'mould' of the roof shape, build the cells onto the 'mould' indoors and then attach the roof-shaped solar panel when it's done. All the electronics and so on can be mounted just below the roof, out of the windstream. I think solar cells can bend a tiny bit (even a cracker will bend a bit) but even if they had to be mounted dead flat, one could sand multiple flat areas on a slightly curved fibreglass panel to mount the individual cells onto. Water-clear resin over the top, smoothed and polished.

Raw solar cells can be arranged on a gentle compound curve quite easily, covering the area optimally, therefore maximising wattage on any given panel area. The cells themselves are very cheap.