Civic VX MPG project (Delete Alternator, add solar)

[ctgottapee]

not on my car, but as a little side project for the home. I'm generating my home's base load to lower my power prices a bit - grid tie is not allowed here so I can't go higher.


They are flexible but thick, and would be impossible to flex in multiple directions. Unless the surface was flat and square, you might have problems keeping the edges down with the wind wanting to tear them back off - the edges won't round, just bend in one axis, and will have some variances from the center of the panel.
There are cheaper much thinner panels but they don't generate much of anything. I have one in my car on the dash as a battery maintainer.

If you have ever tried to put window film on a car window, just imagine it being thick as plexiglass and trying to get it flat and all the bubbles out.

The best way I can describe it is think of them as the thickest posterboard you've ever seen, heavy laminated on both sides BUT it doesn't give/crease like a posterboard would. They are tough so it wouldn't hurt the panel to try if you can use them elsewhere if it doesn't work. I'm not sure about cutting them, it should work as each cell is touted as being separately wired so it doesn't die with shading.

One issue I'm having is keeping them clean. If not mounted at a steep angle, rain water sticks to them more than a glass panel, thus leaving dirt behind.
Also as they are not meant for continuous bombardment (road debri, bugs, etc at 70mph) I would guess the plastic film would dent/deform a bit losing further efficiency. Just think about all the nicks and scratches on your car, or tar spots; it wouldn't break the panel but damage that portion beyond any repair. I've noticed a few dents and nicks in mine.


They do produce - at peak - the power they are rated for, but if you lay them flat you are far from optimal solar gain, and then you'll have the losses from conversion to 12volts. Remember they can reach 45v+ so electrocuting yourself is a possibility.

[ctgottapee]

one idea i think might help is using a charger that also has a dead battery car starter function - ie provides 80amp boost.

If you charge your battery(s) at home, and then start the car with the battery boost plugged in, you'll drive away with a topped battery. There is the inconvenience of getting out after you start it to unplug the cord.

[paulgato]

Thanks ctgottapee. That's pretty much as I imagined re the flexible solar panels, but there's no substitute for getting the gen from someone with first-hand experience. They look like quality gear but I'm not planning on sticking any on my car roof just yet.

I was thinking of getting a pair of 20w 'semi-flexible' panels...

(like these... Renytek. Semi Flexible Solar Panels ...although they don't seem to have the 20w ones on their web site at the moment)

...suspending them in the two rear-most side windows in the load area of my Mk4 Golf estate (wagon), and using them to top-up the charge on a battery which is recharged daily from the mains and almost never charged by an alternator. They wouldn't be hugely efficient I guess as they will be almost vertical, and will be behind glass, but those rear windows serve no function otherwise as the driver can't see out of them, so I may as well use the space for something useful.

If they're mounted inside the vehicle then there would be no aero drag from them, ...and of course they are very lightweight. I'm hoping that 40w of panel would deliver at least an amp or so under most daylight conditions. Even one amp or solar would go a long way towards extending my alternator-free driving range, especially over, say a long weekend, where plug-in charging is not possible at a destination but where the car is used just to get there and to get back, ...which is quite typical usage for me on a camping trip, for example.

For day-to-day driving, for work and so on, charging from the mains power supply is proving more than adequate, but even under those conditions a solar panel would reduce the overall daily Depth of Discharge and extend the life of the batteries to some extent.

From your experience of solar panels, do you think that might be worth doing? Do you think one amp of current from 2x 20w panels is a realistic expectation?

By the way, I have been getting mpg consistently at least 10% higher since I started plugging in every night. Well, nearer 15% higher in fact, but I put some of that down to the 2kW engine coolant pre-heater being switched on for half an hour before driving off every morning. Whenever I've done tests I've found a good 10% mpg boost from not using the alternator. Obviously that figure will be greater as a percentage with an already efficient vehicle like mine, as an efficient vehicle will already be using a greater percentage of fuel to produce electricity, but the actual amount of fuel saved per hour will be about the same in any vehicle (with the normal level of electrical equipment on board.)

[ctgottapee]

have you considered a battery warmer wrap? size it to warm battery to optimum temp in the time the pan heats up. it may do nothing but cheap to try.


you might want to make sure those rear windows don't filter UV or any other spectrum like almost all car windows do now.

i know my old '93 caddy doesn't as it heats up fast in dead of winter with sunlight and no heat running - not so awesome in the summer though.

a vertical mount is probably better than horizontal for most of the year.

it depends on the type of converter you use, if it has MPPT or not, and how the cells are wired and deal with shading. if you use the same small inverter for both panels (it will likely only have one input or combine them inside the unit), you'll have to keep both windows in the sun, otherwise the shaded panel will kill the output as the inverter can't cope with that on a single input.

'maybe' and i am doubtful, but you could get away without an inverter with the right type of panels and just wiring direct with that small of size. as long as you have a blocking diode on them and shut them off while you recharge at home (so you don't overcharge or mess with the chargers detection circuitry)
you can't overcharge while driving as you'll use at least that many watts. if the panel voltage ranges are close to vehicle specs, the vehicle should cope; it probably won't care about low voltage. your cpu might trigger a fault code. i don't think the expense is worth it with an inverter, unless you drove long trips and parked shortly. you'll have to cut the panels when parked for any length of time as you can't control the charging.

my little panel is safe as it doesn't put out enough juice to effect anything in a possible overcharge state. plus i tested my car's usage when parked and it's about the same as max solar output. unfortunately the engineers didn't seem to care about the drain in a big car that normally has a gigantic battery. if i keep the radio constant power on (stores settings) then it doubles. i scored it for $10 bucks open box so it was cost effective. I removed the frame and it's barely noticeable on the dash; i had it on the visor flipped down, but passengers got annoyed flipping it back and the wiring connection to the circuit board is fragile without the frame. the dimming strip across the top of the window also cut the solar input so i had to flip it vertical and i would get constant looks like it was a gang symbol or something.


do you have a link to your changes to reduce your power usage?
i was planning on trying the alt delete with a switch as my alternator comes with a kill wire; you just ground it so no hacks needed. even has a nice male plug blade connector on it. the service manual has many tests the require the alt to be killed so i guess back then they included as a courtesy to the techs.

[paulgato]

Originally Posted by ctgottapee

have you considered a battery warmer wrap? size it to warm battery to optimum temp in the time the pan heats up. it may do nothing but cheap to try.

Considered it. I actually don't have a pan heater but a coolant heater. I was considering adding a small oil pan heater pad and could fit a battery warmer pad at the same time.

you might want to make sure those rear windows don't filter UV or any other spectrum like almost all car windows do now.

Good point. I'll try to find out.

a vertical mount is probably better than horizontal for most of the year.

I'm glad to hear you say that. I was hoping it might be the case. I was thinking anyway it would be better to optimise the orientation for winter use as in winter there are fewer daylight hours.

it depends on the type of converter you use, if it has MPPT or not, and how the cells are wired and deal with shading. if you use the same small inverter for both panels (it will likely only have one input or combine them inside the unit), you'll have to keep both windows in the sun, otherwise the shaded panel will kill the output as the inverter can't cope with that on a single input.

Not posssible to keep both sides of the car in the sun ;-), so yes, I'd need one charge controller for each panel. (I guess by 'inverter' you mean 'charge controller'.)

'maybe' and i am doubtful, but you could get away without an inverter with the right type of panels and just wiring direct with that small of size. as long as you have a blocking diode on them and shut them off while you recharge at home (so you don't overcharge or mess with the chargers detection circuitry)

I wouldn't risk running ANY solar panel without a controller when charging a sealed battery after seeing this video...

https://www.youtube.com/watch?v=z5RtZe9AW2E

...and yes, the controller would be switched off via a relay triggered when the mains battery charger is connected.

you can't overcharge while driving as you'll use at least that many watts. if the panel voltage ranges are close to vehicle specs, the vehicle should cope; it probably won't care about low voltage. your cpu might trigger a fault code. i don't think the expense is worth it with an inverter, unless you drove long trips and parked shortly. you'll have to cut the panels when parked for any length of time as you can't control the charging.

my little panel is safe as it doesn't put out enough juice to effect anything in a possible overcharge state. plus i tested my car's usage when parked and it's about the same as max solar output. unfortunately the engineers didn't seem to care about the drain in a big car that normally has a gigantic battery. if i keep the radio constant power on (stores settings) then it doubles. i scored it for $10 bucks open box so it was cost effective. I removed the frame and it's barely noticeable on the dash; i had it on the visor flipped down, but passengers got annoyed flipping it back and the wiring connection to the circuit board is fragile without the frame. the dimming strip across the top of the window also cut the solar input so i had to flip it vertical and i would get constant looks like it was a gang symbol or something.

Yes, I am concerned about the car drawing attention. I would always prefer that it looks completely standard, but I think panels in the rear side windows could be made to look like those sun-shields people sometimes fit on side windows with the little sucker feet. The sheet metal backplates of the semi-flexible panels could be easily drilled and fitted with sucker feet to attach to glass.

do you have a link to your changes to reduce your power usage?
i was planning on trying the alt delete with a switch as my alternator comes with a kill wire; you just ground it so no hacks needed. even has a nice male plug blade connector on it. the service manual has many tests the require the alt to be killed so i guess back then they included as a courtesy to the techs.

Yes, if you click on my fuelly.com link in my signature you can see graphs of my fuel usage over the past several months. A couple of months ago there's a marked jump from 'about 70mpg' to 'about 80mpg' (Imperial gallons) that coincides with when I started plugging in the car every night.

I also have a thread on my alternator delete project and I'll try to link to that. It's quite long but it's all there. Near the beginning I have a list of the power drain of all the various electrical kit on the car...

http://ecomodder.com/forum/showthrea...mod-27179.html

...but what alternator do you have? It would be really cool to have an alternator with a bulit-in 'kill' function. I actually permanently KILLED my alternator last weekend by trying to ground the field wire.

In the first place that didn't work, and in the second place the alternator was permanently ON after that little experiment and was draining the battery even with the engine off. I don't know how but it seems I've blown at least one diode and the field winding is now being permanently energised via the main B+ cable to the battery. In any case I now need a new alternator (grrr) and if I could fit one with a built-in 'kill' facility that would be really cool as what I wanted to do was wire the thing up so that it charged when the brakes are applied. I've been leaving the IGnition wire disconnected, which is just fine for preventing the alternator from starting (well, it isn't now because of the blown diode!) but I have no way to disable the alternator while the engine is running.

[California98Civic]

Imagine using a set of flexible solar panels as a sunshield on the outside of the windscreen when parked... would want to consider anti-theft steps but the angle and the outside placement and the heat reduction inside the car would all be fairly ideal.

[paulgato]

Originally Posted by California98Civic

Imagine using a set of flexible solar panels as a sunshield on the outside of the windscreen when parked... would want to consider anti-theft steps but the angle and the outside placement and the heat reduction inside the car would all be fairly ideal.

I'm imagining that, but I'm also imagining curious ne'er-do-wells trying to remove them. Nice idea, but I won't be doing it.

Roll on transparent PV glass...

Solar Photovoltaic thin film products from Polysolar

...There's no reason why half a car's surface can't be made PV active, including body panels and half of the glass.

[ctgottapee]

Yes theft or more likely damage shenanigans would eventually occur. and you would only gain the most if you parked your car uncovered outside frequently.

Your notes on my terms and such are correct, you are clearly thinking far ahead, I was just trying to keep the long post less long

While there is the charging danger, you could automate a case where it didn't exist and save on the inverter cost and 15% loss. Of course covering the car would require some safety.


My GM alternator as the OEM part for my car has the kill switch, a '93 Cadillac Deville. My only guess as to why is because the car's service manual has a number of procedures which require the kill so they added it as spec for easier service.


I was also thinking about the coolant heater as the best step. It seems you lose a lot of efficiency with the pan heaters unless your electricity is free.
Another nice feature about my big old car is that it has oil and transmission fluid coolers built onto the sides of the radiator. These has the effect of also warming those fluids during the winter.

Did you go with the inline heater or full version with the pump attached? Which brand? It'd be nice if I had a block plug to key into but this model engine doesn't have one.

[paulgato]

Originally Posted by ctgottapee

My GM alternator as the OEM part for my car has the kill switch, a '93 Cadillac Deville. My only guess as to why is because the car's service manual has a number of procedures which require the kill so they added it as spec for easier service.

Thanks. I'll look into that.

I was also thinking about the coolant heater as the best step. It seems you lose a lot of efficiency with the pan heaters unless your electricity is free.
Another nice feature about my big old car is that it has oil and transmission fluid coolers built onto the sides of the radiator. These has the effect of also warming those fluids during the winter.

Did you go with the inline heater or full version with the pump attached? Which brand? It'd be nice if I had a block plug to key into but this model engine doesn't have one.

No, my car has no OEM block plug heater option either. I would always prefer to keep things simple where possible.

I ended up getting a 2kw Kenlowe heater and pump kit. Kenlowe make 3kW and 2kW versions. (Expensive, but it's a good unit, and it's a local company with a good warranty and so on. I'll be using it year-round so a good warranty is a big plus.) I went for the 2kW version so as to leave enough leeway to add a 1kW fan heater in the cabin to run in parallel with the coolant heater on cold mornings. I've fitted a mains socket under the dash for that purpose, and have tested a fan heater's ability to warm the cabin to a good number of degrees about ambient, but have not used the fan heater properly yet as the weather is too warm to need it. It's just an ordinary house 1kw/2kW fan heater which I 're-wired' to produce 500w/1kw. 1kw is plenty inside a car. Also, I wanted to be able to add a sump/oil pan heater of up to about 250w at some point. (Theoretically 3kw is the limit on a single mains socket in the UK, but in practice you can push that by another kW or so without problems. Even the standard 13A plug fuse won't blow below about 20A continuous.)

The coolant heater works very well, but doesn't heat the oil. It heats the coolant to 87 degrees C (with a 10 degree hystersis, so maintaning 77-87 degrees). However, once the engine starts the temp drops by another 10 degrees at least, which I presume is mainly due to the coolant/oil heat exchanger ('oil cooler') passing heat to the oil. It's not a big deal, and I believe I am avoiding the really bad mpg I would get below 50 degrees C, but a small sump heater running in parallel with the coolant heater would be no bad thing. I would run them for between 30 minutes and 90 minutes before drive-off time, depending on time of year.

Sump heaters tend to be inefficient mainly because you can't fit powerful ones for fear of overheating the oil if they are left on a long time, and if you have a low power one they have to be left on for a few hours to do the job, although anything over about 4 hours is a total waste, so you really need a timer. It's always more efficient to use the max amount of heat for the shortest time, as heat loss to the surroundings is then minimised. From the point of view of preserving the engine and easing starting in very cold weather though, the oil is where you really want the warmth I think.

If you have a 'big old car' with plenty of space around things, perhaps you could do what one person suggested on another thread, which is to get an ordinary travel iron and attach it to the oil pan (with heat transfer epoxy or similar.) Those things have proper thermostats (and folding or removeable handles) so you can use a 1kW iron quite safely as there would be no danger of overheating the oil. (You would of course have to take steps to waterproof the thing, but that shouldn't be difficult. Maybe set the t.stat to what works, then encase the thing with glass fibre and epoxy resin.) But using a travel iron is only an idea. No one has tried it yet, as far as I know.

[hayden55]

Edit: Posted to wrong thread. Oops.