Replacing alternator with solar panel array on roof?

[blackjackel]

Has anyone thought about doing this? You could get all your electrical power from the sun isntead of your engine/gasoline...

[MetroMPG]

Lots of people have wondered about this. It's entirely doable, but: hugely expensive (roughly $1000-1500 in panel costs alone to supply ALL my car's electrical needs); potentially difficult to mount the panels without adversely affecting aerodynamics, and potentially not enough surface area to mount the panels, depending on the vehicle.

[cfg83]

MetroMPG -

Blackjackal and I were talking about this today. How about this scenario :

1 - Voltmeter to monitor battery charge.

2 - Switch to turn off/on the alternator at will (I know this is doable in a Saturn S-Series).

3 - Large solar panel that can be used to recharge the battery while at work. Panel would not be deployed unless you were at work.

Assuming the above works (big assumption), then the scenario would be an alternator "recharger" that is deployed when you get to work. That way, there would be no aero penalty.

Benefits:

a - You could have a smaller solar panel that does the same as a "trickle charge". I am not talking about the 6"x12" panels or the VW panel. I am talking about a "marine battery application" style solar panel.

b - The voltmeter could allow you to make an "intelligent choice" when it comes to activating the alternator.

Problems:

a - I don't know if you need special "in between" electronics to keep the battery from being damaged. Maybe you do, maybe you don't, maybe it depends on the panel?!?!?!

CarloSW2

[justpassntime]

This little car has solar panels on the roof to recharge it's batteries.



Free Drive EV - Solar Bug

[metromizer]

It would be fun to do, but you would have to undertake this with a mindset 'regardless of cost benefit'.

If you were skilled in bodywork, you could 'cut in' a solar panel or panels into you roof, much like an aftermarket sunroof. Safe with the trunk deck (if you have one) maybe the hood (but I'm not sure about the heat and solar panels).

[Hankinator]

Hi all.. 1st post. Solar would be a great idea. A little off topic but if you couple the "alternator kill" switch idea with the use of a battery charger at home when your car is in the driveway..then you would not be using any alternator drag to recharge your battery. You still have to pay...its not free it just ends up on your electric bill...I have not done the calculations but I am sure the cost is minimal to charge your battery.

Depending on your work schedule you could put your solar array where you park at home for recharging purposes...

I know without the use of the headlamps that I can go almost a week without an alternator (found out this out on accident when my alternator fried). If you monitor your batt voltage when you see it getting low you could flip the switch and engage your alt. again.

I have also put in a request to have my place of buisness allow me to plug in my car every day (if necessary).

I have a CPU controled battery charger that changes from charge mode to maintain mode automatically.

I have heard charge and discharge of a standard car battery will decrease its life span....not sure. A deep cycle may be more suited for this.

Also what about a solar array in the back window area inside the vehicle.

Great ideas...keepem comin.

Thanks,

Hankinator

[cfg83]

Hankinator -

Originally Posted by Hankinator

Hi all.. 1st post. Solar would be a great idea. A little off topic but if you couple the "alternator kill" switch idea with the use of a battery charger at home when your car is in the driveway..then you would not be using any alternator drag to recharge your battery. You still have to pay...its not free it just ends up on your electric bill...I have not done the calculations but I am sure the cost is minimal to charge your battery.

Depending on your work schedule you could put your solar array where you park at home for recharging purposes...

I know without the use of the headlamps that I can go almost a week without an alternator (found out this out on accident when my alternator fried). If you monitor your batt voltage when you see it getting low you could flip the switch and engage your alt. again.

I have also put in a request to have my place of buisness allow me to plug in my car every day (if necessary).

I have a CPU controled battery charger that changes from charge mode to maintain mode automatically.

I have heard charge and discharge of a standard car battery will decrease its life span....not sure. A deep cycle may be more suited for this.

Also what about a solar array in the back window area inside the vehicle.

Great ideas...keepem comin.

Thanks,

Hankinator

Welcome to EM and thanks for the info. The "charge/maintain" mode is what I want to know about. What brand of charger are you using?

CarloSW2

[MetroMPG]

Originally Posted by cfg83

Problems:

a - I don't know if you need special "in between" electronics to keep the battery from being damaged. Maybe you do, maybe you don't, maybe it depends on the panel?!?!?!

You'd need a charge controller - a little circuit designed to dump power once the battery comes up to a pre-set voltage. Otherwise, depending on the strength of the panel, you could overcharge the battery.

But the most damage will come from simply discharging deeply. Batteries don't like that, and only have so many cycles in them.

I'm in agreement with metromizer: a fun energy efficiency project, but not something to undertake if the goal is saving money.

[MetroMPG]

Originally Posted by Hankinator

If you monitor your batt voltage when you see it getting low you could flip the switch and engage your alt. again.

You may actually get worse gas mileage doing this than if you simply leave the alternator connected full-time.

Considering alternators are not very efficient to start with, you'd be throwing away gasoline in the conversion losses. The alternator would be working extra hard to simultaneously (1) provide the vehicle's power needs and (2) replace the energy in the battery.

If you're going to run without an alternator to save fuel, it needs to be grid/solar charged, or carefully set up to deliver current when braking or in engine over run conditions.

[IvanAndreevich]

Hello, first post

I think it would be a far better idea to plug your car into a regular outlet (with a AC/DC power supply of course) and recharge the battery that way. It's cheaper and works anywhere at any time, unlike the solar array.