Warm air intake - Page 8 - Fuel Economy, Hypermiling, EcoModding News and Forum

ECONORAM · 04-30-2017, 10:37 PM

Quote:

Originally Posted by Magician

Here's my 13 Watt solar panel with controller that I just installed. Going to test it out to see how well it keeps the battery topped off. My EOC driving tends to drop the battery charge a little bit. Fully Charged is around 12.9V and after driving thru most of a tank, it drops to 12.5 or 12.6.

So, how is it working out? Is that in the back window? still able to see behind you okay?

Magician · 04-30-2017, 10:41 PM

I just put it in the other day and it's been rainy, so not much charging power...just a little bit according to my controller. It actually doesn't block my view at all. A bit hard to explain, but it is a pretty good set-up. I really don't think the glass will have much if any negative impact on the efficiency as some have commented because even with it raining it is still able to provide a small amount of charge while in my car. I'll of course keep you all posted over the next few weeks.

Stubby79 · 05-01-2017, 03:33 AM

12.6v is resting voltage. 12.9v is the minimum to get the battery to take a charge (2.15v/cell). 13.8v is fully charged/float voltage. 14.4v is cyclic/bulk charging voltage to balance the cells, and won't harm anything if it is switched over to float voltage once the battery is charged...chargers usually switch over from 14.4v at the end of bulk phase (80% charge) to 13.8v. Charging the battery over 14.4v will cause gassing, where the water in the electrolyte converts to hydrogen and oxygen. These voltages are for a battery at room temperature, and go up the colder the temperature and down the higher the temperature.

12.9v is probably as high as a 1-amp (peak) charge coming from the solar panel or a small charger can make the battery voltage rise. Or you have an inaccurate meter.

oil pan 4 · 05-01-2017, 08:45 AM

There is no way that panel is putting off an amp.

Magician · 05-01-2017, 12:07 PM

Why do you think it can't put out an amp? According to the manufacturer, it does. And... if you take 13w/12v = 1.083 amps... in dierect sunlight that is. Do you own this panel and have you tested it? Just curious... I'll let you know. I'm sure the controller will drop it a bit.

Stubby79 · 05-01-2017, 01:05 PM

Just put a meter inline with it and settle any potential disagreements.

Magician · 05-01-2017, 10:53 PM

I will test it this weekend... it will be sunny skies. I'll test it with the glass closed and open as it seems the glass may cut down on efficiency a fair amount, but not all glass is created equally. I've got a multi-meter and it's a good one.

stovie · 05-02-2017, 12:50 AM

So stubby79, are you saying I could make a 13.5v solar charger on the roof of my truck and not need to shut it off ever??

If so I've been planning on taking some solar cells I bought on amazon a few years ago to make a charger in place of the alternator!?!

Stubby79 · 05-02-2017, 04:39 AM

float voltage (13.8v) can be maintained indefinitely. That's what they keep SLA's at in backup lights/power supplies. It's what your alternator and plug-in chargers drop down to after the initial ~14.4v bump.

oil pan 4 · 05-02-2017, 08:43 AM

Quote:

Originally Posted by Magician

Why do you think it can't put out an amp? According to the manufacturer, it does. And... if you take 13w/12v = 1.083 amps... in dierect sunlight that is. Do you own this panel and have you tested it? Just curious... I'll let you know. I'm sure the controller will drop it a bit.

Because I found when you put a layer of auto glass in between the panel and the sun it can cut the panel output by 1/3 and not having the panel perpendicular to the sun can cut panel output by half.
There is no way that panel is making an amp.
I put solar panels in and on vehicles and I have amp meters.
I use a fluke325 amp clamp meter.