Double solar roof panels—overkill?

[padlin]

Mike do you have a real battery monitor, as opposed to the Gopower controller? The Victron along with a shunt seems to be popular.

[Perry Butler]

Originally Posted by Mike Lewis

How do you measure your usage? My battery monitor measures drain and charge. Is there a way to measure drain only?

I haven't installed it yet, but our Victron Battery Monitor is supposed to keep a history of power in and power out. If it would have been installed this past winter I could have figured out we had a failing battery much sooner.

Enjoy,

Perry

[Mike Lewis]

Originally Posted by padlin

Mike do you have a real battery monitor, as opposed to the Gopower controller? The Victron along with a shunt seems to be popular.

I have a Bogart Engineering Tri-Metric TM-2025-A battery monitor, installed and connected to my 12V system with a shunt by AM Solar. Perhaps it's time I read its fine manual.

[AKCamper]

Originally Posted by Mike Lewis

I have a Bogart Engineering Tri-Metric TM-2025-A battery monitor, installed and connected to my 12V system with a shunt by AM Solar. Perhaps it's time I read its fine manual.

Mike,
Did AM Solar install your panels as well? Do you have the Bogart charge controller as well?

[John in Santa Cruz]

I suspect my solar requirements are about to go up significantly, I electrified my wife's bike, and after a 15 mile or so brisk e-powered ride including some hill climbs, it can use around 500 watt*hours to recharge (about 120 watts for 4 hours, then tapers off). If I ran the bikes battery flat, in theory its 860 watt*hours. 2 GC2 batts on my trailer are like 1400 watt*hours total, but you really don't want to suck more than half that from them, so 700 watt*hours. I'm wondering if my single solar panel will be adequate to keep things happy. the charger is 55VDC, but runs off 120VDC, I have a 200 watt inverter I plan on using since I can't seem to find any 12VDC powered '48V liion' chargers...

previously, just using the trailer power for ventilation fan, minimal LED lighting, phone and tablet charging, and maybe running a 12V stereo, the 160W solar system was way more than enough, we'd not even use 5% of the battery at night, and it would be fully charged by mid morning. I should mention, most of the places we dry camp are wide open with no shade, as I'm doing astronomy, shade blocks the night sky.

[Mike Lewis]

Originally Posted by AKCamper

Mike,
Did AM Solar install your panels as well? Do you have the Bogart charge controller as well?

My trailer came with the 95W panel that Escape offered at the time (April 2014). On my trip home after picking up the trailer I had AM Solar install one more panel and the battery monitor. They offered a Bogart controller and three panels, for a total of four, but I couldn't afford the complete package as I had just purchased the trailer. So I just got the one panel with provision for adding two more later.

On a subsequent trip I tried to do this, but AM Solar had discontinued the particular panel they were going to use for the 3rd and 4th panels, and I didn't like the way the replacement panels were mounted, so I got only one more instead of two. So currently I have three panels-- one from ETI and two from AM Solar, the Bogart battery controller, and the Go Power solar controller from ETI.

[Mike Lewis]

Originally Posted by John in Santa Cruz

I should mention, most of the places we dry camp are wide open with no shade, as I'm doing astronomy, shade blocks the night sky.

How much power does the drive of your scope use? I presume it's negligible, as the guys in my astronomy club bring small power packs when they set up their portable scopes for our "gazes". But I'm curious.

[Telescopist]

Originally Posted by Vermilye

The result is I use between 40 - 50 amp hours per day during the winter in Arizona. A pair of 160 watt rooftop solar panels does not keep up with the low angle winter sun. I modified the mounts so I can tip the panels at the ideal angle for Quartzsite, AZ, and that helps, but if I have a string of cloudy days, or end up parked in the shade, I dig out a portable 160 watt panel. I've found that adding the portable during December & January keeps the batteries topped off during the shortest days.

I'm curious how you modified the mounts. Can you share images and/or describe what you did? How did you calculate the declination of the Sun? So for example on Feb. 2 in Tuscon, AZ the Sun is located at @42° above the visible horizon. Maybe you just made an educated guess re: tilting the solar panels?
Of course that would be enough just ball parking it!

[Perry Butler]

GoPower now makes a 190 watt panel with the same physical dimensions as the 170 watt. I wonder when ETI will offer this panel?

And time marches on.

Enjoy,

Perry

[Vermilye]

Originally Posted by Telescopist

I'm curious how you modified the mounts. Can you share images and/or describe what you did? How did you calculate the declination of the Sun? So for example on Feb. 2 in Tuscon, AZ the Sun is located at @42° above the visible horizon. Maybe you just made an educated guess re: tilting the solar panels?
Of course that would be enough just ball parking it!

I have photos on my Escape 21 Modifications page. This was a 2 step process, the easier one first that only tilts to the rear, and later (scroll down) to allow tilting to either side of the trailer.

As to finding the proper tilt angle, I used this app (scroll down for the table) for Phoenix, the nearest city to Quartzsite. I went with 39°, since December was 34° & January 41°.

If you only wanted to tilt to one direction (the rear) they were selling a nice unit at the Big Tent show at Quartzsite that used a 12V linear actuator driven system that let you choose the tilt between 0° and 60°.

[Vermilye]

Originally Posted by Mike Lewis

How do you measure your usage? My battery monitor measures drain and charge. Is there a way to measure drain only?

It isn't an exact measurement. I check how far down the amp hours are in the morning, compare to where they were when the sun went down to get the overnight usage. That is pretty accurate, but I have to fudge the day use since the panels are putting amps back into the batteries as well as me taking them out.

I know what my usual loads are (coffee pot 6 amp hours, toast 9 amp hours, MacBookPro 3 amps times hours of use, etc) and use that to figure the daytime use. If I'm concerned about usage (cloudy weather), when using the microwave I'll note the amp hour reading before & after the microwave run to determine how much I used. At the low power setting, the 950 watt inverter microwave uses an amp hour per minute at 500 watts, full power of 950 watts is 2.9 amp hours per minute.

I also periodically check the output of the GoPower controller and compare it to the battery monitor to determine how much the trailer is drawing (the difference is the trailer current draw).

[John in Santa Cruz]

Originally Posted by Mike Lewis

How much power does the drive of your scope use? I presume it's negligible, as the guys in my astronomy club bring small power packs when they set up their portable scopes for our "gazes". But I'm curious.

2 AA batteries for the little red LED in the Telrad finder, which last for years or until I forget to turn it off for a month.

my scope is otherwise human powered.

[Mike Lewis]

Originally Posted by John in Santa Cruz

2 AA batteries for the little red LED in the Telrad finder, which last for years or until I forget to turn it off for a month.

my scope is otherwise human powered.

A Dobsonian! Very nice.

[Telescopist]

Originally Posted by John in Santa Cruz

2 AA batteries for the little red LED in the Telrad finder, which last for years or until I forget to turn it off for a month.

my scope is otherwise human powered.

John, when you get a chance consider adding in between steps to your ladder. You'll never have to scrunch or stand on your tiptoes again. I got the idea from Dave Kriege about 15 years ago. Not great detail in these Picts but at least it will give you an idea of the spacing.