Charging recommendations

Hi,

The rvdreams site is dated and has some errors.

Thanks for the replies and advice.
Have some research to do now...

RoyB wrote:
When I am out off the power grid I just watch my BATTERY BANK DC VOLTAGE reading with a meter panel (NOT THE % METER that comes with the trailers)

When the DC VOLTMETER meter drops down to around 12.0VDC then I know my batteries are getting close to their 50% Charge state. Then I know I need to run my 2KW Generator that has the trailer shore power cable connected to it using a RV30A-15A adapter. I will run it for 3 hours or more to get my batteries back up to their 50% charge state.

My situation is I need to have my battery bank at its 90% charge state before we really start using them after 4PM each day. What you want to happen using the SOLAR PANELS is to get your batteries to at least their 90% charge state before you start using them again.

Just keep in mind a typical 120WATT SOLAR PANEL only generates around 5-6AMPS of DC CURRENT when in high sun so you are hoping the 6 hours or so of being in high sun all will be enough DC CURRENT to re-charge your batteries back up to to 90% charge state.

If we don't start out our evening run off the batteries at their 90% charge state it will get dark on us around 10PM at night. Usually where we camp here on the EAST SIde of the US we can't run our generator after 8PM at night due to the campground generator run time rules.

I would play with your setup at home with how many panels it takes to get your batteries up to their 90% charge state before committing to the camping off the power grid.

Your generator will always be your PLAN B but in my case if my batteries did not get to their 90% charge state before the high sun went away I would not have enough time to run my generator before the 8PM deadline for running generators haha...

Roy Ken

Thank you, very well said.

I agree with 5 - 6 Amps DC from 120 watt panel!

It seems like that is the most I ever got from my two 75 watt panels combined.
Sure they would perform better if they were adjustable and could be oriented better towards sunlight, but...


I will run it for 3 hours or more to get my batteries back up to their 50% charge state.

Did you mean to say "back up to their 90% charge state"?

http://www.jackdanmayer.com/rv_electrical_and_solar.htm
http://www.rv-dreams.com/our-rv-electrical.html

The two websites above contain great info regarding RV solar.

When I am out off the power grid I just watch my BATTERY BANK DC VOLTAGE reading with a meter panel (NOT THE % METER that comes with the trailers)

When the DC VOLTMETER meter drops down to around 12.0VDC then I know my batteries are getting close to their 50% Charge state. Then I know I need to run my 2KW Generator that has the trailer shore power cable connected to it using a RV30A-15A adapter. I will run it for 3 hours or more to get my batteries back up to their 50% charge state.

My situation is I need to have my battery bank at its 90% charge state before we really start using them after 4PM each day. What you want to happen using the SOLAR PANELS is to get your batteries to at least their 90% charge state before you start using them again.

Just keep in mind a typical 120WATT SOLAR PANEL only generates around 5-6AMPS of DC CURRENT when in high sun so you are hoping the 6 hours or so of being in high sun all will be enough DC CURRENT to re-charge your batteries back up to to 90% charge state.

If we don't start out our evening run off the batteries at their 90% charge state it will get dark on us around 10PM at night. Usually where we camp here on the EAST SIde of the US we can't run our generator after 8PM at night due to the campground generator run time rules.

I would play with your setup at home with how many panels it takes to get your batteries up to their 90% charge state before committing to the camping off the power grid.

Your generator will always be your PLAN B but in my case if my batteries did not get to their 90% charge state before the high sun went away I would not have enough time to run my generator before the 8PM deadline for running generators haha...

Roy Ken

I am generally skeptical about these Amazon specials on Solar power, but the two you cited appear pretty reasonable, to me. The price difference is getting a MPPT vs PWM controller. If your budget is real tight, I don't see why the PWM controller would not be adequate for you. Both controllers have enough capacity to add another 100W panel if you decide 200W isn't enough. the fact that your space has plenty of sunshine is encouraging.... 200W should be plenty sufficient to keep your fridge going during the day if you don't run any other significant power users.

2solar dot com has decent prices, but not sure how much to ship to Alberta?

The solar system will pay for itself in several ways. Your bank is likely getting sulfated due to the long drawn out discharges between weekend charges. And you're likely going thru about 20 gallons of gas per season with the eu2000i, not to mention wear and tear?

Some folks have found poly panels handle clouds and shading better. PWM is likely all you need with 200w of solar. You can likely do much better, price wise, building your own system, using the components you choose. Should come out to less than $2 per watt, either way.

There is a solar wholesale seller in Calgary:

solar panels in Calgary

Prices are as low as $1 per watt.

Here is a simple flow chart.

Budget-->Energy Audit-->Battery bank size-->number of watts-->PWM or MPPT. What ever type of controller is chosen, make sure it has adjustable set points and a temperature probe that is on the battery.

If you use solar as a battery charger, one rule of thumb is between 60 and 150 watts of panels per 100 amp-hours of storage. The smaller the battery bank the higher the wattage needed (per 100 amp-hours). Here is a link to the rather special spreadsheet which includes an energy audit, that N8GS has created to help size solar battery charging systems!
solar spreadsheet by N8GS

If you full time or use an inverter lots, then populate the entire unshaded area of the roof with panels. I'm considering replacing my awning with solar panels.

For a nice explanation of solar, try this link:
Golden rules of solar

We have a Renogy but also check out Zamp and Go-Power. I'm sure there are others but here are just a few of the many. Let the research begin.