Battery usage percentages

Topic: Battery usage percentages (Read 2722 times) previous topic - next topic

Re: Battery usage percentages

Reply #100 – March 04, 2014, 01:04:09 pm

Quote from: fouroureye – March 02, 2014, 08:10:51 am

Hey Larry,

Can I ask you something about my set up?

900w in 12-75w panels, 40A controler

Looking at removing 2-4 panelsand updating with these 270w panels.
Can you mix wattages? $:-\$

You can mix wattages. just keep the total within reason with your controller.

Re: Battery usage percentages

Reply #101 – March 04, 2014, 01:31:29 pm

Thanks Larry, sounds like I might be getting a couple of 270w panels

that will increase my capacity;
2 @ 270 watts @ 60% capacity because of dirt clouds no tilt etc =720watts input
3 @ 270w =940watts input
4 @ 270w = 1000watts input

Re: Battery usage percentages

Reply #102 – March 04, 2014, 01:45:38 pm

Make really sure your voltage does not exceed the controller rated voltage. Remember, in the morning, a cold PV panel will put out more voltage than the rating on the lable. I could have gone all series wiring and on paper, would have seen 144 volts with the Classic 150 being rated for 150 volts but was advised the voltage on an all series wiring on a cold morning could exceed 150 volts by a significant amount. Controllers will either not turn on until the voltage drops or will be fried and not covered by the warranty. As the sun is starting to come over the horizon in the morning, our controller indicates over 80 volts (four 36 volt, 280w panels in series/parallel) but won't turn on until enough watts become available. Our panels have a 92 amp potential with the MidNite 150 maxing out at 96 amps so this is also an important consideration in planning the installation. In other words, we have maxed out the wattage/amperage the controller can handle. If any doubts or questions, call the controller retailer or manufacturer and ask questions.

With the panels flat on the roof and dirty, we still get 80+ volts in the very early morning from a 2 x 36 volt panels series wiring that would normally see 72 volts. They are also shaded by the AC at that time.

Pierce

Re: Battery usage percentages

Reply #103 – March 04, 2014, 02:18:14 pm

Thanks Pierce good advice.

Re: Battery usage percentages

Reply #104 – March 04, 2014, 07:54:28 pm

Just note that you can only safely parallel connect banks of solar panels if each bank produces exactly the same voltage, otherwise you will be applying the voltage differential across a length of wire, heating the wire, possibly to destruction, and wasting power.

I would feel safest if each parallel connected bank is the same configuration and the same solar cell type, otherwise there might be small differences in voltages under identical conditions. I wouldn't try paralleling an amorphous UniSolar cell with a traditional crystalline cell, or two cells from different manufacturers with different blocking diodes used or not used.

Series connections on the other hand are just fine, as long as you never under any conditions (for example no load and cold) exceed the controllers max PV voltage.

Re: Battery usage percentages

Reply #105 – March 05, 2014, 02:51:40 am

Quote from: red tractor – March 04, 2014, 09:23:05 am

running the refrigerator on ac from the inverter is not a good way to go as it will kill your batteries very quickly

Maybe. My RV refrigerator uses two 210 watt ac heater elements. How does this 420 Watts compare with the power used by a residential refrigerator? I assume the duty cycle to maintain a static temperature would be pretty similar.

Re: Battery usage percentages

Reply #106 – March 05, 2014, 10:32:12 am

Think I have read most of the installments here on the Battery useage and the PV Cell use, wire size, wire run, length, amp draw, voltage drop etc.
My question concerns those that are using the electric heat in bath and front flooring. I have no idea of the kw draw on the battery, I do not know if the heat strips are 12 VDC or 120 VAC, surely someone has considered this issue, this will surely come up one day, so am wondering.
Dave M

Re: Battery usage percentages

Reply #107 – March 05, 2014, 01:22:14 pm

Easy heat - warm tiles, which we use mostly in bathrooms as follows;
Mat type 2' width vs length

60 sq ft - 720watts, 6A
75 sq ft - 900watts, 7.5A
90 sq ft - 1020watts, 8.5A

Use the flex grout in a can - will color code to any MAIP grout color

Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 09, 2025 ...

Re: Battery usage percentages

Reply #100 – March 04, 2014, 01:04:09 pm

Re: Battery usage percentages

Reply #101 – March 04, 2014, 01:31:29 pm

Re: Battery usage percentages

Reply #102 – March 04, 2014, 01:45:38 pm

Re: Battery usage percentages

Reply #103 – March 04, 2014, 02:18:14 pm

Re: Battery usage percentages

Reply #104 – March 04, 2014, 07:54:28 pm

Re: Battery usage percentages

Reply #105 – March 05, 2014, 02:51:40 am

Re: Battery usage percentages

Reply #106 – March 05, 2014, 10:32:12 am

Re: Battery usage percentages

Reply #107 – March 05, 2014, 01:22:14 pm

Affiliate Notice