What size panel

[expara]

What size panel should I have to run six lights a WiFi booster ( big one cost 280 pounds) and a device that works like a mobile phone. These lights etc.. are not on all the time just now and again and not all at once but to work out the size of panel I need I have to assume they are on all the time. I have the correct batteries and a 1500w inverter but my panel is only 10w PV and cant cope. It all works but needs to be boosted with a generator.

[SunEagle]

What size panel should I have to run six lights a WiFi booster ( big one cost 280 pounds) and a device that works like a mobile phone. These lights etc.. are not on all the time just now and again and not all at once but to work out the size of panel I need I have to assume they are on all the time. I have the correct batteries and a 1500w inverter but my panel is only 10w PV and cant cope. It all works but needs to be boosted with a generator.

Well my first question is what is the watt rating for your lights, booster and mobile phone device and now long does each run?

Without that specific information it is almost impossible to determine any device for a solar / battery system.

You really have to understand what you have asked is very incomplete and almost useless for anyone to help you.

[bob-n]

Yup, SunEagle summarized the question nicely. To elaborate:

Assuming that your lights are 10 watt LEDs, your booster uses 15 watts, and your device needs 10 watts, you need 85 watts of power for 24 hours per day. That's a wild assumption but let's go with it. That's roughly 2kWh per day.

A solar panel only gets sun during part of the day, and less in winter than summer. It also depends on the weather in your area, where you put the panel, and other things like shade from trees. If we assume that it gets 3 hours of full sun on the worst day of the year, you need panels that produce 700 watts, including losses for the inverter and charger.

Now replace my assumptions with reality. How long will the lights be operating per day? How much power do they use? How much sun do you get on a worst case day, etc.

Just to add one more important detail, do you expect full operation on a rainy day in winter? Rainy days produce very little solar power because the clouds and moisture block most of the light. Or are you assuming that the battery has enough capacity to ride through a few days of rain. That could require a large battery.

Keep in mind that energy is expressed in a unit like kilo-watt-hours or watt-hours. Batteries are often rated in amp-hours, so multiply amp-hours by volts and you get watt-hours. Most batteries hate being deep discharged. It shortens their life, so some people buy more battery capacity than they need.

Just to make things even more complicated, batteries lose capacity with time. Inverters and chargers are not 100% efficient. But these errors may be minor compared to the bigger questions.

I hope this helps.

[Mike90250]

I've been through 1 week of cloudy weather, got 7 minutes of Absorb today, and looks to be another dim week !

solar clouds 1-2020.jpg

[expara]

Thanks for the replies the lights are 60w low energy and used one or two at a time on these dark mornings the device is only used in the summer months the WiFi booster is on all the time but not at night. I know little sunshine means little storage. I have two 12v mobility batteries in series and as I have said I have to boost them with a generator this time of year but would like the system to run without any help during the summer. The place I need all this stuff for is on land I have where I keep birds and I am not there all day to use electricity. I thought I could get away with a 100w/150w panel. My generator a 90kva deasel is a bit over the top for my needs. At the moment it goes in to 4 days without charge. I am a time served electric ion but know little about solar power. If you think I could manage on 100/150w panels please let me know.

[SunEagle]

Thanks for the replies the lights are 60w low energy and used one or two at a time on these dark mornings the device is only used in the summer months the WiFi booster is on all the time but not at night. I know little sunshine means little storage. I have two 12v mobility batteries in series and as I have said I have to boost them with a generator this time of year but would like the system to run without any help during the summer. The place I need all this stuff for is on land I have where I keep birds and I am not there all day to use electricity. I thought I could get away with a 100w/150w panel. My generator a 90kva deasel is a bit over the top for my needs. At the moment it goes in to 4 days without charge. I am a time served electric ion but know little about solar power. If you think I could manage on 100/150w panels please let me know.

Again you still need to calculate the number of watt hours your system uses each day. You can only determine the size of your battery and panel wattage from that information. Just guessing what your batteries can do and how many watts you "think" you need will end up with a dead system no matter how little you use it.

For quick calculations you need about 1/10th the battery Ah rating in charging amps. So if you have a 200Ah battery you will need 20 amps. With a 100/150w panel you will have only about 5 to 6 amps of charging so you battery can only be around 50 to 60ah. But with only 60Ah you can safely generate about 360watt hours for a 24V battery system and half that for a 12V battery.

With lights that use 60watts for even an hour and a WiFi that may use the same for 24 hours you will need a much bigger battery system to run your loads. Especially if you get a couple of days without useful sun to charge them.

Oh and with a 24V battery system you will need at least 36V from the panels to charge it. So a single 100w/150w panel is just too little.

[expara]

Thanks for your time and I will do as you advise.

[SunEagle]

Thanks for your time and I will do as you advise.

We want to help you but with the information you have provided it would be a big guess to size your system.