Newbie - Need help

**SunEagle** · 08-31-2021, 09:21 AM

Hello Green Hog and welcome to Solar Panel Talk

Before you purchase any solar equipment you really need to determine what your daily watt hour usage is. If that number is high (which is will be if your loads are big) then you will probably have to decide to go with a higher voltage battery system (say 48V) or find a way to run grid power to that building. In the past the average cost to put in a solar/battery system has been about $1500/kWh it can safely deliver. So if you plan on using say 3 kWh then the system may cost about $3000. That 35000watt inverter will easily consume more then 3 kWh a day so the cost will be higher. Which usually means a 48V battery system that is about 400Ah which is way bigger then what you figure.

I always say "do the math" first and then open the wallet.

**Mike90250** · 09-01-2021, 12:53 AM

The motors in the Drill and Grinders will consume a lot of power. Lots. And they need a large pure sine inverter to start and run them

Look at the electrical tag/label on the machines, and see if they have a Wattage or Volt Amp ( VA ) rating. Then you simply add up tha watts for the number of hours you plan to use each one

Drill 800W x .75 hour = 600watt hours
kettle 900w x 2 hours = 1800wh
solder iron 300w x 3 hr = 900wh
grinder 1200w x 2 hr = 2400wh

Add all the wh up, and that is 30% of the wh your battery needs to be. Then you size ( several ) solar panels and charge controllers to be able to recharge the panels.

or you can purchase a generator and run your gear from that.

An small, efficient house can use about 10,000 watt hours in a 24 hr period.

**bcroe** · 09-01-2021, 09:46 AM

I would go for all battery powered tools, charge the batteries at home. For something
that must be line powered, get a small portable gen set when you run it.
good luck, Bruce Roe

**Green Hog** · 09-01-2021, 12:42 PM

Thanks for the replies, unforunately not answering my question.

I will not be in the garage working full time, only on weekends about 10 hours in total, the only appliances that will be on whilst I am working will be the 2 optimates & the 2 LED lights.

A gen is not an option as the location of the garage is in a residential area & I'm sure the residents wouldn't appreciate the noise & pollution, for the amount of use I would use the power tools it doesn't make econmonic sence to buy them.

Adding up the wattage of the appliances I will be using adds up to 108 watts. I understand a 100 watt panel & a 100AH battery will give me 1200 watts of power. I'm not setting up a commercial workshop, a pure sine wave is not need for what appliances I am going to run, a modified wave inverter will be fine for my usage.

The best way I can describe what the intended use is, think of having LED lights set up if you were camping, that's how much power I would need.

Andy.

**SunEagle** · 09-01-2021, 01:56 PM

Originally posted by Green Hog

Thanks for the replies, unforunately not answering my question.

I will not be in the garage working full time, only on weekends about 10 hours in total, the only appliances that will be on whilst I am working will be the 2 optimates & the 2 LED lights.

A gen is not an option as the location of the garage is in a residential area & I'm sure the residents wouldn't appreciate the noise & pollution, for the amount of use I would use the power tools it doesn't make econmonic sence to buy them.

Adding up the wattage of the appliances I will be using adds up to 108 watts. I understand a 100 watt panel & a 100AH battery will give me 1200 watts of power. I'm not setting up a commercial workshop, a pure sine wave is not need for what appliances I am going to run, a modified wave inverter will be fine for my usage.

The best way I can describe what the intended use is, think of having LED lights set up if you were camping, that's how much power I would need.

Andy.

Your math is off. A 100Ah 12V battery can provide maybe 360watt hours a day (12V * 100Ah * 30% = 360wh) which can easily be used up with a 3500watt inverter. And a 100 watt panel will never put back what you take out of that battery. A 100watt panel can support a 55Ah battery but it is not enough for a 100Ah. And that 100Ah battery is not enough for your load usage.

But hey it is your money and IMO you will find out the hard way that the battery will die quickly and it won't even light up those LEDs

**bcroe** · 09-01-2021, 03:05 PM

Brand H has some really quiet gen sets, should be no problem. An inverter style
will not even rev up until you apply a serious load. Bruce Roe

**Mike90250** · 09-01-2021, 06:52 PM

You listed a bunch of power tools, any of which need a seriously large PV system.

Now you are backing off and just some lighting..

> x2 - Optimate 4 battery chargers - 0.384 watts (these will be on constanly, when the bikes aren't being ridden)
That wattage is wrong. it's not 0.4 watts, it's closer to 104 watts, if the 4 batteries are being trickle charged at 2A each. The chargers will likely require pure sine wave,
on mod-sine, they may last 10 minutes and then fry. All depends on their internal construction. Cheap out and take your chances.
2 chargers, you will need 300W of PV just to run the chargers.

Same with the Grinders and other motors. They will run on mod sine for a while. Then overheat and die.

**checkthisout** · 09-01-2021, 11:52 PM

Originally posted by Green Hog

Thanks for the replies, unforunately not answering my question.

I will not be in the garage working full time, only on weekends about 10 hours in total, the only appliances that will be on whilst I am working will be the 2 optimates & the 2 LED lights.

A gen is not an option as the location of the garage is in a residential area & I'm sure the residents wouldn't appreciate the noise & pollution, for the amount of use I would use the power tools it doesn't make econmonic sence to buy them.

Adding up the wattage of the appliances I will be using adds up to 108 watts. I understand a 100 watt panel & a 100AH battery will give me 1200 watts of power. I'm not setting up a commercial workshop, a pure sine wave is not need for what appliances I am going to run, a modified wave inverter will be fine for my usage.

The best way I can describe what the intended use is, think of having LED lights set up if you were camping, that's how much power I would need.

Andy.

You can get a little Honda 2200 watt inverter generator for less than you will spend on your system and have plenty of power to run your tools.

For your lights, you could get a battery charger and just keep a couple Group 31's powering some cheap 12V led spotlights. They will run off the batteries for several hours. Whenever you fire up your gen just make sure the charger is plugged in and it will top the batteries back off.

Like others have said though and what I said above, just get a generator or if you're hell bent, just get a 3000 watt inverter (with 6k surge) and run it off your car battery. That would be fine if all you have to do is make a few cuts but then you're over half the cost of a generator sooo.......

**Green Hog** · 09-02-2021, 07:49 AM

Thank you again for the replies.

Can anyone give me a list of what equipment I need to run my 2 optimate 12v battery chargers & 2 50 watt LED lamps please?

Many thanks,

Andy.

**Mike90250** · 09-02-2021, 12:33 PM

No.
You need to tell us how much power the battery charges consume, and for how many hours ( example : 300w for 24 hours, or whatever they use )
How many hours do you want the 100w of LED lighting to run

Then, with those numbers, we can calculate how many PV panels and what size battery you need.
We'll guess you get just 5 usable solar hours in the winter and no clouds ever and size it from there.

**SunEagle** · 09-02-2021, 06:35 PM

Originally posted by Green Hog

Thank you again for the replies.

Can anyone give me a list of what equipment I need to run my 2 optimate 12v battery chargers & 2 50 watt LED lamps please?

Many thanks,

Andy.

I understand that you want a solution but we need more information as Mike has asked. Just providing what you have is not enough data.

**Green Hog** · 09-06-2021, 06:59 AM

OK, to reiterate, the two chargers will be on 24 / 7, apart from when I will be out riding, the total output is 0.384 watts, the 50w LED lights will be on for approximately 10 hrs. per week. Does this help?

**SunEagle** · 09-06-2021, 09:17 AM

Originally posted by Green Hog

OK, to reiterate, the two chargers will be on 24 / 7, apart from when I will be out riding, the total output is 0.384 watts, the 50w LED lights will be on for approximately 10 hrs. per week. Does this help?

Somewhat. Based on that info your daily watt hour load is about 150 watt hours. That is a very reasonable amount. I would say build a solar/battery system that can produce 4 times that amount or 600 watt hours which is about a 200ah 12v battery (2 x 6V wired in series) , a 30 amp CC and either 400 watts of solar panels (wired in parallel) with a PWM CC or 250 watt of panels with an MPPT type CC.

Don't forget that with more than 2 items (panels or strings) wired for the CC you will need separate fusing for each string. So while you may pay less for a PWM type CC you will also pay more for solar panels and fusing. That is a choice you have to make.

If your estimated watt hour usage is higher then expect a bigger battery system (more than 200Ah) and more panel wattage.

**Green Hog** · 09-06-2021, 10:28 AM

Thank you.

Is this a good starting point - eBay item number: 324251259536, with two deep cycle 12v 100AH batteries wired together?

Andy.

Newbie - Need help

Newbie - Need help

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