45 watt solar panel setup...

Realistically, how much power is this? They sell them at Harbor Freight, I thought it would be a good gateway into solar power. The project I came up with was it would power my shed, and trickle charge my electric tractor. My idea was to have the cells charge a battery station and draw power from there. It sounds solid, how applicable is it? Thanks...

Think of it as a battery charger. The amount you get is what is stored in the battery. the size of the panel determines how fast it will recharge.

I'd guess that this is the equivalent of a 5 amp battery charger which would basically take all day to charge a drained battery. The question is how long of use you get before the battery is drained. You didn't elaborate on the uses.

There are better kits out there that are expandable. Most panels are 100 watt and the controllers can accept more than one panel. This gives expansion down the road.

I've got 200 watts on 4 batteries with a 3000 watt inverter to make it 120v. It runs 12v lights, 12v pump to water garden from rain tanks, 12 v aeration for minnows in a stock tank, plus can handle power tools on a short term basis.

The price per watt from harbor freight is quite high. I suggest shopping around. I buy all my panels from Missouri wind and solar mwands.com I've been running 4, 100 watt panels and a 4 T105 trojan knock off batteries. They are 6 volt, so 2 are wired in series and each pair is paralleled for 12 volts at 450 amp hours. This has been a ton of power for me. I'm running a window air conditioning unit, my lights in my shed, phone charger, flashlight charger etc.

Its so important to think about every device your going to plug in. For all my lights I use LEDS so it takes 14 watts total. I'm so impressed with solar electricity I have no intentions of ever hooking up to the grid. I just purchased another 1.4 kw worth of panels from MWANDS and an Outback flexmax 80.

I highly recommend getting into solar electricity. Heres what I recommend. Purchase a "Kill-a-watt" meter, this will allow you to plug into a regular outlet in your house and plug an appliance in and tell you exactly how much electricity its going to use. Very important for all your calculations. I would purchase, 2-100 watt panels around $1.30 a watt, a simple pwm charge controller $60 this will keep your batteries from overcharging, and 2 6 volt t105 style batteries around 140 each. Try to get all of the appliances you want to run as twelve volt dc. If you need 120 volts dc you will have to buy an inverter. Modified sine will work fine.

You will also be able to get 30% back on your tax return for renewable energy credit.

Don't worry about purchasing the wrong panels etc, they are infinitely expandable in the future.

I agree with all of the above ,shop around for panels ,the prices have really come down , I bought a 12 volt 205 watt panel for $350 , shop around and watch the freight charges , they are the sting in the tail . I have seen the freight cost more than the panel .

Okay, thanks for the advice; it all seems very solid.

My use requirements would be to have some lighting, in the shed, and the trickle charge my tractor. I mow once a month for 40 minutes. So, I am not too worried about charge time. But I like the idea of being able to build onto the system.


I am going to look into your suggestions. Thanks...

I do not own any solar, but I am a certified solar installer admittedly with minimal experience.
So for what it is worth, HF has has these kits on sale for as low as $145.00, I believe.
It is a good size for your current uses, but not for anything further. We used it as
A class room demo...

If it's just lights and a trickle charger, then by all means go for it. While it won't be expandable, it will have uses on its own separate from a bigger unit if you choose to grow.

One thing about a charge controller is that it knows the battery is charged, so it shuts off the juice. This makes it a great mobile battery charger that won't overcharge the battery.

many many uses for this. A simple solar hot water heater would use a pump directly to the charge controller (no batteries) so it turns on when the sun shines, turns it off when it's not.

Aeration and filtration. For a frog pond, minnow tank, etc.

Transferring water from point a to b such as rain water collection. I can run a small sprinkler off a rainwater IBC tank to water my garden. Without solar, the flow is too small and would take a lot of moving the hose to water the whole garden.

The list can go on and on.....

We have used the HF solar kits in the past. While they are not bad for a very low wattage system, Amazon.com has a similar "kit" now that is less money for a 100 watt system that is also expandable. Much better value for the money. About half the cost per watt than the HF 45 watt kit. Just a thought.

Jhonny,

if you are trying to charge the tractor that I see when clicking the link I can not recommend this setup. 45W is the manufacturers boiler plate. That value needs to be de-rated, look for the Photo Voltaic USA Test Conditions (PTC) value.
They will most likely not print this value on those type of 'low end' panels. If you are lucky you get 80% of the value: 36W effective output. To make things worse the supplied charge controller does not deliver you that power on the output side.
It will loose another 10-15% unless you purchase a rather expensive MPPT charge controller.

Long story short: you can use it for some LED lights and as a cellphone charger. The total daily energy it will be able to produce should be no more than 200Wh

I have the Harbor Freight kit and I like it. Its a good starter kit if you want to get into solar. I use it to charge cell phones, tablets, cordless drills, my 6 year old son's electric motor car, etc.

Keep an eye on craigslist or classifieds. I have 920 watts micro grid tie but came across a HF 45 watt kit complete new in box $100