How Many Batteries For a 600W Solar System?

If you want to boondock with friends or family for more than a few days, you will need 600 watts of solar power at least. Of course a battery bank is also required to store the energy, but how many batteries is sufficient? And can 600 watts supply the power you need?

A 600 watt solar panel requires a 300ah battery. This solar array can charge up to five 100ah 6V batteries, which is what most RV owners need.

How Much Power Does a 600W Solar System Produce?

To determine how much power 600 watts can provide, we need to know the amount of sunlight available. If there are 5 hours of sun available, the expression is:

600 watts x 5 sun hours = 3000 watts

In theory a 600 watt solar power array can produce 3000 watts. Note that we are talking about a solar array, not solar panel. No single solar panel can produce 600 watts.

You have to combine 2 x 300W, 6 x 100W or 3 x 200W. We like the Renogy 300W Solar Panel Kit for its reliable performance and easy installation.

During the summer you can expect the output to be close to 3000 watts. In places like Nevada, Arizona and Texas you’ll get up to 6-7 hours of sunshine, so 3000W is feasible. In the Pacific Northwest, New York and other cold places, the numbers will be lower.

Keep in mind that 300 watts is the maximum production the module can produce. Solar panel output differs from its rating for many reasons so instead of 3000 watts, you may get 2800 or even 2500 watts.

The point is you need to adjust your expectations accordingly. In some cases you may get maximum output from your solar system, and in other cases you may not.

In most instances however you should get somewhere close to the peak output. Most boondocking takes place during the summer when solar production is at its peak. With 600 watts you should have ample power even if it doesn’t get to 3000 watts daily.

If you live in your RV, you may need more than 600 watts though. You will not get 5 hours of sun during the cold season, so additional power sources are required. While this solar system may be able to run a small microwave and small appliances, it cannot power an air conditioning system.

Series and Parallel Solar Panel Wiring Explained

A parallel connection increases the amps but keeps the voltage at the same level. A series connection increases the voltage but the amp level does not change.

• A typical 12V 300W solar panel is 25 amps.
• Connect 2 x 300W solar panels in parallel and you have a 12V 600W 50 amp system.
• Connect 2 x 300W solar panels in a series and you have a 24V 600W 25 amp system.

In most cases a parallel connection is preferable because of the extra power. But there are instances where extra voltage is required too. You can also set up a series and parallel combination.

You can set up a parallel connection by connecting the positive leads of the solar panels together, ad repeating it with the negatives. to do a series setup, just connect the panel positive to the negative. Either way you end up with 600 watts, though the voltage or amps will increase depending on what you chose.

How Many Batteries Do I Need For a 600 Watt Solar System?

Let us assume you have 5 hours of sunlight and want to go camping. How many batteries should you bring? It depends on many factors, mainly how much power your RV needs and the solar panels’ capacity.

The general guideline with solar powered boondcocking is 100 amps per individual. Couples camping will need one 200ah battery or two 100ah batteries. A family of four needs 400ah and so on.

If you take the minimalist approach you could do with less than 100ah per person. This is the case if you have a generator installed in the RV or ground mounted solar panels.

For a single person you can get by with a something like the Weize 100ah12V and add another 100ah depending on your needs. The rule of thumb is 100ah per person but this can vary.

Here is a quick guide on roughly which batteries a 600W solar system can charge. This calculation assumes the system generates 3000 watts with 5 sunlight hours available. Use the formula above if you get more or less than 5 hours of sunshine.

Number of Batteries	Capacity	Voltage	Depth of Discharge
1	250ah	12V	100%
2	250ah	12V	50%
3	150ah	12V	100%
6	150ah	12V	50%
5	100ah	6V	100%
10	100ah	6V	50%

In the chart we have both discharged and fully discharged batteries. Flooded lead acid, AGM and gel have to be recharged at 50%, while lithium can be discharged completely.

The type of battery you use determines how much power the solar panels have to supply. You can only use half capacity with FLA for example, but charging time is faster.

Using these formulas you can try different battery volts and sizes to see which your system can charge. Again you need to make adjustments depending on how many watts your solar system is drawing.

• Watts / volts = amps
• Amps x volts = watts
• Watts / amps = volts

By using the same steps as above you will how the difference in voltage results in a higher or lower wattage / amp capacity. The higher the voltage the greater the capacity. However you need to make sure your solar panel, charge controller and inverter are compatible with higher voltage batteries.

Lead Acid vs. Lithium Batteries

There are many aspects of this debate, and some prefer one over the other. But this is what it comes down to.

If you use less than 400ah, lead acid batteries are fine. If you more than 400ah, go with lithium. Lead acid batteries are heavy, and anything more than four is impractical in an RV.

FLA batteries are not only heavy but also occupy lots of space. They also need maintenance which can be cumbersome. Lastly, having so many batteries and only being able to use half the capacity is not ideal.

Lithium batteries may be double the cost of FLA, but there is no maintenance required. The life cycle is longer and they are lighter too. If you are going to spend a lot of time in your RV -or live in it- a lithium battery bank is the best option. Consider the extra amount you pay as a investment for the future.

What Appliances Can Run on 600 Watts Solar Power?

There is a lot you can do with 600 watt solar systems. The following are some common RV appliances you can run with a 600w solar array. The actual wattage and amps drawn may vary because of differences in manufacturing and design. use these only as a guideline and check your appliance for the power usage.

Appliance	Watts	Amps Drawn
Small Blender	600	5.5
Small Coffee Maker	600	5.5
Computer	200	1.5-2.0
Crockpot	300	2/5
Electric Blanket	500	4.5
Printer	50	.5
Washing Machine	500	4.5
Mini Fridge	500	4.5

You cannot use a blow dryer, AC, electric frying pan, space heater or other power hungry appliance as it will overpower the system. You will also need a bigger solar panel array or generator for large appliances like a 1500 watt heater for instance.

But by charging the battery and letting the solar panel power appliances, you can use solar power day and night. Connect your appliances to an inverter. The inverter draws power from the battery to run your appliances.

As long as the solar panel charges the battery, the battery will not lose power. This is easy to do during summer, but come winter will be more challenging. If you camp during non summer days, consider getting a larger battery bank or backup generator.

What Inverter Size Do I Need For a 600 Watt Solar System?

There are differences of opinion about how large an inverter must be, but generally you want the inverter to be at least 25% bigger than your total watt draw. So if you are consuming all 3000W a day, a 3500W to 4000W inverter is ideal, as they are the next largest sizes available.

You can use a battery while running an inverter , and because the battery us full you can use it all night. Next day charge it with the panels and repeat. For this to work, the battery bank must be large enough to power your appliances.

if you have another power source you can use a fridge, dryer etc., but if not you have to consider the solar panel capacity and the sunlight hours available. For most RVers, a 600W solar system plus a generator for the larger appliances is more than enough for boondocking.

Where to Buy 600W Solar Panels?

There is no 600 watt solar panel available. You have to combine smaller PV modules to get to 600 watts. There are solar panel kits that consist of 2 x 300W solar panels, giving you 600 watts.

The best place to buy is online since it is the most convenient. If you are new to solar or just want the easiest setup, a 600W solar panel kit is the way to go. A typical bundle includes all the required cables, wires, MC4 connectors and charge controller.

The only thing you need to buy are the inverter and batteries. When you have all the parts you can go ahead and install the solar system. Most solar kits have room for expansion, in case you need more power. You can even connect solar panels to a portable solar generator if you have one.

Conclusion

You can do a lot with 600 watts of solar power, and even more so when paired with batteries. In the end, how many batteries you need depends entirely on your situation, but in most cases, 600 watts will be sufficient.