Newby needs help with choosing batteries

[Jessejames801]

Thank you so much suneagle you're making this project seem more attainable. im going to look for a smaller fan that runs off of 12volts and uses a lot less power cause I won't use the led lights very often but I do want to run the pump and fan at night cause I'm making a small little air conditioner (swamp cooler) to keep us cool at night and it doesn't need to be super powerful cause the inside of the trailer is only 4'x6' wide and 4' tall. If I get a battery thatis closer to the 66ah instead of 50 ah would that give me a little more run time ? Also what amp of charge controller would be best for this set up ? And are deep cycle batteries the best type of batteries to use ?

[SunEagle]

What I'll be running is actually just one fan that says it uses 0.75 amps unfortunately it doesn't say how many watts and a pump that uses 3watts and a led light that uses 10watts I thought about installing a 9" tv/dvd player but I haven't decided if I want to do that yet but the other 3 items I will be running for sure . I thought a single 100 watt panel would be enough to run those if I got a decent 100watt solar panel,battery, and charge controller am I wrong ?

A 100watt, 50Ah battery system will be able to run about 120 watt hours a day. I am guessing that fan is runs on 120volts so at 0.75amp you are probably talking about 90 watts. When you add the fan at 90watts to that 3 watt pump and 10 watt LED you are looking at 113 watts total. That battery would allow you to run all 3 of those loads for just about 1 hour a day.

I don't think you only want to run those loads for 1 hour a day so a 100 watt panel and 50Ah battery will not meet your needs.

Now forget the fan and you should be able to run that pump and light for about 10 hours provided you recharge the battery back up to 100% after using it each time.

[Sunking]

What I'll be running is actually just one fan that says it uses 0.75 amps

At what voltage? 12 volts Dc or 120 volts AC? 12 volts x .75 amps = 9 watts. 120 volts x .75 amps = 90 watts. I suspect the fan operates at 120 volts AC otherwise you would have no need for an INVERTER. That being said you are dead in the water. Read on to find out why.

How many hours do you want to run the fan?

9 watts x 10 hours = 90 watt hours. Or 90 watts x 10 hours = 900 watt hours

Assuming the fan is 90 watts x 10 hours = 900 watt hours. Assume the Pump, LED, and TV run 10 hours per day. [3 watts for pump, + 10 watts for the LED, + 40 watts for the TV] x 10 hours = 530 watt hours. Add it all up and you use 900 wh + 530 wh = 1430 watt hours in a day.

Battery AH @ 12 volt requirement = [1430 wh x 5] 12 volts = 595 Amp Hours or round up to 600 AH @ 12 volts. That is a 400 pound $1400 battery.
Panel wattage using MPPT Controller = [Daily Watt Hours x 1.5] / Sun Hours in winter. For you that is roughly 3 hours. So [1430 wh x 1.5] / 3 hours = 715 watts. You can get away with just 700 watts.

Panel Wattage using PWM controller = [Daily WH x 2] Sun Hours in Winter. So [1430 wh x 2] / 3 Sun Hours = 953 watts. Round Up to 1000 watts

Next is controller size MPPT Controller = Panel Wattage / Battery Voltage = 700 watts / 12 volts = 58.3 amps. You can use a 60 amp MPPT Controler.

Last is determine the largest connected load that will be operating at the same time. For example I will assume your fan is 90 watts + 3 watts for the pump, 10 watts for the LED light, and 40 watts for the TV = 143 watts. You would need no more than a 200 watt Inverter.

There you have it all figured out.

Panel Wattage = 700 watts
MPPT Controller = 60 Amps
12 Volt Battery = 600 AH
Inverter = 200 watts, or you could use up to 700 watts but not recommended.

Now plug in your real numbers and see what it takes. Bet you $1 if that fan is a 120 VAC fan, and you will never do this once you understand what you are asking for. It would cost a fortune.

You owe me a dollar. I just saved you a from wasting any more money.

[Jessejames801]

This is the specs on the solar panel I want to get and it is a
RENOGY 100 Watt 100w Monocrystalline Photovoltaic PV Solar Panel Module
Specifications
Maximum Power: 100W
Maximum System Voltage: 600V DC (UL)
Optimum Operating Voltage (Vmp): 18.9V
Optimum Operating Current (Imp): 5.29A
Open-Circuit Voltage (Voc): 22.5V
Short-Circuit Current (Isc): 5.75A
Dimensions: 47 X 21.3 X 1.4 In
Weight: 16.5lbs

Warranty Information
25-year transferable power output warranty: 5-year/95% efficiency rate, 10-year/90% efficiency rate, 25-year/80% efficiency rate

[Jessejames801]

What I'll be running is actually just one fan that says it uses 0.75 amps unfortunately it doesn't say how many watts and a pump that uses 3watts and a led light that uses 10watts I thought about installing a 9" tv/dvd player but I haven't decided if I want to do that yet but the other 3 items I will be running for sure . I thought a single 100 watt panel would be enough to run those if I got a decent 100watt solar panel,battery, and charge controller am I wrong ?

[SunEagle]

So with a 100 watt panel what minimal ratings specs should I look for in a deep cycle battery be and what kind of places should I look to find this battery I want to buy local because shipping is way too much for a battery p.s. I'm located in Utah

A 100 watt panel can produce a maximum of 5.5amps. So to keep the battery within the C/8 to C/12 range would require something between 44 to 66Ah. You can probably find a number of places that sell 50Ah 12volt batteries in Utah.

[Jessejames801]

Thank you sun eagle I really appreciate your help !

[Jessejames801]

So with a 100 watt panel what minimal ratings specs should I look for in a deep cycle battery be and what kind of places should I look to find this battery I want to buy local because shipping is way too much for a battery p.s. I'm located in Utah

[SunEagle]

Is this a fiamm 12flx400 100ah 415wpc high rate ups standby battery a good battery to use with the 100 watt solar panel listed above ?

Most UPS "standby" batteries are not designed to be cycled on a daily basis. A solar battery needs to be listed as "Deep Cycle" and have a reliable 20hour Ah rating and will also provide you with an estimated amount of "cycles" at a specific DOD (depth of discharge). If it has a cranking or standby rating it is not what you want to use.

[Jessejames801]

Is this a fiamm 12flx400 100ah 415wpc high rate ups standby battery a good battery to use with the 100 watt solar panel listed above ?

[SunEagle]

Someone local to me is selling 10 of these batteries for $50 12 Volt 9 Amp Hours Length 5.94 Width 2.55 Height 3.7 Terminals F2 Weight (6.5) Manufacturer CSB Model # CSB HRL1234WF2FR 12V 9AH CSB Battery
I was wondering if these would be good to use as a battery bank for a solar set up for a really small trailer (6'x5') I have not bought anything for a solar set up but I was looking at Xantrex PROwatt 600 SW true sine wave Inverter , Sunforce 60031 10 Amp Digital Charge Controller and a RENOGY 100 Watt 100w Monocrystalline Photovoltaic PV Solar Panel Module 12V Battery Charging
would these batteries work with this set up since there are 10 of them ? I plan I running led lights two fans a small 2 watt water pump and maybe a couple of other accessories through the power inverter any recommendations for this set up would be amazing !!!! Thank you so much for any help you can provide .
P.S. I'm new to this forum so if I posted this in the wrong location please let me know where to post it .

Save your money and don't buy those 9Ah batteries, that 10amp CC or just one 100Watt panel. None of them will give you what you desire.

Now that 600 watt Xantrex inverter is a good piece of equipment but will it provide what you need?

Have you calculated your daily watt hour load? That is the first thing to do before you purchase anything else. Just saying "led lights, 2 fans and a 2 watt pump" is not enough data to calculate what you need. Each item uses an amount of "watts" and will be run for an amount of "hours". Calculate that for each load and then add them up. Then add a fudge factor because you will have underestimated the correct amount of "watt hours" needed.

Once you know what you need in watt hours you can then design your battery system. Depending on where you live will help with the panel wattage and charge controller. Then you look at sizing your inverter.

As Sunking stated, a solar battery system needs to be balanced. That means panel wattage, battery charger, battery Ah rating and inverter need to match up or you will quickly find the weakest link.

[Sunking]

I have seen people run 600 watt or bigger power inverters with solar panels much smaller than 600 watts

Sure you will, but that does n ot make it right. You can get away with it as long as you never use the full power. The issue is in both battery AH capacity and panel wattage. There are directly related.

Batteries have internal resistance. The smaller the battery the higher the resistance. This limits the battery ability to deliver current at a specified voltage. For flooded lead acid (FLA) batteries the maximum charge and discharge current is C/8 where C = the battery Amp Hour capacity and the number 8 is 8 hour discharge rate. So if you have say a 60 AH battery the maximum current you can pull out of it without significant voltage sag is 60 AH / 8 H = 7.5 amps. Well 12 volts x 7.5 amps = 90 watts.

Physically a 60 AH battery can deliver 50 amps which is what a 600 watt inverter will draw at full power. However the voltage will sag significantly say down to 10 or 11 volts. The Inverter has circuitry inside it called Low Voltage Disconnect designed to turn the invert off when the voltage goes down to 10 or 11 volts. So you can easily have a fully charged battery, turn the Inverter on and apply a 500 to 600 watt load, and the Inverter trips off-line from under voltage. That would lead you to think there is something wrong, when in fact it is doing exactly what it was designed to do. The real problem is Operator Error.

Batteries also have a minimum and maximum charge rate they can accept. The minimum is C/12 which is needed to prevent the electrolyte from stratifying where the heavier acid sinks to the bottom of the battery jar and floats the water on top. It takes a C/12 current to stir and agitate the electrolyte. C/8 is the upper limit to prevent excessive gassing, heating, and warping the battery plates. Using the 60 AH battery model again means you need at least 5 amps of charge current and no more than 7.5 amps, just call it 8 amps. Well if you use a PWM charger it requires a panel wattage of 90 watts to generate 5 amps of current, or 144 watts to generate 8 amps.

Note the relationship. Panel Wattage roughly = Inverter wattage is you have the system balanced.

honestly your replies seem kind of rude if this is what people are like to new members on this forum maybe I should just try a different forum out

OK you got thin skin. Don't let the door hit you in the butt on the way out. Try the Wind and Sun Forum. They sugar coat everything over there and treat you like a customer because that is what you are. They will tell you exactly what you want to hear then sell it to you. Around here you get answers and no one will sell you anything.

[Jessejames801]

Ok I will get a bigger charge controller but the thing about needing a 600 watt solar panel in order to use a 600 watt power inverter makes absolutely no sense to me cause I have seen people run 600 watt or bigger power inverters with solar panels much smaller than 600 watts and please remember I'm completely new to this and honestly your replies seem kind of rude if this is what people are like to new members on this forum maybe I should just try a different forum out

[Sunking]

Nothing about your design will work. In a proper design you only use a single string of batteries. In your application a single battery of appropriate size.

A 100 Watt panel if using a cheap PWM 10 amp controller can only support a single 60 AH battery powering a 50 to 75 watt Inverter.

To power a 600 watt inverter will require roughly a panel wattage of 600 watts with a 50 Amp MPPT charge controller, and a 12 volt 400 AH battery. What you are trying to do is pull a 18 wheel truck with a motorcycle.

[Jessejames801]

What do you mean Too many interconnections ? Isnt having multiple batteries ok to do ? And I thought ups batteries are good for solar applications? Can you recommend a good batter for this exact set up (solar panel and charge controller listed above ?