Need Help Calculating.

[shocked277]

Watts used in a 24hr period each day.

TV= 600W
W/PUMPS= 250W
Freezer= 500w
Lights= 150w

Total load= 1500w.

I am using 220ah golf cart batteries for my bank. how many would I need so I could charge each day and use each day.Q2 how many amps with a 12v system would I need to do this? Also what is the max DOD you can have and charge back up in 24 hrs. thanks for the advise.

[Sunking]

Do you mean watt hours? You would need 6 Trojan T-105's if using them. But using 6 - 6 volt batteries for this application is a poor choice because it would require you to use 3 parallel strings.

As for panel wattage is going to depend on your location and type of charge controller you use. Just guessing off the top of my head based on 1.5 Kwh per day use you are looking at around 800 watts with a 80 amp MPPT charge controller, or around 1400 watts using an 80 amp PWM controller.

[shocked277]

Do you mean watt hours? You would need 6 Trojan T-105's if using them. But using 6 - 6 volt batteries for this application is a poor choice because it would require you to use 3 parallel strings.

As for panel wattage is going to depend on your location and type of charge controller you use. Just guessing off the top of my head based on 1.5 Kwh per day use you are looking at around 800 watts with a 80 amp MPPT charge controller, or around 1400 watts using an 80 amp PWM controller.

yes sorry I did mean watt hours.Are you saiing that you should not use 6v golf cart batteries for a battery bank or am I misunderstanding you. I am using 8-6v 220ah energizer batteries from sams club. If its not a good idea what are the pros and conns.

[Sunking]

Are you saiing that you should not use 6v golf cart batteries for a battery bank or am I misunderstanding you.

That is exactly what I am saying. If you need 880 AH, you need to be using 800 AH cells, like 6 2 volt 880 AH cells in series to make a single 12 volt 880 AH battery.

Using parallel cells it is almost impossible to get them to load share equally. This will cause one string to do most of the work and wear that string out, and then bring down the rest of the parallel strings with it.

Secondly Golf cart batteries are not true deep cycle batteries. They are basically a Marine Grade battery which is a hybrid cross between a cranking battery and deep cycle battery. That is why Trojan makes a T-105 for golf carts, and a T-105RE renewable energy deep cycle battery.

The standard T-105 weighs 62 pounds, the T-105RE weighs 67 pounds. The difference is the T-105RE has fewer but much thicker heavier plates with a total of 5 pounds more lead in them. So if you used a standard T-105 you would expect 2 or 3 years service out of them. With T-105RE you can expect 4 to 5 years out of them.

[Mike90250]

Here's a great article about connecting batteries in parallel (on the diagonal)
http://www.smartgauge.co.uk/batt_con.html (connect batteries on diagonal )

and some other battery stuff:

http://www.windsun.com/Batteries/Battery_FAQ.htm (short & sweet)
http://www.batteryfaq.org/ (very large)

Generally, much easier to manage 2, 6V in series, than 2, 12V in parallel. Same wattage.

[shocked277]

[QUOTE=Sunking;26353]That is exactly what I am saying. If you need 880 AH, you need to be using 800 AH cells, like 6 2 volt 880 AH cells in series to make a single 12 volt 880 AH battery.

I looked around at the price for the batteries and weather its 6- 2v 88O ah cells or 3 -
4v 880 ah cells or even 2 - 6v 880 ah cells we are looking at about $2,000.00 to $6,000.00. I paid $640.00 with local pick up and no shipping. I realize the batteries you are sugesting are much better and will charge equily but what if I use method 4 in this chart given to me by Mike90250. I hate to be cheep and I know you get what you pay for but can't we find a happy medium. I can replace my batteries almost 4 to 1 unless you see something im not...I dont want to sound ungreatful because im am but money is any issue..... thanks for any more input...

[Sunking]

Use what you got for now and just understand you maybe replacing then in a couple of years. When the time comes you will be more informed and might look at a quality 10 year warranty battery rather than 1 or 2 year warranty.

I feel your pain as I own 2 electric golf carts.