Hello New member in Sherman WV

[2bugtony]

Hello all
I just took the leap into solar.
I built a barn and decided that I would try a small off grid solar system for the lights and outlets. I don't think that I will need much just enough for some led lights.
I have bought a 400 watt system from Windy nation. Has anyone bought form these guys? How did they do? Let me know how you like your unit if you have one form them.
I plan on using 6 volt golf cart batteries in a series to get my 12 volts.
Thanks I'm sure that I will be picking your brains form time to time.
2bugtony

[Mike90250]

a pair of golf cart batteries is not a bad way to start. Good luck.

[SunEagle]

Welcome to Solar Panel Talk.

Going with 6volt deep cycle golf cart batteries is a good step but before you spend any more on your off grid system you should first determine what your daily watt hour electrical load is.

A great tool to is called a "kill a watt" meter. It will be able to measure the amount of watts each item uses. Then you determine how many hours in a day you will use that item. Without that information you can't properly size your batteries or determine if you have enough solar panel wattage.

Check out this link on battery sizing. http://www.solarpaneltalk.com/showth...Battery-Design

It will give you an idea of what you need to research to size your system.

Also be aware that most "off grid" systems will cost you 10 times as much as what you would spend using grid power. Just keep in mind that going "off grid" is neither a cost savings or GREEN project but don't let that stop you if that is what you really want. Just do the research first before you purchase anything else. It will save you some money.

[2bugtony]

Thanks for your reply's
I understand the cost is more but there is no other power where this remote barn is and this gives me a excuse to try solar. Thanks for the KW hour tool. I will add up my watt hours and figure the batteries i need.
Thanks

[FloridaSun]

Thanks for your reply's
I understand the cost is more but there is no other power where this remote barn is and this gives me a excuse to try solar. Thanks for the KW hour tool. I will add up my watt hours and figure the batteries i need.
Thanks

You have a 22A max charge with that system at 12V so a pair of 225Ah 6V golf cart batteries is all that the 400W of panel and very cheap PWM controller in that kit will handle. You might be better off with a pair of cheapo walmart 100Ah 12V marine/deep cycle, hybrid batts and configure to 24V from the start, save some future inverter investment by going 24V now. Read up on the threads in off grid section here. You may want to grow your system in the future.
For more battery capacity you would need a higher charge rate. For best battery care you need a 4 stage MPPT controller.

Beware of statements such as this from their Amazon ad,
"Kit will provide on average 1600 Watt Hours (Wh) or 135 Amp hours of charge per day (depends on sunlight availability)"

1600Wh/135Ah= 11.85 volts.... hahaha, that's not going to charge a 12V battery. In reality you'll get more like 100-110Ah of charge (minus losses) from those rare days when you actually do get a full 4 hours of direct mid day sun. Plan for worst case, not only in solar hours available for your location but weather conditions, cloudy days also.

[SunEagle]

You have a 22A max charge with that system at 12V so a pair of 225Ah 6V golf cart batteries is all that the 400W of panel and very cheap PWM controller in that kit will handle. You might be better off with a pair of cheapo walmart 100Ah 12V marine/deep cycle, hybrid batts and configure to 24V from the start, save some future inverter investment by going 24V now. Read up on the threads in off grid section here. You may want to grow your system in the future.
For more battery capacity you would need a higher charge rate. For best battery care you need a 4 stage MPPT controller.

Beware of statements such as this from their Amazon ad,
"Kit will provide on average 1600 Watt Hours (Wh) or 135 Amp hours of charge per day (depends on sunlight availability)"

1600Wh/135Ah= 11.85 volts.... hahaha, that's not going to charge a 12V battery. In reality you'll get more like 100-110Ah of charge (minus losses) from those rare days when you actually do get a full 4 hours of direct mid day sun. Plan for worst case, not only in solar hours available for your location but weather conditions, cloudy days also.

You are correct that the 400 watt solar panel system he has will limit his battery size.

I was hoping on getting back to step 1 by first knowing his watt hour requirements. Then he could size his battery system for his needs and then determine if he even had enough panel wattage to charge the batteries.

If he needed more panel wattage than replacing his PWM CC with an MPPT would be the next step. He would then need less additional panel wattage to meet his needs using the better charge controller.

[FloridaSun]

You are correct that the 400 watt solar panel system he has will limit his battery size.

I was hoping on getting back to step 1 by first knowing his watt hour requirements. Then he could size his battery system for his needs and then determine if he even had enough panel wattage to charge the batteries.

If he needed more panel wattage than replacing his PWM CC with an MPPT would be the next step. He would then need less additional panel wattage to meet his needs using the better charge controller.

yah... well... he said he already bought the kit. Not the best way to go but it's done. I found it on Amazon, $640 for 400W of panel, a $25 controller, a few pieces of bent aluminum flat bar and a 40' 12AWG connector wire with 'all necessary' MC4s. A great deal.... for the seller

[2bugtony]

Thanks for the come back
That's all I was planning of was a pair of 6volt batteries. If I need to buy another charge controller I will. What would be a good one? All that I will be charging is the two 6 volt 225a batteries.

[SunEagle]

Thanks for the come back
That's all I was planning of was a pair of 6volt batteries. If I need to buy another charge controller I will. What would be a good one? All that I will be charging is the two 6 volt 225a batteries.

Morningstar MPPT type charge controllers are really good but for your 12 volt 225Ah system you will need about 22 amps output and their models jump from a 15amp to a 45amp. Morningstar and for that matter most reputable MPPT CC manufacturers don't make a 30 amp charger. You can find those on eBay but they are really PWM type and not a true MPPT type.

Now if you go with a 24volt battery system the Morningstar MPPT 15A model can accept up to 400 watts of PV but only 200 watts for a 12 volt battery system.

So your choice is to go with a 24volt battery system and 15amp charger or the 12volt battery system and a 45amp charger.

Since you really don't know if the 12volt 225Ah battery system will be enough for your needs (it is small) going with the 45amp charger allows you to enlarge your battery system and add more solar panels to make a balanced system.

It all depends on what you need to provide your electrical requirements. One thing you should not do is try to save a few bucks on a small system only to find out it won't perform to your needs and now you have wasted money because you can't expand without buying all new equipment.

Determine what your daily electrical watt hour load is and then size your batteries. You can always expand your pv panel system from the 400watts you all ready have.

[Naptown]

Keep in mind that the watt hours in a 225AH 12V battery is identical to the watt hours in a 24v 112AH battery.