Originally posted by Mike90250
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Sorry couldn't get back to all, had to go out of town for a couple of days
I did check the diodes and they check out good so that leaves that theory out. Now remember that controller was fried and the plus terminal was totally melted going to the battery but I didn't know that until I got on the roof and took the panel down saw the burnt spot. I'm thinking that the controller was the problem and Sunking was right and max out the amps but if that was true it must of had to pass the diodes to do that and they are good. OH WELL!Comment

Originally posted by ufoexpert View PostNow remember that controller was fried and the plus terminal was totally melted going to the battery
No question about it, the battery is the only thing that has that kind of energy,. Your Controller is the smoking gun.
MSEE, PEComment

Well SunKing I'm back and I'm going to ask you some question but before I do that , its my birthday today and I sometimes get cranky so be good.
My inverter went south on me (and this was just a hobby) and now I'm thinking of your great wisdom that you have given me in the past and have decided to go 24 volt system which I believe takes me out of the beginners class. To go back on my system....80 amp controller 12 or 24 volt, 6 T105s, 7 160 watt panels(was 8 before poof and now 7).
My total KW use is max. 500 but usually around 250 to 350 KW. Need to know what your opinion what size inverter I need? Also I know I need 2 more batteries another solar panel. That is if I can talk the wife into it. wb8ziiComment

Originally posted by ufoexpert View PostMy total KW use is max. 500 but usually around 250 to 350 KW. Need to know what your opinion what size inverter I need? Also I know I need 2 more batteries another solar panel. That is if I can talk the wife into it. wb8zii
First Happy Birthday.
OK 500, 250, and 350 Kw cannot be right. Those would be Commercial and Industrial sized Inverters used for a large UPS system in a data center. You are talking big enough to run 200 to 400 horse power motors. I know that cannot be right.
OK your limit is set by the batteries as batteries can only deliver so much current before voltage sags to low to be usable. Understand? T105's are pretty good at delivering high CRates. They can deliver C/5 to C/4 where C is the AH capacity. Example a T105 is rated at 225 AH so C/5 would be 225/5 hours = 45 amps. But you have a math problem, there is no way to make 24 volt battery with 6 T105 batteries. It takes 4 of them in series to make 24 volts. Understand? You have either 2 more than you can use. or short 2 to make 2parallel strings. You can only use 4 or 8 of them. 6 does not work.
OK let's assume you use 4 T105 wired in series to make 24 volt 225 AH battery. You do not want to exceed 45 amps, so 45 amps x 24 volts = 1080 watts. So you are looking for a 1000 watt or 1 Kw 24 volt Inverter.
Another limit you have is the 80 amp controller. Input power limit is determined by the battery voltage. So at:
12 volts limit is 1000 watts.
24 volts is 2000 watts
48 volts is 4000 watts.
So you can see the advantage of moving from 12 to 24 volts. You can input twice the panel wattage. Another thing to consider is your batteries have a minimum and maximum charge rate. Minimum for T105 is C/12 (18.75 amps, call it 20), and C/6 or 37.5 amps call it 40 amps. So if you used 4 T105s in series means minimum panel wattage is 20 amps x 24 volts = 480 watts (call it 500 watts) and maximum is 40 amps x 24 volts = 960 watts call it 1000 watts.
Everything needs to be designed to work and support each other. So stay within the limits. Here is a good rule of thumb to live by. Inverter wattage should be no larger than panel wattage. If you look at the math above, you see that works and fits.
Tip if you were to have 8 trojans wired in series for 48 volts @ 225 AH, you need 1000 to 2000 watts of panels and can use up to a 2000 watt 48 Volt Inverter. At 48 volt battery with 2000 watts of panels gives you 40 Amps of charge current, a piece of cake for a 80 amp controller with lots of room to grow. Think about that.
I can even help with the wife if she likes wine. Take her to a nice place for dinner, buy a bottle of wine, have her drink it, you take a blue pill and take her home. When the moment is right ask permission to buy an Inverter and two more batteries. Works great with my wifey, one botle of wine and her clothes magically falls off.
Last edited by Sunking; 03312017, 01:55 PM.MSEE, PEComment

Originally posted by ufoexpert View PostI messed up, the batteries are T605s
You have 8 panels, plus 1 makes 9. There is no way to configure 9 12 volt battery panels for 48 volts. You would need 10 panels or 8 configured either 5S2P or 4S2P.
Give mamma another kiss and see if she will go for 2 panels with the 2 batteries.Last edited by Sunking; 04012017, 10:13 PM.MSEE, PEComment

Welcome back...I'm thinking on were to start on this post. OK, go with solar panels I just order 1 to replace the that got burned and that will be here Thursday. Now while you were on the golf course (god knows were) my inverter went south on me, Why? Now I'm sitting like that statue of the great thinker and do what SunKing said and that is what I been doing while you were playing golf.
I got on the roof and this old man started to switch wires around and came up with 3 sets of 24 volt panels and soon to be 4. Now I just got back from the battery place and bought 2 more T605s. The controller is a 12 or 24 volt so no problem there. Oh yes, I order a 24 volt inverter and its was here in the next day and its a 1000 watt.
Now I got one more question for you and putting 4 6 volt batteries in series I notice that the batteries are making gurgling sound. Can you explain that to me. 73s
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Originally posted by ufoexpert View PostNow I got one more question for you and putting 4 6 volt batteries in series I notice that the batteries are making gurgling sound. Can you explain that to me. 73s
When you here the noise measure the voltage. Gassing occurs when cell voltages hit 2.4 vpc so on a 24 volt system around 28.8 volts.
Additionally pop the caps off and look inside. Make sure it is not just one battery or one cell.
Do you have a hydrometer yet? If not get off your wallet and find a 10spot for a Deka Temperature Corrected Hydrometer and learn how to use it. Let it tell you what to set the charge voltage to.
In the mean time read this.Last edited by Sunking; 04032017, 10:32 PM.MSEE, PEComment
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