series/parallel PV wiring clarification

krharley

i'v got 4 Sharp panels
pmax 250 w
voc 37.35
isc 9.03
imp 8.34
i have 4 6v Trogen L16-E-AC 370 AH , a MS MPPT 45 Amp CC, Power bright 2300-24volt inverter. the 4 batteries wired in series for 24 volt. not sure the amp hr 370 or 720??? i think the target being 370ah. i'm confused about the series/parallel connection at the panels and weather i need each string fused or not. i got the 2 in series making a string but if i need to parallel also where do you parallel from? if i need to fuse them i would need a combiner box as well. it is only 2 in a string i shouldn't have to right? i know how to connect the - to + for series bringing the voltage to 59.96 to properly charge the 24 volt system . i'm confused on the parallel part.

i also have spare parts now: CC pro-star 30, 12v zantrax inverter, 4- marine batteries @ 95 ah each
3 sunteck panels
pmax 130w
imp-7.47
vmp-17.4
isc-8.09

bp panel
pmax-180watt
35,6v
imp-5.05
voc-43.6
isc-5.04

bp panel
225watt
vmp-29.1
imp-7.7
voc-36.6
isc-8.3

Cariboocoot

Re: series/parallel PV wiring clarification

Okay, four panels with a Vmp around 29.9. You need two in series to have high enough array Vmp for a 24 Volt system. So you would wire these panels as two parallel strings of two in series. There is no need to put fuses/breakers on the strings in this configuration because there are only two parallel connections. This array would produce about 32 Amps maximum on a 24 Volt system. That should be good for 320 Amp hours @ 24 Volts. Your four 370 Amp hour 6 Volt batteries in series would be 370 Amp hours @ 24 Volts. Slightly more battery than ideal for the array (8.6% peak rate) but it should work.

I've got a diagram of two parallel strings of three in series; just leave out one panel in each string.

Your other panels are not compatible with this array due to the Vmp differences. The one BP panel is close at 29.9, but with only one it can't work.

Two of the Suntek panels could be used in series on a separate controller to provide a bit more charge current if wanted.

krharley

Re: series/parallel PV wiring clarification

thanks for the quick reply. and a big thanks for the diagram, guess i just needed a diagram in my head. and i could add add 2 of the 12v sunteck panels as well.......... thats good news as well. i will add those.
i'll play with other little projects with the spare parts list.
thanks alot

Cariboocoot

Re: series/parallel PV wiring clarification

krharley wrote: »

thanks for the quick reply. and a big thanks for the diagram, guess i just needed a diagram in my head. and i could add add 2 of the 12v sunteck panels as well.......... thats good news as well. i will add those.
i'll play with other little projects with the spare parts list.
thanks alot

You can only add the SunTek panels on a separate controller: the Vmp of two of them will be 34.8.

krharley

Re: series/parallel PV wiring clarification

so that would have to be a MPPT controller as well?

Cariboocoot

Re: series/parallel PV wiring clarification

krharley wrote: »

so that would have to be a MPPT controller as well?

No; the 34.8 Vmp is fine for a 24 Volt system and PWM controller. It would add 7 Amps to the total so 39 Amps peak.

krharley

Re: series/parallel PV wiring clarification

ok, got it. thanks again

krharley

Re: series/parallel PV wiring clarification

i'm having some shading issues from trees that are not on my property. i'm also wanting a buy a new energy star A/C, and a new energy star refrigerator. i'm wondering if i should also buy a good battery charger with the highest amps from IOTA that i could buy to charge with my 3000 watt champion generator, or if i should buy a inverter/charger- generator to recharge the battery bank. or should i- could i go back to 12 volts in parallel with another MS CC but 60 amps and stack with or parallel wire to my MS 45 amp, or split the array up into 2 arrays but parralled because of shading. i get get good sun from 10:00 a.m. - 3:00 pm. with parallel i get good sun from 8:30-5{30-6:00pm. ii need to improve system again, i know.... but i'v got to get it right somehow and try to use as much equipment as i already have plus buy what i need to keep batteries charged. i'm currently running an old a/c off the generator during the day and switching to batteries at night for a fans. i'm protecting those batteries but using a lot of fuel. could use all suggestions before i buy more than i need or all the wrong stuff .

vtmaps

Re: series/parallel PV wiring clarification

krharley wrote: »

or split the array up into 2 arrays but parralled because of shading. i get get good sun from 10:00 a.m. - 3:00 pm. with parallel i get good sun from 8:30-5{30-6:00pm.

Splitting the array and using two controllers may be a good idea if there is shading. Or not. There is the cost of a second controller and its two circuit breakers and there is the increase in tare loss caused by operating two controllers. (I'm assuming that we are referring to MPPT controllers because you have GT panels). Your panels are (or should be) in a string length of two. That means you already have two parallel strings. Make sure your four panels are configured in such a way that all the shading is on one string. That will yield more improvement than having two controllers with shading on each string of the array.

krharley wrote: »

i'm also wanting a buy a new energy star A/C, and a new energy star refrigerator.
<snip>
i'm wondering if i should also buy a good battery charger with the highest amps from IOTA that i could buy to charge with my 3000 watt champion generator, or if i should buy a inverter/charger- generator to recharge the battery bank.
<snip>
buy what i need to keep batteries charged. i'm currently running an old a/c off the generator during the day and switching to batteries at night for a fans. i'm protecting those batteries but using a lot of fuel.

So your loads are growing, you use a lot of fuel to keep the batteries charged, and you want to improve your system. My advice is to start from the beginning, and design (on paper) the perfect system. Start out by determining your loads. Then we figure out what battery and system voltage, then we figure out how much solar panel you need. Finally, we can figure out how to get from where you are to where you would like to be. There will inevitably be some compromises... hopefully you can use much of your existing system.

Your post was a jumble of thoughts on how to spend money to improve your system. The money will be wasted if you don't have a clear picture in your head of a system that will meet your needs.

--vtMaps

krharley

Re: series/parallel PV wiring clarification

what if i was able to get some power from my neighbor to a good charger like the Iota to keep my batteries charged up. how well do you think something like that would work out?

Cariboocoot

Re: series/parallel PV wiring clarification

krharley wrote: »

what if i was able to get some power from my neighbor to a good charger like the Iota to keep my batteries charged up. how well do you think something like that would work out?

You planning on running an extension cord over under cover of darkness or what?

krharley

Re: series/parallel PV wiring clarification

laughing, but no sir. what if i were able to get permission and run a proper line over here just for a battery charger. not to run my other stuff. but just for the charger. a good one that would keep them up perhaps

Cariboocoot

Re: series/parallel PV wiring clarification

Yes, the Iota should be able to keep the batteries above sulphation level. With 370 Amp hours @ 24 Volts you'll need at least the 25 Amp one though.

krharley

Re: series/parallel PV wiring clarification

you don't think the 40 amp would be better?

Cariboocoot

Re: series/parallel PV wiring clarification

krharley wrote: »

you don't think the 40 amp would be better?

Well, yes it would. That's why I said "at least" the 25 Amp unit.

krharley

Re: series/parallel PV wiring clarification

ok, need help trying to read the kill-o-watt meter. i'm running it through the extension cord coming from the generator. 4 times readings
118 v/amp 2.78/233 watts 2:40 .6 L 2nd day- 1.45 amps /14.6 watts 166 watts 2 kwh 00:08 .89 PF 3rd day 2.86 amps 246 watts 340 VA .72 PP 0.14 kwh 4th day- kwh time 3:59 118.5 volts 2.47 amps 195 watts 292 VA 0.66 PA .07 kwh 4:04 kwh
i can't make sense out of it........... not that bright.
that's without the A/C because i know it wont run that too. when the sun goes down of course all my numbers start going backwards too which is depressing because it goes so fast. if the sun is out next day, it charges right back up. my hydro battery checker is all good in the high red numbers all 4 batteries balanced-very pleased with that. my power bright 2300 has been clicking off after hooking up the GT panels. it will go to 29.9 for so long and i have everything on ,guess i need to get a small heater to turn on for a few seconds- that all it would take because its a MSW and it also doesn't reset itself. so if i'm not home, and sun's out that's it. and even then as soon as sun goes down even with no load the cc goes to yellow, it doe stay their all night. only a few times it went to red led, but still re-charged quickly. i still don't have a battery charger. been looking for a good one, but will wait because i think i need a better inverter- like you suggested before the samplex. i could hard wire it. i would like one with a charger in it and a reset. i think its too low. maybe 33 ?v would be better for me?? i measure 54-55 volts today, yet it was cloudy, but that"s about average if i remember right coming from the panels. does that sound right to you should it be 55- 60 volts measured with a multimeter ? down to my CC is where i took the reading.

BB.

Re: series/parallel PV wiring clarification

krharley wrote: »

ok, need help trying to read the kill-o-watt meter. i'm running it through the extension cord coming from the generator. 4 times readings
1st day-118 v/amp 2.78/233 watts 2:40 .6 L
2nd day- 1.45 amps /14.6 watts 166 watts 2 kwh 00:08 .89 PF
3rd day- 2.86 amps 246 watts 340 VA .72 PP 0.14 kwh
4th day- kwh time 3:59 118.5 volts 2.47 amps 195 watts 292 VA 0.66 PA .07 kwh 4:04 kwh

I am having a hard time understanding what you wrote up there... I am not sure if you are miss-reading the meter, or if the generator is causing the meter to be confused (depending on the model of KaW meter, when you cut AC power, they reset. Some models have batteries that keep readings--Although, you can only read the the LCD when they have AC power, as I recall).

Generally, the readings should be something like this. The first list are "real time" measurements--No storage or long term average--Just what is happening "this second":

118 VAC (line voltage)
1.45 Amps (line current from generator)
171 VA (volts*amps)
0.8 PF (power factor)
137 Watts (VA*PF)

And these two are long term measurements:
0.685 kWatt*Hours (average Watts * # of hours * 1/1,000 = kWH)
05:00 Hours (hours meter has been running/plug into AC power

I do not see a lot of consistent readings from day to day.

that's without the A/C because i know it wont run that too. when the sun goes down of course all my numbers start going backwards too which is depressing because it goes so fast. if the sun is out next day, it charges right back up. my hydro battery checker is all good in the high red numbers all 4 batteries balanced-very pleased with that.

What are you using to measure your DC loads/charging (a Battery Monitor)?

And does you hydrometer actually give specific gravity values (such as 1.265)? Make sure you rise out the hydrometer with distilled water before you put it away for the day. They can get sticky/gummy inside and the float will stick if the are put away with electrolyte inside.

my power bright 2300 has been clicking off after hooking up the GT panels. it will go to 29.9 for so long and i have everything on ,guess i need to get a small heater to turn on for a few seconds- that all it would take because its a MSW and it also doesn't reset itself. so if i'm not home, and sun's out that's it. and even then as soon as sun goes down even with no load the cc goes to yellow, it doe stay their all night. only a few times it went to red led, but still re-charged quickly.

29.9 volts is pretty high for flooded cell lead acid batteries to be held at "absorb" charging voltage... Are you using a lot of distilled water every month to refill the batteries? Your solar charge controller may be running a bit high on the charging voltage.

Yes, for many off grid inverters, they will "fault" on 30 volts or more on the 24 VDC battery bus. Lead Acid flooded cell storage batteries really need around 30-32 volts to "equalize", and many AC inverters will fault (you can find some brands/models of better units that will not fault).

i still don't have a battery charger. been looking for a good one, but will wait because i think i need a better inverter- like you suggested before the samlex. i could hard wire it. i would like one with a charger in it and a reset. i think its too low. maybe 33 ?v would be better for me??

If you live in sub freezing weather and the battery bank can approach freezing--Then yes, you really need something more than 30 VDC as the inverter cutoff voltage for a 24 volt battery bank (as the batteries get colder, their charging voltage rises).

i measure 54-55 volts today, yet it was cloudy, but that"s about average if i remember right coming from the panels. does that sound right to you should it be 55- 60 volts measured with a multimeter ? down to my CC is where i took the reading.

What kind of solar charge controller do you have? The solar array voltage is pretty variable depending on the type of charge controller and what mode it is in. It sounds like you have two Vmp~30 volt panels in series with a MPPT type charge controller.

-Bill

krharley

Re: series/parallel PV wiring clarification

right about the Kill-o-watt meter. mine only works plugged in to A/C. so i called myself trying to use the clock.so i just started writing them all down when i first plug in then when i go to bed, but i think i forgot a few times before i turned it off. i know they are all different but i'm having everything i have-plugged in. sometimes a light i might turn off after a while. so i was thinking i could get an average, but i'm too confused now. that was the only one available at the Lowes in my area. it certainly would be better if their was a back-up battery to hold the reading. its a small chest freezer,small fridge, ceiling fan with light kit, small tv 19", and my laptop with router.and another light i turn on/off at my bed. thats is everything i own. maybe the readings are different with the 2 compressors cycling on/off. i don't know.
during the day if the sun is willing its all on the solar till 4:00 pm. i have to un-plug as my cc goes into yellow mode with voltage of 25.5.it goes to 29.5 by 12:30-1:00 and i have to have everything on or the inverter will click off.then i'll start turning things off as sun acts accordingly. by 6:00 pm i run generator till 10:00. the inverter voltages goes down and the cc in yellow . i'v measured many times the voltage on battery bank vs inverter and their close enough. but i don't understand why they continue to go backwards with no load/ while using generator. i leave everything off until the a.m when sun comes back out and they quickly go to green on cc (MS MPPT 45 amp ) and i slowly plug stuff back up. fridge 1st, freezer 2nd, etc
i would have never figured out the V*A , or PF.
i do not have a battery monitor yet, do you have a suggestion for me?
my hydro-meter is reading in the red-1.265-1.275- do i draw the water up twice. i have added about a shot glass amount to each cell for the last 3 months. i'm in Louisiana and its hot here. i have the EZ-RED sp101 model.i do rinse 3x after use- read that here some time ago.the post all look well,, i check and do have to tighten a little every month.
i have 4 250 watt sharp panels hooked in series/parallel, so the vmp is 29.9 i think, but you think that sounds like only 2 panels? perhaps i have a problem at panels then. what should i be reading with the 4 GT series/parallel?

BB.

Re: series/parallel PV wiring clarification

krharley wrote: »

right about the Kill-o-watt meter. mine only works plugged in to A/C. so i called myself trying to use the clock.so i just started writing them all down when i first plug in then when i go to bed, but i think i forgot a few times before i turned it off. i know they are all different but i'm having everything i have-plugged in. sometimes a light i might turn off after a while. so i was thinking i could get an average, but i'm too confused now. that was the only one available at the Lowes in my area. it certainly would be better if their was a back-up battery to hold the reading. its a small chest freezer,small fridge, ceiling fan with light kit, small tv 19", and my laptop with router.and another light i turn on/off at my bed. thats is everything i own. maybe the readings are different with the 2 compressors cycling on/off. i don't know.

Depending on their actual power consumption... It is pretty easy to see that taking 2-4 kWH per day (guessing) if you run enough hours on the genset (more than just a couple hours per day).

during the day if the sun is willing its all on the solar till 4:00 pm. i have to un-plug as my cc goes into yellow mode with voltage of 25.5.it goes to 29.5 by 12:30-1:00 and i have to have everything on or the inverter will click off.then i'll start turning things off as sun acts accordingly. by 6:00 pm i run generator till 10:00. the inverter voltages goes down and the cc in yellow . i'v measured many times the voltage on battery bank vs inverter and their close enough. but i don't understand why they continue to go backwards with no load/ while using generator. i leave everything off until the a.m when sun comes back out and they quickly go to green on cc (MS MPPT 45 amp ) and i slowly plug stuff back up. fridge 1st, freezer 2nd, etc

If you are using the MorningStar TS 45 MPPT charge controller--You should double check the dip switches (or programming)... Normally, you should be able to keep the peak voltage around 29.0 volts or so.

i would have never figured out the V*A , or PF.

VA and PF are used to represent the difference between "work" (energy, Watts) and the "inefficient use of current" by various loads (induction motors, many CFL/LED lights, and many switching power supplies). The "worse" the Power Factor, the heavier wire, inverters, and such needed to carry the "extra" current that "inefficient" loads use. We can talk more about that if you are interested.

i do not have a battery monitor yet, do you have a suggestion for me?

Unfortunately, Battery Monitors are not cheap, and they do need some programming/understanding how they work (they can drift over time/use if not properly programmed and/or the batteries are not fully recharged every few days to week or so). You might look at the Trimetric or Victron Battery Monitors as a starting point.

my hydro-meter is reading in the red-1.265-1.275- do i draw the water up twice. i have added about a shot glass amount to each cell for the last 3 months. i'm in Louisiana and its hot here. i have the EZ-RED sp101 model.i do rinse 3x after use- read that here some time ago.the post all look well,, i check and do have to tighten a little every month.

Sounds like your battery bank is OK... However, you should check every cell for SG every month or so--And look for cells that are "different" (high or low readings vs the rest of the cells).

I have 4 250 watt sharp panels hooked in series/parallel, so the vmp is 29.9 i think, but you think that sounds like only 2 panels? perhaps i have a problem at panels then. what should i be reading with the 4 GT series/parallel?

You probably have them connected with 2 panels in series (for 2x 30 Volts = Vmp~60 volts) and then the 2 strings in parallel (8.3 amps * 2 = 16.6 Amps Imp for the array). This would be the recommended configuration for charging a 24 volt battery bank.

-Bill