I can only get 4 hours 11 to 3 pm of unshaded sun on my panels in June. I park in the shade and use an umbilical cord. A couple times a month I Hook the tt to the truck to dump the tanks, 30 minute round trip. So an isolator wouldn't help much. I use 1000 watts per day and with a 5 day reserve 416 amp hour @12 volt golf cart battery bank. With my limited sun My question is would 2 separate arrays 4 100 watt panels on a 30 amp mppt and 2 260 gt panels on a 40 mppt cause any problems or damage.
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Look into the price break using several 300w grid tie panels, not 100w 12v panels.Powerfab top of pole PV mount (2)  Listeroid 6/1 w/st5 gen head  XW6048 inverter/chgr  Iota 48V/15A charger  Morningstar 60A MPPT  48V, 800A NiFe Battery (in series) 15, Evergreen 205w "12V" PV array on pole  Midnight ePanel  Grundfos 10 SO59 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run  Runs off PV 
 Midnight Classic 200  10, Evergreen 200w in a 160VOC array 
 VEC1093 12V Charger  Maha C401 aa/aaa Charger  SureSine  Sunsaver MPPT 15A
solar: http://tinyurl.com/LMRSolar
gen: http://tinyurl.com/LMRLister 
[USER="4037"]Mike[/USER] I agree that its much cheaper that way. I can get new suniva panels for 38 cents a watt CL. Thing is I already have the 4 12 volt panels. (That cost me 3 times as much). And I have the 40 amp cc. To fix what I have now instead of starting all over. I can buy a 30 amp cc for the 12 volt panels and 2 260 watt panels for $300. Would 920 watts on 70 amps of controllers be to much for my batterys?Comment

If they are Golf Cart batteries, you can get away with C/6 charge rate. However there is no amount of power that will ever charge your batteries with just 4 hours of direct sun. It takes 4 to 6 hours to go through the Absorb phase after Bulk. Morale to the story is you cannot tolerate any shade on a battery system. There is just not enough daylight in a day to properly charge batteries on solar. That is why a generator is mandatory to top them off once a week.MSEE, PEComment

Last summer I saw that 4 hours wasn't enough. I would bulk each morning from the generator and let solar take over never saw float. So charging at c/6 only shortens bulk time. In absorb the batteries will only accept a limited amount of amps and the rest the array could produce for charging is wasted. [USER="2334"]Sunking[/USER] absorb takes 4 to 6 hours is it depth of discharge that determines 4 or 6?Comment

Originally posted by Ho jo View PostLast summer I saw that 4 hours wasn't enough. I would bulk each morning from the generator and let solar take over never saw float. So charging at c/6 only shortens bulk time. In absorb the batteries will only accept a limited amount of amps and the rest the array could produce for charging is wasted. [USER="2334"]Sunking[/USER] absorb takes 4 to 6 hours is it depth of discharge that determines 4 or 6?
There is one thing you can do. Raise the voltage set points higher. With you very limited sun of 4 hours just makes an impossible job even harder. I wished I could change that but the law of physics cannot be changed. Your application might possible be solved with a Lithium battery as they do not require being full charged, and not as sensitive to Peukert's Law as Pb batteries. The catch is the expense and risk involved. A lithium can be fully charged in 4 hours with a C/3 charge rate.
MSEE, PEComment

> A lithium can be fully charged in 4 hours with a C/3 charge rate.
And you need a larger PV array to generate the higher charge amps  No free lunchPowerfab top of pole PV mount (2)  Listeroid 6/1 w/st5 gen head  XW6048 inverter/chgr  Iota 48V/15A charger  Morningstar 60A MPPT  48V, 800A NiFe Battery (in series) 15, Evergreen 205w "12V" PV array on pole  Midnight ePanel  Grundfos 10 SO59 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run  Runs off PV 
 Midnight Classic 200  10, Evergreen 200w in a 160VOC array 
 VEC1093 12V Charger  Maha C401 aa/aaa Charger  SureSine  Sunsaver MPPT 15A
solar: http://tinyurl.com/LMRSolar
gen: http://tinyurl.com/LMRListerComment

Can't justify the cost of lithium for 12 cents of electricity a day. At 80℅ soc how long would it take at c/10 to fully charge. With generator?Comment

Anyone? If from 90% takes 3 or 4 hrs for absorb to finish. Would 10 % charge rate be needed since in absorb it takes less amps as the batteries get closer to full? And im assuming it takes 12 hours bulk and 4 hours for absorb if it takes 16 hours from dead. So 12 hours from 0 to 90 at c/10. 1.33 hrs bulk time from 80 to 90, and 4 hours absorb to 100%. So 5 hours 20 minutes charge time.Comment

Originally posted by Ho jo View PostAnyone? If from 90% takes 3 or 4 hrs for absorb to finish. Would 10 % charge rate be needed since in absorb it takes less amps as the batteries get closer to full? And im assuming it takes 12 hours bulk and 4 hours for absorb if it takes 16 hours from dead. So 12 hours from 0 to 90 at c/10. 1.33 hrs bulk time from 80 to 90, and 4 hours absorb to 100%. So 5 hours 20 minutes charge time.
Powerfab top of pole PV mount (2)  Listeroid 6/1 w/st5 gen head  XW6048 inverter/chgr  Iota 48V/15A charger  Morningstar 60A MPPT  48V, 800A NiFe Battery (in series) 15, Evergreen 205w "12V" PV array on pole  Midnight ePanel  Grundfos 10 SO59 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run  Runs off PV 
 Midnight Classic 200  10, Evergreen 200w in a 160VOC array 
 VEC1093 12V Charger  Maha C401 aa/aaa Charger  SureSine  Sunsaver MPPT 15A
solar: http://tinyurl.com/LMRSolar
gen: http://tinyurl.com/LMRListerComment
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