ShaneB
New Member
How large we talking?
Help me fix my situation please.
- Thread starter ShaneB
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400+ W panels are about 8x5’ each, so, 10 in a row, or double stacked horizontally take up a bit of space.
ShaneB
New Member
My thought was 16 - 400w bifacial panels
Hedges
I See Electromagnetic Fields!
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Since lead-acid has a preferred charge rate, I would suggest looking at either Victron charge controller + Cerbo, or Midnight Classic + Whiz Bang Jr. These use a battery shunt to measure battery current and adjust SCC output to keep that at target CV/CC while delivering additional current for loads. Multiple SCC as required to deliver total current demand.
But if your loads are generally < 1000W as you report, just setting SCC for constant 112A (or whatever data sheet indicates) could be good enough, without using shunt to close the loop. A shunt and Ah or SoC reporting device could still be useful.
That's to maintain desired charge rate.
Now if your average draw is 500W, 12kWh/day, need to produce 1.5x that much.
Check an insolation calculator for your location. I'll assume 2 hours effective sun in the winter.
12kWh/day / 2 hours = 6kW of PV panels. About 8kW (STC) puts out 6kW.
So I'd say 10kW (STC) is a suitable array.
[Edit: I forgot to include 1.5x; make 18 kWh/day, 9kW output from 12kW (STC) of panels for 2 hours. So maybe a bit bigger than 10kW (STC).]
41 kWh of battery and 12 kWh/day gives you 3 days at 87% DoD (something you don't want to do very often!)
I'd say it is all well sized, if you put in sufficient PV and SCC.
Looks like 2x Midnight Classic 150 or 200 would do it (see curves for current vs. battery voltage)
[Edit: And by the way, I'd put some SE and some SW facing strings on each Classic.]
Probably other brands people here can also recommend.
[Edit: You can buy 12kW of panels new for $2400 to $3000, or a bit more depending on brand. Also various top names used presently similar price. It seems like used market doesn't acknowledge the glut of new panels presently being dumped for $0.20 to $0.30/W. Mounting hardware can add up, though - try to DIY with surplus/salvage material.]
But if your loads are generally < 1000W as you report, just setting SCC for constant 112A (or whatever data sheet indicates) could be good enough, without using shunt to close the loop. A shunt and Ah or SoC reporting device could still be useful.
That's to maintain desired charge rate.
Now if your average draw is 500W, 12kWh/day, need to produce 1.5x that much.
Check an insolation calculator for your location. I'll assume 2 hours effective sun in the winter.
12kWh/day / 2 hours = 6kW of PV panels. About 8kW (STC) puts out 6kW.
So I'd say 10kW (STC) is a suitable array.
[Edit: I forgot to include 1.5x; make 18 kWh/day, 9kW output from 12kW (STC) of panels for 2 hours. So maybe a bit bigger than 10kW (STC).]
41 kWh of battery and 12 kWh/day gives you 3 days at 87% DoD (something you don't want to do very often!)
I'd say it is all well sized, if you put in sufficient PV and SCC.
Looks like 2x Midnight Classic 150 or 200 would do it (see curves for current vs. battery voltage)
[Edit: And by the way, I'd put some SE and some SW facing strings on each Classic.]
Probably other brands people here can also recommend.
[Edit: You can buy 12kW of panels new for $2400 to $3000, or a bit more depending on brand. Also various top names used presently similar price. It seems like used market doesn't acknowledge the glut of new panels presently being dumped for $0.20 to $0.30/W. Mounting hardware can add up, though - try to DIY with surplus/salvage material.]
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Used are decent priced, new are around 480W, 7.3 x 3.5ft…
DIYrich
Solar Wizard
250 watts continuous is 6kwh per day. So battery sizing would give 3 days of power. 6kw of panels would recharge 20kwh with one good day of sun in the summer.
Hedges
I See Electromagnetic Fields!
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Although we don't have a way to automate it, because your battery is 8s2p it could be possible to alternate between charging one 8s while discharging the other, then switch back. That could allow 0.13C from a PV system half the size I suggested, about what DIY rich says.
Having just 6kW of panels to charge the entire bank I think would be half the desired charge rate.
I don't know how sensitive FLA is to charge rate. I have read of compressed air bubblers to keep electrolyte stirred.
I favor massive over-paneling when possible, makes up for a multitude of sins.
Visit Santan Solar and Inxeption websites. (Just avoid oats which have already been through the horse, I mean "snail trail", "cracked backsheet" etc. and look for premium brand panels.)
Having just 6kW of panels to charge the entire bank I think would be half the desired charge rate.
I don't know how sensitive FLA is to charge rate. I have read of compressed air bubblers to keep electrolyte stirred.
I favor massive over-paneling when possible, makes up for a multitude of sins.
Visit Santan Solar and Inxeption websites. (Just avoid oats which have already been through the horse, I mean "snail trail", "cracked backsheet" etc. and look for premium brand panels.)
seneysolar
Solar Addict
If building an array on a budget, this is tempting- EG4 mppt, 100A charge controller with up to 500voc input. Could possibly solve most of your charging issues with a single string of panels, and really simplify the install.
$400 right now
signaturesolar.com
Example: Get 8 of these on a string to the CC. The idea being to try and max out the charge controller with 1 string. You can get close with good planning.
a1solarstore.com
Yes theres cheaper panels out there but youll need more of them, in multiple strings. The mounting and racking can add up too.
$400 right now
EG4 Solar Charge Controller MPPT | 500VDC 100A | MPPT100-48HV
Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL
signaturesolar.com
Example: Get 8 of these on a string to the CC. The idea being to try and max out the charge controller with 1 string. You can get close with good planning.
JA Solar 545W Solar Panel 144 Cell Bifacial JA-JAM72-D30-545MB - A1SolarStore
JA Solar 545W Solar Panel 144 Cell Bifacial JA-JAM72-D30-545MB buy at A1SolarStore
a1solarstore.com
Yes theres cheaper panels out there but youll need more of them, in multiple strings. The mounting and racking can add up too.
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Hedges
I See Electromagnetic Fields!
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A bit smaller and 0.5x to 0.585x the price of those JA Solar, $80 for 420W used (10.5kW) or $100 for 445W new (13.8kW)
www.santansolar.com
www.santansolar.com
(Not finding anything under $0.40/W at Inxeption right now. Have seen ads at $0.26 recently. Sometimes by the pallet, sometimes only by the cargo container.)
Used SunPower 420W Solar Panels Lot of 25 | SanTan Solar
These 25 high-wattage panels are surplus panels with scratches and / or scuffs. They are in good working condition. The back spec label is faded; see pictures for more details. They are all covered with our 1-year SanTan Warranty.
www.santansolar.com
New Out of Box Ureco 445W Solar Panels Pallet of 31 | SanTan Solar
These panels are new out of box and have some minor discoloration on the frame.
www.santansolar.com
(Not finding anything under $0.40/W at Inxeption right now. Have seen ads at $0.26 recently. Sometimes by the pallet, sometimes only by the cargo container.)
sunshine_eggo
Happy Breffast!
That inverter is likely consuming 100-120W all the time, so > 2.4kWh/day - more than a typical residential fridge. Assume about 4kWh/day between inverter and fridge, and you don't have enough PV to consistently charge charge to full as once you've replaced all the Ah you've used that day, you need to supply about 15% more due to the inefficiency of lead charging.
80-100A of MPPT output and 4000-6000W of PV, and your situation will be transformed.
80-100A of MPPT output and 4000-6000W of PV, and your situation will be transformed.
Obviously your supply is inadequate for your loads. I have no idea if your storage (Batteries) is appropriate for your loads but it is also obvious that the PV you have is not going to charge them properly. Your inverter sounds like it handles running and startup at the moment but is constrained by inadequate solar.
So first things first is to get a handle on your predicted daily loads. Once you have that you can calculate the solar panels you will need to cover that plus leeway to cover days that are lower production.
Ex: You calculate your daily needs at 10kWh. You have an average of 5 hours of PV production in March. 10kWh/5h=2000W worth of panels. However there is loss between panels and loads to consider so as a rule of thumb say you need 25% percent more or 2500w. you would like to cover some bad weather production days so double that to 5kW.
W=VA If you have 5kW of panels charging 48vDC batteries 5000w/50v= 100a
So in this example you know that a 100a SCC is needed to make full use of panels. So long as your batteries can safely accept a 100a charging rate that part is taken care of. Capacity of the battereis for a 10kWh day is the next consideration. During solar production days you only need enough to cover sun down to sun up time. However in bad weather you need to cover the entire day of 10kWh. Amp-hour of battery times volts gives you watt-hours. Thus a days need of 10,000wh/50v=200ah.
Plug in your own situation to start planning things you need.
seneysolar
Solar Addict
Honestly, living full time off grid, I would be tempted to buy a pallet of panels even if you can only mount and hook up half of them now. This is where you will find the best price and you will eventually use them. Look around for sales, even on ebay there are some companies just dumping 330-390W panels less than $100 each in pallet quantity. Example- I picked up a brand-new pallet of 365W Hyundai for $2800 delivered. Partial pallets are also available, just not as common. Most companies have a min order, and the price is higher if they have to split a pallet. I don't recommend used panels, but that's just me.
Your current inverter and battery set-up should serve you well. Right now your money is best spent on solar. To be functional, you need to target 100A of PV charging. So, focus on getting 1 complete array up to get you there. Victron and Midnite, are my go-to reliable brands for this size charge controller. The EG4 one mentioned above hasn't been out long enough to compare, but is well regarded by those that use it, High voc limit is attractive and the price is right.
In your case, as @sunshine_eggo mentioned above, a single functioning 100A PV charging source will be life changing!
Your current inverter and battery set-up should serve you well. Right now your money is best spent on solar. To be functional, you need to target 100A of PV charging. So, focus on getting 1 complete array up to get you there. Victron and Midnite, are my go-to reliable brands for this size charge controller. The EG4 one mentioned above hasn't been out long enough to compare, but is well regarded by those that use it, High voc limit is attractive and the price is right.
In your case, as @sunshine_eggo mentioned above, a single functioning 100A PV charging source will be life changing!
ShaneB
New Member
Thank you, everyone. I went ahead and ordered 16ea of the 400w bifacial panels to get a higher supply. Best place to start, I may even go more later.
sunshine_eggo
Happy Breffast!
What are the specs on the panels?
Have you decided on an MPPT?
FWIW, you can leave your existing array in place. There is no harm in having two MPPT on the same battery bank.
ShaneB
New Member
Hyperion
Wattage:400W
VOC:37.07
VISC:13.79A
Cell Type:Bifacial | Mono PERC
Haven't decided on an mppt yet but still have time to research and check around.
And that is good to know about leaving existing array in place. Will give new panels a helping hand.
sunshine_eggo
Happy Breffast!
On a Victron 250 controller, you might be able to get 6 of those in series, but with 16 panels on order, a 4S4P Array would be just right.
400W * 16 = 6400W
You need at least 100A to capture what that array can produce most of the time.
400W * 16 = 6400W
You need at least 100A to capture what that array can produce most of the time.
seneysolar
Solar Addict
How far away will the array be from the charge controller?
With a 4S4P, that will be 50A making the run to the charge controller. Would need 6/2-UF. Keep it close, the wire cost will add up! Example: 130ft would be around $500
Not sure if it would be worth kicking this idea around? - making 2 runs with 10/2, Then using 2 less expensive charge controllers? Benefit would be redundancy and capture the extra 1600W - 30A potential. Costs might wash out or be close. 2 of those EG4 charge controllers sure would be easy, one string of 8 on each and the wire savings and no combiner box will pay the difference vs the single 250/100 Victron.
With a 4S4P, that will be 50A making the run to the charge controller. Would need 6/2-UF. Keep it close, the wire cost will add up! Example: 130ft would be around $500
Not sure if it would be worth kicking this idea around? - making 2 runs with 10/2, Then using 2 less expensive charge controllers? Benefit would be redundancy and capture the extra 1600W - 30A potential. Costs might wash out or be close. 2 of those EG4 charge controllers sure would be easy, one string of 8 on each and the wire savings and no combiner box will pay the difference vs the single 250/100 Victron.
