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I'm not an expert, but I have stayed in a Holiday Inn a few times.

It would appear that it was either much sunnier or you were parked outdoors longer '3 days ago' than any other day. You yielded 260Wh in 4 hours, whereas 'yesterday' you yielded just a little more but it took almost twice as long. I'm not sure what your weather or parking situation was like over those three days, but I would assume that if you have 600W of total yield, that if you were in direct sunlight you should see a higher Pmax than 178W.

There are several experts on here who will be able to provide you much better information and correct any of the mistakes in my thought process.
 

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Discussion Starter #4 (Edited)
I'm not an expert, but I have stayed in a Holiday Inn a few times.

It would appear that it was either much sunnier or you were parked outdoors longer '3 days ago' than any other day. You yielded 260Wh in 4 hours, whereas 'yesterday' you yielded just a little more but it took almost twice as long. I'm not sure what your weather or parking situation was like over those three days, but I would assume that if you have 600W of total yield, that if you were in direct sunlight you should see a higher Pmax than 178W.

There are several experts on here who will be able to provide you much better information and correct any of the mistakes in my thought process.
Yes weather has changed.

I hooked up the solar for the first time on Tuesday so I don't know how it has 4 days of history including today. I think I got it hooked up at about 2:30. Full sun that day. I did plug into shore power at some point on Wednesday. Cloudy and rain yesterday due to Harvey.

Edit:
I'm thinking that I disconnected the controller on the first day so that is why it is split into two days. So that is 600Wh over two days.

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Hi Josh,

Nice that it gives such a detailed report.

If you look at "yesterday" (day 1), I think it is saying that you generated a total of 280 watt-hours for the day. Watt-hours are an amount of energy, so if your PV panel produces 100 watts output for 2 hours, that's 200 watt-hours of energy. You can convert watt-hours to amp-hours by dividing by 12 volts, so 280 watt-hours is about 280/12 =23 amp-hrs into your batteries on that day.

The 116 watts says the max power your PV panels delivered at some instant during "Yesterday" was 116 watts.
The 37.5 volts is the maximum voltage your PV panel produced at some instant during the day -- your charge controller converts this to something in the 12 to 15 volt range to charge the battery.

It looks like the 9.25 is saying that you were charging the battery for 9.25 hrs on that day. I guess it divides this into bulk charge time, absorb charge time, and probably float charge time (I can't see the last one on the picture).

If it seems like the watt-hour numbers are low on a given day, it can be for two reasons: 1) its cloudy or you are in the shade, so not much sun on the panels; or 2) your battery may already be nearly charged at the start of the day and it gets to full charge early in the day and can't take anymore charge even though the PV panels could provide it.

The top 600 watt-hours is the total energy produced for the 4 days -- about 50 amp-hrs.

People get confused over watts and watt-hrs. Watts are a rate of producing energy -- in the fluid world it would be like gallons per minute -- its the instantaneous RATE at which your panel is producing energy. Watt-hrs are a quantity of energy -- in the fluid world its like gallons.
So, if a panel produces a steady 100 watts for 4 hours straight, it has produced a total quantity of energy of 400 watt-hrs.
You see the phrase watts per hour sometimes -- this makes no physical sense as watts are already a rate of producing energy. What they probably meant to say is watt-hrs per hour.

It would be nice to see one of your controller reports for an actual trip or two -- just to see how much we actually get our of our solar in your typical use.

Gary
 

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Victron makes some neat stuff.
 

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Very interesting to see that. I have the same color teller and installer to install with the Bluetooth dongle. Just so I and others don't have to go look for it can you post your solar setup so I can put the figures to a panel size/wattage etc? I will have 2x100 watt renogy panels so I'm curious.

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Discussion Starter #8 (Edited)
Hi Josh,

Nice that it gives such a detailed report.

If you look at "yesterday" (day 1), I think it is saying that you generated a total of 280 watt-hours for the day. Watt-hours are an amount of energy, so if your PV panel produces 100 watts output for 2 hours, that's 200 watt-hours of energy. You can convert watt-hours to amp-hours by dividing by 12 volts, so 280 watt-hours is about 280/12 =23 amp-hrs into your batteries on that day.

The 116 watts says the max power your PV panels delivered at some instant during "Yesterday" was 116 watts.
The 37.5 volts is the maximum voltage your PV panel produced at some instant during the day -- your charge controller converts this to something in the 12 to 15 volt range to charge the battery.

It looks like the 9.25 is saying that you were charging the battery for 9.25 hrs on that day. I guess it divides this into bulk charge time, absorb charge time, and probably float charge time (I can't see the last one on the picture).

If it seems like the watt-hour numbers are low on a given day, it can be for two reasons: 1) its cloudy or you are in the shade, so not much sun on the panels; or 2) your battery may already be nearly charged at the start of the day and it gets to full charge early in the day and can't take anymore charge even though the PV panels could provide it.

The top 600 watt-hours is the total energy produced for the 4 days -- about 50 amp-hrs.

People get confused over watts and watt-hrs. Watts are a rate of producing energy -- in the fluid world it would be like gallons per minute -- its the instantaneous RATE at which your panel is producing energy. Watt-hrs are a quantity of energy -- in the fluid world its like gallons.
So, if a panel produces a steady 100 watts for 4 hours straight, it has produced a total quantity of energy of 400 watt-hrs.
You see the phrase watts per hour sometimes -- this makes no physical sense as watts are already a rate of producing energy. What they probably meant to say is watt-hrs per hour.

It would be nice to see one of your controller reports for an actual trip or two -- just to see how much we actually get our of our solar in your typical use.

Gary
Wow. Thanks Gary exactly what I was looking for. That makes sense as well because my batteries should be full. The only thing running is my fridge and a little phantom drain from the USB plugs.

My fridge temp was set at the halfway mark so it looks like that along with the Phantom draw is roughly 25A a day.

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Discussion Starter #9 (Edited)
Very interesting to see that. I have the same color teller and installer to install with the Bluetooth dongle. Just so I and others don't have to go look for it can you post your solar setup so I can put the figures to a panel size/wattage etc? I will have 2x100 watt renogy panels so I'm curious.

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I have two 100 watt Renogy Eclipse panels wired in a series with a Victron 75/15 mppt controller charging two Vmax slr125 batteries wired in parallel.

Today I had changed the absorption charge voltage to 14.8 as per vmax's recommendation. Anyone know why my charger never changes from bulk?

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Discussion Starter #10 (Edited)
Update:

So with Harvey over us yesterday I think my panels were producing 7-14W most of the day with a peak of 104W. It took 12 hours to yeild a total of 240wh or 20ah.

I thought that Gary's response above answered all my questions until I plugged in my van to shore power last night. My charger has 3 lights, red, yellow, green. If the red light is illuminated it means approximately the batteries are at 21-40%, yellow: 61-80%, green: 91-full. When the charger came online, the red light came on. I went inside and came out 50 minutes later and it was yellow. I went back out 2hrs later and it was green. Now here's where I'm struggling. If my batteries were full from the start and the solar yielded 50ah each day and yesterday yielded 20ah, my batteries should have pretty much been full. The only thing running is my fridge. No way should it have been down to 21-40%.

The first day I hooked up my batteries(Monday) the solar was not connected. I connected the batteries to the charger and within an hour the light was green on the charger so I assumed they must have come almost fully charged. Also I think I left it plugged in Monday night and unplugged at 6:45am Tuesday. So atleast 8hrs on the charger. My assumption is that I've been dealing with fully charged batteries and Gary's assumptions above would be correct if that is the case. But if that is the case how did my batteries get down so low? Also if they are that low, it seems that it would take longer than 3 hrs to charge. I was also confused as to why my solar charger never changed from bulk mode to absorption then to float if my batteries were full.

I left the shore power connected last night and it is still connected now just to make sure it gets a full charge. In the picture below you can see that when the solar started this morning, it was in bulk mode for 1hr20min, absorption 17min, and 11min in float. So it appears that now the batteries are full. Last night I also removed all the fuses from my dc loads so nothing is connected right now.

You can also see that on the first day it did go into absorption mode for 24 minutes. Just a reminder, I think days 3 and 4 on the history are the same day just after it was disconnected and reconnected.

Do ya'll think my batteries weren't full originally or is there something draining my batteries that I don't know about? Is it possible that the lights on my shore power charger aren't correct? I guess I'm going to have to buy the victron battery monitor.





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I'm no expert, but here are my thoughts....

You have the following:

200w of solar
Victron 75/15 MPPT
250AH of AGM Batteries
tripplite aps1250 inverter/charger with 30amp charger
I'm guessing a Virtifrigo C62IBD4-F (draws 3.38 amps)

Your fridge uses 3.38 amps, so in 24 hours that's 81 amps at 100% duty cycle, which this probably isn't at. If we say 50% duty cycle, that's still 40 amps. If you are taking in 260Wh for the entire day that's only 20 amps for the entire day. So you are operating at a net loss of 20 amps at a 50% duty cycle for the fridge off the battery. That is assuming you are running the battery of DC. If you are plugged into AC with the fridge, it takes 5.3 amps then round up to 6 amps to factor in the efficiency of the inverter, now we are at 144 amps at 100% duty cycle or 72amps at 50% for the day. That would be a net loss of 52amps. However I assume you have a DC fridge.

Now when you plug in your shore power with a 30 amp charger, you are getting 30 amps PER HOUR to the batteries. So it can charge MUCH faster.

Solar is great, but with a small setup on a cloudy day (or even a big setup on a cloudy day), you can't match the power from a dedicated charger or alternator with a relay.

Your batteries were most likely NOT fully charged when you go them as AGMs will self discharge. I'd do some more testing now that you've fully charged the battery.
 
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Discussion Starter #12
I'm no expert, but here are my thoughts....

You have the following:

200w of solar
Victron 75/15 MPPT
250AH of AGM Batteries
tripplite aps1250 inverter/charger with 30amp charger
I'm guessing a Virtifrigo C62IBD4-F (draws 3.38 amps)

Your fridge uses 3.38 amps, so in 24 hours that's 81 amps at 100% duty cycle, which this probably isn't at. If we say 50% duty cycle, that's still 40 amps. If you are taking in 260Wh for the entire day that's only 20 amps for the entire day. So you are operating at a net loss of 20 amps at a 50% duty cycle on the battery.

Now when you plug in your shore power with a 30 amp charger, you are getting 30 amps PER HOUR to the batteries. So it can charge MUCH faster.

Solar is great, but with a small setup on a cloudy day (or even a big setup on a cloudy day), you can't match the power from a dedicated charger or alternator with a relay.
Thanks for the thoughts nebulight. Without people here helping I would have no clue.

So two possibilities:

As Gary said, I'm only taking in 20ah in a day because that's all the batteries can hold because they're full OR I'm only taking in 20ah a day because something is wrong. If it is the latter, how would I begin to figure out the problem?



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Well you have said it's been very cloudy and that you've only been getting 14w when looking at the live data. I'd do some more tests during sunny days when you can get 150-170 watts. My guess is that you'll be fine once the sun comes out. Also, I couldn't find it in your build thread, but did you wire your panels in series or parallel. They should be wired in parallel to help reduce the negative effects of shaded panels. And what gauge cable did you use going for the panels to the Victron?

EDIT: I see that you wired in series based off your screenshots. I don't think this is your problem right now, but it's always best on a small installation (that can fit on the roof of a van) to run the panels in parallel. Basically if you have shading on one panel, but the other is in the sun, the entire array output drops as if both panels are shaded. The main reason people don't run in parallel for larger installs is the voltage drop and the need for thicker cables. However since in vans we have short runs, voltage drop isn't an issue, and we aren't running high current through the cables that we would need super thick cables.
 

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Discussion Starter #14
Well you have said it's been very cloudy and that you've only been getting 14w when looking at the live data. I'd do some more tests during sunny days when you can get 150-170 watts. My guess is that you'll be fine once the sun comes out. Also, I couldn't find it in your build thread, but did you wire your panels in series or parallel. They should be wired in parallel to help reduce the negative effects of shaded panels. And what gauge cable did you use going for the panels to the Victron?

EDIT: I see that you wired in series based off your screenshots. I don't think this is your problem right now, but it's always best on a small installation (that can fit on the roof of a van) to run the panels in parallel. Basically if you have shading on one panel, but the other is in the sun, the entire array output drops as if both panels are shaded. The main reason people don't run in parallel for larger installs is the voltage drop and the need for thicker cables. However since in vans we have short runs, voltage drop isn't an issue, and we aren't running high current through the cables that we would need super thick cables.
Thanks. I wired in series because most everything I read said to wire in series with an mppt controller. Also if I wire with parallel the circuit wizard says I need 6awg wire (25' round-trip run). The biggest I can buy from Renogy already made with their ends is 10 guage. And 10 guage is the biggest that will fit in that victron controller.

Any ideas?

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Again, I don't think your wiring is what's causing your low input from solar as you said it's been very cloudy in your area, and that is probably what is causing your issues.

Now for parallel vs series, just because you have an MPPT controller does not mean you MUST wire in series it means that you CAN wire in series. In your example with a 100w panel, your panel can max do 17.7v (vmp) at 100 w, so that will give you 5.7 amps. Now with two of them in series, what that does is increase the voltage, but keeps the current (amps) the same. So when you have both panels in series, that will put in 35.4v into your MPPT at 5.7 amps. The MPPT controller can adjust the current and match the battery voltage to give you all that powering going into the battery (which is why the cost more than PWM). Now if you do two in parallel, you are keeping the voltage the same at 17.7, but now that you have two panels, you are doubling the current so now you are pushing through 10.7amps to the controller. Your controller can still handle that current and according to this chart, your 10awg can handle it too.

The reason a lot of people recommend series is if you had say 600 watts of panels, you'd be looking at a max current of 57 amps, so you'd need a much larger cable. However since you have a much smaller setup you'll be fine because remember that you solar panels will never be 100% efficient.
 
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Discussion Starter #16 (Edited)
Again, I don't think your wiring is what's causing your low input from solar as you said it's been very cloudy in your area, and that is probably what is causing your issues.

Now for parallel vs series, just because you have an MPPT controller does not mean you MUST wire in series it means that you CAN wire in series. In your example with a 100w panel, your panel can max do 17.7v (vmp) at 100 w, so that will give you 5.7 amps. Now with two of them in series, what that does is increase the voltage, but keeps the current (amps) the same. So when you have both panels in series, that will put in 35.4v into your MPPT at 5.7 amps. The MPPT controller can adjust the current and match the battery voltage to give you all that powering going into the battery (which is why the cost more than PWM). Now if you do two in parallel, you are keeping the voltage the same at 17.7, but now that you have two panels, you are doubling the current so now you are pushing through 10.7amps to the controller. Your controller can still handle that current and according to this chart, your 10awg can handle it too.

The reason a lot of people recommend series is if you had say 600 watts of panels, you'd be looking at a max current of 57 amps, so you'd need a much larger cable. However since you have a much smaller setup you'll be fine because remember that you solar panels will never be 100% efficient.
So are you saying my panels would charge my batteries twice as fast if they were in parallel because they'd be pushing 10.7 (double of 5.7 is 11.4 so I assume that was a type unless that isn't where you got that number)?
 

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Discussion Starter #17
Update:

So a friend came over and we spent some time going through all the numbers. Basically it appears that my batteries we never fully charged and that makes sense since my charger never went into absorption, then float. You're spot on nebulight. It looks like at the end of Tuesday my batteries low voltage showed 12.62 volts. I'm assuming that was just before sunrise? So I think that'd be somewhere around 66% (166ah). The next day my panels yielded 23ah. So assuming fridge and other stuff drew approximately 40ah, that means it's a net loss of approximately 20ah. So if that continues and I go down to 125ah which would be 50% battery life. My APS1250 shore power charger showed a red light so battery life of 21-40% but it's very possible its guage could have been off by 10% since it is just an approximate number. Also within 3 hours it showed a green light which was 90% - full. So that makes since if it was approximately 50% full. I'll guess that the APS1250 doesn't charge much over 14v (we measured it at 14.05v) so I'm not sure it will actually push enough to fill my batteries to 100% and that's why I saw my solar controller on bulk/absorption for about 1 hr at daylight this morning and then it began to float.
 

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Discussion Starter #18
So after spending more time reading, I can't really find a clear answer. But it looks like parallel and series would charge at about the same amount of time. The only advantage is that parallel does better if part of a panel is shaded. Can anyone give me your opinion?

I ordered the pieces to wire the panels in parallel. I'm sure I'll have them by the end of the week. I'll change to parallel wiring and see how it performs for a few weeks and compare the history between the two. I'm borderline on the wire sizing. I may have too much loss to continue using the 10AWG wire that I have. I'll use the 10AWG and see if it feels warm at all. If parallel requires moving to 8AWG wire I'll stick with series wiring. I don't want to change out wires again. I've already done it once and it's a pain.
 

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Josh your first paragraph is correct!
The 10 AGW will be fine. I use it.
In full sun on both panels there will be no difference due to rewiring. In partial shade the new wiring will produce more power. It is worth doing just for those times the van sits in a slightly shady spot.
 
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As RD said, you'll charge with the same amount of power and time, but it will work better with shaded scenarios.

Have you checked your charge profile on the victron? Are you sure you have the correct battery type selected and the correct charge profile setup in the victron?



Also since I'm asking, is your inverter/charger setup for charging AGM batteries on your inverter/charger? 14v seems a bit low for bulk charging AGM.
 
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