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Solar panel output low
#21
Also, does your controller have a remote battery voltage sensor?
Wondering about Wandering.
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#22
After thinking this over....
Well, here is what I believed.... that the solar panels/controller would drive thee load directly to the maximum extent possible. Battery would come into play only when the load exceeds the max the controller would deliver. So, the controller was not charging the battery...it was driving the load.

With that heavy a load ... shouldn’t those panels be putting out far far more than they did? Or rather, shouldn’t the controller have been delivering far far more directly to the load?



1989 Honeywell motorhome
Ford E350 chassis.  460 engine
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#23
I would think so, but I am not sure how Lifepo4 holds its voltage under load.

Surface voltage on LEad acid hass fooled many a person into thinking their batteries are more charged than they are in the early evening to find the mornig voltage to be much lower than hoped.

i do not know about Lifepo4 surface voltage retention. if they are being held at 13.8v by the solar, whether they can easily maintain that 13.8 under 120 amps of load.

The solar controller is only going to allow as much to pass ( upto the max available) to maintain that 13.8v setpoint.

I would think 120 amps of load would release the solar floodgates. It certainly would with lead acid batteries.

You said you have portable panels available, bust them out and see if the amperage through controller rises with their added available wattage If it does then it would indicate your dual 345 watters are underperforming. If it stays the same then it indicates that their wattage is not needed to maintain the 13.8v setpoint.

Check to see if any of those Lifepo4 cells is getting warmer than the others.

There is more than the price reason that Lifepo4 cells are not widely adopted.
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#24
Latest test...

    I hung 4 100w flex panels, tilted to the sun, kept them covered up.

Covered the two solar panels (2 345w) up top.

Batteries were at 13.8.   Battery monitor also showing 100% full.

Turned on the AC.    While I was watching I saw the volts drop to 13.4 rather quickly.

At 13.1 I turned off the AC.  Uncovered both the panels up top which are connected to the Morningstar, and the flex panels which are connected to the Victron.   


Turned the AC back on. Watching the charge controllers......

The 400w of flex panels were delivering 27 amps according to the Victron.
The 690w of fixed panels on the roof were delivering 15 amps according to the Morningstar 

I continued to lose amps from the battery.   I was at 78% when I uncovered the panels.  After 5 minutes I was at 74% .... still at 13.1 of course, because lifepo4 will hold that flat till it dips to about 20%.  

I think those panels up top (690w) are not functioning according to spec.   They are wired in parallel...BUT! it seems that both of them are behaving the same....(info from the previous test.) Cannot figure out why they would both be acting the same if there was any kind of damage to one. Plus, baffled how identical damage could have happened to both. There is no physical evidence of any damage. There must be something more basic that effects the entire system of both panels and the controller.....? The only things they have in common are the combiner box and the cable (6 gauge) coming down to a 60 amps circuit breaker. Then to the controller.

Or, the damage was systemic occurring to both from having the circuit breaker popped in the midday sun? Since they share the same cable down from the roof. But, does it even sound plausible that both panels would have been effected in exactly the same manner? How might I test that directly to prove or disprove that?

Btw...I moved the temp probe around each battery (pack of 3 cells). Found no variation in temperature after waiting several minutes each time. Balances are all showing green. The battery does not seem to be acting in a manner inconsistent with its spec.



1989 Honeywell motorhome
Ford E350 chassis.  460 engine
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#25
Perhaps the morningstar's amperage reading is wrong.

If all the loads are turned off, then the victron and Morningstar amperage readings should be the same or nearly so

if I were there I would put my clamp on ammeter over the cable from morningstar to battery to verify.
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#26
Is there any kind of thin, protective plastic skin on the face of the panels that should be removed?
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#27
Possibly!

A protective skin is common with the flexible panels but maybe yours came that way...it should be obvious because the plastic peel-off skin will probably have wrinkles in it by now...and sometimes they have a blue-ish tint.
Wondering about Wandering.
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#28
It is not the flexible panels that are seeming to deliver low amps.....it’s The fixed rigid panels up top.

Crawled up there this evening....no plastic protective covering.

I have not tested this system with all the loads off. But, tomorrow I will check with the ampmeter to see what is actually coming from the roof...that is...test each of the mc4 cables before they join the combiner box. That way I can either prove it is the panels or eliminate them as the issue.



1989 Honeywell motorhome
Ford E350 chassis.  460 engine
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#29
(09-21-2018, 08:01 PM)RoamingKat Wrote: It is not the flexible panels that are seeming to deliver low amps.....it’s The fixed rigid panels up top.

Yes, that is what I understood. Flexible panels normally have a removable plastic film applied. Your rigid panels on the roof may have come that way as well, is the reason I said, 'possibly'...
Wondering about Wandering.
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#30
Took the RV to the local solar installers.   
Unfortunately, the panels were putting out low amps.   Once they were off the roof the components were tested.  There was no physical damage...whatever happened, the internal electrical system was at fault.

We tried to think of a way to mount a tilting rack up top.   Something that could stand up to the rattle, rock n roll...no one could think of a way to do it.  (See the thread here on mounting solar panel).  

So, new panels go on today, using the same old way...ie: mounting brackets to the roof.   I have the awning panels that I can tilt to the sun, so I think I will have pretty much all the power I will need, and then some.     Henceforth, I will always cover the panels whenever I need to disconnect them from the mppt



1989 Honeywell motorhome
Ford E350 chassis.  460 engine
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