Thought I had enough power

[OleMan2765]

Bought two 6500w MPP 6548 inverters. 12 TrinaSolar 330W panels, and three 48v BigBatteries each 103Ah.

Original plan was to power two campers off grid, One 50A the other 30A.

Was told this system would be enough.

Problem I have run into is lost power to the 30A camper, which is the only one connected now. (It is only using one of the inverters, as it is connected to L2).

Have monitored battery level, and after running the Class C A/C over night, and next morning Victron shunt showed 97% left.
Thought I had it made.
But about 6 hours later, with good Florida sun, power cut off. Batteries went down to cutoff setting of 44V. Had good sun angle, and not sure what's up.

Each string of three panels put out about 110vdc to the combiner box. But the inverter only registers 90vdc or so. Not sure why, as I have good quality wires.

Anybody else have a similar system, and have any problems?

Internet reviews only have praise for the system. I think I have something good, but not too sure now.

 

[Supervstech]

Well… what are you trying to run on the 5kWh of battery? Or, do you have two 103Ah batteries?

 

[Supervstech]

Those two inverters can handle 4 times the solar you currently have, so you are far from a fully charged system. If you are running Hvac, and much else, you can easily outpace the solar and drain the batteries down.

 

[OzSolar]

How many watts is the array producing according to your charge controller?

 

[Ampster]

Was told this system would be enough.

Without numbers it was enough, until it wasn't.

 

[acdoctor]

Not sure how you came up with what you had but.
You have 15 kWh total battery capacity of which you don’t really want to completely cycle. 80% would be best but, you lack the solar capacity to fully recover more than about 50% daily while consuming at about the same rate as the battery consumption to 50%. Sometimes commercial Lpf batteries are not fully balanced and not capable of full capacity.
You can produce about 20 kWh from the 12 panels angled correctly and in a location that allows sun exposure for about 150 deg. of sky with no shading.
On a cold windy day with no haze you might get 24 kWh, that’s 1000 watts per hour for 24 hours. Or 8.3 amps continuous without calculating efficiency losses.
My growatt consumption is 1.5 kWh per day. Yours are bigger and 2 of them so, 3 to 5 kWh per day. Plus conversion efficiency from battery to line voltage.
For the sake of argument let’s say usable protection is 16 kWh daily. The bulk of that comes from the top 90 deg of sky, or about 6 hours. If your 15 kWh battery is 50% depleted you need 7.5 kWh to recover it during production hours. So the most you could consume during the day time is 8.5 kWh. 8.5 kWh/ 12 hours is 700 watts continuous consumption during the day. And 7.5 kWh/ 12 hours is 625 watts continuous consumption during the night.

Factory A/Cs consume more than discussed above. During the hot the compressor won’t cycle. A 13500 btu running wattage is about 1250 or 1.25 kWh and could consume as much as 30 kWh during a 24 hour day if the compressor ran continuously. The 5th wheel I used to have had 2 A/Cs if I only ran 1 which is all my generator would handle it never cycled until late at night.

Factory RVs are energy hungry. They have thin walls, single glass windows, poorly sealed, and low efficiency appliances. If you are running a absorption refrigerator on electricity don’t.

 

[boondox]

Without numbers it was enough, until it wasn't.

This is exactly why a proper energy audit is the basis of a successful system. The folks that told you it would be enough were just guessing. Before you decide what to do, conduct a thorough energy audit. Then your system can be re-designed to suit.

 

[timselectric]

Sounds like everything is working as designed.
Just a bad design.

 

[OleMan2765]

Well… what are you trying to run on the 5kWh of battery? Or, do you have two 103Ah batteries?

Have three batteries.
Have to dig up my numbers from when I calculated total loads. Think it was less that 12K watts.

 

[OleMan2765]

Sounds like everything is working as designed.
Just a bad design.

Ouch

 

[OleMan2765]

Those two inverters can handle 4 times the solar you currently have, so you are far from a fully charged system. If you are running Hvac, and much else, you can easily outpace the solar and drain the batteries down.

Only had room for the 12 panels on my trailer. Thought about getting 8 more to mount on my smaller trailer.
Everything is mounted on trailers.

 

[timselectric]

You have to produce more power than you use, if you don't want to run out. Not sure if you have enough storage, to make it through the night. And definitely don't have enough solar.

 

[OzSolar]

Have monitored battery level, and after running the Class C A/C over night, and next morning Victron shunt showed 97% left.
Thought I had it made.
But about 6 hours later, with good Florida sun, power cut off. Batteries went down to cutoff setting of 44V. Had good sun angle, and not sure what's up.

So you you ran the AC overnight but only lost 3%? But then 6 hours later with almost 4KW of solar you hit the LVD setting. Something is not adding up. How long have you had this set up? Maiden voyage? I suspect some set up issues at this point.

 

[Will Prowse]

Bought two 6500w MPP 6548 inverters. 12 TrinaSolar 330W panels, and three 48v BigBatteries each 103Ah.

Original plan was to power two campers off grid, One 50A the other 30A.

Was told this system would be enough.

Problem I have run into is lost power to the 30A camper, which is the only one connected now. (It is only using one of the inverters, as it is connected to L2).

Have monitored battery level, and after running the Class C A/C over night, and next morning Victron shunt showed 97% left.
Thought I had it made.
But about 6 hours later, with good Florida sun, power cut off. Batteries went down to cutoff setting of 44V. Had good sun angle, and not sure what's up.

Each string of three panels put out about 110vdc to the combiner box. But the inverter only registers 90vdc or so. Not sure why, as I have good quality wires.

Anybody else have a similar system, and have any problems?

Internet reviews only have praise for the system. I think I have something good, but not too sure now.

Who told you that this would be enough? Was it a solar equipment company?

 

[OleMan2765]

Who told you that this would be enough? Was it a solar equipment company?

Yes. In fact, you did a video for them. SolarKits

 

[OleMan2765]

So you you ran the AC overnight but only lost 3%? But then 6 hours later with almost 4KW of solar you hit the LVD setting. Something is not adding up. How long have you had this set up? Maiden voyage? I suspect some set up issues at this point.

Had it set up for six weeks. And, yes, maiden voyage to test out system.
One of the two MPP's gave me a problem with stem 28 at first. Then got it to work.

 

[OzSolar]

Had it set up for six weeks. And, yes, maiden voyage to test out system.
One of the two MPP's gave me a problem with stem 28 at first. Then got it to work.

So what was different about the maiden voyage then the prior 6 weeks?

 

[OleMan2765]

So what was different about the maiden voyage then the prior 6 weeks?

No load attached. Wire is crazy expensive now. Was looking at stats of the inverters.

 

[OleMan2765]

How many watts is the array producing according to your charge controller?

Sun is almost set here. I will get you numbers tomorrow.

 

[Bobert]

Check for un expected loads. If you have an electric element in your water heater and an absorption style fridge could really add to your loads. I’m not sure how your system is going to work to run ac in 2 rvs. I calculated that I would need that much to run a single ac in my 38’ 30 amp camper in sunny weather. Those rooftop ac units are hungry especially in the heat of the day.