I am hoping to get some opinions because I am debating whether or not to save up the money and get a better MPPT charge controller like a Victron for instance. The issue I am facing is that I dont think my current set up is optimizing my solar as efficiently as it should. I have 5x100 watt solar panels. I have a 40 amp Makeskyblue MPPT and a cheap 30 amp PWM charge controller. I set up the solar panels the other day in a 2S2P to the MPPT and the extra solar panel hooked to the PWM. I noticed at peak sunlight I was getting a max of 190 watts going into the batteries from the MPPT. So yesterday I set up the solar panels in a 3S configuration to the MPPT with the 2 extra solar panels in parallel to the PWM. I noticed I was getting 195 watts going to the batteries from the MPPT. I feel like I should be getting about 220-250 watts atleast, so I started thinking maybe this MPPT is just a cheap piece of junk and I should probably get a Victron and maybe that would give me the 220-250 watts I am looking for. Also, I am wondering why when I had my panels in a 2S2P setup I got the same amount of power as a 3S setup. I would think the extra solar panel would have produced more power but its like it was never even there. Weird...anyways thanks in advance.
Do I need a better MPPT?
- Thread starter PsXtreme
- Start date
MisterSandals
Participation Medalist
That is good sleuthing. I wonder if you have a bad panel in the mix? Have you checked the individual volts and amps from each panel with a digital meter?
While i am a super fanboy of Victron, my gut feel is that your charge controllers are not to blame because of their quality. Maybe a current limit setting on the MPPT?
195W / 12.8V = ~15A do you see 15A set anywhere?
Check your individual panels and let us know what you find.
Yeah I measured the voltage at each panel which was between 18-19 volts first thing in the morning. The sun was just coming up and not on the panels yet so considering I was getting that high of a voltage I figure the panels are fine. Also, on this MPPT the only settings I have are to set the max charge voltage which I have set to 14.4 volts, float charge which I have set to 14.2, and then the type of battery which I have set to 01 for lithium phosphate. The only other 2 settings are for the load which I dont use. I could have charge limiting on this charge controller, I didnt think of that. I just have no way to know if thats the issue or not.
MisterSandals
Participation Medalist
If you are only measuring volts of the panels, you are only measuring a small part of the energy. You need an amps number also to have any meaning about what the panels are producing.
Just figured I would update on my situation. So yesterday it rained all morning and around 2pm (which is peak time for me) the sun came out and I got 271 watts to the batteries from 300 watts of solar panels. The clouds kept coming in but every time the sun was fully out I got to the 270's pretty easily. So I think my issue with the power loss is heat related because on a hot sunny day the panels have the sun beating on them and yesterday they were cooled by the rain all morning and preformed as I would expect them to. So I am going to build a new wood structure that leaves the back open for air to hit the panels. Right now my platform has a piece of plywood going across that I screwed the panels flat down onto. I didnt realize heat would effect solar panels that much but it was a lesson learned. Thanks guys for all of your help. Now onto building the new structure. I might take pictures and show you guys after its done in another thread.
pollenface
Solar Wizard
I have 300w to a PWM and 750w to an MPPT. When both are running together with the same charging parameters the MPPT seems lazy. Once I isolate the 300watter on the PWM, the MPPT cranks right up.
It might be worth checking the bypass diodes in your panel too with a multimeter. I once had a dead one which caused a few dramas during shading.
It might be worth checking the bypass diodes in your panel too with a multimeter. I once had a dead one which caused a few dramas during shading.
peterwareing
New Member
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- Dec 4, 2019
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This may not help but in the lithium setting the float voltage gets overridden and shows the same as CC/CV but I believe the CF is just not used. The manual is badly worded. The advice I got was to input the settings and leave on PB.
The amps cannot be set in the parameters it will just try to belt out the rating of the MPPT. At least that's for V119.
The amps cannot be set in the parameters it will just try to belt out the rating of the MPPT. At least that's for V119.
peterwareing
New Member
- Joined
- Dec 4, 2019
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- 23
The use of PB was advised because I have grid tie inverter 24/24 so when in float power goes direct to inverter not via batteries with input/output losses (or so I was told)
I am working on a mod for the makeSkyBlue CC.. their mppt is lacking, to be polite and say the least..u can see my work here--
Warpspeed
Solar Wizard
What I suggest you do is measure the no load voltage of each panel, and also the short circuit current of each panel.
In a clear blue sky it should come pretty close to the figures on the rating plate.
Next, hook it all up to your solar controller and measure the voltage coming direct from the solar panels. With a battery at a low state of charge, the solar controller should be trying to find the power peak, and the solar panel voltage should be very close to the maximum power voltage shown on the rating plate.
If the controller is working properly the solar panel voltage should remain pretty constant regardless of sky conditions, until the battery is fully charged. Only then should the solar controller throttle back the current going into the battery, allowing the solar panel voltage to rise well above the maximum power voltage.
In a clear blue sky it should come pretty close to the figures on the rating plate.
Next, hook it all up to your solar controller and measure the voltage coming direct from the solar panels. With a battery at a low state of charge, the solar controller should be trying to find the power peak, and the solar panel voltage should be very close to the maximum power voltage shown on the rating plate.
If the controller is working properly the solar panel voltage should remain pretty constant regardless of sky conditions, until the battery is fully charged. Only then should the solar controller throttle back the current going into the battery, allowing the solar panel voltage to rise well above the maximum power voltage.
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