question

bmac avatar image
bmac asked

EasySolar limiting charge from solar

EasySolar 3000 48v

Unit (mppt?) is limiting charge. looked at previous questions on here but didn't find resolution.

as per attached video.

won't get batteries to absorption voltage 58.8V. appears to target voltages other than what it should.

batteries 8 trojan fla 6v

on full sun days it still won't get to voltage yet i can see on those days it has put back in what i use. problem is on the non sunny days i don't make headway to putting charge back in. some days it can hold back over 200w input from the 1kw solar panels which is a fair chunk missing in daily use.

attached video is with vacuum cleaner starting up.

EasySolar All-in-One
videocompressor-20200610210458587.mp4 (586.5 KiB)
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5 Answers
bmac avatar image
bmac answered ·

bump..............

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Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @bmac

What charge settings are you using in the MPPT? and in what charge state is it when you recorded this?

also: are you using DVCC? if so, what are the charge settings of the inverter?

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bmac avatar image
bmac answered ·

Hi Daniel,

Sorry, got caught up with a bunch other prirorities since i saw your post.


I've run DVCC on and DVCC off, it will do it in either scenario.

Settings are :

absorption 58.8v

float 54.0v

max absorption time 4h

not running any assistants, not running AES. Very simple off grid setup.

charge state when this happens - under DVCC can't see the charge state, DVCC off charge state is bulk.

charge algorithm on multiplus is "adaptive+battery safe".

Charging/topping up batteries using genny works fine (except twice saw it drawing from batteries and genny at the same time when the genny would normally supply the load on its own).








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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ commented ·

Hi @bmac

How do you know that it's holding back?


is the system online on VRM?

are you using ESS?

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lklmenterprises avatar image lklmenterprises commented ·

Probably need to know more details about how you have your 1000w Panels configured. For instance there is the potential if you have them all in Parallel the Charge current is being limited by the MPPT and you won't see it all (I doubt that based on only seeing 470w coming in though...so more like the MPPT does not see the Need to provide any more than that.)


Can you disconnect the Batteries after making sure they are 100% charged via the Genny (via a DC charger? or input into the Multi?)

Let them sit for a bit without input or output - then measure the Voltage with a multi-meter. Let us know what that comes to, it may determine a little of what the MPPT is doing.

Also when you set up the MPPT - what settings did you set in VeConnect?

Do you also have a Shunt installed? if so it MUST be the Last thing connected to the Negative terminal(s) or else the GX will not measure the DC power usage correctly.

Further to this - can you include an image or diagram of how you have your 6V cells setup - presumably 2S4P - and what is their capacity. It may be important to see how the Parallel setup is - for instance making sure the correct paths are implemented, as it is often done incorrectly where it ends up that only a Single Cell (or more in series) gets all the Charge and Discharge, due to being a straight connect to the Inverter without appropriate distribution via a busbar, etc.

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Alexandra avatar image
Alexandra answered ·

The only other possibility is that the max current on the charge controller has been set down.


screenshot-20200710-145523-comvictronenergyvictron.jpg (282.3 KiB)
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bmac avatar image
bmac answered ·

Hi all,

Thanks for the responses. There is normally an email alert to say the thread was updated but there has not been any so hadn't checked back on the thread.

Just to go over the setup again :

48v easysolar 3K

4 x 250w panels (2Sx2P)

batteries : 8 trojan 6v FLA in series T105-RE, 220 A/H @C20

Offgrid (no grid connection at all)

Use generator to cover any large loads and top batteries up

Current limit of MPPT - 30A

Absorption : 58.8V, Float : 54.0V as per Trojan

Max Absorption Time : 4H

Not on VRM, not using ESS

No internet at property other than via mobile phone


Loads on System :

Fridge - 400w/h a day

LED downlights - Say 60 w/h day

Laptop - Say 100 w/h day

Any large loads such as tools or microwave etc i run the genny

Main power consumption is the inverter

All water heating is gas and room heating by wood


Why do i think it is limiting charge?

·as per the video, charger in bulk stage, turn on load and power via MPPT increases

·batteries not getting to float, often not getting to absorption but the panels are able to generate the power (as evidenced by connecting a large load and turning on to see input from the MPPT increase)

·turn on generator and charging goes to correct absorption & float voltages

·due to working from home i just bought a TV couple of weeks ago to use as a second monitor and my power generation has jumped up (so the same result as when i turn on the load in the video but over a more protracted timeframe)


What have i tried :

Was using DVCC, but have turned off - no difference

Checked all battery connections (disconnect, wire brush terminals/connectors, add vaseline, reconnect)

Checked battery voltages after left sitting for few hours disconnected, all showing fully charged, no variance in voltages

Checked software settings same between multi and mppt


Thoughts :

  • Don't believe it is to do with panel alignment/orientation etc as connecting a load shows they are producing more than what is being let through to charge the batteries whilst in BULK charging state
  • The multiplus hits the right voltages when using the generator so not likely to be issue with wiring and voltages seen by Easysolar
  • Can the MPPT see different resistance/response from the batteries to accept charge than the multi?








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klim8skeptic avatar image klim8skeptic ♦ commented ·

I suspect the Vmp of your 2 series panels is to low.

Please confirm panel specs, and ambient / panel temps.

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bmac avatar image bmac klim8skeptic ♦ commented ·

had similar thoughts. i can see on the ccgx they are sending around 60-61v to the easysolar.

will check the panels tomorrow and the ccgx reading.

in my mind discarded the series voltage being the prob as the power is being limited so the panels can produce.

specs on the mppt also say the V shouldn't be an issue :


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1596100675701.png (48.0 KiB)
bmac avatar image bmac bmac commented ·

here's photo i took of one of the panels specs. when i looked on the CCGX it showed around 62v so in my mind this discounts the array voltage. If it does this "throttling" when batteries are at 55v that's around 7v difference, well within spec.


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1597098502451.png (735.6 KiB)
klim8skeptic avatar image klim8skeptic ♦ bmac commented ·

Depending on panel temp, Vmp/Voc is going to be lower than STC ratings.

As per IV Curve, once mppt voltage goes above the panel Vmp@temp, current available take a dive.

Do the maths for your panel@temp, add a bit of voltage drop for dc cabling, and possibly some derating due to panel aging.

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csp-255p-iv.jpg (83.4 KiB)
cs6p-255p-data.jpg (55.2 KiB)
bmac avatar image bmac klim8skeptic ♦ commented ·

Thanks for the graphs. I had looked at those previously when trying to understand the issue.

Maybe i've got it back the front but the ambient air temp during sunlight hours here at the moment is around 3-12 degrees celcius - would that not make the Vmp higher? I've taken this to be the reason why the solar voltage showing on the CCGX to be higher than the STC rating @25 degrees C on the panels.

If the CCGX is reading solar input at around 62V i'm not clear what voltage drop calculation needs to be done & why if i can see the value at the CCGX is 62V whilst it is throttling (the I V curve shows still a way to go at that V & temp), could understand the need if i was taking measurements at the solar panels. Solar only has to be 1V higher than battery V to charge according to MPPT specs - from what i can see it's got heaps of head room, i've seen it do the same thing with the battery around 51v. That's 10v headroom.

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