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timonen avatar image
timonen asked

Charging issues with SmartSolar 100/30

Hi!

I am debugging charging issues with my setup:

- SmartSolar 100/30

- single 345W panel (~10A at ~35V)

- 15 meters (45-50ft) of 10mm2 (8awg) cable between panel and charge controller.

- Lifepo4 battery with lifepo4 preset (soc 10-30%) and small lead acid backup battery only for making sure that the battery is not the problem.


Setup is located in a remote place, and therefore, trying to isolate the cause before bringging stuff back to home for possible replacement.


Problem is that charging works very very rarely. It ramps up (to 200+W) for a second or two and then immediately goes back to 0 where it stays for a while. Everything was working fine for a while when I installed the system week ago (charged 150Wh on a cloudy day). Yesterday I returned to the cabin and noticed that I haven't got any change at all during the past week.


I have been rebuilding cables and trying to debug what is the problem. Once, after restarting (enable disable changer in the app), I managed to get bit charge (200+W for few mins, total of 20Wh) until charging stopped without any obvious reason. Today is very sunny day. Panel is in direct sunlight without any shading.


Charge controller blinks the blue light indicating there is not enough solar input. App says that solar input voltage varies between 14-17V. At the same time voltage measured (with multimeter) from charge controller input terminals is ~37V.


Is there something I could do to figure out where the problem is?


Thanks!

MPPT Controllers
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timonen avatar image
timonen answered ·

I'll add some additional details. VictronConnect app shows quite weird volts/amps for solar input. For example:


screenshot-20220804-140202.png

This is the moment charger turned off. It was charging for 5 seconds. While charging my clamp meter recorded maximum of 9.57A going through the 10mm2 wire (panel's lmpp is 9.96A).

The app shows approx double input current vs. measured current. I assume this is not normal behavior?

Example from Trends tab in VictronConnect app (no clouds / shade):


screenshot-20220804-155905.png


screenshot-20220804-140202.png (158.0 KiB)
screenshot-20220804-155905.png (171.6 KiB)
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klim8skeptic avatar image klim8skeptic ♦ commented ·
Interesting..


Your mppt is smart networked to another device?? Whatisit?

Could your battery (??) bms be disconnecting the mppt due to overcurrent, or cell balance issues?

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timonen avatar image timonen klim8skeptic ♦ commented ·

It is networked with smart battery sense. Useful little device up here in the north during autumn/winter/spring when temperature goes below freezing.

When debugging tried without the battery sense. In addition to that limited charging current to 1A, 5A & 10A and tried with lead acid battery. Today, I brought battery back home (was running low) and it is now changing with mains charger just fine. Also BMS works just fine with constant discharge up to 100A. I think that should rule out possible issues with BMS?

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Rob Fijn avatar image
Rob Fijn answered ·

Could it maybe that you by accident made the wrong connection. Solar to PV and Battery to Bat ?

I read that you have this on a remote location, maybe you have a picture from the moment you leave the site to check the connection.

best regards, Rob

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timonen avatar image timonen commented ·

Sorry for the late response.


I have re-checked connections several times and those are correct. I have also moved battery&mppt close to the panel, made new shorter cables, nothing extra and still the same issue I described in my previous messages. Battery receives charge (not much, but few Whs) which is shown also in battery manufacturers' BT app. Afaik this is not possible with incorrect connections.


This is my current wiring:screenshot-20220821-124008.png


Thicker cable goes to lynx distributor (40A fuse) and thinner cable (length ~15cm, 6mm^2) goes to my dc isolator switch from which the 10mm2 solar cable goes all the way to the panel.


What is actually shown in the VictronConnect app in Solar - Voltage/Current section? Are those suppose to be raw from the panel or measured after some mppt processing / dc-to-dc conversion?

I have also noticed that whenever solar input power is low (e.g. below 100 Watts) it is more likely that the charger stays on for longer periods of time.

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screenshot-20220821-124008.png (913.4 KiB)
klim8skeptic avatar image klim8skeptic ♦ timonen commented ·
Looks like a faulty mppt, given the oddness of the first pic.

Contact your supplier regarding warranty replacement.

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mariner avatar image
mariner answered ·

Can you share a trends picture of Solar Voltage (V) and Battery Current (A)?

With the picture, test the voltage with the multimeter when it looks like it’s producing battery current and also when it’s not producing.

I’m starting to assume it’s the MPPT also since you said you verified all of the connections were clean/solid.

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timonen avatar image timonen commented ·

Unfortunately I have already left the site and won't be there for few weeks (cannot get those pics). Before I left I measured voltage with multimeter (from PV terminals as instructed in the manual) and compared that to the app.


Not charging:

1661113257469.png


Changing:

App displayed around 14-18V and multimeter displayed around 27-35V

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1661113257469.png (196.9 KiB)
mariner avatar image mariner timonen commented ·

I’d say that your MPPT might be pausing/stopping the charge because it thinks it’s PV voltage is too low vs the battery voltage. The incoming voltage needs to be Battery V +5v to start and remain no less than Battery V +1v to continue. A guess that might be the back and forth nature of the MPPT (verifiable via that trend I acknowledged to watch).

If you’re then measuring the PV input voltage at the terminals and those don’t align with what the MPPT is saying it’s bringing in then you’re starting to verify that the discrepancy is with the MPPT, like what your photos are showing.

I think you’re at a point of contacting your dealer and seeing about swapping this out for different unit.

Good luck. Keep us posted.

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johanndo avatar image
johanndo answered ·

What is your BMS disconnect setting, and are your cells balanced / you may have running off cells that disconnect the battery at 13.8V.

Also your panel voltage is way too low for MPPT on a big panel, you may have a shortcut in your install between panel input and charger output. The input / output values suggest a pass-trough and not a MPPT operation.

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stephen-olner answered ·

I’m getting something similar since the latest update with a 100/50 MPPT. Every day I’m having to reset the controller to get it to start charging.my other charger works fine. I see voltages on the solar side and battery side but no ampage or wattage until I do a rest


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