1 of 3 MPPT not always starting

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swtrcloud9 asked 5 hours ago

1 of 3 MPPT not always starting

I have 3 x 455W solar panels each connected to its own SmartSolar MPPT 100/50 (for redundancy) on my boat. The three mppt units are then conneted in parallel to a set of 3 x 260Ah GEL batteries. There is also a multiplus conected to the same batteries. No external A.C. supply.

The first two panel/mppt combinations are ok.

But mppt #3 sometimes doesnt come back on in the morning - the staus stays off. Even though #1 & #2 are both on and at the bulk status. This screen shot is a short time after the first two panels have started.

Unplugging the panel from the mppt unit and plugging it back it in gets it going again.

I have checked that all three panels are producing approximately the same voltage at each of their respective mppt units and that the battery voltage at all three mppt units is the same.

Any clues? The whole setup is just over a year old and has been working perfectly up till now.

MPPT SmartSolar

screenshot-20240717-081559.jpg (303.7 KiB)

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pwfarnell commented · 4 hours ago

@swtrcloud9 Not related to your issue I notice thst your battery voltage is very low, did you have a large load on your system when you took that screenshot. If not your are discharging your batteries overnight much more than is ideal.

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swtrcloud9 pwfarnell commented · 3 hours ago

Yes, that is another issue I am trying to resolve. The main loads overnoght are the fridge and computer charging. Working through a process of elimination in the first instance. I suspect my computer as the voltage was well over 12 when I got up at 0430 and only 11.1 a couple of hours later. The only thing that changed was using the laptop.

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Answer 1 · 2024-07-17T07:05:47Z

nickdb answered · 5 hours ago

you will need to show trend charts for each so we can see the battery/pv voltage over the period.

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Answer 2 · 2024-07-17T08:54:48Z

swtrcloud9 answered · 3 hours ago

@nickdb Here are the trends for the three MPPT units.

So, there is a significant dip in the battery voltage around 0500 which was when I got up, turned on one led light and opened my laptop.
The second dip at around 0930 may have been when my wife attempted to make a cup of coffee (not sure).

Note that I have used a load tester on the batteries which show that 2 of them are working at full capacity and the other one has a 15% reduced capacity. They are less than 18 months old.

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nickdb ♦♦ commented · 2 hours ago

One LED and a laptop shouldn't do that to healthy batteries.

What charger settings are you using on each mppt?

Are they networked?

Firmware up to date?

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swtrcloud9 nickdb ♦♦ commented · 1 hour ago

@nickdb The laptop and the light were the only things that changes. The fridge/freezer was running all night and I presume it was cycling correctly.

VE.Smart Networking configured for the 3 controllers and the battery sensor.
Synchronised charging
MPPT Firmware v1.64
Battery Sense firmware v1.13

The charging settings for all three controllers are the same. (GEL batteries) From memory, these were set based on the info written onthe side of the batteries.

As mentioned, I borrwed a load tester to test the batteries and two were indicated as good and one slightly less.

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