question

david-stone avatar image
david-stone asked

Load output turns off when I connect something

Hey there,

I've got the MPPT 75/15 and the Load output turns off once I connect my 12v laptop charger. Other charger for a different laptop works... I recently switched from a Lithium ion Battery to a lead starter battery... it worked before... I've tested the charger to see if its broken but seams to work just fine. When I connect the charger to the MPPT it turns the complete output off and I see the Laptop charger LED pulsing like the MPPT is testing If its still connected.. When I connect an inverter the MPPT shuts down for a few seconds and then back on.

So it seams when there is a high load/short the MPPT shuts down. But it does it with the charger even if no laptop is connected.

Thanks in advance

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1 Answer
rossasaurus avatar image
rossasaurus answered ·

I'm having a similar issue with a SS 100/20 24V system.

What was your system battery voltage, do you know?
Victron App will show your lowest Battery voltage for each day.

I suspect my battery was too low of voltage(25.3V, though above load cutout spec of 23.6V) and when a 2nd fan(the load) switched on, the Load Output dropped completely.

It seems to have recovered, though battery voltage is only marginally higher than before.

I will likely convert to a BatteryProtect to run the fans instead of the MPPT Load Output terminals.

Oh, Looking at the Spec sheet again, I now see under 'Low Voltage Load Disconnect', "Battery Life Algorithm", so I'm guessing this means the Load Disconnect Voltage is not fixed, but varies according to the algorithm, since I do have "Battery Life Algorithm" chosen in my settings.

Spec Sheet for 75/15 & 100/20:
https://documents.wholesalesolar.com/media/specs-20190820213111.2940150-2.pdf

It would be useful to be able to view the cutoff voltage the algorithm is choosing, otherwise I think it's an equipment issue not meeting spec.

Much to learn!


Good Luck David

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david-stone avatar image david-stone commented ·

Hey thanks for your answer!

it seams like its not a problem with low voltage.. I now have a new 110ah battery connected and the problem remains.. Battery is fully charged and im getting solar energy..

Also happen when output is set to always on..

Still when I connect that 60w charger it turns off instantly.. That doesn't happen with another charger wich takes 90W...

Also my inverter worked fine all the time and now decided to trigger that exact same problem...

Cheers

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ejrossouw avatar image ejrossouw david-stone commented ·

It seems to point to the charger. Can you post a picture of the charger specification label? Not all chargers are equal and maybe you can also measure the current flow when it powers up as well as voltage level? Is this during the daytime when the mppt is also charging the battery? What does your configuration look like? A simple connection diagram will help.

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david-stone avatar image david-stone ejrossouw commented ·

Well as soon as I connect it to the mppt it shuts off. There is just an adapter to the car outlet in between. Worked before with Lithium.

I tried during day multiple times. Battery is in float with about 13.5V-14V and there is like 70W on the panel.

When I connect it to the battery without the mppt it works fine. Voltage drop or too much amps shouldn't be a problem since I use it with way higher consuming devices.

I'll add the charger lable.

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