Avoiding dead lead acid battery on smartsolar MPPT

Question

question

simplesimon asked Nov 20, '23

Avoiding dead lead acid battery on smartsolar MPPT

So have been using a small phoenix inverter run off a MPPT100/20 to power a laptop. Re-charging has been done with conventional car charger as no solar panel as yet.

Normal use discharge as shown except for the dip at the end:

Normally the inverter or charger trips and I switch off. After a couple of hours the battery voltage is somewhere 12.3 - 12.5V so I think the State of Charge is ok before being charged again. However this time the on / off cycled like so:

... and even after a full charge the battery is a 10V battery so dead.

The jumper was set on the middle pins of the controller so should operate:

Conventional algorithm:
low voltage disconnect: 11.8V
Automatic load reconnect voltage: 14.0V

However that doesn't appear to be as it's behaving as it's re-connecting at 11.9V or so.

Any ideas what has happened?

Now I will run the load as BatteryLife with the jumper removed to see if that behaves better but it's an expensive experiment if I'm doing something else wrong...

low battery warning lead-acid

discharging.png (196.9 KiB)

battery-killer-settings.png (152.2 KiB)

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

snoobler answered · Nov 21, 2023 at 01:07 AM

If you're using the load ports on a charge controller to power an inverter, stop immediately.

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Modifications Space

Node Red Space

Answer 1 · 2023-11-21T04:23:52Z

regman54 answered · Nov 21, 2023 at 04:23 AM

I agree, if you don't have solar panels you shouldn’t be using a solar charge controller to charge the batteries. Use the automotive battery charger to charge the batteries.

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Answer 2 · 2023-11-22T19:45:57Z

simplesimon answered · Nov 22, 2023 at 07:45 PM

Ahh, maybe I didn't explain that fully. Yes I'm using the automotive charger to charge the batteries directly. I'll try using the inverter powered directly from the battery with a remote connection from the controller.

But as the inverter is within the power rating of the controller, why shouldn't it be used from load connection?

2

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Justin Cook ♦♦ commented · Nov 22, 2023 at 08:31 PM

The user manual is a good reference point for what and why this should not be done, and how to do it instead:

2 ·

load-output.png (58.2 KiB)

simplesimon Justin Cook ♦♦ commented · Nov 23, 2023 at 04:44 PM

Thanks, now looking for the inverting remote on-off cable as now the old Pheonix inverter is only on when the load output is off and vice versa, so would loose the battery protection without it.

I guess now the only way to monitor the load is with a BMV or similar.

0 ·

Answer 3 · 2023-11-22T20:43:33Z

snoobler answered · Nov 22, 2023 at 08:43 PM

Most laptops are 19V input. A DC-DC converter powered by the load port would work:

Example:

https://www.amazon.com/Converter-Voltage-Regulator-Adapter-Vehicle/dp/B0B7481QCY

2 |3000

Attachments: Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

question