I need help on Off-grid Solar DC Freezer

[Damscart]

Installed with 2pcs of 12v/155watts, 12v/200ah battery 30A Charge controller but still not freezing at all 1hr after sunset the freezer shut down. Later I added to it making
2pcs of 24v/210watts panels, 2pcs of 12v/155watts in series 24v, 24v 60A Moot charge controller, added 1more 12v/200aH making 24v/400aH batteries still not giving me want I want by 6pm after sunset it shut down again. Any solution to this I can't even enjoy my freezer.....
DC 12/24v
8A/4.5amps
80w
208liters

 

[schmism]

Your going to need a volt meter at the minimum. A clamp meter that can measure DC amps is ideal. You'll want to to verify the voltages and currents that are being produced by the various panels and charge controlers you have once the sun is up.

 

[Hedges]

A single 200 Ah battery, draining to 50% SoC, should still run a 12V 8A freezer for 12 hours.
What shuts down? Is there something like the charge controller with a load terminal performing low-battery disconnect? Or does freezer decide voltage is too low?

Sounds like you've already tried adding one more battery (2 total?) but you say 24V, 400 Ah. It is one or the other ... connecting two 12V 200Ah in series gives you 24V 200 Ah. In parallel, 12V 400 Ah. Which did you do?

Could be the freezer has some operating voltage range, but low side below 12V cuts out too soon. If you wire as 24V battery (which I think you may have), that's likely to work better.

12V of panels charging 12V battery and 24V of panels charging 24V battery may or may not work well. A 12V panel is typically 17Vmp to 18Vmp but that varies with conditions. A MPPT charge controller sometimes needs PV voltage 5V above battery voltage (but some work with less.) Likely battery isn't getting fully charged.

Post the specs of PV panel and MPPT charge controller.
Could be that connecting two 24V 210W PV panels in series for "48V" (or about 72Vmp, 90Voc), feeding MPPT charge controller, charging two 12V 200A batteries in series for 24V will work. But very important to consider maximum input voltage spec of charge controller first.

Finally, it is better to run the freezer while sun shines and shut it off at night. You can store cold as ice (or salt water ice for a lower temperature) rather than in battery. For the ideal setup, a second thermostat to turn freezer on at night anyway, if temperature gets too high an salt water ice has melted.

 

[Damscart]

I connected two 12v battery in series making 24v 200Ah

 

[Hedges]

So you have 24V battery to freezer, and it shut down 1 hour after sunset.
With 200 Ah of battery and 4.5A draw, should have run 20 hours before even reaching 50% SoC.

You need a volt meter to check the battery. Does charge controller display voltage of battery? of PV panels? Does it show charge current?

 

[Damscart]

A single 200 Ah battery, draining to 50% SoC, should still run a 12V 8A freezer for 12 hours.
What shuts down? Is there something like the charge controller with a load terminal performing low-battery disconnect? Or does freezer decide voltage is too low?

Sounds like you've already tried adding one more battery (2 total?) but you say 24V, 400 Ah. It is one or the other ... connecting two 12V 200Ah in series gives you 24V 200 Ah. In parallel, 12V 400 Ah. Which did you do?

Could be the freezer has some operating voltage range, but low side below 12V cuts out too soon. If you wire as 24V battery (which I think you may have), that's likely to work better.

12V of panels charging 12V battery and 24V of panels charging 24V battery may or may not work well. A 12V panel is typically 17Vmp to 18Vmp but that varies with conditions. A MPPT charge controller sometimes needs PV voltage 5V above battery voltage (but some work with less.) Likely battery isn't getting fully charged.

Post the specs of PV panel and MPPT charge controller.
Could be that connecting two 24V 210W PV panels in series for "48V" (or about 72Vmp, 90Voc), feeding MPPT charge controller, charging two 12V 200A batteries in series for 24V will work. But very important to consider maximum input voltage spec of charge controller first.

Finally, it is better to run the freezer while sun shines and shut it off at night. You can store cold as ice (or salt water ice for a lower temperature) rather than in battery. For the ideal setup, a second thermostat to turn freezer on at night anyway, if temperature gets too high an salt water ice has melted.

So you have 24V battery to freezer, and it shut down 1 hour after sunset.
With 200 Ah of battery and 4.5A draw, should have run 20 hours before even reaching 50% SoC.

You need a volt meter to check the battery. Does charge controller display voltage of battery? of PV panels? Does it show charge current?

Yes it shows the battery volt and PV panels also as pV 27.8v and battery 25.6v

 

[Hedges]

Yes it shows the battery volt and PV panels also as pV 27.8v and battery 25.6v

25.6V battery is 12.8V per "12V" battery.
After a battery has rested 4 hours with no load and no charge, 12.8V is 100% charged. See page 35 of this manual:

http://sunxtender.com/pdfs/Sun_Xtender_Battery_Technical_Manual.pdf

While charging, 12.8V is below both absorption and float voltage. See page 19.

27.8V PV is barely above battery, probably not sufficient to charge.
That is an odd PV voltage - higher than Voc of a "12V" panel, lower than Vmp of a "24V" or two "12V" in series.
What is the maximum input voltage limit of your MPPT charger?
If sufficiently high (needs about 15% extra headroom for cold weather), then more panels in series should charge better.

Given your assortment of panels, could try just two 24V panels in series, no others connected (again, assuming charger allows input voltage 1.15 x 2 x Voc of a panel.)

Alternate experiment to get batteries charged is to wire them in parallel as 12V so plenty of headroom between PV voltage and battery voltage. (This assumes you really do have MPPT not PWM charger)
Then once fully charged, reconnect in series and see how long it runs freezer.

Have links to all the spec sheets?