Novopal 2000W/12V Inverter acting up

[diysolarmx]

I'm new to this forum. Looking for some answers to a weird set of issues...

I purchased a Novapal 2000w/12v inverter about 11 months ago from Amazon in the US.

My system is off-grid in a home as a backup.

It receives power from 4x 90AH FLA batteries (in parallel) and a Victron MPPT 100/30 controller fed by 4x ~450w solar panels.

The inverter rarely went over 20% of capacity. It has been running a chest freezer (~65w), a few lights and computers.

This worked, but was under powered if I wanted to use it with additional loads... so I upgraded to an 80A AMPINVT controller.

Unfortunately, now I'm having issues with the inverter shutting down randomly several times a day under both heavy (no more than about 40%) and light loads (10% to 20%).

The display goes blank while the alarm goes off and the sound slowly goes down to nothing over about 10 seconds. I get no specific error messages. I turn the power switch to off and wait 10 seconds and it comes back on.

All connections are tight with heavy duty wiring. No shorts.

I did connect a 160W refrigerator on top of the other light loads (during the day only) after installing the new controller... and it worked for a while until it went crazy and shut down. Removed that new load and now it is doing the same thing with the usual past load... even if light.
Any thoughts?

 

[Rednecktek]

Well, the first 2 thoughts I had were:

1: Your inverter has failed. Not uncommon for cheaper HF inverters but with no kind of diagnostics or codes it's hard to really troubleshoot other than getting another one and seeing if it holds the load. Is there a cooling fan? Does it run? Maybe the unit is overheating?

2: The new SCC you put in is set to too high a voltage and when it's feeding the system the inverter is tripping out on high voltage? The ranges should be similar enough but if your new SCC is putting out 14.6v as an example and the inverter is tripping out because the detected voltage is over 13.8? Disconnect the new SCC and take everything back to the way it was before and see if it holds a load or not.

Just my initial thoughts.

 

[diysolarmx]

Your two thoughts are floating in the right direction.

From research I've done on FLA batteries, I learned (hopefully correctly) that if you charge a FLA battery at or a little bit above 15.2V, then it will keep from sulfating. The first SCC in combination with this inverter could handle that. I did test the limit a bit and did hit an over-voltage error once after I originally set things up. Specs said that 15.5v would trip it... I backed off and then things were happy, even at a saturation charge of around 15.2v.

I've stayed conservative with the new system. The thing is, when it fails, I get no error.

Any good inverters you would recommend? Perhaps in the 24v-48v area?

 

[diysolarmx]

Upon further investigation, I'm suspecting a heat problem. Things are running ok so far today, but suspect things will go south as the day warms up. I've also started adding some load to see how it handles it. The odd thing is that the fan on the inverter didn't come on when one would have expected.

I also sent an email to support@novopal.com yesterday. They responded with comments that were completely useless.

For those who don't know, the novopal.com website is down as of this writing, but the email works. Clearly useful support is lacking for a product that seems to sell frequently on Amazon.

 

[mikefitz]

15 volts and over, as the normal charge voltage, will kill your batteries . Depending on the actual batteries you have, a charge, absorbtion, voltage will be 14.4 to 14.8 volts , float volts 13.6 to 13.8.
Your confusion regarding high voltages may be related to equilisation charge. This is an infrequent ' over charge' condition carried out on fully charged batteries at intervals of every 3 to 6 months. The batteries are subjected to a charge voltage in excess of 15 volts for a few hours. Not all lead acid batteries tollerate this, seek advice from the battery manufacturer.
Note charge voltages quoted are for a temperature of 25C, 77F, at higher temperatures the charge voltage must be reduced. Most quality chargers have temperature compensation.

Mike