ssmith1952: AC inverter shuts solar system down

ssmith1952 · April 2019

I haven’t had a chance to use this solar set up yet. Turned on the fan just to see if it worked then turned it off. The inverter, not wired at present, will be wired directly to the battery with a 150 amp fuse on the positive line. Pos to pos, neg to neg. I am on my second battery. We tested the panels with a dc tester and they are putting out 200 watts as required.

ssmith1952 · April 2019

https://www.amazon.com/gp/product/B00IKMWNBO/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1

This is the fan I have

Estragon · April 2019

When running with no solar, the fan likely draws not far off what the inverter would with nothing plugged in. When running the fan, does it draw the battery down faster than expected? At 3a draw, the fan should be able to run for quite a few hours (~16 to 50%SOC) on a good, 100ah battery. Running it on battery alone for a few minutes should have little effect on a good battery.

What size wire will the inverter be hooked up with?

ssmith1952 · April 2019

Fusing the fan and the meter won’t be a problem. I don’t know the amp draw on the fan. I’m guessing around 3-4 amps I’ve not run the fan. Only to turn it on and off to check that it worked. I could turn it on the see if it does pull from the battery a lot but I really don’t want to drain the battery again. I understand that it damages it. Since I have another inverter coming Friday, I’ll try that. If it happens again, I’ll try another new battery ☹️( this will make the third).

littleharbor2 · April 2019

https://forum.solar-electric.com/discussion/comment/397335#Comment_397335

Either that, or a bad/shorted connection to the inverter. As mentioned earlier, taking a good, fully charged, 100ah battery down to 10v cut-off in a matter of seconds takes a lot of current. Enough that I'd expect something to get pretty hot in the process.

You mean like molten metal and smoke hot? If the battery is healthy and fully charged, that's what I'd expect to see

ssmith1952 · April 2019

Inverter comes with two 3ft #4thhn with a 150 watt and fuse installed on the positive side. We have already taken the connections apart and cut any extra insulation on them that may be pinched, then reassembled. That wasn’t it. It does have a temperature shut off. But nothing felt hot. Maybe the fan wired is pinched and is shorting out the system. I’ll try unhooking that next time.

BB. · April 2019

And to clarify... Yes, to take a good 100 AH @ 12 volt GEL/AGM type battery from fully charged to less than 10 volts in a few seconds, we are talking about turning the 4 AWG cable pretty close to red hot.

That is why I asked about the battery terminal voltage when you saw the voltage drop. If the battery is going "dead" in that short of time without smoke/melting metal, it is likely that battery has failed.

Of course, there is always the question as to why the battery failed... Mfg. Failure, left dead for days/weeks/months, battery was dropped and broke internal bus connections, etc....

-Bill

ssmith1952 · April 2019

So even if the new battery was fully charged, it may be defective by not holding a charge? Nothing gets hot and that little meter says the battery is 100% (connected to panels). I’ll try whatever you may suggest to get it working. Thanks

BB. · April 2019

I don't know what is happening... It is possible for a battery to be bad, even if new. It is rare, and not my first guess where the issue really is.

I still am leaning towards the AC inverter was not bolted to the battery terminal clamps, but instead your friend was holding the copper wires just to the terminals & Clamps. And non-bolted electrical connections that are supposed to carry 100's of amperes--They just don't.

My suggested test... Bolt of the DC wiring to the AC inverter, and connect your DC meter to the battery terminals too, and fire the inverter up without any AC loads. Assuming there is no Solar Charging going one, you should see the battery voltage drop to ~12.5 volts or so and stay there. And then you can add a few loads to your AC inverter's output and you should see the voltage stay relatively stable or drop a bit towards 12.0 volts and hold. I would suggest that the "nominal" AC loads for your inverter would be in the 100-200 Watt range.

If you have your solar charge controller connected and full sun on the array, your battery voltage will probably be in the 13.5 to 14.2 volt range--At least until your AC loads exceed the available solar power.

If the inverter was bad or its +/- connections were connected backwards to the battery, There would be some smoke and heavy sparks if the inverter was shorting out the battery bank and you were just pushing bare wire to the battery terminals.

-Bill

ssmith1952 · April 2019

inverter cables were indeed bolted to battery terminals. We only did the hand held thing for a test. With nothing else attached, my friend held, not bare wires, but the inverter cable connectors (rings)to the battery terminals. Inverter read 13.4 and held. Then we went to van and connected inverter to the battery along with everything else that is connected and that’s when it took a dive. WTH. I’m so discouraged with this.

We will try your suggestion tomorrow or Saturday after the new inverter arrives. Or may try on the old new inverter.

Nothing has been done backwards. At least we got that part down. We have a dc meter now so will try your suggestion. Without solar panel connections. Thanks

sherri

BB. · April 2019

Sherri,

I am very sorry. Debugging can be a bit of a pain, especially if you do not have a meter/test hardware/known good equipment, etc...

There is nice test equipment that can make checking the battery much easier/quicker, but few people (or even shops) will have the gear--It mostly gathers dust from non-use. I don't suggest you buy one for a one-time-test, but here are some examples.

https://www.amazon.com/s?k=car+battery+tester+load&ref=nb_sb_noss

If you have a local auto parts store nearby, frequently they will have a battery tester that could verify if your battery is good or bad.

Can you find somebody nearby that has a bit more car/boat/DC power experience to help?

-Bill

ssmith1952 · April 2019

Yes there’s a mobile rv tech I plan to call if it fails after the new inverter and/or after their new battery

Solfyr · April 2019

Renogy seems not to have that charge controller Wanderer 30A anymore on their website,

but a newer one 30A-Li .

Manual downloaded and read ?

Overall , I would have spend $20 for the 10A version , since that includes a

display , or spend also for the bluetooth box additionally .

The battery might not been charged much , and the voltage is a "ghost" value ,

bounced back up under no-load conditions up to those 13 V .

Those 100W panels might even not deliver enough Volts under overcast conditions and hot outside temperatures

to charge the battery , and probably would need to be wired in series during Summer ;

50 Vdc are some 72 cells 300+Watts panels alone , so those two 100 Watts need to

be wired in series , and not parallel , and then the 10A version would be good enough .

I would also charge that battery by a grid connected charger , and try again .

ssmith1952 · April 2019

Final outcome: hooked up new Renogy inverter today and switched out the painted battery connectors for bare metal ones. I dont which one made the dif but it works like a charm. Plugged in a small fan, great. Ran the exhaust fan, great. Plugged in coffee maker and made coffee, worked. So happy. Thank you all for your time and many suggestions.

Sherri

BB. · April 2019

I am happy to hear Sherri that all is working well...

Not sure what size AH battery bank, Watts for your AC inverter, and your final solar array Wattage is/will be... But be careful, it is very easy for a large AC inverter (and AC loads) to suck dry your batteries unless you have enough solar array+sun to keep up.

And batteries are the major item that is easy to kill (in days/weeks/few months if over discharged/undercharged.

-Bill

ssmith1952: AC inverter shuts solar system down

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