Inverter(s) tripping

[john p]

many of the cheaper 12v inverters do trip at about 15 to 15.5 v especially TSW ones. Most but not all quality 12v inverters dont trip below 16.5v

[BritishPete]

Russ, I am impressed you did leave my comment, so in fairness to all I removed it.

[BritishPete]

Mine; Power max TSW 15.5V
Aims 15.5V
Vector 15.5V

All trip above 15.5V for more than a second or so.

The inefficiency in my 1600w system is not really a problem as it is used only a total of about 5% use time so the 5% loss becomes 5% of 5%.

[billvon]

Normally it is fine but when a charge controller changes to ABSORB the current also soon dimishes. When fast moving cloud changes MPPT voltage from say 14V to 14.8V at reduced charging current it will often overshoot for a fraction of a second. My Flexmax 80A (Australian) controller frequently records 16V and in this situation enough to trip all 3 of my inverters. Also 15.5V is required (for most flooded battery banks) to equalize. this will trip just about any inverter.

Hmm, odd. The 12V inverters I have experience with:

Trace SW series DC voltage 11.8 to 16.5V
Prosine 2.0 10-16V
Outback FX2012 10.5-17.5V
Xantrex Freedom SW 3012 10-16V

But I suppose some inverters might have trouble.

There is a simple fix (thanks for asking) Installing a Silicon diode between the battery bank and the inverter(s) will drop the voltage at the inverter(s) by 0.7V.

Wouldn't work for any of my installations. For a 2000 watt load that's a loss of 140 watts in the diode. That's more cost, power loss and heat than I'd want to try to deal with in a system designed for long term operation. But for smaller systems it might be a simple fix for an inverter problem.

[BritishPete]

If anyone could show me a reasonably priced inverter that won't trip at 15.5V I would buy it.

PS. I worked in the Attaturk area for a while I enjoyed the food.

[russ]

Whatever with the "should s" THREE inverters do the same AND most inverters are good to only 15.5V sometimes 15V

I really think it best I ignore your posts in future.

Mod note - New and obnoxious? Careful - I have a bigger ignore button

[BritishPete]

I am new here but I have just discovered the "Ignore button" It is a wonderful tool.

[BritishPete]

Whatever with the "should s" THREE inverters do the same AND most inverters are good to only 15.5V sometimes 15V

I really think it best I ignore your posts in future.

[Sunking]

A 12 volt battery inverter should work with an input voltage of 10.5 to 16 volts. If it doesn't get it fixed or replaced. Sure adding a diode is a work around, but if that is say a 1000 watt inverter and actually delivering 1000 watts to a load you are burning up 60 watts on the diode. That is one huge expensive diode.

[BritishPete]

In your case you could put two in series for a reduction of 1.4V and your eff.loss would only be 1.4/67 = 2%

[Mike90250]

Ahhh Very clever. Just a diode and a bypass for it. Thanks for sharing that tidbit.

There is a simple fix (thanks for asking) Installing a Silicon diode between the battery bank and the inverter(s) will drop the voltage at the inverter(s) by 0.7V. Hence 15.5V now equals 14.8V irrespective of current draw (it's not a resistor) This is true of ALL silicon diodes, just get one large enough to handle your inverter loads.

I am using a 1N1055 diode good for 260 amps with the correct heat sink. I can quickly (switch) bypass it when not needing to equalize, or not near Absorb voltage on a cloudy day and thus save about 0.7/14 = 5% on efficiency. So normally I do have it bypassed but need it in circuit often too

I use my heavy copper (negative) bus as the heat sink for this diode too. It just bolts directly on to it then just the other wire to the inverter(s).

That half volt may make my system happier, I'm charging the NiFe's at 67V, and sometimes, my inverter logs an over-voltage error of 68V, while in absorb. I don't EQ.

[BritishPete]

Thanks, and this does not affect battery charge time etc, as the diode output goes ONLY to the inverter(s). I find that if I only use the ABSORB voltage of 14.8V recommended then there is not enough sunlight hours in the day to get more than an 85% charge so once a week I Equalize to about 95-100%. This seems perfect because in 2 months on new batteries (8 equalize cycles) my fluid level has only dropped from 1.5" to 1".

[tandrews]

Nice.

[BritishPete]

Britishpete how does fast moving cloud cause overvoltage? I dont have problems from overvoltage as I set the charge controller at a max of 15v and that seems to keep ant inverters (12v) happy. But interested in your fix if the problemoccurs.

Normally it is fine but when a charge controller changes to ABSORB the current also soon dimishes. When fast moving cloud changes MPPT voltage from say 14V to 14.8V at reduced charging current it will often overshoot for a fraction of a second. My Flexmax 80A (Australian) controller frequently records 16V and in this situation enough to trip all 3 of my inverters. Also 15.5V is required (for most flooded battery banks) to equalize. this will trip just about any inverter.

There is a simple fix (thanks for asking) Installing a Silicon diode between the battery bank and the inverter(s) will drop the voltage at the inverter(s) by 0.7V. Hence 15.5V now equals 14.8V irrespective of current draw (it's not a resistor) This is true of ALL silicon diodes, just get one large enough to handle your inverter loads.

I am using a 1N1055 diode good for 260 amps with the correct heat sink. I can quickly (switch) bypass it when not needing to equalize, or not near Absorb voltage on a cloudy day and thus save about 0.7/14 = 5% on efficiency. So normally I do have it bypassed but need it in circuit often too

I use my heavy copper (negative) bus as the heat sink for this diode too. It just bolts directly on to it then just the other wire to the inverter(s).

My diode cost me $18 from Ebay.

[john p]

Britishpete how does fast moving cloud cause overvoltage? I dont have problems from overvoltage as I set the charge controller at a max of 15v and that seems to keep ant inverters (12v) happy. But interested in your fix if the problemoccurs.