Inverter Low voltage restart

[greenkarson]

I've been posting more then my share of questions lately.  but you guys have put up with me so I will try another.

I have a cheap mod wave inverter to run the satellite Internet and security camera at my remote cabin. There are going to be times that the solar and turbine are not going to be able to keep up with the usage. And the inverter is going to shut its self off LVD. It does not have a auto restart function. Which is a pain. When your 150kms away.  The inverter has a mechanical rocker switch that has to be turned off then back on again to restart.

So that got me to thinking would it be possible to run a jumper from the positive terminal  on my dump load terminal on my c40 charge controller? To one of the pins on the rocker switch? So that when the batteries hit full charge the inverter is triggered back on again? Tricking(for lack of better word) the inverter into thinking that the rocker switch has been turned off then on again?

Or any other cheap and easy ideas?
Thanks

[madlabs]

I really doubt that will work. I'm not familiar with your inverter or charge controller but it's hard to see how it could work. In any case, what happens when the CC dump load goes off? Your inverter still won't be reset.

SO, I'd look at a solenoid that could hit the switch. You will likely need a transistor to switch the solenoid and use the CC dump output to switch the transistor. The solenoid will almost certainly use more current then the CC dump pin can provide.

Seems like a recipe to kill your batteries though. Why does the LVD keep tripping? That is the key question.

JOnathan

[greenkarson]

As to why the inverter  lvd shuts off could be any of a number of reasons. Like a couple cloudy days in a row or a snow storm. Sometimes I'm not there for weeks at a time. But I need the inverter to Beatle to restart with me.

I'm thinking (hoping) once the dump load is activated sending power back to the switch. Whatever shut power off the to the switch will think that the switch has been cycled and turn back on with no further need for power from the dump load. 

Sorry if this idea sounds shocking stupid. Sounds good in my head.  Haha

[Flux]

I don't think the inverter will tolerate what you propose.

Replace the inverter switch with a normally closed relay and extract a signal from the charge controller to momentarily turn the relay on long enough to reset the inverter.

You really need to modify the inverter to cut off at a higher voltage, the normal 10.5v is way too low for a low load discharge, the battery will be dead flat at 10.5v with low load. 11.5v would be better. Does the controller have an adjustable low volt disconnect that you could use?

Flux

[greenkarson]

I haven't officially checked the cut off voltage but I believe it is around 11-11.5v

I like the relay option that would work. But if I was to connect it to the dump load the relay would stay open(inverter off) as long as dump load was activated.  Do you know if when the c40 controllers reach full charge do the dump load turn on and off for the first couple seconds(flicker)? And then plane out. That would be idea for me. The flicker would reset the inverter.    If there is no flicker then the relay would remain open leaving the inverter off. But in my uneducated reasoning I think there would have to be some shuttering of the dump load as the batteries reach full charge

This is starting to sound very feasible

[Mary B]

I would never pull a battery down to 11.5 volts either. My LVD is 12 volts on a 12 volt bank(24 volts on my system) I like my batteries to last.

[bart]

  Did not read all the specs on MorningStars relay driver. but looks like it will do what you want.

http://www.solar-electric.com/inverters-controllers-accessories/chco/mochco/moredr.html

[OperaHouse]

I use a relay across the switch on my inverters to turn them on and off.  You need a voltage sensing relay that turns off at 12.4V and on at at least 13.6V Anything less than that will probably have it cycling on and off two quickly.  You could always find a cheap charge controller that has a switched output.  I have some old Morningstar SL-10 that can do that.  Power a relay to switch it because most inverters use that switch as a sense line too.  A nice job for a UNO.

[Mary B]

I use a Morningstar relay driver to turn power to the inverter off at 24.2 volts and back on if batteries are at 25. Use a SSR on the power input to the inverter. The outputs on the relay driver will not drive big loads, need some sort of outboard relay or FET or...

[bart]

   Since he was talking of hacking the power switch of his inverter, although am not familiar with his brand, was thinking of using those wires through the relay driver for on/off. Would not think they would be to much of a load, but could be wrong.

[OperaHouse]

It's too bad that this group doesn't have an active electronics following.  The Arduino mini board pictured is less than $2.50 shipped.  Add a couple resistors for a voltage divider and a relay and it can be a sophisticated voltage monitoring system, dump load, controller, linear current booster or anything else you want.

[DamonHD]

As it happens I do the high-level battery monitoring on my RPi, but yes, an Arduino variant would do nicely with an efficient power power supply so as not to be a vampire and eat significant energy itself.

Rgds

Damon

[OperaHouse]

You could use something like this   http://www.ebay.com/itm/370988930035?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Rather expensive, but you could use the schematic to build your own with any single opamp.   I will be posting a simple TL431 version in a couple weeks after I get out a project a customer has been pushing me on.

[OperaHouse]

Another one.  http://www.ebay.com/itm/331328916471?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT   Though I must admit I'm totally confused by the options and what it does, like three different cost options.  And then if you want to experiment there is this http://www.ebay.com/itm/131398119209?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649