ELK-M1G Power DC Only

[Digger]

I know that this is possible and if I remember correctly just connect negative of battery to common and positive to the one side of the AC input.  Just dont remember if there was anything else to it.
 
I searched for a post from around 2007 or 2008 on this but I cant find it. 
 
Anyone doing this?  I have a solar setup I want to run the ELK and a few other things off of.
 
Thanks

 

[RAL]

I think this thread may be what you were looking for.
 
http://cocoontech.com/forums/topic/20887-elk-m1-in-uk-can-elk-take-direct-dc-input/
 
It sounds like it can be done, but you will need to provide about 18VDC to keep the battery charged.
 
Also, you would connect your input to both AC input terminals, not just one of them plus common.

 

[Digger]

Not the thread I remember but it will do.  I dont need to charge the battery as it will be running off a battery charged by a solar panel.  Thanks for finding that.  I didnt see it when I searched.

 

[RAL]

14V probably isn't enough to allow the voltage regulator to operate.  If you read Spanky's post in the thread discussing this, the input voltage, whether it is AC or DC, needs to be high enough to allow for the voltage drops created by the voltage regulator circuit.  Even though you aren't connecting a battery to the M1, the voltage regulator is still set to 13.9V, and that same voltage output is powering the M1.
 
With a 14V input, the voltage regulator would only be able to provide about 10V out to the M1, at best.  Or it may cut off completely, since that is so far below the set point.
 
I think you'll need to provide something close to 18V for it to work.

 

[Digger]

There are others that do it.  I actually have it working now.  I had the polarity reversed. Just need to see how to clear the ac fail indicator.

 

[RAL]

There are others that do it.  I actually have it working now.  I had the polarity reversed. Just need to see how to clear the ac fail indicator.

 
Ok, good.  I'd be curious to know what voltage you measure on the VAUX outputs with a 14V input.
 
[Edit]:
 
It just dawned on me... if polarity mattered, then you must be connecting your DC input to the battery terminals rather than the AC input terminals.  In that case, 14V would be adequate since it doesn't go through the voltage regulator.  It would also explain why you have an AC fail indicator.  Is that what you've done?
 
To avoid getting the AC Fail indication, you need to set the AC Fail Report Delay to 255 in the System Report Codes menu.

 

[Digger]

No I connected to the AC terminals.

Started out at 14v and by this morning it was 12.2v so I really don't have quite enough capacity. It's a large marine deep discharge battery. I think it's 150 ah but I would have to look it up again. Solar placement is far from ideal as the entire backyard and rear roof is shaded. I put the panel on the shed and it gets direct sun for 3 or 4 hours at most.

Technically it did pretty well. Buss dropped to 10.8 to 11v.

Want to see how well it refreshes. If it is back up to 14v then I will add another battery next. If it falls short of that I will add a second panel first.

In the end I am set up to easily get to 4 panels (labeled 100 W but really 50 W) and 2 or 3 batteries.

At that point hope to power the rest of the alarm system and the modem and router. This way if cable is up I can get to the CS and also have wifi.

 

[Del91574]

Keep in mind the whole item that everyone's forgetting about these and other solar panels now the proliferation is really happening.....nobody has really done a study as to what the loss in efficiency of the units are as they age and get dirty and/or environmental contamination on them.

 

[Digger]

Mine is 7 feet off the ground.  Easy to clean and remove the snow. The one panel was not enough to fully refresh the battery today from what I can tell but I dont have a datalogger on it and I got home at 9 pm so cant be sure how far off it is. 
 
Most likely add a second panel and then eventually another battery so I have 3 days in reserve. 
 
In regards to loss of efficiency most mfg's have done the studies so that they can warranty them.  Many panels are rated 80% or higher at 20 years.  Solar companies like Vivint actually monitor their systems and will come out and clean the panels etc if they are not producing enough.  If they don't its lost revenue to them.

 

[Del91574]

Yes and no. The big items being discussed in the industry (electrical and generation/RMR world) is the effect of the environment and the dirt/surface contamination. The units just haven't been out there long enough for them to answer that yet. Warranty is one thing, but it's also very easy for the manufacturer to get a unit and then clean for their purposes and test accordingly. We had to go through this with a bunch of emergency phone towers powering a light and a cellular communicator. The units wouldn't and couldn't keep up no matter what we did and were within spec for general output and voltage yet when sent to the manufacturer, they took the glass and basically just buffed them out (want to say cesium oxide). Warranty replacement denied. Same thing goes with dust and surface contaminants....you can clean it off and be right back to square 1 in a day or two (or during pollen season).
 
The leasing companies are in the business of selling the lease. While they do stand to lose some revenue, until it's more cost effective for them to roll a truck and pay the tech to clean and test the units than eat the loss, it doesn't make sense for them to PSA them. I'm sure the contracts cover a basic maintenance scheme, yet everything else is billable, it's the only way to make sense on the design/build investment.