# Generac Smart Managment Modules - do they work?



## dockeradz (Oct 25, 2019)

I have an install with 2 Generac Smart Management Modules to lockout 2 EV chargers. They are setup to lockout the load when on generator. The manual has an insert that updates the behavior to lockout when the generator gets overloaded. They don't seem to lockout in either of these cases. If there was only one I would say it's bad and replace it, but with 2 doing the same thing I'm wondering if either I did something wrong or they just don't work. They want the load to lockout on generator, not shed.


----------



## The_Modifier (Oct 24, 2009)

Tell you what, fill out your profile as per the sign up agreement- specifically your electrically related profession and general location (it helps others in your area with the code citations and even for someone to know what country you're in :wink: ).

I bet others will happily chime in with their advice and opinions after that. :wink::wink::wink:


----------



## MechanicalDVR (Dec 29, 2007)

Welcome aboard @dockeradz!

Is this a brand new install with two new modules?

The shop I used to work at was a factory service dealer. Not unusual for them to be bad out of the box. 

Call tech service and let them go through the troubleshooting with you on the phone.

888-GENERAC 

888-436-3722


----------



## Jerome208 (May 10, 2013)

They work by sensing frequency fluctuations when on generator power. A cockamamie setup if I ever saw one. 



Generators have tight frequency governing these days and power can be indistinguishable from utility power. So these modules may not be sensing that they are on generator at all.


The only reliable solution to lock out EV (or load shed anything really) is to run a wire and use a relay. These things must be used more when codes call for a ridiculously oversized generator and they have to do something to show they tried to shed when they know in real life it is never going to shed.


When on numbered priority, these things wait for the engine to start struggling to shed load and that is no way to design a proper system.


----------



## HackWork (Oct 2, 2009)

Everyone has their own opinion, and as is often true, mine is different. 

The SMM's are to appease code, that is it. In the 2008 NEC the change required the generator to be sized to handle the entire calculated load placed on it, no matter how unlikely it is for that load to be used while the generator is running. So these modules help you install a reasonable sized generator such as a 14-22Kw instead of a giant 30-40Kw that would be completely unnecessary for a cheap (Generac) residential application.

I have spend hours running control wiring thru houses to pickup a remote condensing unit or range or whatever fed from a subpanel on the other side of the house in the past. These modules make that so much easier.

So as long as they don't shut off as inopportune time (which I haven't heard happening) they are doing their job by just existing and getting the inspector to pass the installation. If the customer runs too much and the SMM's don't shut down the load, who cares. That's a design issue, the NEC should not be involved. The end result is the same as if they had a manual transfer switch (which code doesn't require the generator be sized to the load) and ran too much.


----------



## nrp3 (Jan 24, 2009)

It can be dependent upon the version, initially they would do just that, lockout as you wanted, then some trouble was had with unstable utility power and they would drop out, a later version, if I recall, would only drop out after it started to be overloaded and then stay locked out, the latest, may be back to drop out after utility loss. I use them and only have had one instance of them dropping out on utility power. They are convenient with no connection to the transfer switch. PSP products has different stand alone load shedding systems if these are giving you trouble, or possibly going to the latest version of the SMM.


----------



## nrp3 (Jan 24, 2009)

HackWork said:


> Everyone has their own opinion, and as is often true, mine is different.
> 
> The SMM's are to appease code, that is it. In the 2008 NEC the change required the generator to be sized to handle the entire calculated load placed on it, no matter how unlikely it is for that load to be used while the generator is running. So these modules help you install a reasonable sized generator such as a 14-22Kw instead of a giant 30-40Kw that would be completely unnecessary for a cheap (Generac) residential application.
> 
> ...


The only issue is with this is if the person isn't home and the generator is overloaded and it fails. Further south may not be an issue with frozen pipes, but up here it is (though maybe mold and food). Agreed that the service calcs are a bit conservative. I use the shedding when I think its wise from an inspection standpoint or just prudent based upon the situation. Sometimes it ends up just being easier, similar in cost just to have the larger generator because of the cost in materials and labor for a bunch of shedding, sometimes because of fuel limitations ie small propane tanks or maybe older natural gas infrastructure that you are limited on size and btu draw and then load shedding becomes more of an issue with a whole house set up.


----------



## HackWork (Oct 2, 2009)

nrp3 said:


> The only issue is with this is if the person isn't home and the generator is overloaded and it fails.


 The same end result happens with a manual system that the homeowner left running while they left- the breaker trips or the generator stalls. 



> Further south may not be an issue with frozen pipes, but up here it is (though maybe mold and food).


 Hmmm, it sounds as if you are talking about a vacation home that the owner won't be there for days or longer. In that case, I am not sure if I would trust a Generac system in the first place. I like the Generac systems and I think they are great for the money, but certainly not mission critical standby systems.


----------



## nrp3 (Jan 24, 2009)

None of the brands are critical systems and they all spell that out in the manuals. You run the risk with any of the brands. Right now, I really like what Generac produces regardless of what past experiences people, including myself have had. Briggs has new models with new controllers and I'm interested in seeing what that offers. All of these systems are built and engineered to a level of affordability (relative) and it is what it is. People need to temper their expectations. If you install them carefully and conservatively, they function well. I really don't have much trouble with my installs, Kohler, Briggs, or Generac. Its usually others. 

We have a lot of second homes up here around the lakes, so monitoring is a good thing regardless of brands.


----------



## dockeradz (Oct 25, 2019)

Sorry for the late reply, I don't get a lot of computer time. Thanks for all the comments. Very helpful. I could tell them that these just don't work and suck it up, but I would rather provide them a working system.
@nrp3 I will look into PSP products. The GLD-50 looks promising. They don't list a distributor that I can find, can you point me the in right direction there?


----------



## nrp3 (Jan 24, 2009)

Buy PSP directly from them. I have found their customer support to be knowledgeable too. Don’t abandon the smms just yet though, you may need a later version. I have had very little trouble with them,


----------



## dockeradz (Oct 25, 2019)

@nrp3 Do you have access to one to check the board revision? Also what generator are you pairing these with that works? Thanks for the help, much appreciated.


----------



## nrp3 (Jan 24, 2009)

Honestly, I couldn't tell you what version is out at the moment. Rereading your first post, sounds like you may have the second version and it's doing what it's supposed to do, due to previous versions having some trouble with dropping out on unstable utility power. I believe later versions are back to what you would expect for load drop during standby use. As Hack mentions, the load calcs can be conservative and there's not enough load for these to drop out. I just did a similar install with load shed on heat pump with gas back up as well as the two ev chargers. I had a couple of different versions of modules as some of the ones like you have are still on the shelf. If I were closer, I'd bring the load bank over to see how it reacts. I have used the SMM's on a variety of installs from 10kw and up. I have seen them used with other brands of generators. I have used them to control relays made by PSP.

Do you still have the manual that came with the SMM?


----------



## macmikeman (Jan 23, 2007)




----------



## dockeradz (Oct 25, 2019)

@nrp3 as you said there is a newer version. They have the 6873 and the current version is 7000. I'll pick one up and swap it out and report back...thanks again for the help. If that doesn't work I'll see if they want to try the psp products GLD-50.
@macmikeman HA, heard of that, seems to defeat the purpose. Also that rig would have to sit there a couple hours to get a decent charge...I don't get it.


----------



## Forge Boyz (Nov 7, 2014)

So I am looking at an install that wireless load shedding will make my life a lot easier. How do the PSP relays hold up and do they function reliably? I need to shed the heat strips in two heat pumps.


----------



## nrp3 (Jan 24, 2009)

As far as I know they hold up fine. For larger than 50 amps I use to combine one of their relays and a smm. They have all the documentation for this. Generac has a 100amp SMM now so that’s an option. PSP stuff seems to be pretty good and if you have questions, call and ask, they have been good in the past.


----------



## Glenn rousset (Apr 28, 2021)

dockeradz said:


> I have an install with 2 Generac Smart Management Modules to lockout 2 EV chargers. They are setup to lockout the load when on generator. The manual has an insert that updates the behavior to lockout when the generator gets overloaded. They don't seem to lockout in either of these cases. If there was only one I would say it's bad and replace it, but with 2 doing the same thing I'm wondering if either I did something wrong or they just don't work. They want the load to lockout on generator, not shed.


Put one switch on number 1 the other on number 2


----------

