Auto-Gen Start

Anyone have experience using Automatic Generator Start on their trawler? My Selene came with a new Magnum inverter/charger with plug-and-play capability for the AGS module. My understanding is that you set the parameters (example, start at 12.3V, stop at 12.8V), the module auto starts the genny and shuts it down when it reaches whatever you set. Of course, you can turn it off at night or whenever and it has auto-off if genny doesn't start right off. The module costs $285. I'm thinking about adding it to my charging system. Assuming your generator is maintained to same standards as the main engine (I know, that's a big assumtion ;-) seems like a neat feature!

How does the AGS handle the preheating? I have a Magnum inverter that also has the ability to add AGS but so far haven’t needed it.

I used a Magnum AGS in my system with a 4024MS inverter and BMK battery monitor. Really nice. I originally had the original version that just started on voltage. Don't get that one. Get the updated remote and the AGS-N. Why? 1) because it can be set to start on a given SOC%. No unnecessary starts when using the microwave or coffee maker in the morning and temporarily drawing down the battery voltage below the cut-in level. 2) it allows the genset to warm up a little before bringing on loads... because all of a sudden you have (in our case) a few battery chargers, a water heater, and the aforementioned appliances all starting at once. Our old 20kw Onan handled that with aplomb, but it was not good for it in the long run. 3) it also has the ability to program a cool down period with loads off before shutting down.

We were full time liveaboards who hung out on moorings instead of slips and anchored for weeks at a time while cruising. This was a terrific feature, made electrical management a no-brainer and we needed all those we could get on our fairly complex boat.

I have a trace inverter/charger parallel power manager. Its 20 years old now. I liked it so much I took it off my old boat and added it to my new boat. The auto-gen feature is kind of an uncessary gimic but it works very well. In my case I have it programed to come on only between 8am and 4pm and only if the voltage is below 12.2, I can also program in the warm up period. It has only auto started about 4 times in the last 20 years but the last time was quite funny. The wife was at the dock running every concievable electrical appliance and operating the stereo at high volume. She couldn't figure out why evey one walking by the boat was giving her a dirty look, then the gen auto started, she called me in a panic. I had to explain to here that the entire city was with out power and the boat was just doing what it was programed to do.

Thanks for the replies. The AGS I have bookmarked is the "N" model...it "Networks" with the Magnum inverter/charger remote located in the pilothouse. A few weeks ago we added a shunt so I can now monitor SOC, along with other charging parameters. Btw, I read somewhere that this AGS unit "toggles" preheat as part of the start procedure. Maybe Santa will put one under the tree...?

I don't have any experience with the Magnum AGS specifically, but have been using auto gen start for close to 20 years now. I love it, but there is one think you need to watch out for, particularly on a boat.

You need to be sure to stop and start the gen with no load on it. Otherwise you risk burning out the voltage regulator.

If the Magnum inverter is the ONLY load, then you are all set since it will wait for the gen to start before it applies it's load, and drop the load as soon as it sees the gen falter, or before it commands a shutdown.

But on a boat there are typically other loads that do not go through the inverter like a water heater, other chargers, etc. Those loads will have to be manually turned on and off, or just left off when using the auto start. If you want to get fancy, you could automate switching of those other loads, but that's probably more complicated that you want.

nwboater said:

Thanks for the replies. The AGS I have bookmarked is the "N" model...it "Networks" with the Magnum inverter/charger remote located in the pilothouse. A few weeks ago we added a shunt so I can now monitor SOC, along with other charging parameters. Btw, I read somewhere that this AGS unit "toggles" preheat as part of the start procedure. Maybe Santa will put one under the tree...?

Click to expand...

Yes, it does, you program it to fit the exact starting protocol of your particular generator. So in my case, I wired it into the Onan control board, it activated preheat for the time Onan specified, and then the cranking for another specified time. Likewise, the time to hold down the shut off mechanism. Very slick.

I forget the model number offhand, but the N does require you have their top of the line remote. The whole thing made for a really slick, seamless and easy to use system.

twistedtree said:

I don't have any experience with the Magnum AGS specifically, but have been using auto gen start for close to 20 years now. I love it, but there is one think you need to watch out for, particularly on a boat.

You need to be sure to stop and start the gen with no load on it. Otherwise you risk burning out the voltage regulator.

If the Magnum inverter is the ONLY load, then you are all set since it will wait for the gen to start before it applies it's load, and drop the load as soon as it sees the gen falter, or before it commands a shutdown.

But on a boat there are typically other loads that do not go through the inverter like a water heater, other chargers, etc. Those loads will have to be manually turned on and off, or just left off when using the auto start. If you want to get fancy, you could automate switching of those other loads, but that's probably more complicated that you want.

Click to expand...

It's not all that complicated. You have a couple of options. You can install a timed relay to the generator transfer switch .Some generators have this built in. Something like this is used in a lot of back up generators on land. Or, you can simply turn off the panels to the non-inverter powered loads whenever you are using the inverter and turn them on when using shore power or the genset.
Remember, the inverter loads should be on their own dedicated panel.