AGS (auto gen start) How many here use it?

270win

270win

Well-Known Member
PLATINUM Sponsor
Jul 12, 2009
1,019
Atlanta, GA
Boat Info
1991 Sea Ray 350 SunDancer
Engines
7.4 V Drives
We use AGS to ensure our motorhome has power in case the power goes out while we’re away. With the cold temps we’re having we could have issues if we lost power at the marina during a cold snap. We plan to use the boat all winter.
 
I’m familiar with the concept, we have it on our whole house back up gen. I’m not sure it’s available for a recreational marine gen though. The biggest obstacle is that the 110 switch over circuits are entirely manual and would have to be replaced with an auto switch.

What are you using for a heat source? If you are counting on the reverse cycle heat from the AC unit, it’s not going to provide any heat if the lake water temp drops to a level to be a freezing problem. Once the ambient water temp dropped below 60 degrees, the one on our 280 was useless.
 
Lake Lanier rarely gets below 48-50*. It never dropped below 50* the entire year last year. Currently it is sitting at 57*. When we had the 44DB, I left the salon unit on 55* and never a problem. Now with the 420DA, I have been setting the MSR unit on 55* and it never dropped below 52* last night with a low of 25*. We boat all winter and have never had an issue with any of the HVACs on Lanier not making good heat....

Bennett
 
Last night out cabin temp never went below 65. I also setup a ceramic space heater to help suppliment the onboard system.

I'm only 30 minutes from the boat so I could go up and start the generator is if we lost power.

I also think the water temps staying in the 50s helps keep things above freezing.

I went to check on the motorhome yesterday afternoon and when I was double checking the AGS I wondered if there was a marine option.
 
There are several marine options for AGS but they are typically associated with inverter/chargers and batteries. If the boat is running on an inverter/charger and battery charge is becoming depleted or needs to be supplemented due to load (aka Victron Quatro Inverter/Charger) the system will start the generator and recharge the batteries or supplement the load then shut back down.
What you are asking is should shorepower be lost can an AGS system be implemented to replace the lost shorepower. I would think in most instances that a generator coming on line whenever shorepower is lost would be a waste of fuel. However, to heat the boat in winter conditions or some other critical function it makes sense. To do that though you would first need an automatic transfer switching capability then need some way to determine load demand (ie temperature drop in the boat below a set point) then the generator needs to have the circuitry to sequence a start/run cycle like the Onan eQD series of generators. An interesting design challenge but rather intrusive and expensive.
 
ttmott said:
There are several marine options for AGS but they are typically associated with inverter/chargers and batteries. If the boat is running on an inverter/charger and battery charge is becoming depleted or needs to be supplemented due to load (aka Victron Quatro Inverter/Charger) the system will start the generator and recharge the batteries or supplement the load then shut back down.
What you are asking is should shorepower be lost can an AGS system be implemented to replace the lost shorepower. I would think in most instances that a generator coming on line whenever shorepower is lost would be a waste of fuel. However, to heat the boat in winter conditions or some other critical function it makes sense. To do that though you would first need an automatic transfer switching capability then need some way to determine load demand (ie temperature drop in the boat below a set point) then the generator needs to have the circuitry to sequence a start/run cycle like the Onan eQD series of generators. An interesting design challenge but rather intrusive and expensive.
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Good points. In the motorhome we can set it to come on due to low or high temps, low battery voltage or loss of shore power. Probably a complex (expensive) addition for this particular boat.
 
The marine AGS systems I have looked at seem only to have a high temp turn on, not a low temp, or what I thought would be better is a low Temp and loss of main power combination. If its 32 and below and the shore power fails, I would like some aux heat to come on.
 
Probably would be a fairly easy thing to build DIY. A temp switch, a timer or two and some relays.
 
ttmott covered the AGS side pretty well, the generator should also have a water flow sensor/alarm on it if it's going to be operated in freezing conditions.

The problem with heat pump type of AC/Heating when it's water cooled like our boats are, is when in reverse mode (heat) the water that typically cools the unit down for AC is now expected to be hot water to stop from freezing exchange coils. In short as temps get closer to freezing the "cooling" water flow will freeze very quickly and not allow the cool exchange to happen and burn it self out. I am not sure what that temperature is but it's somewhere around 50 degrees maybe 45 depending on conditions but could also be 55 or so. I have seen the raw water freeze from this in non freezing temps.
 
I'll talk to the people that do our rv service and see what's involved.
 
SKybolt said:
ttmott covered the AGS side pretty well, the generator should also have a water flow sensor/alarm on it if it's going to be operated in freezing conditions.

The problem with heat pump type of AC/Heating when it's water cooled like our boats are, is when in reverse mode (heat) the water that typically cools the unit down for AC is now expected to be hot water to stop from freezing exchange coils. In short as temps get closer to freezing the "cooling" water flow will freeze very quickly and not allow the cool exchange to happen and burn it self out. I am not sure what that temperature is but it's somewhere around 50 degrees maybe 45 depending on conditions but could also be 55 or so. I have seen the raw water freeze from this in non freezing temps.
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That's accurate, but how effective is it going to be? Without a flow sensor the HVAC shuts down with an HPF fault, or lack of "cooling" water flow. But with a flow sensor that won't sense anything until water freezes in the raw water lines, modulating the HVAC may prevent freezing the raw water lines, but in doing so will have to shut off the heat and won't do much for the potable and waste plumbing lines.

If you are going to go in this direction, better to install boat specific heaters like the Boatsafe ones and try and sort out the gen auto start and circuit switching.
 
Henry Boyd said:
... If you are going to go in this direction, better to install boat specific heaters like the Boatsafe ones and try and sort out the gen auto start and circuit switching.
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Exactly, and your right about the additional sensors. As the cold weather protection really has no end of what is needed as it gets colder. Not to mention what do you do about the water tank from partially freezing as well ...

EDIT: I re-read my other post, I was referring to a flow sensor on the raw water of the generator to aid in detecting an ice jam.
 
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SKybolt said:
Exactly, and your right about the additional sensors. As the cold weather protection really has no end of what is needed as it gets colder. Not to mention what do you do about the water tank from partially freezing as well ...
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I was rethinking my sensor comment. Ice blockage should appear in the condenser coil first. So since we are re-designing the 280 HVAC system anyways, I suppose we could wrap the condenser (although in heat mode isn’t it now the evaporator?) with a heating element. Something flexible like the wire stuff used to keep gutters ice free. There would have to be some sort of logic built in, as having a functioning
heating element in the summer would be counterproductive for cooling.

On the water tank it depends on where it’s located. On the 280 the water tank is mounted on a wooden shelf that spans the ER stringers over the fuel tank, where as the water tank on our Sabre lies on the hull over the keel. The 280’s is at a higher risk of freezing given the greater extent of surface surface area exposed to cold air.
 
Henry Boyd said:
I was rethinking my sensor comment. Ice blockage should appear in the condenser coil first. So since we are re-designing the 280 HVAC system anyways, I suppose we could wrap the condenser (although in heat mode isn’t it now the evaporator?) with a heating element. Something flexible like the wire stuff used to keep gutters ice free. There would have to be some sort of logic built in, as having a functioning
heating element in the summer would be counterproductive for cooling.

On the water tank it depends on where it’s located. On the 280 the water tank is mounted on a wooden shelf that spans the ER stringers over the fuel tank, where as the water tank on our Sabre lies on the hull over the keel. The 280’s is at a higher risk of freezing given the greater extent of surface surface area exposed to cold air.
Click to expand...

Funny I had the same discussion with myself about the condensing coils vs evaporator when in heat mode. I never got back to myself on that one. I also thought heat tape might work as well, but hard to keep on the coils correctly I would think.

Yeah I didn't know where the water tank is located so hard to say on the freezing, only it's a concern.
 
For you gassers, don’t forget to include a method to run your blower for a few minutes before your contraption starts up the generator.
 
tc410 said:
For you gassers, don’t forget to include a method to run your blower for a few minutes before your contraption starts up the generator.
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Yep, I hadn't thought about that one either. Very good point.
 
Don't forget any system that is installed and not CG approved would be frowned upon by your insurance company!
 
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