Inverter for when main engines are running

[OldDan1943]

I have a generator and I am not afraid to use it!!!

 

[rslifkin]

You don't mention the size of your boat. It must be a "Big un". Maybe I didn't understand the post, but whats wrong with running the genny?

pete

I get the impression that this is more of a backup when out fishing (or to reduce generator hours a bit). Avoids the need to run like hell for shore power (before the freezers warm up) if the gen goes down.

 

[TBill36]

RS got it. The boat is a 53 ft Ocean sportfish. The current set up is ac dependent. Even the freshwater pump is 110.

I just want the prevision to be able to run refrigeration and water if I'm far from home and have generator problems.

I'll probably just live with what I have for a while as there are lots of other things the boat needs before I start worring about back-up systems.

My old boat had a Northern Lights gen that never let me down in 20 years. This one also has a Nothern Lights that is a lot newer, so maybe it's nothing to worry about.

 

[Lepke]

I have 2 mains and 2 generators. Before the current inverter I ran a generator any time away from the dock. I did have a 12V 2200 watt inverter I ran at night.

I went to 48v bank and 10,000 watt inverter that supplies 120/240 AC. I run a large reefer, 2 freezers, shallow well pump. All my lights and appliances are 120/240. Only nav lights and radios are 12v. I have 2 Incinolets.
My mains each have a 60 amp 48v alternator. The only time I run a generator is when I've been anchored for 2-3 days. At that time I also make water and do laundry.
When I cook, I either use a diesel stove or induction plates.
I like the 48v because my batteries can be further away from the inverter, need smaller cables, and available inverters have more power.

 

[Simi 60]

If you're staying with lead-acid (flooded or AGM) batteries and don't care about getting the fastest recharge possible from the alternators, you can just add ACRs and skip the external regulators. You won't cook the batteries and they'll still power your loads fine.

I smoked two large frame alternators trying exactly that charging AGM.

 

[Simi 60]

A decent battery bank and a decent inverter seems the obvious solution to me and anyone else who runs a boat on 240/110v power.

 

[Jeff F]

A decent battery bank and a decent inverter seems the obvious solution to me and anyone else who runs a boat on 240/110v power.

That 'anyone else' is a bit broad, no?

I'm skeptical on how long an Ocean 53 is going to keep going running everything from the 12v system. It's not going to be business as usual.

I'm no fan of gensets, but for the OP a second genset could provide unlimited full failover. Getting similar from alternators/ batteries and inverter is going to be more expensive and/or come with a bunch of limitations.




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[OldDan1943]

if you do not want to run your generator, remove it to save weight and space.
if your generator craps out, then rely upon your back up systems.
Someone paid big bucks for the generator so be thankful and used it. (Mumble mumble)
Some folks would love to have a generator onboard and use it everyday

 

[Simi 60]

That 'anyone else' is a bit broad, no?

I'm skeptical on how long an Ocean 53 is going to keep going running everything from the 12v system. It's not going to be business as usual.

I'm no fan of gensets, but for the OP a second genset could provide unlimited full failover. Getting similar from alternators/ batteries and inverter is going to be more expensive and/or come with a bunch of limitations.




Sent from my moto g play (2021) using Trawler Forum mobile app

I don't know anyone out here doing it for real that just keeps adding Genset before battery and inverter.

I guess all of us out here doing it and having continual results must be doing it wrong.

 

[rslifkin]

I smoked two large frame alternators trying exactly that charging AGM.

Good point, depending on the size of the battery bank and the alternator in question, dumping full output with just the internal regulation may lead to a cooked alternator.

Interestingly, I've found my stock 55A small frame alternators seem to de-rate themselves sufficiently as they warm up to avoid cooking when asking for full output for hours on end (which was a pleasant surprise).

 

[SteveK]

Good point, depending on the size of the battery bank and the alternator in question, dumping full output with just the internal regulation may lead to a cooked alternator.

Interestingly, I've found my stock 55A small frame alternators seem to de-rate themselves sufficiently as they warm up to avoid cooking when asking for full output for hours on end (which was a pleasant surprise).

What is the SOC of your house bank when that occurs. wondering if the ALT is allowed to operate under internal reg parameters as there is less demand. As in a certain voltage is reached.

 

[rslifkin]

What is the SOC of your house bank when that occurs. wondering if the ALT is allowed to operate under internal reg parameters as there is less demand. As in a certain voltage is reached.

I've fired up the engines with the house bank around 60% and run for hours before voltage got up to the alternator set points (around 14.1 volts). With both alternators online, I start off seeing ~65 amps into the batteries, which drops down to 40-ish after a few minutes as the alternators warm up and then stays there for a while until the voltage comes up a bit. I have noticed that these alternators will taper current down as voltage approaches the set point (starting noticeably below it) so by the time we're up to 13.8 volts I may only be seeing 20 amps of charge current. That's a slightly odd behavior in my mind (and does result in slower charging), but the alternators don't cook themselves, so they're doing something right.

I think part of the result is that they're only 55A alternators, so even in the small case, they're not particularly power dense. That likely means they can be worked harder (relative to their ratings) before getting too hot than a higher output unit can. There are also no belt guards or anything to restrict airflow to the alternators on my engines.

 

[SteveK]

Your house bank is not oversized for your ALTs working together so they perform as intended. What size is your house bank Ah.
you start off with 65A into batteries, was/is there a load on top of this. an example if each battery puts out 40A, total 80A then 15A is being consumed.
You have a balanced system

 

[rslifkin]

Your house bank is not oversized for your ALTs working together so they perform as intended. What size is your house bank Ah.
you start off with 65A into batteries, was/is there a load on top of this. an example if each battery puts out 40A, total 80A then 15A is being consumed.
You have a balanced system

The current house bank is 415ah. The 65a and 40a were total power going into the house bank. There is a bit of power consumption at that point (electronics, ignition systems on the engines, etc.), so actual alternator output is a bit higher. But they definitely de-rate below their full 55a output once they warm up. The house bank will happily accept 40+ amps until it's around 90% full, so it'll take whatever the alternators give for a few hours after startup when the bank is down to 60% or so.