Using grill and inverter kills my house battery

[RT25_LouLou]

I looked around TugNuts and couldn't find an answer so I'll ask it here. Looking for some help.

When we are at anchor, turning on the inverter to use the grill within 10 minutes of cooking we get the low battery alarm and the house battery shows it's at one bar. Once we turn off the grill and inverter - the house battery shows 4 out of 5 bars and looks charged. All stats look good. Powers the 12V just fine. I'm lost?

Background - before departure, all battery levels are high and normal. Charging perfectly fine on shore power and solar. Under other cruising conditions, not using the inverter, the house battery stays strong and runs all 12V items with no problems.

It's a 2021 R25 OB with only 117 hours on it - batteries "should" be fine.

Thanks,
Ray

 

[Martin610]

We would need more specific details to help you. What kind of batteries? How much power does the electric grill draw?

If you have AGM batteries, which is common, 4 years is a good run.

I have two group 31 AGM's on my boat for the house side. At full power, the electric grill that I have draws 12 to 13 amps at 120 volts AC. That could be 120 amps or more on DC power. That's a lot for batteries to keep up with. You can use a device like a Kill A Watt to see how much your grill draws. You can get these on Amazon.

I find that my batteries can keep up with the grill if I turn it down a bit, using the 4 setting out of a possible 5, and the burgers cook just fine.

Some of the variables you have here are the inverter itself, length and size of cables to the batteries, amp hours of the batteries. No inverter is 100% efficient. Some are better than others.

I'm sure other people can add to the conversation.

-martn610

 

[RT25_LouLou]

I'm too new to the boat to know these things off the top of my head. I'll go to the boat and get that info.

Thanks,
Ray

 

[Chimo]

I would never try and run a 2400W grill, or anything else, on batteries. Our inverter is a 2000W unit so check the rating of yours.

I don’t use the inverter for anything other than a really low power unit without the engine running.

As an example, I was on the hook last week, dropping anchor around 1100. It was a nice sunny day so I was picking up good solar powere during the day. I used the usual lighting and radio overnight and obviously had the LED anchor light on. The following morning my batteries (I switch my thruster battery in with the house at anchor) totaled 315 Ah when new. They are 2 years old so will have degraded somewhat. In the morning I had a battery level of 95% and I wanted to use the microwave to make tea. That only takes a couple of minutes so I’m sure the batteries could have handled it but I started the engine anyway. I made sure the battery charger was turned off and turned on the inverter. When I turned on the microwave I could hear the load on the engine change. Typically the output under those conditions is about 120A at 14V. The engine is supplying the microwave and charging the batteries. The heavy load comes off as the microwave finishes and I turn off the engine.

The d3 in a RT25SC has about a 150A alternator. Check yours in an OB but I suspect it’s much less. Maybe install a Victron shunt so you can see what is actually happening.

 

[croakz]

Does your R25 OB have lithium or AGM house batteries? Is it a NW or Luxury edition?

 

[RT25_LouLou]

Thanks, everyone. Keep in mind I'm new at this, our first boat, and the second owner of this boat. We are learning together. 😀

Here is what I have.
I'm pretty sure it's an NW edition - not luxury.

I have Centennial Marine Deep Cycle Battery DC27MF Group 27 Maintenance Free - not AGM or Lithium - they are Flooded Lead Acid - Maint Free. All 4 of my batteries are this type. I can only guess they are originally from the factory.
https://www.centennialbatteries.com...ycle-battery-dc27mf-group-27-maintenance-free
My OB has a 70A alternator.
I have a Kenyon grill which is a 1300 watt unit and draws 11amps.

Can you run the motor and turn on the inverter to run the grill? Are there no polarity issues? At anchor do people do this often to support 120V system usage? I learned the Neutral Hold button on the Yamaha allows for higher rpm's for battery charging - do people do that as well to help the batteries along? What RPM?

Thanks,
Ray

I forgot to get the inverter number to see what size it is. I'll be back.

 

[DMD3]

We mounted a small Magma gas kettle grill for use while on the hook. Typically use Kenyon while on shore power only. We have 2023 R27LE with 560ah of lithium. When I run heavy loads on the 3000w inverter it gets cranky after about an hour.

 

[Brian John]

A viable option would be to use a Honda 2200 generator on the swim platform quiet and reliable. Saving your house batteries for your less demanding loads.

 

[Martin610]

Yes you can absolutely run the motor while using the inverter. I do that at sea all the time. That's how I'm making coffee or something.

May not help you with the grill though. At full power you are saying the grill draws 1300 watts. Your batteries may not be able to provide enough power, quickly enough, for that demand.

I have a built in generator, but I don't always feel like running that, so I turn down the grill a bit. If I keep the demand at 100 amps DC or less I'm good. A battery monitor is a great help for this kind of application. That seems to cook my food just fine. In general, cooking simple things like burgers or hot dogs is a ten minute project. I don't think that hurts the batteries at all. My batteries are three years old.

More elaborate cooking would likely demand a generator.

-martin610

 

[BB marine]

I looked around TugNuts and couldn't find an answer so I'll ask it here. Looking for some help.

When we are at anchor, turning on the inverter to use the grill within 10 minutes of cooking we get the low battery alarm and the house battery shows it's at one bar. Once we turn off the grill and inverter - the house battery shows 4 out of 5 bars and looks charged. All stats look good. Powers the 12V just fine. I'm lost?

Background - before departure, all battery levels are high and normal. Charging perfectly fine on shore power and solar. Under other cruising conditions, not using the inverter, the house battery stays strong and runs all 12V items with no problems.

It's a 2021 R25 OB with only 117 hours on it - batteries "should" be fine.

Thanks,
Ray

I would expect your battery voltage to quickly show low voltage when using a inverter powering 11amps at 120V. You are using about 122 amps. This means if you grilled for 1 hour you would use 122 AH of stored battery capacity. If you have 2 group 27 maintenance free batteries rated at 100AH each and they are in parallel you have a total of 200 AH of stored capacity. A maintenance free battery will give you about 50 % of its capacity that will be usable in a situation as you are using it in. If you used the grill for an hour with 200 ah batteries your voltage reading would be about 12.2 VOLTS WITH NO DRAW after you turn the grill off.

In your description you had the grill on for about 10 minutes and got a low voltage alarm. Theory states you are using 122amps @ 12.7 V to power the grill. In 10 minutes you used about 21AH of stored battery capacity. This would drop your battery voltage to about 12.5V or 75%. At this time your grill is on using 122 amps which is lowering the fully charged battery voltage to about 12.4V. Now add the ten minutes of 122 amp use which lowers the charged battery voltage to 12.5 Volts add the voltage drop from the amp draw from the grill and the battery voltage alarm will go off because the battery voltage is now below 50%. Turn the grill off and the 122 amp draw is removed and the battery voltage now returns to about 12.5V or 75% charge.

Any time you are measuring what battery capacity you have left the batteries should be at a neutral use. Measure battery voltage with no draw for an accurate reading. Using a Victron battery monitor will take a lot of the guess work out. Even with a battery monitor the alarm will go off when the Voltage thresh hold goes below the alarm set point. But the battery capacity will still read correctly .

I'm not good at explaining this but the bottom line is I don't think you have an issue. As your batteries get used more and go through more cycles of discharge the 10 minutes will probably be 5 minutes as the battery full charge capacity drops.

I may suggest adding another battery to your house bank this will buy you a bit more time. Or get rid of that electric grill that should have never been installed and get a Magna gas grill for the cockpit!!!

 

[RT25_LouLou]

Thanks everyone. This is all incredibly helpful. I'm new to this and I can say this type of forum is so valuable - thanks to @RangerTugs for setting it up and thanks to everyone who participates.

Key takeaways:
I can run the motor and use the inverter to help with battery usage & Buy a Victron battery monitor. I'll do both of these. I'll also do a better job of understanding the load on the appliance/items I'm using.

Other options:
Buy a small Honda generator to support these uses - tying this into my electrical system might be a challenge or I'm using extension cords for everything.
Buy a Magna gas grill - great idea but not sure having two grills is in my future.
When these batteries reach their useful life upgrade to Lithium Batteries!

I'll keep you posted on how this all works out.
Thanks,
Ray

 

[glider4]

Second everything BBMarine said. If you’re not on shore power the electric grill is more of a problem than it’s worth. But nice to have when you are on shore power I’d imagine!
There’s a Ranger Tug video series on YouTube called As The Prop Turns. One episode is on power (aka battery) management.
Converting from maintenance free wet cell batteries to lithium batteries is a really expensive and complicated process. Lots of posts on this forum about all the parts that need to be changed out or reset to make the conversion.
Bringing a small Honda generator onboard is another option with another set of issues.
Good luck!
https://m.youtube.com/watch?v=Uj_am-ecSt4

 

[Rocky Lou]

I'm with Martin610...

If I need power, I can fire up one or both engines and I also have a generator that I rarely use. My highly unreliable Westerbeke 5.0 MCG is never something that I count on working. I've changed most every switch and sensor despite the fact that it has less than 50 total hours.

Of course, this isn't an 'elegant' solution, however, I'm usually only grilling 6-10 grill items and that's about 15 minutes.

 

[Submariner]

Thanks, everyone. Keep in mind I'm new at this, our first boat, and the second owner of this boat. We are learning together. 😀

Here is what I have.
I'm pretty sure it's an NW edition - not luxury.

I have Centennial Marine Deep Cycle Battery DC27MF Group 27 Maintenance Free - not AGM or Lithium - they are Flooded Lead Acid - Maint Free. All 4 of my batteries are this type. I can only guess they are originally from the factory.
https://www.centennialbatteries.com...ycle-battery-dc27mf-group-27-maintenance-free
My OB has a 70A alternator.
I have a Kenyon grill which is a 1300 watt unit and draws 11amps.

Can you run the motor and turn on the inverter to run the grill? Are there no polarity issues? At anchor do people do this often to support 120V system usage? I learned the Neutral Hold button on the Yamaha allows for higher rpm's for battery charging - do people do that as well to help the batteries along? What RPM?

Thanks,
Ray

I forgot to get the inverter number to see what size it is. I'll be back.

On a NW edition if you run the motor, and turn on the grill, thr voltage drop will be immense, the ACR’s will isolate the the engine battery to protect it. Thus, your engine will be running and your house battery will drain, and your engine will not help to run anything.

The grill is 1100 watts. 11 amps is at 120volts. The inverter converts 12 volts dc to 120 volts ac. It’ll draw 91 amps at 12 volts for 1100 watts.

Short answer, I do not recommend anybody with AGM batteries run the electric grill or the hot water heater off the inverter.
I’ve killed two sets of AGM batteries in less than 18 months trying.

120volt ac is why I converted my boat’s house bank to LFP.
And even still, I do not run the electric grill off my house bank. I absolutely can with LFP. But it doesn’t make sense to consume 50amp-hours in about 10 minutes to cook a couple burgers and few hot dogs. I have seen my boat pull 133 amps at 12 volts from 3 AGM batteries, and I had 400 watts of solar to help out. This is not good.

If you want your engine to help out with electrical on a NW edition, you have to parallel the house and engine banks which by-passes the ACR’s which would otherwise isolate the banks. Now you have your engine battery helping. It’s a starting battery, not a deep cycle and thus should not be used for house loads else damage may occur.

The Yamaha outboard with a 70 amp alternator will output at most, 50 amps. I have measured it. The boat will consume 10 amps, the grill another 90, and your engine puts in 50. You still have a 50 amp deficit for a pair of AGM batteries designed to give up 5.5 amps each.

This video I published explains it in more detail.

https://youtu.be/9saVMEZY3YE?si=ybr5IGzbLZTDS4l7

 

[RT25_LouLou]

Again, many thanks for such a detailed and helpful description of the scenarios. I guess why is this grill electric installed if the only time I can use it is dockside under shore power? I guess I'm confused. The other question is how do people cook while underway? The small Kenyon single burner? Of course, if you have an R25 like me 😛

I guess what I'm learning is an alternative power source is the key - this small generator solution now looks much more inviting.

This is all an incredibly helpful learning experience. Thanks. If you are ever in NYC or on the Hudson River come find me.

thanks,
Ray

 

[scross]

Why would FM put in an electric grill that is best used on shore power? Because they think their customers buying that boat will primarily be on shore power - going from full service marina to full service marina. They think you will also get hot water on shore power. Maybe using the boat for day fishing trips but back on shore power by dinner time. The boat was designed for that mission and it does it pretty well.
Our mission is extended cruising and 2/3 of our nights are away from shore power. Our average trip is 10-14 days with occasional 3 week cruises. Our diesel inboard C-28 was designed to work well for that purpose. Hot water from engine heat produced going between anchorages. Diesel cabin heater. Propane powered galley. Bigger fresh water and black water tanks. Room for big solar system. Being able to deploy the dinghy in 3 minutes or less. Easily trailerable to take it from place to place. We don’t have a generator and in 9 years have never used the inverter since we don’t have a need for 110 volt appliances while on our cruises.
We identified our mission first then looked for the boat that had the features that matched that mission. An R-25 O/B would simply not be a good boat for us at all.

 

[Martin610]

The good thing about this forum is the wealth of information available. However, it can be a bit over whelming for someone new.

Portable gas generators can be very useful. There are lots of caveats to using them on board though. Lots of existing posts about them. If you do get one your're not going to want to get it out and fire it up all the time. My generator is bult in and I don't run it all the time.

For some basic cooking I keep a small induction burner on board. I have NuWave as seen here: https://www.amazon.com/Nuwave-Precision ... C93&sr=8-4


I turn the wattage down to 900 watts. My batteries can handle that just fine. You can make eggs, grilled cheese sandwiches, burgers, etc. You need a ferrous metal fry pan of course. It's been a good option for me, might work for you.

-martin610

 

[croakz]

The other question is how do people cook while underway? The small Kenyon single burner? Of course, if you have an R25 like me 😛

We went from a 2014 R25-SC to an 2024 R25-OB and one the things we miss the most was the propane stove. The electrical part of the single burner is fine, but I can't get use to using the burner as an alcohol stove top. That said, we upgrade our solar went to lithium batteries, so we can at least use the electric stove away from the dock 😀

 

[Submariner]

Again, many thanks for such a detailed and helpful description of the scenarios. I guess why is this grill electric installed if the only time I can use it is dockside under shore power? I guess I'm confused. The other question is how do people cook while underway? The small Kenyon single burner? Of course, if you have an R25 like me 😛

I guess what I'm learning is an alternative power source is the key - this small generator solution now looks much more inviting.

This is all an incredibly helpful learning experience. Thanks. If you are ever in NYC or on the Hudson River come find me.

thanks,
Ray

The electric grill is an amazing grill, it cooks fantastic. It just needs shorepower. I know some folks with an LE and 600amp-hours of LFP use it off their house battery. I have 320ah of LFP and would rather have hot water for a shower instead of spending all my battery on dinner. But I also have the R27-OB which has a propane stove and oven. So that's how we primarily cook onboard.

I miss NYC. I graduated high school there, West 18th street, downtown Manhattan, Chelsea district. Lived on Governors Island back when the USCG owned it.

Instead of a generator, you might want to look into this option for your boat.
https://youtu.be/gSgGiuvB9-A

 

[RT25_LouLou]

Thanks again - this has been such a useful learning experience. Please understand my tone is not of criticism for my boat or its parts or FM but more of curiosity and learning...I think tone can be tough on these forums. I'm thrilled folks are here to help. It's one of the things I appreciate about what FM has built. I completely understand FM's choice and who thier audience is! I get that.

I love the induction cooktop idea. It's clever. I also appreciate the point of buying exactly what you need for your boating adventures. We are honestly so new, that we are still trying to figure that out exactly. We are thrilled to be figuring it out on our Ranger Tug R25 - we do love the boat. We do love the Kenyon Grill on shorepower - it's great! We just didn't understand the nuances of its use on the hook. Now we do! Thanks to you all.

I also appreciate the operations and potential use cases for the small gas generator. Honestly, at this time I think we are going to continue to learn what we need and not buy anything until we are completely certain it works for us.

I appreciate the videos from @Channel Surfing - super helpful - I'm a subscriber.

I went out last night to go for a pump out and single-handed the boat - my first time - are there threads about this I could learn from? I won't likely do it often but just in case. It was a super quiet day on the Hudson so it went without incident...but happy to learn more. No I did not use the grill :lol: