Battery life expectancy questions

P

portlandtug25

Well-known member
Joined
Jun 17, 2014
Messages
89
Fluid Motion Model
C-26
Vessel Name
Regalo
Hello All,
Some electrical advice would be appreciated.

Trying to decide if it's time to replace the factory AGM batteries In my R25 SC. It was delivered in June 2014 and has just under 300 hours. Only accessories driven by house batteries are the 12v refrigerator and rarely the Espar furnace and of course cabin lights. It's always plugged in to shore power in the slip and rarely do i go more than 2 days without shore power when cruising. Also have a solar panel from factory. On my last outing, after one day without shore power, I didn't have enough house battery to ignite the Espar heater the next morning. The refer was set at its lowest setting and it was not hot outside.. It was sunny the day before so I assume i was getting a little help from the solar panel.

So here are my questions:
1. Is 5 years a typical life span for the factory AGM batteries?

2. If I replace the house batteries (I think there are two of them), should I replace the starting and thruster batteries at the same time? Never any problems starting the engine and I use thrusters very sparingly.

3. How can I tell which batteries are which without disconnecting them?

4. If I replace any or all, what's the best replacement type? I like not having to check water levels , but maybe the AGM don't have the lifespan of a flooded.


Thanks
Electricity is not my forte!
 
1. In my experience typical life is 4-5 years on my 2007 Ranger Tug R-25 Classic for well cared for batteries
2. I only replace them when they start exhibiting signs of age (not retaining charge for the normal timespan for the most part). I replace the house batteries as a pair.
3. If the 25-SC didn't change, when facing the batteries, the two house batteries are on the right, the thruster is upper left, and starter on the lower left. Ranger changed a lot of things over the years on the R-25, so this might have as well. A 25-SC owner of that time period may have a better answer.
4. A loaded question I won't even begin to try to answer 🙂

Thanks,
Doug
 
Following! My batteries are the originals (2012 C26, 4x 110ah AGM’s) and this past week they couldn’t run the microwave. Seems like they’re beginning to tire out.
 
Portlandtug25,

I suggest you review the FAQs at the following website - Northern Arizona Wind & Sun:

https://www.solar-electric.com/learning ... 0Batteries

I recommend this website since they have the expertise from selling and installing solar panels, charge controllers and batteries for storage of solar energy in the harsh environment of Arizona and regions beyond since 1979.

What you will find is that life span of deep cycle batteries in our boats varies greatly by these parameters: battery type, number of discharge cycles, and especially temperature and Depth of Discharge. So, there is no typical number of life span years when batteries in boats exist in all types of extreme conditions affecting these parameters.

A few months ago, I preemptively replaced all the original 5 year old AGM batteries in my R31S. I might have gotten another year or so out of them, but I did not want to potentially deal with dead batteries on an extended cruise with the attendant expense, headache and trip disruption.
 
As others here have stated, battery life is related to how well they have been treated. Roam just replaced his after seven years. He has always been diligent with treating them properly and never had a full discharge. I have flooded and change them every three years, but with the cost of AGM I would wait much longer and not replace until necessary. Initially I would do a load test to indicate the capacity of the batteries. You will find that the engine and thruster battery will last longer than the house since they rarely get discharged. If replacing the house batteries always do both at the same time since one bad battery down the pike can ruin a good battery. Also, if you are using AGM with the engine and thruster stay with AGM with the house. Charger settings for different type batteries are different and you can't mix and match.
 
I believe you shouldn't be able to run the microwave on inverter/battery only. But correct me if I am wrong?
 
All of this is really good advice, based on experience. If you want to do over again what you’ve done so far which is five years of boating battery trouble free replace all four and never look back!

My personal philosophy is to treat my batteries like the delicate roses they are and at the first hiccup around five years out they all go!

3. How can I tell which batteries are which without disconnecting them?

Here you tell who’s who in the zoo by photographing and drawing the connections prior to disconnecting anything.

What appears as spaghetti is actually pretty straightforward, ground going from negative to negative to boat ground all one color and red taking power to where it’s used, these often have a label on them near the battery. Perhaps a few black, fuzed lines carrying power to bilge pumps and smoke detectors and carrying current from the charger.

Perhaps it’s not quite as straightforward as I’m thinking it over.

Start off with newly cleaned and very very tight connections covered in grease and you’re on the way to another five fun battery trouble free years!

You are who we all want to be, a guy who apparently has never had to fiddle with his batteries and never has had his batteries fiddle with him!

Now, if you are as you say, unfamiliar with batteries and can find a boatyard that’ll swap them out for a couple hundred bucks; let ‘em. Also, stick with AGMs.

Me, I’m very familiar with batteries and unless I’m standing tall just looking down on them I wear safety goggles and a full face shield as problems with batteries can involve acid flying through the air.

Thinking it over, taking on four AGMs in a confined space is nowhere to cut your teeth on batteries, treat yourself to a nice lunch while someone else does it. Money well spent.
 
NautiTug":38co1sr1 said:
I believe you shouldn't be able to run the microwave on inverter/battery only. But correct me if I am wrong?
Click to expand...
I will run my microwave off the inverter, however, I will have my engine running so that the batteries do not get a major discharge. I also do that when using an electric coffee maker.
 
My engine was running while trying to run the microwave, and my batteries had been fully charged (which may only be X% charged due to age). I would think that would be enough, even with the older batteries presumably putting out fewer bolts.

The microwave uses a max of 15A at 120V, or 150A at 12V, plus figure an extra 20% to compensate for energy lost in the inversion process. So let’s call it 180 total amps required to run the microwave for an hour.
That means to run the microwave (at full draw) for 5 minutes you need 1/12th of 180ah, or 15 total amps out of your batteries. I wouldn’t consider that a ”deep drain” at all....obviously the longer you run the micro, the more the drain.

It was just strange to me. I had nothing else drawing off the inverter at the time. And the moment we had shore power, the microwave worked perfectly.

Ken
 
BaylorU":2v4e1zvn said:
My engine was running while trying to run the microwave, and my batteries had been fully charged (which may only be X% charged due to age). I would think that would be enough, even with the older batteries presumably putting out fewer bolts.

The microwave uses a max of 15A at 120V, or 150A at 12V, plus figure an extra 20% to compensate for energy lost in the inversion process. So let’s call it 180 total amps required to run the microwave for an hour.
That means to run the microwave (at full draw) for 5 minutes you need 1/12th of 180ah, or 15 total amps out of your batteries. I wouldn’t consider that a ”deep drain” at all....obviously the longer you run the micro, the more the drain.

It was just strange to me. I had nothing else drawing off the inverter at the time. And the moment we had shore power, the microwave worked perfectly.

Ken
Click to expand...


First question is what inverter is installed in your boat? 2000W, 1500W,1000W, What is the peak output and continuous output. If you have a microwave that has a max input of 15 amps a 1500w inverter will not provide enough amperage to operate the microwave. Even with new fully charged batteries. A 1500W inverter is rated for max output of 12.5 amps.
If you have a 2000W inverter with a battery bank 120 AH you will be able to run your microwave for about 30 minutes continuously.A 2000W Kisea inverter, wired to a 180AH battery bank will have no issue powering the factory installed (Cuisinart) microwave (1000w) or convection oven(1500W) with this inverter. A 1500W inverter would have no issue powering the microwave portion, may be marginal for the convection oven.

If you have marginal batteries 70% of rated capacity and have the engine running with a alternator output of 120 amps and your using a 1500W inverter it will output 12.5 amps
What microwave is installed in your boat that requires 1800 watts to operate?

We use our inverter for cooking, electric stove top, microwave, convection oven, coffee, toaster, crock pot, TV, hair dryer, electronic chargers, 12V/120V vacuum, air pump for our paddle board and RIB. We use power management and generally one breaker on at a time to eliminate inverter over load. ( I changed the wiring in the AC panel to all circuits available when using the inverter) This requires an awareness of power management. The inverter does have an auto overload safety shut down but I avoid testing it.. I also use the inverter to operate the circulation blower from the marine air unit. We have used this if cruising on a rainy day. It circulates the air when the cabin/pilot house windows are closed. ( it will not power the compressor) If I had room for a large battery bank I would have installed the Kisea 3000W ( 3000 W 6000w peak, 25.0 amp continuous output. This inverter would power the Air unit. It would require ( 4 ) group 31 batteries 100AH each along with the engine running to properly run the Marine Air without compromising the batteries.

I was interested in this topic because I am installing new AGM batteries. I have always used flooded, maintenance free Deka batteries made by EastPenn. My factory installed maintenance free Centennial batteries (house fail to hold a charge) (Thruster is marginal),( engine battery is still good). My use of house and thruster batteries with the inverter has prompted me to look at AGM D/P batteries. I tend to demand more and full cycle my batteries, more then most. Knowing what the average life expectancy of the AGM is and comparing to my usage will gauge if it was worth the extra cost. I purchased (4) NorthStar AGM batteries Group 27.
 
BaylorU":2ubwkiwl said:
My engine was running while trying to run the microwave, and my batteries had been fully charged (which may only be X% charged due to age). I would think that would be enough, even with the older batteries presumably putting out fewer bolts.

The microwave uses a max of 15A at 120V, or 150A at 12V, plus figure an extra 20% to compensate for energy lost in the inversion process. So let’s call it 180 total amps required to run the microwave for an hour.
That means to run the microwave (at full draw) for 5 minutes you need 1/12th of 180ah, or 15 total amps out of your batteries. I wouldn’t consider that a ”deep drain” at all....obviously the longer you run the micro, the more the drain.

It was just strange to me. I had nothing else drawing off the inverter at the time. And the moment we had shore power, the microwave worked perfectly.

Ken
Click to expand...

Hi Ken,

You are correct that running the microwave for a short period does not amount to a significant amount of the total capacity. However, capacity is not the only thing that is affected as your batteries age. The internal resistance also goes up. When you draw that much current you get a significant voltage drop at the battery output. When the battery is new this drop may be more than a volt, when older it may be several volts. At some point the voltage drop is large enough that the input voltage is not sufficient for the inverter to produce the output demanded.

As an example, We can run the microwave off the inverter even without the engine running on our 3 year old AGMs. When batteries are fully charged with the microwave running via the inverter drawing 90 amps from the battery the battery voltage drops from 12.8 volts to 11.8volts.

Try measuring the battery voltage while the inverter and microwave is turned on. If the voltage drops too much your batteries may no longer have the capability to meet the need.

Curt
 
The batteries that came with our 2017 R25SC are AGMs model 121100 from UPG. Each 110Ah. The specification sheet can be found at http://files.upgi.com:8086/UPGFileServi ... heet/45824.

What is interesting is the data on page 2 showing such things as temperature effect, SOC and open voltage and for me most important, cycle life vs depth of discharge. Depth and frequency of discharge obviously have a dramatic effect on life.

I have combined the thruster battery with the house bank through a switch (photo under 'modifications' in my album) for when I am out on the hook. I got the same numbers as Curt (who I always defer to on electrical matters 😉 ) so I now always run the engine when I run the inverter for the microwave, coffee maker etc.. The alternator has a rating of 14V/180A but that won't be at idle. A Volvo tech told me to think around 140A at idle or about 1680W. Of course a chunk of that goes to the engine and parasitic loads but watching the battery voltage and power output on the 2000W inverter I see little voltage drop.
 
I apologize, as I incorrectly said my microwave was 1500W. I was going off memory. It’s the factory-installed Cuisinart and so it’s 1000W as a microwave, 1500W as a convection oven, as stated above.

My guess is exactly what was being described above was what is causing the issue...voltage drop due to age is impacting it. The microwave will start, and a second or so into running will beep and shut down (when on batteries/inverter/engine running).

I have the 1500W TruPower inverter installed by the factory. It’s a fine unit.

The reason I was saying 1800 watts are required was because you do not get 100% efficiency when inverting from 12V to 120V. All inverters lose an amount of output during the process. I didn’t have the exact efficiency number for the TruPower 1500 when I wrote that, so I estimated 80% efficiency. I just looked it up and it’s actually 85% for all the TruPowers until you get to the 2500W + models, where it jumps to 90%.

Using 85% efficiency, to get 15 amps of 120 volt output, you’d actually need to draw 2,118 watts from your batteries, or 176.5 amps.

Here is the math (all assuming an hour of run time):

Desired Inverter Output of 120V Power: 15 amps x 120 volts = 1800 watts
Required Inverter Input of 12V Power (assuming 85% efficiency and pretending I have a 2000W inverter): 1800 watts divided by 85% efficiency, which is 2,118 watts from the batteries. 2,118 watts of power at 12V (for an hour) equals 176.5 amp hours drained from batteries.

Incidentally, the TruPower 1500’s rated “input amps” is only 150, which I’m wondering if depending on voltage could actually hamper its ability to produce its rated 1500 watts of output. If the batteries are outputting less voltage, simple math would show how quickly the inverter can be rendered incapable of providing its rated output. Later I’ll have to play around with that.

I think I’m realizing (this boat is new to me) that my 1500W inverter may not be capable of running at least the convection part of the microwave. Assuming my batteries are in good order, it should easily run the microwave if that only draws 10 amps of 120V power, but if the convection oven draws 15 amps, then a 1500 watt inverter is insufficient to handle that demand. The TP1500 does have a 3000W “surge” capacity, so it can certainly go over 1500W for a short time, but it’s really not designed to handle a 15A load.

In this case, if the voltage being output by my old batteries is low, it’s clear to me that’s why the microwave won’t run off the inverter.
 
BaylorU

Just for interest, what motor (I’m assuming outboard) do you have? What’s the alternator output at idle? Obviously not enough to bridge the gap with the battery output.
 
I have the 4BY2 180hp Yanmar. The alternator produces 150amps, which is why it was surprising that the microwave wouldn’t work when the engine was running. I think it’s just because A) a lot of those amps go to running the motor (I’d love to know approximately how many amps the boat itself consumes just running the motor, if anyone knows) and B) because the rate of charge going into the batteries was still not enough to compensate for the lower voltage they were producing (or they were already fully charged and therefore the alternator wasn’t adding any additional amperage into the equation).

Would love to hear people’s opinions on that.
Ken
 
Ken,
I assume your engine was at idle. Not sure what current the alternator puts out at idle but probably a lot less than max. Watch your house battery meter when the microwave is running from inverter and let us know what it does.

Curt
 
I did try it at idle and at cruising speed with the same result, unfortunately 🙁

I will definitely report back, but REALLY unfortunately it won’t be for another couple months most likely. Right now I live in Colorado and the boats are in San Diego, which is like daggers in my heart. We’re considering bringing the C26 here for the summer to live on Lake Dillon up in the mountains, but I’m not sure yet.

Either way, we’ll be back in San Diego in a couple months and I’ll look into it. Small chance it will be sooner as I want to maybe send her down to Ensenada for a paint job, but don’t know if I’ll have time in next couple months.

K
 
So I was down at the boat messing around with odd jobs and I thought to have a test. I turned off the shore power and did a bunch of odd jobs for about an hour and a half. With the radio and the fridge drawing on the house batteries the voltage at that point (I look at the digital readout from the solar panel because it is a lot easier than the analogue next to the breaker panel) was 12.7. For interest, the engine battery was 12.8. I then switched over to inverter. The display on the the 2000W inverter was showing 12.7V and 000 for power out output.

I had always thought that my little one cup water heater was kinder to the system than the microwave (which I believe is 800W). Not so when I look at the plate! It's actually rated 1450W!!! So I start the engine. The voltage on the Volvo gauge and the inverter settle at 14.1 after about 30 seconds. Then I turn on the 1450W water heater. The engine takes a noticeable change in tone, rumbling from 690 to 720 rpm, as it takes on the load. The inverter shows it is delivering 1440W and the battery voltage drops to 13.8. After a couple of minutes the water is heated, the inverter shows 000W and reverts to 14.1V.

So what did I learn?

1. Use the microwave to heat the water for my tea in the morning on the hook.
2. Start the engine before putting a load on the inverter. It's much kinder to the batteries.
 
knotflying":3o4k1gg7 said:
We have an electric pot for boiling water. It does a pretty good job.
Click to expand...


What’s the power consumption? If it works well could you share details?
 
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