I have a Xantrex True Charge2 12 volt 40 Amp battery charger in my 2011 Beneteau 40 that charges:

three Group 4D 904D Deka 12 volt  1280 MCA @32degrees F wet house batteries

and one Group 24 DP24685 MCA @32degrees F  wet starter battery.

The boat is plugged in at the slip during the week with the refrigerator, freezer on and I have noticed the battery charger is always on when I return to the boat.

When sailing I have two Raymarine E90W, a Raymarine auto pilot, two ST70 Instrument displays and a Raymarine Digital Raydome 4kw running along with the refrigerator and freezer off of the house batteries.

Under power of the Yanmar 4JH5E, I am running a Balmar 120 AMP Alternator with an external Balmar ARS-5 Regulator System

I have gotten three years of service from the above batteries which are now being replaced.

Can I get more years of service out of these batteries with a better charger....... 

Thanks in advance 


B40 #197

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Replies to This Discussion

Chris, I initially typed a detailed answer but I'm afraid it wouldn't post so here goes a shorter version.

Replacing your 40 amp Xantrex charger isn't really necessary. Yes a larger unit would charge faster but your charger only operates when your shore cord is connected. Unless you tend to stay plugged in for short periods of time your original unit will do just fine. Replacing it won't extend battery life. What will is to install a battery monitor such as Victron brand, and use it to track the amp hours in your house bank. Use too many amps (more than 50% of total) and you'll shorten battery life. A monitor helps you check so you can avoid discharging too much. Also make sure you keep the water to the recommended levels. Performing an "equalization" periodically also helps extended life. Read up on that before you do it though.

As to why you hear it running frequently there are two answers that come to mind. The first is it's simply replacing what the fridge and freezer are using. The second is it may not be the charger you hear but it's cooling fan. Check the voltage the next time you hear it run. If it's charging you'll see the reading go up. If it's the fan the voltage should remain the same.

Your overall setup should serve you well. I have a similar set up and I'm quite pleased with it's performance. I think the only difference is we have 4 6V Trojan T104 golf cart batteries for a house bank. They're apt 6 years old and still going strong.

What are you replacing the Deka's with?


H Mike:

I just replaced the above house batteries with identical batteries except the 

Group 24 DP24 685 MCA @32degrees F  wet starter battery was replaced with a Group 27 DP27.

Thanks for your reply!


Chis, I have a 2008 B43 with what I expect is the same charger. Its a Xantrex 40 Amp.

It does "run" a lot. As Mike responded. the fan is often on. Mine has done this  since essentially day one, cycling often.I have 660 amp hours of house AGM's and a starting battery and a thruster battery (both AGM also) and the charger has handled the duty well. ps, I just changed out my house batteries after 9 years of service life on the Lifelines(6 6volt )

Mike's suggestion of adding a real battery monitor ( I too have the victron) is spot on. With it you can actually tell what is going on and the state of charge . Relying on the Beneteau panel is problematic.

I would install the monitor before changing the charger unless you know for a fact it is not functioning properly.


Longhawk B43, 2008

Thanks Sam!

Good to know.

All the best,


TENACITYII B40 #197, 2011

All great advice!

Did you check the charger's "battery type" selector switch position (flood,gel,agm)?  Mike gave a very good recommendation  (equalization on occasion).

Our Dekka agm's ( 396ah house and 98ah engine) gave us over 7 1/4 years of usage before replacement . The batteries were still accepting charge at over 7 years but we noticed the battery charger seemed to be running continuously.

The batteries no longer reached "fill" with "bulk charge" voltage from charger. The charger continued  charging the old batteries,  attempting to attain 14.3-5 volts but, due to battery "sulfation" after 7 years of usage, the batteries would not accept the increased voltage so the charger just kept running trying to reach "full" voltage. Batteries became very warm to touch ( very warm, not normal warm) when this began to happen. We replaced batteries, charger operates fine.

Refrigeration requires 12volt power and even though the battery charger is keeping the batteries charged while you're away, you're still "using"  battery power (hours) thus reducing battery lifespan. If you wish to prolong the batteries life you may wish to avoid leaving refrigerator/freezer on when a way for extended periods.

We have 280watts of solar power ( with solar controller) that ensures batteries remain topped off while away and we do not leave our boat connected to shore power to minimize galvanic corrosion possibility. We do not leave refrigeration/freezer on when away for extended periods. All thru hulls are closed prior to leaving boat.


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