Many larger class “A” coaches are opting to AGM batteries, particularly if they are all-electric rigs.  This is primarily due to their cleaner operation and they are less ventilation dependant.  We are, however, going to see even greater advances in the batteries from those we use today.  They will offer more power, last longer and be far lighter.

Mastervolt Battery

One new offering that has shown up is the Mastervolt lithium battery.  Currently it is only available in a 24 volt model, but a 12 volt is in development.  Weighing only 115 lbs. its output is equal to four 8D’s.  Keep in mind, the average 8D is over 140 lbs.  That would mean the Mastervolt would supply the same power output at 115 lbs. that four 8D’s at a total weight of 560 lbs. could.  In addition, the makers of Mastervolt claim the lifespan of their battery will exceed that of the 8D by three times.

Now don’t get ready to run out and buy one until you know the price.  At about $7,500 each, they probably won’t be flying off the shelves anytime soon.  Hopefully, after the introduction of a 12 volt model, smaller versions will become available as there are few RV’s that would ever need four 8D batteries.  The future promise may be good as the prices will inevitably come down.




Not to be caught sleeping, Odyessy is redesigning a new AGM product.  Using thin, pure lead plates, their new smaller package promises to deliver dramatically higher output with three times the lifespan.

Battery output and weight is important news for both the RV and the marine industry.  This is because both rely on electrical power not only to start and run, but for powering the comforts of home when away from normal household energy.

Keeping You Informed    –   Lug_Nut    –     Peter Mercer


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  2. Carl, Much depends on your usage and how long you will be keeping your rig. The Interstate should give good service for at least 4 years, providing they are maintained. Trojan batteries have a great rep. but the Interstate are not that far behind. It’s your call, best of luck with your choice. Thank you for your input.

  3. I am currently using the Trojan Series 24 lead acid battery with 140 minute reserve.
    The series 24 is all that will fit in our Class C Motor Home, so I am always looking for better since our kids are not always careful about electricity usage, however price is also a factor on our tight budget.
    These new batteries really intrigue me, assuming the price comes down.

    For now I am going on 5 years on these Trojan’s which is much longer than the previous Interstate lasted (& this is not to knock Interstate as these were fine batteries, they simply did not take the use and did not seem to last as long as these Trojans). My problem right now is money and distance to purchase Trojan Batteries which cost considerably more than the Interstate or “Store” brand, and the Trojans are not even available in our town, so I am thinking of going back to the Interstate or even giving the “store “brand a try.
    Any thoughts if I am being over frugal and maybe should spend the time and money (about $150 more for a pair) and get the Trojan or maybe something altogether different?

  4. Willie Miller, I have total respect for Newmar and their engineering team. I agree with your thoughts and hope one day it comes to market. Thank you for your very expert opinion and great input on this topic.

  5. Willie Miller

    Hey Lug_Nut

    I am a former Newmar engineeer. Was released because of the economy after 34 years of service. These new batteries open up the possibility of an electric drive system for Class A units. It’s not rocket science. Diesel locomotives have run on electric power for many years. The new electronics available could help a lot. I had started to look into the possibility in about 2006. I think the opportunity is there for someone to forge ahead.
    I currently have a 2006 Torrey Pine fiver. Love it.

    Happy Travels

  6. Stan Cencek

    Since we are on the subject of batteries. I am also looking at different ways to extend battery life. Keeping them fully charged using a roof mounted 90 watt solar panel through a charge controller has proven that I could get over 7 years on 2-6 volt deep cycle batteries. Question: I would like to know if there is anyone out there that has been charging their 6-volt house batteries as well as 12 volt coach batteries with one solar panel & if they have, what type of device or devices are you using?

  7. Erik & Jessica Kiehle, I’m not familiar with the allowable charge current for Li batteries of this size, but AGM’s are generally limited to around 14.4 VDC as a maximum. Many RV chargers can be configured to AGM limits, however a resistor of a type is required at the B.I.R.D. to control the engine alternator voltage to the house. Thanks for your great input on this topic.

  8. Erik & Jessica Kiehle

    Would be nice to know about the charging limitations of this Li battery. My understanding of Flooded Lead Acid batteries is that you can charge them at up to 16v if necessary to de-sulfate them. I’ve read charging Gel or AGM batteries at more than 14v will cause damage to them.

    I’ve got a ’93 Class A diesel and traded down from the 8D batteries that were in it originally. They’re just too heavy. I replaced the chassis 8D with a pair of auto engine starting batteries in parallel for more CCA than the 8D. Replaced the house 8D with a random RV/Marine deep cycle. I rarely dry camp so don’t really need the amp hours on the house battery.

    I was tempted by the AGM batteries when I got these others last month but passed on the because I don’t know how to go make sure they wouldn’t get charged at more than 14v by my alternator.


  9. 69RoadRunner, Yes, I would agree, the price will have to come down. The three times the life is certainly worth something, however, nobody keeps their RV that long. Anyway, it is interesting and I’m sure we will see more of this technology in the near future.

  10. 69RoadRunner

    OK, that makes sense.

    I realize that a 12v version would cost less than 24v, but still, they will need to come down in price to be competitive.

    Hopefully this is like a lot of new technology where costs come after the initial launch.

  11. 69RoadRunner, It just occurred to me that the Mastervolt at 160 amps is at 24 volts, whereas the 8D is 225 at 12 volts. The Mastervolt is therefore substantially more amps at 160 @ 24 volts or 320 @ 12. Likewise the 8D is 225 @ 12 volts or 110.5 @ 24 volts.

  12. 69RoadRunner, You are absolutely correct. 160 amp/hrs compared to the average 8D at about 225. I’m not sure, but this comparision information came from the manufacturer and may be based on more than just static 20hrs. amp rating. Thanks for picking that up and great input.

  13. Gregg, Yes, AGM have a good lifespan when compared to lead acid type. Thanks for sharing your experience with them and for your valued input.

  14. 69RoadRunner

    The web site says it only has a 160 amp/hour rating.

  15. Gregg

    AGM’s have been used in motorcycles for years. The upfront cost is more but I had a battery in my first Harley that lasted 9 years. When not riding it I kept it on a battery tender. I just installed an Odyessy in my new bike replacing a battery that was 4 years old. We’ll see how that works out. Normal battery life in a bike is fairly short 2-3 years max. It would be good if the industry would increase the technology for us RV’ers.

  16. Ian McKee

    What is an 8D? I have a37′ fifth wheel which uses 4 6v AGMs which weigh a whole lot less than 140 lbs. My understanding is that 6v is preferable to 12v in an RV.

    What am I missing?

  17. Ray, Glad you found the article of interest. I think we will see some great advances in what we use today for DC power. Thanks for your interest and input.

  18. Ray Ruff

    Peter: That was an interesting article on Batteries. All RVers should be interested in this. I am enticed by these new ideas. I have used 8Ds over the years and have had good luck, only thing is the weight and size. Imagine what a Li-ion about the size of a 12v battery would do for MH, Sincerely Ray Ruff