While the “chassis” batteries start your RV’s engine, it’s the “house” batteries that power the interior lights, vent fans, water pump and other 12-volt equipment. Through the use of an inverter, which converts 12-volts DC into 110-volts AC, they also power the coffee maker, TVs, microwave oven and other household appliances.

Like the rest of our equipment, we take good care of our batteries. But after 6 years of service, we were ready for a new set. We decided to replace the house and chassis batteries at the same time and thoroughly clean and paint the battery tray, too.

We chose to splurge on a set of Lifeline AGM (Absorbed Glass Mat) batteries. They’re direct replacements for our old 6-volt lead-acid deep cycle batteries, with a bank of four, wired in series-parallel. But they’re completely sealed, accept a charge faster and perform better in every way. They’re just extremely expensive!

Since we completed the job in the Phoenix area (where golf carts are everywhere) and there was still some life left in all of our old batteries, we posted them for sale on Craigslist. They were gone in under an hour. The $100 we received from that sale helped to offset a little bit of the cost of new batteries, plus it saved us from having to lug them to a recycling center.

Since it was four years ago, before we started making how-to RV videos, we’ll be demonstrating the process without actually doing the work. But you’ll clearly see how to do this job, which isn’t too challenging for a handy DIY RVer.

If you’re interested in splurging for an awesome (but very expensive) set of AGM batteries like the ones we bought, you can find them on Amazon by clicking the following link. Just be sure you’re sitting down before you look at the prices! ;-)

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  1. Hi guys, thanks for all the information and advice you are providing. I own a 2015 Thor Palazzo 33.2 and it’s been sitting for a long time (9 months) up to few weeks ago I could started just fine. but since last week I plugged in the outlet to get it charge, but it seems like instead of charging it drain it completely. I looked all over (places I could check) but nothing I could find that shows it’s a problem. What can I do to fix this so I can start the rig and take to a shope.
    Thank you for any advice you can give me.

    1. Hi Habib! Sorry to hear that you’re having trouble with your Palazzo. We’re not that familiar with your particular RVs wiring (and, unfortunately, every manufacturer does things a little different), but we did look on the Thor Palazzo Owner’s Forum over on iRV2.com (https://www.irv2.com/forums/f281/) to see if we could confirm if your RV has a similar system to ours =(it’s called a Bi-Directional Relay Delay… or “BiRD” for short) for charging the chassis battery when you’re plugged into shore power… and it seems like it should. So… it sounds like yours isn’t working the way it’s supposed to.

      That said… you have 2 options for getting things working so you can get the RV into the shop:

      1. Check on your dash (probably to the left of the driver’s seat) for a switch that says something like “Batt Boost” or “Aux Boost”. That switch should trigger a relay that connects your house and chassis batteries together… and is designed to let you use your house batteries to start the engine in an emergency (like when the chassis battery has gone dead). So if your house batteries are charged, that should work to allow you to start up the coach so you can get it into the shop.
      2. You could put a standard battery charger on the chassis batteries to see if you can get them charged up enough that you can start the engine.

      Hopefully one of those two options will get you going so you can get this problem fixed!

  2. Hi! How do I know what type of battery to use for chassis starting battery? My 30ft RV has a 1986 Ford E350 chassis, do I need a 29group deep cycle marine/RV batt to start it? Or what?? I have been driving it for 5yrs and parked it a year ago and need a new battery now

    1. Hi Mama Moonlit. No, your RV’s starting battery does not need to be a deep cycle battery. Quite the opposite, you want one with the correct “Cold Cranking Amps” (CCA) rating to ensure it has enough amp output for the sudden boost needed to crank an engine (while deep cycle batteries are designed to provide lower power outlet over a longer period of time). You’ll want to check the battery currently in the engine bay and look for the label to determine the Group Size and CCA rating… then get a replacement to match. If you can’t find/see the label, any major auto parts store or auto battery supplier should be able to look it up. Or you could try calling a local Ford dealer to see if they can tell you what specs your battery is.

  3. Hi RVgeeks,
    I have a problem with the house battery setup on my 2014 Bounder 35k. The cables to connect the 2 6 volt batteries are not labeled and I can’t figure out which ones go where. I know that the batteries should be connected in series, but I’m not knowledgeable enough to figure out the rest of the story. Ideally, if you have a diagram and/or a picture or a website that I might get the information from I would be grateful.

    1. Hey Ronald. Sorry to hear about this. You’re right, the two batteries need to be connected in series in order to turn them into one big 12-volt battery (so one short cable would connect the “+” of one battery to the “-” of the other… you can see a diagram showing that a the top of this page: https://www.atbatt.com/how-to-wire-6v-batteries-in-series-or-parallel-configuration/ ). But the REST of the wires are where things may get a bit more tricky. In general, with only two batteries, it SHOULD be that the red cables will connect to the remaining “+” terminal while the black ones would terminate on the remaining “-” cable.

      BUT (and you knew one was coming, right ????)… RV manufacturers all wire things differently, so there could be some “surprises” that don’t follow the general rule. And, since you don’t want to risk shorting something out or damaging anything, you do have to be careful.

      We’d suggest that your best bet would be to ask in the Fleetwood Owners’ forum over on iRV2.com (http://www.irv2.com/forums/f107/). You can search the forum to see if anyone with the same year/model Bounder has already posted a picture of their batteries & cables. But if no one has, it’s free to join so you can post your question. It’s very likely that someone will be able to take a picture of their setup and post it so you can see where things go.

      Sorry we can’t be of more specific help on this one!

  4. Well, woke up to dead house batteries so time to replace. Fortunately, I remembered this video, so I took a bunch of pictures and numbered everything before I tore them out… thank goodness for that. While I had the batteries out I thought, ‘what would the Geeks do here? ‘Replace the batteries and call it a day?’’ Nope! So, I cleaned and painted the battery compartment and replaced the problematic house solenoid switch (followed same procedure numbering and photos). Worked like a charm! Thanks again for the videos and inspiration.

    1. Uggghhh… sorry to hear about that, Mark. There’s nothing worse than waking up to a problem like that! Glad our video was helpful and that you got the project done without incident… but sorry if our OCD rubbed off on you and made the project longer! LOL! ;)

    1. Hi Steve! We bet you’re going to love your AGMs. They’re a lot of battery performance for the money. We only have AGMs for the house, and actually haven’t heard of them being used for chassis/motor batteries before. They’re really great for deep cycling, like house batteries do, and there’s almost certainly no reason to spend the extra on them, even if they are available for chassis/motor/start battery use. One thing… make sure that if your inverter/charger has a setting for an “AGM” charging profile, you choose that one. If not, simply follow the instructions from the AGM battery manufacturer.

  5. Just wanted to thank you guys…..I was able to replace my chassis batteries with success. Numbering the cables was key to the success. Great video.

  6. How does one find out why your house battery goes dead even if you think everything is off and even the engine battery is disconnected?

    1. Hi Pete! Unfortunately, the single most damaging thing that can happen to the house batteries is to go completely dead. And each time it happens, it damages them further, continuing to shorten their lifespan. Once it’s happened, it can become a spiral of poor performance and inability to hold a useful charge. The way many RVs are wired to the batteries can be more complex than just a single connection that’s turned off with one switch… even the “battery disconnect” switch. There are often parasitic drains that the disconnect switch doesn’t disable. The only sure-fire way to 100% disconnect those drains is to remove all of the ground wires from the batteries when storing them. Before you go about replacing any batteries, you might want to determine if there’s some other issue with the system, such as a charging problem or short. The last thing you’d want to do is install new batteries into a system that just killed the old ones. If you’re comfortable that the battery bank normally works fine until they sit in storage, you should be able to replace your batteries if needed, without endangering the health of the new ones, as your charging system is likely working properly. Then make sure you always remove the ground leads before storing. The other (even better, but not always available) option would be to keep the rig plugged in to shore power to keep the batteries trickle charged while in storage. Again, we know that’s not an option in many situations. One other factor that might be causing the problem is battery age and/or condition. If they’re more than 4-5 years old, or have been drained dead several times, or show signs of bulging, they might be ruined and unable to hold a charge no matter what. Winter conditions may also contribute to the problem. The colder it is where you are, the more robust the batteries need to be to make it through periods of storage. Hope this helps a bit.

  7. Great help on replacing RV batteries. Replaced all 6 batteries in our RV and did some cleanup of the battery area and preventive maintenance while in there. Your video was a great help to me getting the job done right the first time. Thanks! Hope to see you guys on the road sometime. Bill Bircher

  8. We have a 2016 Class C View, 24J, and would like to replace the stock 12v batteries with four 6 volt batteries for boondocking. As these are very heavy, just wondering where we would place these? The two 12v batteries are under the door step, so we would have to completely relocate the battery bank. Of course we have plenty of storage compartments on either side of the coach, but curious as to if the storage flooring would support four heavy batteries? Then, of course, wiring?

    1. Hi Tim,

      Good question. We haven’t ever MOVED our batteries, so we don’t have any specific recommendations. Especially since the arrangement and placement would be different on every RV. You could probably get away with replacing the two 12V batteries with two 6V where they are and wiring them in series to equal one 12V battery. Then put another pair of 6V units as close nearby as you can, again wired in series to equal 12 volts. Then just wire the two sets in parallel and you should be good to go. Use heavy gauge wiring at least as heavy-duty as what’s there. One thing about any consideration of moving them to a new location…. if you’re sticking with deep-cycle lead-acid units, they MUST be in a ventilated compartment. AGM’s don’t need venting, so can be placed in a closed compartment, and perform better overall, but are more expensive. We’d suggest posting your question on the forums at irv2.com to elicit more responses from others.

  9. have a problem with a 1994 Newmar Dutchstar:
    serial # m34-61105-94
    model # 34 cbs dsdp
    We are having a problem with the charging system:
    1. the coach batteries charge up with out any challenges;
    2. the chassis batteries do not charge up at all; even with the generator;
    3. there is not (I am advised by Newmar service) a wiring drawing available for the coach (just did not retain them prior to the new computer system I am told);
    4. I have an extremely knowledgeable electrician who has checked as much as possible but he is not able to identify the problem;
    5. when I try to turn off the coach power by using the coach cut off switch above the entry door, the red light does not go off;
    6. David wants to know (if anyone knows) what the purple wire out of the electrical control bin, possibly that might assist in the identification the problem.
    any thoughts that might assist????
    A great product. It has been super since /94 and this is the first problem that we have had.
    Any suggestions would be appreciated.
    Ken Whent

    1. Hi Ken,

      Our first suspicion is that this involves the bi-directional relay delay (BIRD). We’ve been searching online for a schematic for your coach (there are lots of them out there for various makes, models and years of RV), but have not found one yet. We’re guessing that there is probably a lot of similarity between our own system and yours, but with components possibly located in various different places than ours, which are mounted on the back wall of our main electrical compartment where shore power comes in.

      If it would help your electrician to see the wiring diagram that includes our bi-directional relay delay and battery shut off, we just uploaded it to our server, which you can access here. We’ve also included the wiring color legend for our system, which might help in the process:

      Also, here’s a link to Intellitec’s information sheet covering exactly how the bi-directional relay delay works:

      Your question is very well crafted to relate the problem you’re having, so we would suggest getting in front of the widest, most knowledgeable audience possible: the user forums on iRV2, specifically the Newmar Owner’s forum. If you’re not already familiar with it, there are thousands of knowledgeable RVers (and many techs too) who are happy to share their experience. It’s free to join and post a question. Here is the Newmar Owner’s forum: http://www.irv2.com/forums/f103/

      Hope this helps a bit. Best of luck and please let us know how you make out.

      Peter & John

  10. As usual, I really enjoyed the video on the batteries. You have the most professional voice for videos I have ever heard. I also have a Newmar Dutch Star (2001) and recognized the battery diagram on the front of the tray. I had to replace my batteries about 3 years ago due to low electrolyte levels from the charging system over time. I might mention that when I had the batteries all out I checked the roller bearings on the battery tray. Lubed where needed as I wanted the tray to slide smoothly and now was the time to check as there is a lot of weight on those bearings. I would be curious about your procedure on keeping the batteries charged! I had read the inverter/battery charger manual and found that it was a 3-stage charger. It was suppose to decrease to a trickle charge when the batteries were fully charged. However I did not check water level during storage (about 6 months) and the batteries were almost empty of fluid which damaged them. Since then I have turned the charger on and off to prevent this from happening again and installed a filling system on the batteries. Any other suggestions would be appreciated.

    Thanks again.

    1. Hi Rod. Thank you for the nice comment. Sorry to hear you had a problem with your batteries. As you found out, flooded-cell lead-acid batteries definitely do not like having the electrolyte level drop below the top of the lead plates, so it’s great that you’ve now installed a watering system. The most important thing to do with batteries is to keep them clean, charged and watered properly. We suggest checking the water level at least once a month and keeping them fully charged. A three-stage charger is the best for maintaining them, so you should be in good shape there. Here’s a video we made a few years ago with some tips about battery maintenance that you might find helpful:

      1. Thank your RV guys for all of your videos. I was full time (5 years)12 years ago and am getting ready to go again. It is hard to believe how much i have forgotten over the years. You videos are great for refreshing my memory. I am considering the AGM batteries that you purchased. I have read that most RV’s need to have the charging system modified for that battery type. Is there any truth to that?

        1. Hi Mike! Thanks for the nice comment. The system should not need to be modified, but there are settings that should be changed on your charge controller. It needs to be switched from flooded cell to AGM, which will assure that your system uses the optimal voltage for each charging stage. AGM’s typically use higher voltages for each stage, and changing the setting will provide that. If you have heard about replacing the charger, it’s true that you can get the full benefit of AGMs by switching to one than can provide a much higher charge rate than typical RV units, since AGMs can safely accept that. It’s not essential to make that change (we never did it), but it’s an option if you want to go whole hog and charge as quickly as possible. Hope this helps, and hope you have a wonderful re-launch into full-time life! :)

  11. Your videos are always so helpful. I am planning to add some boondocking capabilities to our RV when we pull it out of storage in the spring and I had heard some good things about AGM’s. They may be a bit cost prohibitive for me in this first application, but it’s definitely good info for the future. Thanks so much!

  12. You guys are great! Love your how to videos. I’ve also noticed yours is such a fine coach, the quality is evident in each of your vids.

  13. This is the third time I’ve tried to leave a comment. I keep getting a time out error, after hitting “Post Comment”. Most frustrating. I had to post my previous comment twice before it took it. Two different browsers, Chrome and Safari, both giving me issues here.

    Therefore, I’m gonna keep this short. Don’t forget that the metal surrounding the battery box is part of the ground. If you use an extension that’s too long, and the improper procedure, it’s possible to get a nasty spark from the battery’s positive post to frame and body.

    Your “confident DIYer” comment is true. Batteries are heavy, over 60 pounds each, and in some coaches, like mine, in an awkward position. If you have any doubts, or physical limitations that would preclude safely lifting and placing the batteries, leave it to a professional.

    1. Sorry you’ve been having a problem with commenting, but glad you got through! We just had the same problem trying to reply to you (after everything was fine up until yesterday) and had to reply via the admin panel. We’ll be getting to work on troubleshooting momentarily.

      Thanks for pointing out the weight of the batteries. A fair degree of physical strength is indeed required for this job, especially if the batteries are hard to access. We take for granted that people know that batteries are heavy, but we should have mentioned it anyway. Thanks for doing that. In addition to “confident” we also purposely talked about the potential for “fire or explosion” to warn (scare?) away the timid. ;-)

      Whenever removing ANY battery from ANY vehicle, always remove the negative lead first and replace it last, as mentioned in the video. This is done to prevent the exact danger you mentioned. If the negative lead were still connected while loosening or tightening a positive terminal, touching the frame of the vehicle with the wrench would complete the circuit and cause a spark. Once the negative cable is removed, the circuit will not complete due to having already separated the battery ground from the chassis, so no spark. This should be standard operating procedure in all vehicles when removing or installing any battery.

  14. I also installed two (very expensive) Lifeline AGM coach batteries about a year ago; for me, easily worth the cost. Advantages?
    1. They can easily handle much higher charge rates than lead-acid batteries; up to 55 amps for me. Much faster charging when boondocking.
    2. Self discharge of 1-3% per month vs 5-10% (or higher) for lead-acid. No need for a trickle charger. I can store all winter in a storage lot (DC disconnected) and startup in the Spring with no problem.

  15. Very good info as usual! I took this a small step further last year and numbered the sides of each battery with a sharpie. I then affixed permanent labels to each battery cable, marking them just as you did in the video. I now have the proper cable routing permanently marked for future use. For those of you like me who can’t justify the expense of AGM batteries (we rarely boondock), I highly recommend the Pro-Fill battery watering system. It makes topping off lead acid batteries a breeze, and virtually eliminates acid corrosion issues. Thanks again for the video….I was hoping to win the little compressor this month, darn it! LOL!

    1. Thanks for the great suggestions about permanently marking the batteries and cables and the Pro-Fill system Craig. You also made great point that we forgot to mention… one of the best justifications for the added cost of AGM batteries is boondocking frequency. The more you camp off the grid, the more worthwhile the investment. Sorry you didn’t win the compressor. We’ll be working to line up more cool giveaways this coming year, so stay tuned for more chances to win. :)

  16. Hi Guys. Another video of helpful info. As for the ratchet shorting out across battery posts: Put a sleeve on the ratchet handle using vinyl tape, shrink tubing or any non-conductor that won’t slip off. I store my taped up box end-wrench with my batteries so I can check post nuts when I check and service the batteries.

    As for the Lifeline batteries, dam they are expensive…

    best holidays,
    mike in san jose

    1. That’s a great idea Mike! Thanks for the tip.

      And you’re right… AGMs cost a lot, but as we mentioned in a reply below, we thought about the difference between new flooded batteries and AGMs instead of just looking at the total cost. That helped us swallow a little less hard when the credit card bill came! ;-)

  17. Another great video, thank you. Most shops want you to take in your old batteries and will give you a discount against the price of the new ones. Hope you had a Merry Christmas an all the best for the New Year.

  18. Thank you for another informative video. Since replacing the lead acid batteries with AGM do you have any performance data which would help in the decision to make the change to AGM? Do they recover faster when recharged by your solar panels? Merry Christmas!

    1. They definitely take a charge a bit faster and hold their charge a bit longer, and supposedly will last longer (of course on that count, we’re only 4 years in, so too early to report). But we can’t say we have any hard-core data on exactly how much better they are. We’d suggest that they’re not better-performing enough to warrant the cost, except in one area that mattered to us a lot… maintenance. We were constantly tending to the old batteries, cleaning up corrosion, checking and adding water, equalizing, spraying anti-corrosion spray (that’s what all that red stuff is on them at the beginning of the video). With AGMs, we do absolutely nothing. Ever. (okay, we dust them off once in a while, but that’s just part of keeping the whole RV clean).

      They simply work, no rust, no corrosion, no mess. If that’s important to you, and you can manage the extra cost, it’s great to never even think about them, with the added bonus hopefully being a few extra years of service, too. As we said, it was a big splurge for us, especially because we’re not rich, and it was a very big decision to spend that kind of money. But each of us has to decide where we want to put our funds, and this choice improved our quality of life by allowing us to completely forget about the batteries, vs tending to them all the time. Haven’t touched them in four years, and would do it again…. although we paid $1,180, and I see that they’re now over $1,300.. so the decision keeps getting more difficult. lol We looked at it as the difference between flooded batteries and AGMs instead of the total cost, and that made it a little easier to go the more expensive route.

  19. Good information, thanks. What battery part number did you use for the chassis battery? Also, could you tell me what brand/part number did you previously have?
    Thanks in advance.

    1. Our original house batteries were Interstate model U2200. The original chassis batteries were made by Douglas, but the only reason we even remember that is we can see that in the video. lol Not sure if the brand matters too much and we don’t even know what brand our new chassis batteries are (sorry we’re traveling away from the coach for a couple of months, so we can’t check right now). You’ll need to get the size and Cold Cranking Amp rating off your old chassis batteries. The physical size is of course important so that the replacement will fit in the same space, but you also want to match the CCA rating, which will ensure that the new battery will have the right amount of cranking power to start your engine. Hope this helps!

  20. I have a travel trailer and plugged it into my home but now I see the relays by the battery are melted the wires are also melted could that be from not enough voltage from my home to the trailer

    1. Your issue can not be truly answered by the info given, Your issue could be from both “Under voltage” or “Overuse” so you need to first know which is your problem and yes you might need to hire a pro to find out for sure. But yes you must find out before there is a fire!!

    2. James, if you aren’t sure what to do and can’t get to a professional ASAP, you should disconnect from the house and disconnect the batteries. This is a potential fire hazard and dangerous situation.

  21. Once again I have learned more from you and your videos than from the self proclaimed “experts”. Thank you. Keep em comin’.

  22. Wow! Glad I heeded your advice and was sitting before clicking the eBay link to check the price on the AGM batteries.

    Thank you for yet another great how to video.

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We're handy RVers, not professional technicians. We're happy with the techniques and products we use, but be sure to confirm that all methods and materials you use are compatible with your equipment and abilities. Regardless of what we recommend, consult a professional if you're unsure about working on your RV. Any task you perform or product you purchase based on any information we provide is strictly at your own risk.

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