Having battery problems, looking for some help.

[KevinK]

I have a 2017 Interstate Grand Tour, 10K miles.

Last week I picked it from the service department. They replaced a connector on a wire harness for the water pump and the compressor and control module for the VB air suspension system, all under extended warranty.

I have 4 AGM batteries. Two included with original delivery and two as part of a boondocking upgrade. So they are 3+ years old.

When I parked the RV after picking it up from service the battery voltage before shutting off the main disconnect was 12.7V. A few days later, it was at 7.8V (disconnect was off, there should have been little drain) and I also had a No Comms fault on the inverter.

Service inspected and says the batteries are shot saying they typically last for 4-5 years. In the 3 years we've had the unit (purchased new), we've never had a battery charging issue. This is the first time the batteries simply won't hold the charge.

Question - when the batteries go bad, do they just go bad one day and no longer hold a charge? Or do you think, as I am wondering, if when they serviced the unit for the water pump and compressor, something was inadvertently disconnected and now the battery charging system is not working properly?

Any help or thoughts would be greatly appreciated.

[Hawk-ination]

Batteries are probably shot. We’ve replaced our AGM batteries two years in a row. First year we were new owners and didn’t realize the Interstate would go dead that quickly. Last year, we both thought each other had switched the circuit on and we hadn’t. Damaged the new set which had sulfated and wouldn’t properly hold a decent charge. They still functioned, but at about 75 percent the original capacity. I’ve sold batteries for years but got out of the business when AGM batteries came to be popular. With that said, I am even surprised they just don’t hold out when they are discharged to far or even over just a few years in a RV.

7.8 volts is enough to cause detrimental damage to your batteries.
I just switched our AGMs out for Lithium. You might look at that option for the expense you will be looking at having to replace four AGMs. You can discharge down to around 10 percent instead of the 50 percent on AGMs which is a huge advantage. Plus the fact you can charge and discharge lithium many times over what you can an AGM before they are shot.

[Titus]

Curious what you had to pay for the lithium conversion - batteries, charger, and whatever other components needed to change (BIM?). My Lifeline AGMs are 7 years old and seem to be going strong but I expect to have tor replace them before too many more years. I wouldn't mind the higher price of lithium batteries because of their greater usable power, but wonder about all the associated costs of lithium. I've read that lithium batteries pay off in the long run due to their longer life. But at 7 years and counting for AGM this seems to have poor ROI. I would guess we'd sell Titus before going through our second set of AGM batteries.

[rowiebowie]

Originally Posted by Titus

Curious what you had to pay for the lithium conversion - batteries, charger, and whatever other components needed to change (BIM?). My Lifeline AGMs are 7 years old and seem to be going strong but I expect to have tor replace them before too many more years. I wouldn't mind the higher price of lithium batteries because of their greater usable power, but wonder about all the associated costs of lithium. I've read that lithium batteries pay off in the long run due to their longer life. But at 7 years and counting for AGM this seems to have poor ROI. I would guess we'd sell Titus before going through our second set of AGM batteries.

With my own labor (no charge ), I did a full Renogy2 X100Ah lithium batteries, inverter/charger, DC to DC chargers, Battery Monitor, cables and ANL fuses for just under $3000. A Battleborn + Victron similar conversion would have been about $1000 more. It doubled our usable battery capacity and I was able to relocate them inside, so no cold weather issues.

It ain't cheap, but I wasn't having the luck you've had with lead acid batteries and we wanted to nuke burritos in the microwave without starting the generator. A bargain at only $100 per hot burrito so far.

[uncle_bob]

Hi

If you have Interstate batteries, that's the brand AS uses for flooded lead acid batteries. They normally go with Lifeline for their AGM's.

Properly managed a good set of AGM's ( Lifeline is a good supplier ) should last 5 years. They have a 5 year warranty, so if they don't you can get some money back ( or money against a replacement set ).

https://lifelinebatteries.com/products/rv-batteries/

The easy way to define "properly managed" is to say they are always above 12.6V. Yes, it's more complicated than that, but that's as good a single parameter definition as you are likely to get.

Most people look at lead acid's as something that will supply 50% of it's rated amp hours before it needs to be charged. Lithium's are often considered to be 100% of rated. One can debate those numbers and they do depend a bit on exactly which battery is being talked about.

If you start out with the two stock AGM's, that will give you 200 AH rated and 100 AH usable. A "same capacity" swap would be to replace the two AGM's with one lithium. Pretty much nobody does that. They all go for (at least) two lithium's to double ( or 4X or 6X or 8X ...) the capacity.

The "equal value" point is one battery for $500 to $800 depending on what you buy and when. The only other thing that *has* to be done is to make sure the converter / charger will handle the voltages needed by lithiums. There will be wiring changes, where various systems interconnect ( TV to 7 pin on a trailer, house to chassis on an MH). The lowest cost solution there is to remove a wire and move on.

Lithium conversion can be pretty cheap. Virtually nobody does a "lowest cost" approach. Adding a variety of bells and whistles is part of how it's normally done. We all love our toys.

Bob

[BoatNutG2]

We had a similar problem after getting our 2015 FC 28RB back from storage and renovations. AGMs were shot even though they were only two years old. Turns out they had shorted a connection on installing additional USB/lighter receptacles, this killed the converter. I ordered a new converter off Amazon had it delivered to a friend on our route about 3 days out. Took me 30 minutes to change out. I purchased a couple of golf cart batteries to work until I could get the new converter. My 2 X 100 watt solar panels were able to keep the batteries charged. We didn't use much electric anyways and the shorepower still worked but would not charge the batteries until we replaced the converter. As long as we kept moving daily the batteries stayed charged enough to keep the controls on the refrigerator working, the furnace lighting and the water heater operating on propane and our phones charging. Test your converter to see if it is putting out a DC current that charges the batteries.

[Hawk-ination]

Well, if we’re adding the cost up in burritos, I’d say I have more than about 20 hot burritos going so far. Somehow that way of measurement makes me feel better than the cha-ching sound dropping out of my pockets!

It’s not an inexpensive upgrade, but unplugging for more than half a day makes it worth the cost in my estimation. I debated for a short while, but after thinking about how I wanted to use our Interstate and the frustrating limitations, I stopped thinking and just went with it.

I want to stay and visit family, and parking on hills to plug in, trying to reach the power cord to their outlets, and just things like that made it an easier decision.

I don’t think I’ve added up our total costs, but some of the more expensive costs have been the Battle Born batteries of course. $849 or so on their Black Friday deal. I went with two to start. $90 in 4/0 cable to eventually upgrade to a 3000 watt inverter. I’d be happy to share the tools that I picked up if you’d ever want to upgrade. We’re not that far from each other Titus.

I’m hoping the 10 year estimate for the batteries to even start to decrease their capacity makes them well worth the expense.

[Rickeyt]

I have a 2015.5 Airstream Interstate Lounge. The battery boxs are under the van behind the drivers side rear wheels. It came with Lifeline 24t batterys. I need new both (2) new batteries. Will a Lifeline 27t fit in the box? Has anyone done this or does the battery box have to be modifyed and if so how much?