Battery Replacments August 10, 2025, 11:15:29 am So my current lead-acid house batteries need replacing. I plan on just going to AGM as I really can’t justify Lithium. I seem to recall one of the threads mentioning special handling of solar charging. Is that the case? Does my controller need to be replaced or can I just swap the batteries out. I was looking at these, Trojan 24-AGM Battery on Sale | Advantage Batteries
Re: Battery Replacments Reply #1 – August 10, 2025, 12:31:09 pm The battery market has changed, as the price of LiFePO4 batteries has dropped drastically in the past few years. Now the question isn't whether you can justify lithium--it's whether you can justify AGM. And the answer is generally "no." AGM batteries are rarely cost-effective nowadays.For example, take the Trojan 24-AGM batteries you were looking at. For $500 (two batteries) you'd get 168 amp-hours of rated capacity, of which only about 90 Ah is usable if you want to preserve the life of your batteries. (For comparison, your factory-installed Trojan T-105s had 225 Ah rated capacity when new, of which about 115 Ah were usable.)If you think lithium batteries are out of your price range, you may be thinking of Battle Born batteries, a name that has been talked about a lot in the past. But those batteries are extremely overpriced by today's standards, and not that well constructed. Manufacturers such as LiTime offer much better value. For example, $520 will get you two 100 amp-hour LiTime batteries - and with lithium batteries, you can use 90% of the rated power, not 50% as with wet-cell or AGM batteries. That's 180 amp-hours of usable power.Another brand that several of our members have been happy with is SOK. For $600 you can get two 100 Ah lithium batteries with built-in automatic heaters. The heaters can be useful if the batteries will be exposed to freezing temperatures, as might happen in winter camping.So there's your choice: $500 to $600 will get you 90 usable amp-hours of AGM batteries (less than your wet-cell batteries when they were new) or 180 usable amp-hours of lithium batteries (substantially more than your wet-cell batteries when new). When you look at the specs and the prices, AGM just can't be justified. 5 Likes As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Battery Replacments Reply #2 – August 10, 2025, 01:28:53 pm Andy forgot to mention that Lithium batteries often have a lifetime of 5000 to 7000 cycles. Many more charges and discharge cycles. That means that they don't wear out as fast. Wet lead acid, or AGM's will usually need to be changed out every 5 to 8 years. After the initial investment, it is less expensive over time. In addition the LiF batteries charge faster. When running the generator, or just driving, LiF's will accept a charge faster, due to their lower impedance. That means a higher charge level with less drive time, or running the genset for shorter time periods to recharge the batteries. Also they are lighter. Iron instead of lead. (OK that is an oversimplification) but 35 pounds per battery as opposed to 65 pounds per battery. Versatility of mounting position: Lead acid batteries have to sit with the leads on top. Lithium's like mine can (and are) mounted on end to better utilize the space in my (or your) battery area. Better protection. The internal Battery Management System prevents over discharge, over temperature and over charging. Many include Bluetooth systems that can provide important information about what is happening inside the battery. A link to the ones I wish I had. (I have older and almost double the cost SOK 206's) Amazon.com: SOK 12V 206AH Lifepo4 Lithium Battery, SK12V206H 4000~8000... RonB 1 Likes As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Battery Replacments Reply #3 – August 10, 2025, 02:57:52 pm See? Thats why I love this forum. You all show me the error of my ways before I spend the money. Thanks Andy & Ron. These Li batteries are definitely within my budget. I guess I’ll just get the heated ones because, um, they’re heated!So is this a simple swap with my current batteries? I'm not confident in the current controller. The previous owner was, let’s say, frugal on all repairs. The controller doesnt even have a brand name and i have no idea how it works tbh. Looks like this one, Cheap, crappy controller on AmazonIf I can swap the batteries without any fuss, then great. If you think it’s smarter to replace the controller, well, the job becomes a bit more effort and cost. And I don't have a battery monitor. There’s that, too. As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Battery Replacments Reply #4 – August 10, 2025, 03:06:45 pm Andy's right. The choice now is 2 warehouse club 6V lead acid batteries ($240 + tax where I live, 107.5 usable amp-hours @ 50%) or a budget lithium. Lead acid prices are going up, and lithium keeps going down.I still use Lead Acid, but probably won't buy them again. That will prompt a number of other electrical upgrades though, which complicates things. I also find the Lithium ion market to have a confusing number of choices, while there is 1 6V Golf Cart battery choice at my local Sam's Club or Costco. LiTime has around 40 different 12v lithium choices depending on the size, capacity, and intended use. Even more if you consider 24v or 48v systems.Cheap lead acids are still the way to go, IMO, if you want something simple that just works with what you already have.Rich 1 Likes
Re: Battery Replacments Reply #5 – August 10, 2025, 03:33:47 pm Quote from: Remicks - August 10, 2025, 02:57:52 pmSo is this a simple swap with my current batteries?Assuming your existing batteries are (two) 6-Volt ones, the 12V lithium (or AGM's) will require the cabling to be changed.
Re: Battery Replacments Reply #6 – August 10, 2025, 04:39:14 pm A cabling change? What kind of cabling change. Is there an existing thread that explains more?
Re: Battery Replacments Reply #7 – August 10, 2025, 05:24:54 pm Assuming your two existing batteries are 6V, they are wired in series to supply 12V power to the coach. If you switch to 12V batteries, they will need to be wired in parallel. Lots of info on the the internet but here’s one article:RV Batteries In Series vs Parallel: How To Wire Them Correctly
Re: Battery Replacments Reply #8 – August 10, 2025, 06:22:47 pm Hi Chris: another option that is pretty simple is to just buy one Lithium battery. The S.O.K. 206 is 200AH, about 180 AH usable without damage to the battery. Plug and play, almost no wiring change either. The Bluetooth, with just one battery will work well enough. I have experience with a 2001 stock electrical, almost identical with original equipment on my '99. The Magnetek, or Parallax converter, if you still have that, should be replaced with a lithium compatible (just a jumper change) more modern converter. I have a Progressive Dynamics 4655, 55 Amp. I should have gotten a 65 Amp version. Slightly higher power to put more into the Lithiums, but not with a constantly running fan. These upgrades aren't totally necessary, but the state of electronics has improved a lot during the last 23 years. That solar controller is a bad joke! Maybe yours isn't quite that cheap. If you plan on more solar, IMHO you would do well with the BlueSky Energy R3000i. Many people here have that controller, good up to about 500W of solar PVs. The wiring of course is the hard part, after the original build. As Rich said, the plain old 6v wet lead acid is hard to beat for simplicity and low cost. But low performance. So much more is easily available now. For an established system, stay with 12vdc for compatibility and ease of upgrades. 24v and higher is more for houses. RonB 2 Likes
Re: Battery Replacments Reply #9 – August 10, 2025, 10:10:18 pm You don't need to change anything in the rig to switch to lithium batteries except to wire 12V batteries in parallel, instead of series like the 6V ones. A battery monitor will be a highly recommended improvement for any system, and I would not trust the effectiveness or readout info from your current solar charge controller - but it WILL charge your batteries, as well will your engine and converter.Steve
Re: Battery Replacments Reply #10 – August 10, 2025, 10:28:27 pm Ron made good points, and I hope he'll forgive my summarizing them for emphasis.1. The fact that lithium batteries charge much faster is a huge advantage.2. Lithium batteries weigh roughly half as much per amp-hour as either wet-cell or AGM batteries.3. The Blue Sky R3000i solar controller that Ron recommended is very popular with Lazy Daze owners, because its MPPT circuitry can milk more power out of any panel(s) you have than a cheap PWM controller like your present one. And it can be programmed to charge lithium batteries in a way that maximizes their lifespan.4. It's a really good idea to get a battery monitor, so you'll know where you stand. It's like a (highly accurate) fuel gauge for your house batteries. Most of us have either Victron's BMV-712, or their SmartShunt. The BMV-712 is a gauge that mounts in a hole in the wall, so installation requires some carpentry. But it can also be read via Bluetooth from your computer, tablet, or smartphone with the free VictronConnect app. The SmartShunt has no display; it's Bluetooth-only. Less expensive, easier to install because you don't need to find a wall space for it. Either one will give you really valuable information about how your electrical system, including your batteries, is doing. 7 Likes
Re: Battery Replacments Reply #11 – August 11, 2025, 08:06:44 am Thanks everyone for sharing. Its super helpful and does give kne more confidence to dig in.When someone said “recabling” i was thinking “rewiring”. Going from serial to parallel is not a big deal. Ok, then. Lemme spend some money and get the batteries and controller replaced. And add a monitor. 1 Likes
Re: Battery Replacments Reply #12 – August 11, 2025, 08:30:41 am Ok, one more question. Is it better to get 2x100Ah run in parallel or just 1x206Ah? The price is pretty much the same. In my simple mind it seems logical to just get the one. Simpler cabling and lighter, no?And yikes, the Blue Sky 3000i is almost $300. Thats half a battery!
Re: Battery Replacments Reply #13 – August 11, 2025, 10:00:05 am Have been following these posts closely.....so we have been using the Lifeline AGM batteries since we took delivery from the factory....but will switch to lithium when it's time....I'll be installing the Victron Smart Shunt.....Andy - using your recommendation of using the LiTime 2 pack I believe it's a straight swap out with my Lifelines and the battery cables are interchangeable? Our controller is the Blue Sky 2000E.....I need to update that to the 3000 model or will the 2000 handle lithium batteries? I'm guessing I need to upgrade...Bill
Re: Battery Replacments Reply #14 – August 11, 2025, 10:22:56 am Quote from: Remicks - August 11, 2025, 08:30:41 amAnd yikes, the Blue Sky 3000i is almost $300. Thats half a battery!Blue Sky is what LD installed in later years, but is not the only choice. This pair should work nicely, for less money:Amazon.com: Renogy Rover 40 Amp 12V/24V DC Input MPPT Solar Charge Controller...Amazon.com : Renogy 20/40A MPPT Charge Controller with LCD Backlit, Monitorin...Steve As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Battery Replacments Reply #15 – August 11, 2025, 11:22:48 am If you don't need a display, you might look at the Victron MPPT 75/15 for $66 at Amazon. It is fully capable of handling 200 AH either in series or parallel. Uses bluetooth to your cell phone (no display). I'm really happy with mine. Amazon.com: Victron Energy SmartSolar MPPT Solar Charge Controller (Bluetooth.... Rich As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Battery Replacments Reply #16 – August 11, 2025, 12:24:14 pm Quote from: Rich Gort - August 11, 2025, 11:22:48 amIf you don't need a display, you might look at the Victron MPPT 75/15 for $66 at Amazon. It is fully capable of handling 200 AH either in series or parallel.This model is high quality, but only handles up to 15A of solar in conventional setups. This could limit further expansion.Steve
Re: Battery Replacments Reply #17 – August 11, 2025, 01:05:14 pm I found this one on Amazon. I can't vouch for it working, but only presenting it for price comparison: Victron Energy SmartSolar MPPT Solar Charge Controller (Bluetooth) - Charge Controllers for Solar Panels - 100V, 30 amp, 12/24-Volt It appears to be about double the price of the one posted. While I am inclined to over-engineer things I don't understand well, I also can pay almost $50 for an extra large pizza. Considering the life span of the unit, is the more powered one worth forgoing a pizza or two?
Re: Battery Replacments Reply #18 – August 11, 2025, 01:41:33 pm Here's another vote for Victron. I've used a number of Victron solar controllers (and chargers, battery monitors, and batteries) on various rigs over the years, and I can vouch for their reliability and good performance. I've never had one fail. Right now I have a 75/15 in my truck and a 100/20 and a 100/30 in my Airstream. (I use separate controllers for the panels on the roof and for portable panels on the ground; they're networked together so they coordinate charging.) The VictronConnect apps are well-designed and give a lot of good information in a very readable form, unlike some I've seen. About Victron's nomenclature: the first number is the maximum allowable input voltage (useful in case you want to put panels in series), while the second number is the maximum number of output amps. For example, a typical 100 watt panel puts out about 5.5 amps maximum (although you'll rarely see that much) at 18 V. The Victron MPPT controller will convert that to a higher amperage at a lower voltage (typically about 14.3 V for lithium batteries), so you might see 6.3 amps going to your batteries in that ideal situation. With two 100 W panels, that would be 12.6 amps.From this you can see that a 75/15 controller can realistically only handle 200 watts of solar panels. (I believe this is what Rich meant to say when he wrote "It is fully capable of handling 200 AH"--he meant to type W rather than AH.) 200 watts isn't a lot in today's world, so I agree with Steve in recommending the more capable Victron 100/30 model. That'll give you room for expansion. As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Battery Replacments Reply #19 – August 11, 2025, 01:43:37 pm Hi Chris; The fact that so many Lazy Dazes have the BlueSky controller tells me that they are durable and work well. I like the red LED display, I can read it in dim lighting from a distance. It is easy to reprogram for Lithium. You won't need the temperature sensor or the variable charge levels (for charging lead acid). You also benefit from the group experience with this device. They are available used: Amazon.com : Blue Sky Energy SB3000i Solar Boost 30A MPPT Charge Controller... Compared to a tank of gas, a better controller is a long term investment that will provide benefits throughout it's lifetime. For Bill, you probably do need to upgrade from the 2000i to the 3000i. I believe they are the same size and wiring in the back, so that may be easier. And you need the programmability of the R3000i for Lithium. The Lifeline AGMs are 6volt batteries. All Lithium's I've seen are 12vdc, so you still need to rearrange the wiring from series to parallel. Parts of the wiring cables can be reused. I'd lose that shut off switch anyway. RonB 1 Likes As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Battery Replacments Reply #20 – August 11, 2025, 03:27:15 pm Andy said: "(I believe this is what Rich meant to say when he wrote "It is fully capable of handling 200 AH"--he meant to type W rather than AH.)"Of course Andy's right on, I meant 200 Watts of Solar. Guess I was thinking that 200 Watts of solar is what is USUALLY recommended for 200 AH of batteries. My thought was to keep the cost down with a quality controller if you didn't expect to go over 200 W of solar.Victron has many models with higher capacities, more expensive of course.Rich
Re: Battery Replacments Reply #21 – August 11, 2025, 05:44:23 pm Like many Victron products, these charge controllers work well for folks that like to see it all on a phone app. The Renogy unit I referenced has a display, and the inexpensive adjunct unit gives you the info on a small wall-mounted display, if you prefer that. That said.... I use a solar charge controller behind the wall with no display - and I can't even read it out on my phone, either! That is because a good battery monitor will tell me just about anything I need to know about solar and all charging sources, as well as the batteries. I would start there, and worry about upgrading other devices later.Steve
Re: Battery Replacments Reply #22 – August 11, 2025, 09:52:26 pm Blue Sky’s 3000i fit in the same cutout as the stock Heliotrope controllers used in older LDs, when equipped with an adaptor ring..I prefer having the important electrical information readily available without having to use my phone. Just call me old school.Larry 2 Likes
Re: Battery Replacments Reply #23 – August 12, 2025, 01:26:46 am Quote from: Larry W - August 11, 2025, 09:52:26 pmBlue Sky’s 3000i fit in the same cutout as the stock Heliotrope controllers used in older LDs, when equipped with an adaptor ring..I prefer having the important electrical information readily available without having to use my phone. Just call me old school.LarryLarry - is the 3000i a straight swap out for our Blue Sky 2000E?
Re: Battery Replacments Reply #24 – August 12, 2025, 02:38:30 am I'm not Larry, but the width for both is 6.4", height is 4.6". The 2000E is 1.8 inches deep and the 3000i is 2 1/4" deep. I believe the temp sensor is the same, but you don't need it for LiF batteries. As far as a battery monitor, I like my BalMar SG-200. Sites-WestMarine-Site Although more for boats, I liked the round gauge format to replace the analog temperature display on my old style display panel. After this picture was taken I painted the mounting screws black. RonB
Topic: Battery Replacments (Read 887 times)
previous topic - next topic
Topic: Battery Replacments (Read 887 times)
previous topic - next topic