Battery type costs February 04, 2019, 04:16:09 pm It's that time again. Baxter needs a new set of batteries. Sooooo being as I being retired and all ....... and my wife claims I think too hard about stuff (plead guilty). I put together a small spreadsheet to help get my mind around the issues. Some disclaimers from the get go. 1. I graded the numbers from various sources. They may be a tad off here and there but I am confident they represent a fairly good snapshot of reality today. Battery Types - Cost and BenefitsExplanation of some of the numbers --- 1. Under cost you'll see two numbers first number is the cost of one battery the second is the cost of two. 2. Cost per cycle is the cost divided by number of advertised cycles of said battery. Observations and thoughtsA. Wet Lead Acid and AGM's should be recharged back to 100% as soon as possible. Lithium can be at any discharged state without harm.B. Lithium can be used at any temperature but can not be charge at 32 or below. C. If use usable amp/hours by cycles for AGM I'd get 55,000 at a cost of about .02 per a/h, Lithium 500,000 at a cost about .004 per a/h, Wet Lead Acid 60,000 at a cost of about .005 per a/hAll the above numbers assume a perfect set of batteries used in a prefect use case. Looks like to me the cheapest path is Lithium. That's a kind of surprise to me.
Re: Battery type costs Reply #1 – February 04, 2019, 05:23:22 pm Quote from: colddog - February 04, 2019, 04:16:09 pmIt's that time again. Baxter needs a new set of batteries.2. Cost per cycle is the cost divided by number of advertised cycles of said battery. Observations and thoughts C. If use usable amp/hours by cycles for AGM I'd get 55,000 at a cost of about.02 per a/h, Lithium 500,000 at a cost about .004 per a/h, Wet Lead Acid 60,000 at a cost of about .005 per a/hIf the number are right, lead-acid seems to be a goodl choice, since nothing needs to be changed, except, possibly,for the addition of a remote watering system.All the above numbers assume a perfect set of batteries used in a prefect use case. Looks like to me the cheapest path is Lithium. That's a kind of surprise to me.Lithium is nice, assuming a battery will actually last for as long as claimed, but the upfront cost of over $3000 causes me to step back. I'm surprised how close lead-acid and lithium batteries are. Sure the decimal points are in the right places?If the numbers are right, lead-acid looks likes a good choice and simple to do, as nothing needs to be changed, other than the addition of a remote watering system. Adding a lithium battery would require a lot of electrical work.I'm still using lead-acid T-105s and do not find adding water to be an arduous job, It's done during the periodic maintenance checks where all the fluid levels are checked. With a remote watering system, it's fast, clean and completed in 5 minutes.Pro-Fill - Flow-Rite ControlsIMO, For most LDs, the only benefit of using AGMs is not having to water them. Larry
Re: Battery type costs Reply #2 – February 04, 2019, 05:47:36 pm Big debates on this in off grid forums with strong advocates on both sides. As Larry stated you have to assume lithium will last as long as advertised for the numbers to add up but there's plenty of off griders that swear they do last that long. I recently had to replace the six batteries that run my house and came very close to going lithium but the up front cost scared me away. IMO though they are the way to go for that application if the purchase price doesn't bring sweat to your brow. Remember though in an RV they are in an unheated compartment and in cold weather camping you could have issues charging them.Some good info on batteries here.Charging Batteries at High and Low Temperatures – Battery University
Re: Battery type costs Reply #3 – February 04, 2019, 06:00:40 pm Did a little more research on this and there's new RV technology but it's likely even more expensive."With RELiON’s RB100-LT LiFePO4 battery, users who sometimes face below-freezing temperatures can now enjoy the many benefits of a lithium battery without having to worry about warming the battery before charging. The RB100-LT features the same size and performance as RELiON's RB100, but can safely charge when temperatures drop as low as -20°C using a standard charger. It's an ideal choice for use in RVs, off-grid solar, electric vehicles, and in any application where charging in colder temperatures is necessary. More models in the Low Temperature series will be available soon."Lithium Battery for Cold Weather Applications | RELiON 1 Likes
Re: Battery type costs Reply #4 – February 04, 2019, 08:19:39 pm I'm surprised how close lead-acid and lithium batteries are. Sure the decimal points are in the right places?The reason they are close is lead-acid has little capacity and cheaper than lithium.Adding a lithium battery would require a lot of electrical work.With a Blue Ski 3000 its not problem. Maybe I'll have to adjust some parameters but that's very easy. Battery Born suggests to remove the temp monitor as it will fight with the internal BMS of their product.<smile> just did a google thing100Ah 12V LiFePO4 Deep Cycle Battery - Battle Born BatteriesUsing the sales numbers makes the move even more cheap ....... 2 Likes
Re: Battery type costs Reply #5 – February 05, 2019, 03:35:39 am So are you planning two of these to match the normal 200 Amp hour capacity. Do they play well in parallel with each other? The weight will certainly be less. And you will be able to discharge them further on a routine basis. I'm assuming you won't be in any really cold areas, and that they'll be able to take the heat. Still, that's a lot of money! If you get 4 years on a Costco pair, that's 3 sets, about $600 vs. 12 years at $2,000. I'd still be a bit more nervous about an increased risk of fire. RonB
Re: Battery type costs Reply #6 – February 05, 2019, 08:53:05 am Some notes and explanation about my methodology in this study .....I gathered a rather random set of different types of batteries I might be using to replace the AGM's the factory installed. I live in the Pacific Northwest on the wet side of the mountains with a rather mild climate ie nothing extreme in seasonal patterns. A few days a year below freezing and a few days above 100. I wanted to have 'drop in' replacement ie just change to the new batteries without any major electrical changes. I used on public information. I assumed prefect condition on battery use. The 6V batteries would be wired in series so the voltage will be 12V and the Amp/hour would stay the same. The 12V batteries would be wired in parallel so Amp/hour will double but voltage will stay the same. zBattery.com | Connecting-Batteries-in-Series-or-Parallel . I took the usable amp/hour times the number of cycles to get what I call maximum life capacity. It the case of a Wet Lead Acid in my example that would be a usable* 60 amp/h times 1000 cycles for a total of 60,000 amp/hour over the lifetime of said battery. Then I divided the total cost of said battery by the number of cycles ie $316/60,000 = 0.005166 cents per cycle.It the case of a Lithium (Battle Born) in my example that would be usable 200 amp/h times 2500 cycles for a total of 500,00 amp/hour over the lifetime of said battery. Then I divided the total cost of said battery by the number of cycles ie $2098/500000 = 0.004196 cents per cycle.*usable capacity mean what a person can reasonably use without killing the battery.
Re: Battery type costs Reply #7 – February 05, 2019, 09:07:07 am Quote from: RonB - February 05, 2019, 03:35:39 amSo are you planning two of these to match the normal 200 Amp hour capacity. Do they play well in parallel with each other? The weight will certainly be less. And you will be able to discharge them further on a routine basis. I'm assuming you won't be in any really cold areas, and that they'll be able to take the heat. Still, that's a lot of money! If you get 4 years on a Costco pair, that's 3 sets, about $600 vs. 12 years at $2,000. I'd still be a bit more nervous about an increased risk of fire. RonBYes they play well together just like lead acid. Not only can you discharge them deeper you don't have to recharge them to 100% to keep them happy. Lead Acid batteries should be kept topped off as soon as possible to get maximum life out of them. The cycles number of Lead Acid is the theoretical life cycle of that battery. The cycles number on a Lithium is the theoretical 80% point of that battery. The fire hazard has more to do with the charge rate then the chemical in the batteries. You can discharge Lithium at below freezing you just can't recharge them. That, btw, is battery temp not outside temp.
Re: Battery type costs Reply #8 – February 05, 2019, 12:42:11 pm Yes, since the batteries don't need to be vented, and would benefit from being kept cleaner, a panel of foam against the outside would keep them warm in a cold environment (below freezing or so). Heat buildup during charging was the bugaboo for Boeing on the DreamLiner. They ended up changing the APU charge rate software, and putting more space between the batteries, with cooling fans. Your converter, being a newer 2014, might have too fast a charging rate on really discharged batteries? RonB
Re: Battery type costs Reply #9 – February 05, 2019, 01:19:59 pm A drop in replacement lithium battery, with a built-n BMS, is something I had not seen before, it makes it easy to install.To provide the same usable amount of amp hours, a 150-amp/hr lithium battery would be a better comparison.A 100-amp/hr lithium has 80 usable amp/hours, the stock, twin 6-volt batteries have 110 usable amp/hours.The Battle Born battery has a long warranty, great if they are still in business 5 five years from now.A search shows little about this relatively new company. For this amount of money, I want to buy from a company with a long history, in case the batteries do not have the lifespan predicted or if the BMS dies.With so many companies getting into the electric vehicle and lithium battery craze, there is going to be fallout.Larry 1 Likes
Re: Battery type costs Reply #10 – February 05, 2019, 02:00:39 pm Quote from: colddog - February 04, 2019, 04:16:09 pmIt's that time again. Baxter needs a new set of batteries. Sooooo being as I being retired and all ....... and my wife claims I think too hard about stuff (plead guilty). I put together a small spreadsheet to help get my mind around the issues. Some disclaimers from the get go. 1. I graded the numbers from various sources. They may be a tad off here and there but I am confident they represent a fairly good snapshot of reality today. Battery Types - Cost and BenefitsExplanation of some of the numbers --- 1. Under cost you'll see two numbers first number is the cost of one battery the second is the cost of two. 2. Cost per cycle is the cost divided by number of advertised cycles of said battery. Observations and thoughtsA. Wet Lead Acid and AGM's should be recharged back to 100% as soon as possible. Lithium can be at any discharged state without harm.B. Lithium can be used at any temperature but can not be charge at 32 or below. C. If use usable amp/hours by cycles for AGM I'd get 55,000 at a cost of about .02 per a/h, Lithium 500,000 at a cost about .004 per a/h, Wet Lead Acid 60,000 at a cost of about .005 per a/hAll the above numbers assume a perfect set of batteries used in a prefect use case. Looks like to me the cheapest path is Lithium. That's a kind of surprise to me. Thank you for the useful comparison. I am preparing to buy a new set of batteries, and this is proving very helpful. I will suggest, however, that you correct your "Usable Ah" column. It seems you should double the values for the AGM and lead-acid. 55 and 60 are very low in comparison to their stored Ah values. Paul
Re: Battery type costs Reply #11 – February 05, 2019, 07:56:13 pm Quote from: Epicardium - February 05, 2019, 02:00:39 pmThank you for the useful comparison. I am preparing to buy a new set of batteries, and this is proving very helpful. I will suggest, however, that you correct your "Usable Ah" column. It seems you should double the values for the AGM and lead-acid. 55 and 60 are very low in comparison to their stored Ah values. PaulFor reference to what numbers I used . AGM Batteries - AGM Battery Banks - AGM Battery . Scroll to bottom of page.Doubling the usable amp/h to 120,000 on Wet Lead Acid ---$316/120,000 = .0026333 cents per cycle. That makes its about .002 cent cheaper then Lithium per cycle. The real point I think is Lithium $900 or so a 12V 100a/h battery has come real close to being a competitor to Lead Acid technology at $350 6V 240a/h battery. I do agree with Larry a warranty is only as good as the company standing behind it. glen
Re: Battery type costs Reply #12 – March 11, 2020, 09:23:34 am Thanks to all for your efforts. have a lot to work with.
Re: Battery type costs Reply #13 – March 09, 2024, 10:39:54 am I'm bumping this old thread. We've been talking to some folks about upgrading and or replacing their AGMs. The spreadsheet is old and the prices of lithium batteries has dropped. When I get home after this trip(needed to see the sun) I'll do a review of my experience with the lithium install with numbers, temperatures and durability. Short story we are happy. Glen 4 Likes
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