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Lithium Ion Drop in Batteries
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“not worry about all the internet disinformation coming from the self proclaimed experts that are out there.”
this seems to be directed at me. I never declared myself to be self proclaimed expert though I have used lithium batteries extensively including building my own battery bank of cells with bms units. Not an electrical engineer but pretty damn close – though not practicing.
but seriously – if you guys each claim to follow the manufacturer advice and utilize their documentation extensively – then how can you say deep discharges to 0/cutoff doesn’t harm the battery ? You are in battery sales – yeah lithium is a newer technology but the concepts of what harms a battery is the same (along with some new ones like below freezing charging. Heat and excessive discharging affect these batteries as well. The “excessive” part is the difference but discharge to zero/cutoff is bad and significantly shortens battery life.and since you don’t want to hear it from me – how about from relion themselves. Here – discharge graph from them for their own batteries. You have I’m sure seen similar ones for lifeline as well.
https://relionbattery.com/products/lithium/rb200
2nd to last graph – claims by them. Not me.. and this follows the lifecycle of lifepo4 cells which they utilize in their battery. Again – /their/ claims of lifecycle life from discharges on /their/ battery under ideal conditions.
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Deep discharge does affect life cycles. Jon’s point about not hurting the Relion’s by deep discharging was correct as the BMS will protect the battery (disconnect) at 9.5 volts. This does not harm the battery, but does effect cycles if 100% discharged regularly. I’ve seen AGM’s not recover from just a few severe discharge cycles and the batteries are recycle material at that point. The smart battery with BMS takes care of that problem.
Here’s a better graph for Lifepo4…
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I cannot determine what works for others, but for decades using every kind of battery I have made a concerted effort to recharge my batteries at around 50% SOC. I also made a decision to replace batteries when they were in service for 5 years. I tested auto-start once to see if and how it worked, but to the best of my knowledge that was the only time I let my batteries deeply discharge.
When I was working toward the decision to use the lithium ion batteries the life of the batteries in terms of recharge cycles was a big part of the decision. The curves shown from the link above were part of the decision, but initially were not believed. Lifeline for example has the same curves relating to their batteries and when I compared relative performances the Li curves seemed like BS. I hammered the Relion rep very hard on that topic and he was able to convince me those projected life cycles are accurate.
Going by memory if an AGM is deeply discharged as it would be using the Marathon and Liberty auto-start voltages the life of the battery would be about 1000 cycles, but if recharged at 50% SOC the cycles could be as many as 5000 cycles. If I do a comparison between the Relion and Lifeline battery life curves my practice of recharging at 50% shows an unbelievable battery life expectancy of 13,000 cycles.
But this gets more complex if we look at other life influencing factors. In my case I have 50% more amp hours available, so if I follow my battery use practices the depth of discharge when I wake up in the morning and start the generator I may only be down to a 60 or 70% SOC. I am sure the battery life then is going to have so many potential cycles if will seem like BS for sure. For users of AGM batteries that do not daily recharge the batteries because they have driven all day, they are actually only doing partial charges which damages batteries, yet Li batteries are unaffected by partial charges so that adds to the spread in the life spans between batteries.
If I were to change habits and rely on auto-start (will never happen) and set the start voltage to the 11.8 volts suggested, the Relion will not be as deeply discharged so the real life cycles will fall somewhere between the 4000 to 13000 shown on the curves. By any unit of measurement the batteries are going to deliver a whole lot more life. My point in all of this is I wanted less weight, I do get more power, but the tipping point as based on my use of batteries they are as close to a permanent installation as possible.
I get a sense of some negativity regarding my decision, but except for the dollars which are a big negative, I cannot find any reason for not doing what I have done. I have never made a change to any of my coaches that I researched as deeply as this one, and while I have always been reluctant to spend money to change headlights or tail lights, change to ipad controls for my Crestron, change the TV or sound systems, repaint the coach, etc. I think this choice was well justified.
Now if I could only get tires and air bags to provide lifetime service.
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And you dont think this also happens with Lithium batteries ? There are plenty of cases of lithium batteries that have been deeply discharged and “not recover from just a few severe discharge cycles and the batteries are recycle material at that point”. . But its irrespective of battery manufacturers or technology – you seem to take the word more of a 5 year old company than Lifeline at this point. Lifeline publishes a cycle chart as well. I’ve included it here as well which I’m sure you’ve seen. Guess what – its rated for deep discharges as well. Not just a “few cycles” but several hundred at 100% DOD(about 300+).. . . So a battery manufacturer you have stood behind ardently for years – is now nothing because you’ve seen this happen and it doesnt follow that chart ? And you dont think this follows for a brand new lithium company trying to make a name in the marketplace ?
LiFepo4 batteries generally are rated at 2000 to 4000 cycles for 20-80 type of use. If you go to extremes, obviously that lifecycle is shorter. The BMS doesnt save it from shortened lifecycles. It saves the batttery from bricking it. As in if you go below a certain point – there is no return.
But I digress. I’m reasonably certain Lifeline/Corncorde has tested their spec all the way through the graph. They arent extrapolating data. I dont believe Relion have tested their batteries to what they have published on their graphs. And while I dont have proof either, I know they dont make their own cells (as they are all made in China by a few manufacturers). And most everyone claims 2k to 4K cycles under ideal conditions.
and if you want to change your definition of “damage” or harm – sure. The reality is that we all talk about damaging the battery from exceeding the 50% DOD point for AGM – and that “damage” is reduced battery lifecycles. The same thing for LiFePO4, but I guess you arent calling that harm. Well, if thats the case – we’ll say that you wont harm a AGM battery if you discharge past 50% either. . . it is just reduced lifecycle count, but no harm is done.
But lets do the math – using their chart, they can test at most 6 cycles of 100% DOD and back for each day. So 24/7 for a year is 2190 cycles. The company isnt but 5 years old, and these batteries were available at least 3+ years ago. So how do you test to 13,000 lifecycles when in 3-4 years time when its impossible to accomplish that given that time travel isnt possible yet. . So the data is pure extrapolation without concrete evidence.
No idea where you got your graph on. So now you’re using some graph pulled from some other places and applying it to Relions performance curve ? Most LiFePO4 manufacturers recognize that 100% DOD results is approximate 1k cycles or possibly even less. You’re claiming 2500 cycles on this chart – but relions own chart doesnt support that.
Jeff and Lindsay
91 Marathon XL -
Jon – – deeply discharged (as in 95-100$%) will get you 300ish cycles (not 1k). 50% DOD will get you 1000 cycles (not 5K). this is from Lifeline’s own chart. Ask Tom if you want confirmation as he has posts saying the same. Assuming he doesnt change his story about discharge cycles. . .
Under ideal circumstances (their published chart) for ReLion – you will get approx 8k cycles for 50% DOD (not 13k). and this assumes ideal temperature, ideal discharge and ideal recharge – we all know that this is under laboratory environment and not real life (and see how they couldnt have even tested out to that many cycles as time isnt on their side to do so).
Look Lifelines have a long track record – they seem to last about 3-5 years, some longer some shorter. it absolutely is NOT 5000 cycles, as that implies 14 years of AGM lifespan withn one cycle per day… Or if once every 2 days, well over 28 years of use – so why are you even changing if you have 23+ years to go on your batteries based on your expected use pattern (outside of maybe saving weight or charging time). . yeah, maybe some have made it pretty far – but the majority are 3-5 years – implying that lifelines specs on their cycle life is pretty accurate.
In regards to using lithiums much further as in to 80% etc – absolutely. Less weight, smaller size, higher C rates for charge/discharge, much faster recovery, and better use of such space. I’ve said this numerous times. I’m a HUGE lithium supporter. There isnt any negativity on my side about it. I use LiFePO4 in my boat. I use it in the Prevost. What I’m trying to have with this discussion is that – it isnt as easy as a drop in. Yeah, it could work awhile, but there are some things to consider if you dont want to risk bricking your 10K battery investment (or whatever that number is). There are concerns with alternator charging/cutoff, solar charging/cutoff, float/absorption limits and time, Low voltage disconnect (ideally before the bms cuts off), low temperature charging etc. I’ve never not advised people to go lithium – just to protect yourself from its idiosyncracies. . The marine guys have been heavily using lithium onboard since 2010/2011 with varying degrees of success. Mostly surrounding those issues listed above (outside of the low temp charging as the bilge on a boat never really drops below freezing).
So I encourage people to explore and use lithiums. I’m just warning people to research and consider all the issues and not just listen to the disinformation of so called internet battery sales people. (sorry swiping back). And in regards to Relion – i actually tried to give them business. And I was fed disinformation by their own employee who couldnt bother to spend a minute to give me accurate information after I actually asked for something specific. He chose to be lazy and not confirm his own numbers and sent me inaccurate information that cost them a lost sale.
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Good discussion. No doubt that there will be a learning curve with Li-Ion. Some early DIY installations had issues believed to be caused by temperature extremes. It will be good to get some long-term reliability data.
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I agree, good discussion.
thanks to the early adopters
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Hey Joe, despite all of the above, you’re a Lithium candidate. I thought you were ready in West Palm, then you snuck away..
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Anthem, talk slow because it takes me a while to wrap my brain around some things. And please be specific.
I bought RB200 Relion batteries to replace AGM 8D batteries. My charging is within the range specified by Relion and I have verified the voltage values every way from Sunday. I am not varying from my charging practices which is basically to go to bed with the generator off and start it when I wake in the morning with typical displayed voltages being between 24.4 and 25. Maybe a little lower if there were more than normal current draws.
What specifically was wrong with the choice. Keep the answer simple and on point. I don’t car how Li batteries operate, not will I ever intend to design my own system. I bought the batteries because of weight savings, more power when the two types are compared, and the number of cycles I expect to be substantially greater than AGM? I’m looking for specific reasons why that was a bad choice.
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I’m still a candidate, I’ve been preoccupied.
I need a new inverter, it will be capable of charging the LifePo batts. Not sure I trust the 458.
Unlike Jon I won’t do a full bank replacement. I need to get a better handle on my DC loads before I decide to reduce the bank to 2 or even 1 batt. I have been slowly converting all the DC loads to lower amp demands. Long gone are the 12 VDC fluorescent lights, replaced with leds, etc. But i have a lot of passibe DC loads I need to understand.
But hey, I think I finally found a good location for pressure pro pulse fx receiver! The run to Oysterfest will determine if I finally found the sweet spot for the receiver and dipole.
The 3/8 tempered glass for the door arrived today. Get to play with the silkaflex in the morning.
Jeff and Lindsay
91 Marathon XL -
Jon – let me get this out – nothing wrong with getting the relion 200ah unit. I have nothing against their batteries. They do have some lazy sales people who give out inaccurate information.
What I do have – is that people should be fully informed about these batteries. I’ve known quite a few people who took short cuts and ended up with bricks. So people should understand what they are getting in to and not rely and read what they want to read or listen to sales people just trying to sell something.
In terms of lithium iron phosphate batteries vs lead acid batteries – it’s best to completely throw out what one knows about batteries. Lifepo4 batteries are not just another type that has different charging voltages. It’s a completely different paradigm shift. For Instance –
AGM batteries need and want 3 stage charging (or even 4). LIfepo4 – want one stage. They don’t want absorbtion and float is actually detrimental to them.
AGM batteries like to be topped up and full or they develop a memory and lose capacity. Lifepo4 prefer to be at 50 percent charged. So if you are storing or not using the batteries – they prefer to be stored at 50 percent. Holding them at a high SoC is actually detrimental to them.
Alternator charging – you need to control and stop it once you hit your charge point.
Cold temp -if it’s below 32 – no charging. Even onetime will cause damage.
Low voltage – yes the bms will save the battery from irreparable harm. But deep discharges down to cut off will shorten life cycles significantly. AGM is 50 percent before cycles shorten significantly. Lifepo4 is somewhere around 90 percent.
But all the benefits are there. It’s lighter, smaller, has a wider usage band, charges faster and everything else. But all those things above and relevant. Whether those are cells or batteries. What people are getting is people trying to package the batteries to market them easier. And I get it. Nothing wrong with that. But some serious compromises are being made. And the basic premises of the issues listed above are still present – no matter how you encapsulate them.
So I’m just pointing out the issues that I’ve seen. And the same lifepo4 companies that are here and now are not going to be the same ones in a few years. And the sales rep who sold you those batteries are not going to back up the warranty he sold you the batteries with. So get the best quality you have and hope for the best. But claiming warranties and that you don’t have to worry about it – isn’t the best advice in my opinion. Especially since the place is littered with people who have had issues as well as some who haven’t. some of it is systems that handled things properly, some with people who thought they did, and some who didn’t think things would happen to them.
You started looking at this years ago and it took you this many years to comfortably get there. I have seen your posts asking about lithium years ago. And the companies that were around then are not the same even just 5 years later.
Jeff and Lindsay
91 Marathon XL -
Please answer my question. You told me about your extensive knowledge, I told you I am not designing a system and don’t care how they work but you keep referring to all we mere mortals don’t know. I don’t know what I don’t know and all I want is for you to tell me if my choice was reasonable and if not specifically why not.
I’ll repeat: I did a lot of reading about my choice of drop in replacements and I cannot find any negatives except cost. I get that. Tell me of other negatives.
If you have a personal problem with Relion try to keep it out of the discussion, but if Relion makes a shitty product and that is why you get negative, share with us why you believe that.
Keep it simple and on point.
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Wow. . I’m just passing information on what people might want to know. If you want to take it – its as much as any other discussion forum, $02, free advice, value of membership, etc is worth.
My previous disucssion point was that some inaccurate statements were being made – namely discharging to BMS cutoff didnt damage the battery – and here – look at the manufacturer documents. Where clearly, they showed heavy discharge shortened battery life.
But in terms of what I disagree with just a “drop-in” and forget replacement – almost every manufacturer of these – also advise having a low voltage disconnect on the load side to disconnect before the BMS takes over. They dont advise using the “last gasp” BMS disconnect.
On the charge side –
if using alternators, needs to be regulated to LiFepo4 specs, or cut off after reaching charged voltage. Protect the alternator form disconnects as well. Essentially a high side disconnect
If using solar – same as above.
Shore/Inverter/Converter chargers. Yeah, you’ve done it with Bulk. Absorption and lower float. Basically match the necessity.
As for Relion – I’ve said it before if you read it, and I’ll repeat it again – I think they make a good product. I was going to be a customer of theirs if it wasnt for a lazy sales person. Their salesperson gave out incorrect information and I didnt go with them. So if thats a personal problem – so be it. But I’ve repeatedly said they make a good product. But that doesnt mean I agree with every thing they or their representatives say.
So you’re being direct – I’ll return fire. You said explicity – discharging to BMS cutoff does not damage the battery. What is your defintiion of “damage” to the battery ? Shortening expected cycle lifespan by 50-80% doesnt constitute damage ?
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First, I appreciate your comments but I am concerned you were saying for a drop in replacement (any manufacturer) it is a mistake. I think you are saying a drop in battery is a good way to go,
I know you have concerns about constant charging via inverter and potential damage via alternators, but I hammered Relion hard on those issues to make sure they understood the application and how we use our coaches and batteries.
If you go to the Relion documentation section, and specifically the charging document you will see they list charging parameters for inverter equipped applications. I cannot speak about other conversions although I believe almost all meet the requirements I find my bulk, absorb and float voltages are well within their specified range.
For cold temperature charging all they require is the current gets reduced.
I pressed them about alternator charging and since our coaches should be charging at 27.7 we are within the voltage range, and if we divide the total potential alternator amps by the number of batteries being charged we are under the 100 amp charging limit.
They do not express any concerns about their “drop in” batteries being used any different than an AGM.
As to their 8 volt shut down, I have a hard nosed attitude about that. If an owner allows the house battery system to drop to that level, too bad. We as owners have to understand how our coach systems work, the limits and what happens when the limits are exceeded.
But in the context of how I use my batteries, as hard as I tried I could not find any negatives, and those you point out are no different than as an owner having to be aware I have limits and operating procedures to follow on my engine, transmission, and even AGM batteries.
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To put a cap on this I looked at Battleborn and Victron. Battleborn does not have an 8D size and Victron will not allow series connections so Relion is the only drop in option for almost all Prevost conversions.
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