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Is There A Simple Li Option?
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Good post Jerry, thanks for your input.
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Since my practices as relating to the use of batteries are the result of 30 years of using various types I will be the first to admit how these batteries function is part of the steep learning curve.
As my last article mentions my brain had not gotten wrapped around the fact that a voltage of an Li battery that is equal to a fully charged AGM for example is an Li battery with little of its power remaining. It isn’t written anywhere in anything I read, and when it bit me in the butt and I finally figured out what was happening it was a huge piece of information everyone should know. In simple terms the voltages usually seen with LA batteries are meaningless when using Li.
Everybody mentions issues but few discuss such mundane things as how voltage is in fact an indicator of state of charge, but I am certain since voltages are impacted by temperature I have to get my brain adjusted to that, as well as determining to what extent temperature impacts the time / temperature / voltage curve.
What I do know that makes a SOC meter unnecessary for my application, is if I use my batteries as I always have I really will not care if I have a battery fuel gauge or know the SOC. The way I use my generator when dry camping makes all the potentially available Li power overkill, especially combined with the fact if my engine hasn’t given them a good charge the inverters will when my generator is running.
As long as my coach is sitting unused in the garage I am going to gather as much information about these batteries as relates to me and my coach as I can. I certainly will be looking for a reliable way to make the auto-start work. That will not be because I ever intend to use it, but the feature should be functional on my coach.
As to potential damage to things like the alternator, I think I am OK, because my chassis batteries are always being charged when my house Li batteries are being charged so if the Li batteries shut down they will still be absorbing alternator output. But of greater concern to me, by far, is preventing anything that will cause my Li batteries to go into shut down. By the time that happens I have bigger problems than a potentially damaged alternator.
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Your number 1 is not completely true. Lithium titanate is even safer than lifepo4 and gas even higher rated cycles than lifepo4. Only issue is it’s higher cost ( and slightly lower specific energy).
as for slightly higher risk – the latest victrons whom do more with “lithium” than most any other company – their newest battery is NMC and not lifepo4.
other than that – good article write up.
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Jon, I know your experience and normal use works for you BUT it seems not to be how many of us desire to use our generator/battery banks.
I would like to feel comfortable leaving the bus plugged in and should a power outage occur, know the automatic systems will take care of things.
Also, some of us don’t go pole to pole as regularly as you do.
I appreciate you sharing your experience but your method won’t work for me.
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Les … you and I are in lock step and on the very same page.
I truly and seriously appreciate Jon being a pioneer with Li-Ion upgrade. But at this point it’s more than what I want to manage. I’m hoping the Li-Ion battery Engineers and/or inverter people come up with a true plug and play Li-Ion (or whatever chemistry of the hour it is) solution that manages all aspects of the issues so you and I don’t have to. And that includes cold temperature operations.
I have enough trouble keeping the GD fan clutch out of my radiator!
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Hi Anthem,
Thanks for your comments. Yes, there are lots of options if one wants to roll their own Li battery pack and control/balance management system. And, there are lots of options coming out of the marine industry that are interesting to consider as well. There very sophisticated companies like Victron who have done the proper battery/control system engineering although most of those remain in the very expensive category that many of our readers would consider over kill for our needs.
My comments are addressing the thread title “Is there a simple Li option?” and that focuses attention on the options that are far closer to drop in replacements for AGMs and cost effective to do so. Right now, my feeling is LiFePO4 is the closest chemistry to meeting that requirement.
Maybe some day we will be drawn to the chemistry Tesla just patented in December based on work they had been funding at a Canadian university. That chemistry promises a battery that could have the discharge/recharge lifetime to last for more than a million miles powering heavy over the road trucks. But, that is a long way off for us and our needs now…..
Jerry
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I cannot figure out what either of you guys are saying. Les, if you have a power outage at home I hope your bus is stored with the generator exhaust connected to a hose that discharges outside of your garage. Otherwise an automatic generator start with a power loss is going to turn into a big insurance claim when your fill your bus and house with diesel exhaust.
But on to how we use our coaches differently. The only difference is you apparently rely on auto-start. I think in your coach you can program the start voltage. So what am I missing? You run your generator only when batteries are calling for recharging and I run my generator all the time when dry camping. What am I missing?
The three significant pieces of learning I have shared are if you go to Li you have to address how you will deal with charging when ambient temps are low. You can do it automatically as I have by keeping them in a warm compartment. The second item I learned is my inverters literally will stay in silent mode until a lot of the Li power has been depleted, but that is a simple programming change to always stay in float 24/7 if I wish. The third surprise was Li operates almost 100% of the time above normal LA battery fully charged levels, and when it gets down to the level a fully charged LA battery would be at its remaining usable power is less than half of what was available. Neither of the last two points have anything to do with how either of us uses our batteries, so what exactly is it that gives you concern about the use of Li as you intend to do?
The Li batteries I have are truly drop in as far as how I use them with the exception of the fact the ambient temperatures will affect charging current which also has nothing to do with the differences between how we use our respective coaches.
Perhaps you and Dick can explain to me what concerns you have.
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“Les, if you have a power outage at home I hope your bus is stored with the generator exhaust connected to a hose that discharges outside of your garage.”
As a matter of fact… I do.
My flexible commercial rated exhaust hose exits outside. We designed the garage with “ports” near both ends, so drive in or back in they are in line with the generator exhaust.
We also have a transfer switch for the separate vital house loads electrical panel so that I can provide power from the bus buddy plug. I used it a week or so ago when we had an outage for 3 hours after a storm.
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Dick,
I know you use your autostart regularly and just a reminder, the Liberty Watchdog start voltage is way low, so you’re taking life away from your Lifeline batteries.
1999 XLV X-6872, liberty #440 -
using lithium can be done – the only issue is that it isnt just a drop in. I know that sounds “expensive” but I find that discussion ironic in that we’re dealing with hundred thousand to Million dollar coaches. And to get it working is essentially doubling the lithium cost (which is already more than AGM). . .
But you can account for all of those temperature considerations, alternator considerations and charging considerations as it is. and there are multiple ways to skin this cat .. but the only thing I disagree is that its a complete drop in replacement. of immediate note –
inverters – victron and mastervolt and you are generally set. Magnums you can make work. Outback you can make work. Most any that are fully programmable” can be kind of made to work.
alternator cut off – tie it in with a starter/gen battery and then just cut off charging after you hit above 14.1 or so. If you leave it lower – its not great, but it isnt catostrophic if it happens.
Load disconnect – easily handled by a smart battery protect.
Termperature is the same – on temperature too low, activate a relay and cut off charging…
Its doable to have everything taken care of. it isnt that difficult, but it will involve you or someone putting it together and installing it. I have my inverter on LiPO4 setting for charging and maintenance. 14.2 charge, 14.2 absorb for 1 hour, and float at 13.55. . . i generally prefer it to be disconnected actually rather than float charge it at the low amps, but the low amps helps keep the refrigerator and other draws going. I have a BMV712 that determines state of charge and monitors all the draws coming from the battery so I have a reasonable idea of what the battery state is (lithium batteries are notoriously difficult to get SOC based on voltage). The BMV also controls a dcdc battery charger off the alternator. it doesnt cut on until the battery SOC is below 60% and then cuts off at 90%. It is hooked in line with the generator start battery. So the inverter handles its charging when its connected to shore or generator. The alternator is handled by the BMV and DCDC charger. I dont have solar (but am considering it). There is a load disconnect on the load side that will cut off at 12.2. It cuts everything off except the battery monitor and GX controller.
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So Les………………what are your concerns based on your suggestion because I do not use or manage my coach like you do yours that makes Li questionable for you?
I also vent my generator outside, but do not want it to kick on due to a power outage automatically although I have provision for that.
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Tom: Painfully aware of that. By the time I was aware of the limitations of the WatchDog and the abuse that is done by drawing down the Lifeline AGM batteries to zero (at least twice, maybe three times no less!) damage had been done. That’s probably why I was barely able to squeak five years out of them.
This set is being managed much differently right from the get go. I’ve educated my wife on the limitations of the WatchDog and have posted 24.4 volts on the inverter control panels as the manual generator start point. Not only trained, she’s been tested and passed the test. I’m using the WatchDog as a fail safe in case both of us stumble and allow the batteries to get low with a manual start.
Since Jeff installed the new Lifelines in late December they have never been at 24.4 volts or below. We’ve learned that after driving all day the 50DN alternator on the Detroit Diesel doesn’t have the house batteries at full charge (how many of you boys and girl knew that?) so if we drive until 7/7:30pm and park for the night in the rest area, we’ll fire up the Wisconsin made Kohler after a few minutes, run that until bedtime (between 10pm and midnight), and the house batteries should be fully charged for the night. Then when we get up in the morning the first time we do is start the generator to shower, make breakfast, etc. before we disembark on the next leg.
With your new Lifelines I’ve found that they very, very easily last the entire night before getting down to where I should be concerned.
At the race track and when dry camping more than overnight elsewhere, I’ll probably be more inclined to run the generator more often and longer.
Having never owned any kind of RV before this one and not giving Jeff much time to indoctrinate us when we picked it up from him and blasted off for the Indy 500 we (I especially went through a steep and seemingly endless learning curve. Now my mission in life is to share my hard earned knowledge with all the wide-eyed neophytes and plebes who are entering Prevost ownership.
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So Dick, now I am even more confused about your Li concerns since you are doing exactly what I have historically done with AGM, and will continue to do with my Li.
I have addressed the temperature issue. If a catastrophe occurs and my Li batteries shut down while the engine is running the 50DN will continue to provide power to the chassis batteries. It is set to 27.7 volts so the Li batteries are OK.
So what are your concerns? Neither you or Les are answering that question even though you both posted after I asked it.
And I get what Anthem is saying about them not being drop in, but we are dealing with semantics and interpretations of the meaning. In my case I never made single adjustment, just replaced my Lifelines and I am good to go. But I was well aware of cold temperature charging, and decided instead of trusting myself to monitor the battery temperatures I would just keep them at 40 to 50 at all times as a minimum.
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Jon, simple. I want to be dry camping at a 4 day dog show and be sure everything stays good in the bus if I’m gone most of the time and/or going in and out frequently.
I don’t mind running the generator when needed or advised (no air conditioners on inverter) but I don’t want to run it all day “just to be safe”.
My big deal is auto start/stop. I would like the electronics take care of things and not rely on frequent visual checking or running the gen set just to be safe.
I know you like to be in control. Just like a thermostat controls HVAC, I want an auto start/stop control my generator and protect my batteries. Simple.
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Maybe Anthem can jump in, but your inverters or generator start system I think allows you to set the auto-start voltage to any value you want.
The more I study the voltage characteristics of my installation the more it appears to me that if I trigger auto-start somewhere between 12.5 and the Relion recommendation of 11.8 everything will work exactly as you intend. Whoever your battery supplier is will be able to guide you on that, but by looking at the Relion curves any voltage within the range I specified will allow you to use 70% or more of the Li battery power.
My dilemma is what hoops I have to jump through to make the Liberty Watchdog think it is time to start the generator because there is no adjustment to the Watchdog so I have to add resistance or open the sense wire circuit. You can accomplish that by pushing a few buttons.
What you do not want to do is use the Liberty or Marathon auto-start set point of 10.9 because at that voltage Li power is in a free fall heading towards the 8 volt shut down and the auto-start isn’t going to work if the batteries shut down before the generator starts, which is the case with a Liberty.
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