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SCSJeff
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# Posted: 6 May 2019 09:47am
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Seeing this come up in several different posts over the last 6 months. Rather than piggy back on other's posts, I figured I'd start a new one.
I still can't make a cost justification for lithium... But, let me talk through this out loud...
I currently have just (2) Golf Cart batteries in series (from Costco). On my 5th year and no signs of degradation yet... When they need replacing (or I want more capacity), I was thinking going (4) GC batteries. Should cost about $350 for about 420AH. Yes, realistically it's about 126AH (As I don't like going below 70% anyway).
Looks like (1) 12V lithium (w/ BMS) is around $1000 for 100AH (80AH usable) or to be more Apples to Apples, I would need (2) of these (Especially, if going 24V) at $2000 for 160AH usable.
Can I expect 20 years out of the lithium? (Hard to know for sure with the current best priced options, but let's assume I can...) For calculation purposes, let's go with 5 years for the GC batteries (although, I expect 7-10 in reality)...
In 20 years, I'd replace the GC batteries 4 times at an estimated cost of $1400. So I'm still $600 ahead...
Yes, I know there is more maintenance with the lead batteries. However, that is only 2-3 times a year that I have to add water. AND I think that is less of a headache than having to deal with keeping the lithium batteries warm in the winter in order to charge.
So for my usage patterns, I've never had to charge off my generator and I've never fallen below 70% SOC. I can see for others, where running the lithium down farther and being able to charge quicker would be an advantage.
Am I missing anything else that would be able to sway an extra upfront $600 - $1600 out of my pocket for a yet to be unknown long term durability in lithium?
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Nate R
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# Posted: 6 May 2019 10:44am
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If you use a junkyard/ebay Chevy Volt battery, the cost #s start to make a lot more sense.
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Brettny
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# Posted: 6 May 2019 12:26pm
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Nissan leaf cells at 7.4v and 50wh cost $80-85 each on ebay. Roughly $340 for a 12v 100ah.
With flooded batterys you pay for 100 percent but only get to use 30*. Lithium is closer to 70-80* useage.
I have yet to buy a system but from all the pre reading and calculations lithium is what i will be doing if i ever do solar. Right now the site has heavy tree cover and no good for solar. Something else that should be figured in.
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slatecreek
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# Posted: 6 May 2019 02:02pm
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Lithium batteries are great for off grid cabin use. I have several banks sitting in my barn for projects that I charged up 4 years ago and they have dropped in voltage probably a total of half a volt over the whole pack. They don't need water cell maintenance, they don't need to be kept warm, and they can be discharged deeper than a Lead acid without shortening the life.
Lithium battery packs are a series of cells or packages similar to the cells in a lead acid battery except not sharing the same chemical. These individual packs require they remain in a certain voltage range, usually 3.4 to 4.2 volts. This varies slightly depending on the Lithium battery but it is in the 3-4 volt range. A pack is built up with several cells to equal 12 volt, 48 volt etc. The packs I have are 48 volt, which consists of 12 cells at 4 volts.
The issue is some Lithium packs is the cells must remain between these operating voltages or they become unstable. The is where the battery management system comes in. It monitors each cell to make sure it doesn't get over charged or discharged outside of the that voltage range. With the absence of a battery management system, the batteries can and often do over heat and catch fire.
So if you are in the market for a lithium battery system, make sure it includes an on board battery management. These are usually a small micro processor to also gives the user feed back at to the health and charge of the pack.
I hope this helps out a little better understanding of how Lithium batteries differ from a typically Lead Acid battery.
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SCSJeff
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# Posted: 6 May 2019 08:31pm
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Thanks everyone for the feedback on lithium.
I guess I should clarify that I would only be doing a "plug and play" system. No buying used car batteries and hooking up my own BMS for me.  Also, don't really need, nor want the expense of having to buy a 48V inverter either.
In addition, I still would need to make sure the lithium batteries are above freezing when charging in the winter or risk ruining them... Since my power shed is outside and uninsulated/unheated, that adds more complication to the whole process that I'm not really keen on...
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rvneil
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# Posted: 6 May 2019 10:27pm
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It's that "above freezing" requirement for lithium that really kills the idea for me. I'm in central Ontario, and we get 6 months of the year with below-freezing temperatures (today May 6th was the first day when I can't find any snow left in the woods). So, why buy something that can't be charged half the time? Some people have mentioned battery heaters, but since I'm rarely at my cabin in the winter, the panels are often covered with snow, resulting in no incoming power to balance out the power to a heater.
I'd love to replace my lead acid batteries with something smaller, lighter and with a 70-80% usable range, but it's the winter charging that's killing the idea.
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Wilbour
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# Posted: 6 May 2019 11:33pm
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Quoting: rvneil So, why buy something that can't be charged half the time? Some people have mentioned battery heaters, but since I'm rarely at my cabin in the winter, the panels are often covered with snow, resulting in no incoming power to balance out the power to a heater.
Umm... if you're not there to use them, do you need to charge them?
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Brettny
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# Posted: 7 May 2019 07:25am
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With lithium being so small and light compaired to FLA personaly i would just bring the battery home.
What kind of plug and play FLA battery system are you getting? Goal zero?
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SCSJeff
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# Posted: 7 May 2019 07:51am - Edited by: SCSJeff
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Wilbour,
I'm guessing your response was aimed more at rvneil. However, I can chime in my thoughts here...
I wouldn't need to charge when I'm not there. However, if they are down to 30% when I leave, I'm still going to have to charge when I come back up the next time (or worse, if they need charging before our stay is over...)
Brettny,
I hadn't thought so much about bringing home. That could work. Of course, I've been known to forget to take my cabin/gate keys several times. So I'd be worried I'd forget the battery too 
Disconnecting & Reconnecting also means no one else (less versed in solar/battery technology) could operate the cabin either. I'm trying to keep it simple, not only for myself, but others as well.
Regarding "plug & play", No, I wouldn't do a Goal Zero. I mean that for Lithium (as in it has a built in BMS). SLA batteries don't need this. (If something goes wrong they just die or spill over, generally don't catch fire). Connecting cables from battery to inverter isn't a problem... this is what I'm thinking of:
URL
EDIT: After thinking about this a while, maybe bringing home wouldn't be so bad??? It would ensure I have a fully charged battery the next time I go up in the winter. It would also prevent theft. (It would hurt a whole lot more to have a $1000 battery that is very easy to move stolen). I'd still have to figure out how to charge if it gets too low while I'm there though... Now, is there such a thing as an easy connect/disconnect for the battery cables?
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offgrididaho
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# Posted: 7 May 2019 04:24pm
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Quoting: SCSJeff Now, is there such a thing as an easy connect/disconnect for the battery cables?
You'd want to do them right (i.e. serious quality crimper) but looks like Anderson Powerpoles handle up to 4/0 gauge wire:
http://dlcparts.com/powerpole-sb350-series-sets-c-68_404.html
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creeky
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# Posted: 7 May 2019 04:55pm
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I use Anderson powerpoles. Pretty e as y install.
Don't forget lithium makes your system 20% more efficient.
I too wish lithium was cheaper. But with the 30 year lifespan some are touting. Well. Beats spending time and money watering lead.
And I just replaced / am replacing a big lead acid battery pack. 4 years old. Dead. Health crisis and no watering ...
No maintenance can mean a lot.
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Wilbour
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# Posted: 7 May 2019 07:12pm
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Quoting: SCSJeff I wouldn't need to charge when I'm not there. However, if they are down to 30% when I leave, I'm still going to have to charge when I come back up the next time (or worse, if they need charging before our stay is over...)
Mine are left to freeze all winter. When it get there for the couple of colder trips I walk in, flip the inverter switch on and bam, I have power.
I then heat up the cabin and when the temperature is up I flip the charge controller and charge the batteries.
They are in the heated space of my cabin because a) they don't off gas, b) they are about the size of a shoe box, c) they weigh about 20 lbs
I'm still not seeing what the issues are with winter storage.
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ICC
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# Posted: 7 May 2019 07:52pm
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Quoting: Wilbour I'm still not seeing what the issues are with winter storage.
There is no issue with winter storage with Lithium batteries. Lead-acid are likely to have issues if they are left in partial discharge for lengthy periods.
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redneckpaul
Member
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# Posted: 7 May 2019 09:50pm
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Lithium works good for Bi-Polar too. 
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SCSJeff
Member
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# Posted: 7 May 2019 10:06pm
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Quoting: Wilbour I'm still not seeing what the issues are with winter storage.
No issue with storage. Concern is charging (because I need to) while still there using power during the winter (late hunting seasons). My power setup is not inside and thus not heated...
Those powerpoles look like the ticket (just like how most batteries are connected inside a UPS). I'd have to see if I can get a hold of a big crimper though...
However, now that I've been researching this and talking out loud, I may be swayed This kid's YouTube channel is good and got me thinking about trying to build a 100ah pack: https://www.youtube.com/user/errolprowse
I know, I know, not Plug-n-Play... but it didn't look that difficult in his videos
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Wilbour
Member
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# Posted: 8 May 2019 02:13am
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Quoting: SCSJeff My power setup is not inside and thus not heated...
Sorry, didn't realize this was an issue.
SCSJeff, this is not directed at you specifically but there will always be reasons not to get into Lithium and each and every excuse is valid.
I did the "Junkyard" Chevy Volt battery build and read, watched and read again. Sought advice from a strange little battery guru and have an amazing Frankenstein sort of system at the fraction of the cost of a Plug and Play kit.
What it comes down to is, "If you're happy and you know it, stick with lead"
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SCSJeff
Member
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# Posted: 8 May 2019 07:42am - Edited by: SCSJeff
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It's funny how I started this thread justifying lead and the more I researched, the more I'm justifying lithium 
Probably because of the ability to discharge at a higher rate and conversely charge at a much faster rate... In addition, based on my occasional recreational use, I "should" get 20 years easy out of it.
Of course, if my current bank dies next month, I'll be in a pickle with $ and may have to stick with lead. But, if I can wait and catch a deal, I'll probably switch to lithium.
Thanks to everyone for letting me talk through this out loud!
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Brettny
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# Posted: 8 May 2019 08:13am
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Crimping big cables you can just use a ball been hammer to do a mechanical crimp, then solder it a bit with a propane torch. Best of both worlds.
Those big anderson power poles are nice. I use the generic brand ones on electric winches. You can just search "battery quick connect" on amazon/ebay and find them. Make sure you get the right gauge terminal.
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offgrididaho
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# Posted: 8 May 2019 11:40am
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Quoting: SCSJeff It's funny how I started this thread justifying lead and the more I researched, the more I'm justifying lithium
Well, your title is still valid, it's not for EVERYONE, and for most it takes some sorting through and thinking about before they can make the right decision for them.
Quoting: SCSJeff Thanks to everyone for letting me talk through this out loud!
Nice thing about this community versus some others, no issues thinking some things through out loud and you'll generally get some good non judgemental input.
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redwolfguild
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# Posted: 8 May 2019 12:37pm - Edited by: redwolfguild
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Not to beat a dead horse about charging/leaving lithium during the cold months, but all this talk and a recent trip to my cabin, I need new batteries this year.
So if I get lithium, what happens if I leave the cabin in the fall, turn off the solar panels, and the batteries are at 70% charge. Is that a problem when I come back 6 months later and connect back to the solar panels? When I close the cabin in the fall, I guess I could also just run the Genny to make sure they were fully charged then disconnect.
I like the idea of taking them home in the winter, but I hate installing and uninstalling the batteries due to their location in my cabin.
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Nobadays
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# Posted: 8 May 2019 01:47pm
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That's one of the beauties of Lithium, they lose very little charge while sitting idle. Someone will correct me if I'm wrong but my understanding is you don't want to leave them fully charged but at 70-80%. The cold does not affect them - as long as you don't try to charge them until they are warmed above 0*C - 32*F.
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Brettny
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# Posted: 8 May 2019 02:09pm
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Lithium battterys would be way smaller in physical size so mabe the old SLA battery location wouldnt do.
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ICC
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# Posted: 8 May 2019 02:57pm
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Quoting: Nobadays Someone will correct me if I'm wrong but my understanding is you don't want to leave them fully charged but at 70-80%. The cold does not affect them - as long as you don't try to charge them until they are warmed above 0*C - 32*F.
True, though different battery makers may vary the minimum charge temperature a bit.
I have lithium batteries in some ATV's, a dirt bike, the snow plow tractor, and my SuperCub. They can sit for months at a time w/o use. Even in the dead of winter they hold charge and can and do crank the engines to start. I don't have issues with the home lithium cells as they are in use and that keeps them warm. A friend with a lithium based off grid system at his seasonal cabin leaves his setup from December through April/May. Batteries are left at about 75%, solar is turned off as there are no loads left running.
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creeky
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# Posted: 8 May 2019 10:18pm
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I'VE had numerous reports this spring from folks returning to their camps. And like the years past, the one thing everyone mentions is how the battery voltage didn't change.
I forgot to take my bms off. Went traveling for 3 months. Didn't matter.
I love lithium.
Just a reminder. For those running without bms. Time to check your cell voltages.
And everyone with lithium. Watch out when you do firmware upgrades on your equipment. It can flush your custom lithium settings.
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ICC
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# Posted: 8 May 2019 11:29pm - Edited by: ICC
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Quoting: creeky Watch out when you do firmware upgrades on your equipment. It can flush your custom lithium settings
Good point; much like a Windows update changes things you really had no intention of doing yourself.  I have all the setpoints I want typed on a card that is taped to the wall by the equipment. Saves searching through books or whatever or to trusting possibly faulty memory.
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slatecreek
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# Posted: 11 May 2019 08:39pm
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I just received my june/July issue of mother earth news magazine and there is an excellent article on off grid battery options and the pros and cons of lead acid vs lithium batteries.
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creeky
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# Posted: 12 May 2019 09:59am
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Quoting: ICC I have all the setpoints I want typed on a card that is taped to the wall
Great idea. I'm going to tape the settings beside the controllers. I get no end of calls, "what were those settings again." smile.
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ICC
Member
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# Posted: 12 May 2019 10:45am
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 Took me a couple of years with the first system to think of it.
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old greybeard
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# Posted: 13 May 2019 12:05pm
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I can't justify the cost of lithium for my small set up. Running 2 80w panels into 4 6v Golf cart batteries is cheap and easy, and provides all the power I need for a small cabin.
And we're in the cold belt, lead while not efficient at those temps does charge and they warm up to quickly to a higher efficiency. Might have $600 in the whole system.
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Jebediah
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# Posted: 13 May 2019 01:24pm
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Check out Will Prowse on Utube everything you ever wanted to know about any type of solar power system set up....this guy has experimented with everything out there, all documented...real time experiments and he explains everything in detail and leaves nothing left to guess...He goes into great detail about Lithium batteries...DIY Solar with Will Prowse....
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