Is Li-ion now viable for off-grid?

[adoublee]

You are defending lead acid in a world where it always has a lower lifetime cost than lithium. Even in a stationary application I would rather my battery bank take up less space, be lighter should I decide I want to move it or replace it, not worry about venting...

Sure you could put BMS on Pb, but now your adding that much more cost to a system than already sucks and is already being built into lithium at scale because it HAS to be. Having the BMS also allows things like paralleling strings/banks which is just another no-no with non-BMS Pb.

Military uses it because it is generally superior, not just specific energy or energy density. How about better surge capacity, or immunity to being held at partial state of charge.

Lithium is superior once it is cost effective and safe.

[Sunking]

To many parameters to get exactly right during operation and hassles to deal with using lead-acid. Lithium gets rid of most of the hassles. Once reasonable protection is built in (pre-integrated for most), cost is reasonable, and interface equipment is readily available lead acid will pass. Commercialization of EVs guarantees it. There are multiple pre-integrated protection systems now and better interface equipment should be coming out this year. The value might be there very shortly for integrally protected systems (where off-grid is required), but cost for a non-DIY protected system is still hard for most to handle. It is becoming much easier to design a lithium system that automates protection from self-destruction and still works properly versus lead-acid, but protection is the key and risky if building yourself.

Do not be silly trapping yourself inside a box. You are right, commercial Lithium batteries have BMS, they have to because they are to damn fragile and do not tolerate any kind of abuse. Pb batteries can take all kinds of abuse and require no BMS.

Where you are trapped inside a box and being silly is you can buy a BMS for Pb batteries that can even add water if you are that lazy and ignorant. Case in point. If Lithium batteries were as good as you think they are, every telephone, cellular, data center, 911 Communications, public safety communications, and military systems would be using the. Care to guess why they all use Pb?

EV's, Cell Phones, Laptops, power tools, ect are an exception to the rule for a 2 very good reasons:

1. Specific Energy expressed as Wh/Kg or how much energy per unit of weight
2. Energy Density expressed as Wh/L or how much energy per unit of volume.

Neither of which are required for stationary applications, nor can be justified by the 400 to 800% long term cost that goes with it. Only EV's and other like applications can justify the cost and short term battery life.

To have equal amounts of usable energy; a Pb battery would have to be 4 to 6 time heavier, and 3 to 5 times larger in volume. That 900 pound Lithium battery in an EV would weigh 4000 pounds and as large as a car if Pb were used. If you know anything about physics you would know that would be impossible because it takes a whole lot more energy to move a 4000 pound dead weight than it does 900 pounds. That is why you do not see Lard Ass athletes setting running speed records. They cannot compete. When was the last time you seen a 250 pound Jockey in a horse race?

[adoublee]

To many parameters to get exactly right during operation and hassles to deal with using lead-acid. Lithium gets rid of most of the hassles. Once reasonable protection is built in (pre-integrated for most), cost is reasonable, and interface equipment is readily available lead acid will pass. Commercialization of EVs guarantees it. There are multiple pre-integrated protection systems now and better interface equipment should be coming out this year. The value might be there very shortly for integrally protected systems (where off-grid is required), but cost for a non-DIY protected system is still hard for most to handle. It is becoming much easier to design a lithium system that automates protection from self-destruction and still works properly versus lead-acid, but protection is the key and risky if building yourself.

[SunEagle]

Someone once told me that everything requires maintenance. Except a brick as long as it stays a brick. Once it becomes part of a wall someone has to make sure to take care of it or it will fall apart and become a brick again or worse.

Battery technology is no different. The more complex the more it takes to keep it happy and working. There is no such thing as "plug, play and forget".

[Sunking]

Thanks guys...there has always seemed to be a FLA bias here, so I'm not too surprised by your responses. But I listened to this advice 3 years ago, and I have been quite disappointed. I have good Trojan batteries...and even before the low-water damage that was admittedly my own fault...I had other problems, like posts melting down, and poor charging efficiency. I'm not very impressed with the technology, and I'm ready to move on. Maybe I'll pick up some clearance Aquion stacks while I still can.

No you did not listen, your own words incriminated you. You flat out abused and neglected your batteries. Melted term post is 110% proof positive your fault from neglect. As is over charging your batteries letting them run dry. LFP batteries would have been dead on your first mistake and can just as easily burn the term post off. LFP and any Lithium battery is very fragile and do not tolerate neglect or mistakes. If you cannot keep a set of Pb batteries healthy, you stand no chance with Lithium. One thing with Pb batteries when you abuse them like you did, they still worked. Do that with Lithium and 1 of 2 bad things happen, or both. You kill them immediately and/or they explode into fire you cannot extinguish. Over discharge them and they are dead. Over charge them and they burn.

[solar pete]

We have recently installed 10 LG Chem batterys, 8 out of the 10 were dead on arrival, we thought it must be our guys stuffing it up but we got in the most respected solar guy in the state to hook up a few of the replacements and we did everything exactly as he did, turns out they were knackered. Dealing with LG to get the replacement batteries has been a very painful experience. We are thinking of a LG ban they suck.

[Bala]

It seems more like set up and maintenance issues that caused problems rather than the battery technology. I would like a better battery tech than fla but I don't want another hobby at the moment so if I had to replace my bank today it would be new fla. My current set is over 10 years old.

[Mike90250]

Lead Acid battery post technology has been around many years, and is well proven. Problems arise from poor connections that heat up and melt the posts.
The first solution is clean and torque the connections.
Second is to re-wire to a higher voltage bank that requires less amps flowing through the connections. Lead terminals should handle 200Amps without issue If you are at 48V already, a 3Kw inverter should only be capable of pulling 80A long term. LFP batteries will not solve the melting post problem, except that the terminals may be made from plated copper or steel and have higher melting temps than lead. Then you get into melting the cases of the cells. I use a copper loaded low resistance electrical grease.

[miahallen]

Bala, yes...that's what I have been lead to believe, but then I went and bought properly terminated 4/0 battery cables and torqued them to the rated specifications, and have still had issues...which again has simply turned me off of the technology. I'm living off-grid, and I respect the fact that many of you are die-hard lead acid believers...no problem. But I have always been tech savvy, and an early adopter...and if I'm going to have issues, I'd rather have them with new technology, than with "tried-and-true" tech. Hence this thread.

[Bala]

Thanks guys...there has always seemed to be a FLA bias here, so I'm not too surprised by your responses. But I listened to this advice 3 years ago, and I have been quite disappointed. I have good Trojan batteries...and even before the low-water damage that was admittedly my own fault...I had other problems, like posts melting down, and poor charging efficiency. I'm not very impressed with the technology, and I'm ready to move on. Maybe I'll pick up some clearance Aquion stacks while I still can.

Why do you think posts melted? Generally the cause of melting is poor termination, which would also explain poor charge efficiency.

[jflorey2]

Thanks guys...there has always seemed to be a FLA bias here, so I'm not too surprised by your responses. But I listened to this advice 3 years ago, and I have been quite disappointed. I have good Trojan batteries...and even before the low-water damage that was admittedly my own fault...I had other problems, like posts melting down, and poor charging efficiency. I'm not very impressed with the technology, and I'm ready to move on.

Well, if you are willing to spend the money, Iron Edison has some pretty good packs. The Fortelion line has been getting very good reviews but are again pricey. The cheap LiFePO4's like the CALB's work OK (we've used them here a bit) but you have to get somewhat home-brewy with the protection circuitry.

[miahallen]

Thanks guys...there has always seemed to be a FLA bias here, so I'm not too surprised by your responses. But I listened to this advice 3 years ago, and I have been quite disappointed. I have good Trojan batteries...and even before the low-water damage that was admittedly my own fault...I had other problems, like posts melting down, and poor charging efficiency. I'm not very impressed with the technology, and I'm ready to move on. Maybe I'll pick up some clearance Aquion stacks while I still can.

[adoublee]

Simpliphi might be the best of the best with price to prove it. Check out some of the other options shown on Schneidersolar li-ion webinar replayed on YouTube. Some of these options still depend on a future bridge component.

[Sunking]

If you had LFP for 3 years you would be looking at replacing them soon. There is no better option than FLA batteries. FLA's are tough as nails and can take a lot of abuse. One mistake with LFP and they are done.

For one you need to get a handle on your daily Kwh usage. For FLA you need 5-day reserve capacity and for LFP you need 3-day reserve to be equal. Example if you use say 1.67 Kwh per day on a 48 volt system you need a 8.4 Kwh FLA of 185 AH, and for LFP you need 100 AH.

A good solid 5 to 7 year 8 x Trojan T-105RE 48 volt 200 AH FLA will cost you $1100 with a 3/6 warranty. Or you can buy a Chi-Com Calb 16 x CA-100 for $2200 and just a 1-year warranty. If you go with Calb you wil be on your second set before the Trojan needs replaced.

Today to go LFP you are looking at a long range cost increase of 400% higher than FLA.

[Mike90250]

I'd let Li batteries mature a couple more years. And realize that they may only slightly outlive lead acid by a couple years unless you grossly oversize them.