Lead Acid / AGM vs Lithium for Off Grid Solar - How to Choose Part 1 of 2 

I have seen quite of bit of misleading information regarding Lithium and Lead Acid batteries on youTube recently and wanted to make this video to clear some things up - or muddy the waters depending on your perspective. This video took more time than my typical planned but non-scripted style so please let me know if you like or dislike this type of content. Thanks for watching!

Glad I stayed subbed. Always look forward to your explanations! Blessings!!!

Just awesome your back with regular video releases & sharing your knowledge again. Thanks !

thank you. this was great. finally someone who knows what they are talking about. the big issue w lead is chronic undercharging; this is the main failure mode for off grid. it's actually relatively hard to complete the required ah reconciliation with solar... but once this is dialled in lead is much more economic... and robust!

Love ppl who realy know stuff and then even share it !!! Best man

Oh wow. First view. I knew you'd be one of the few (only) No BS Versions. Love your work dude.

After the day I've had I needed a Knurlgnar video. Thank you.

From what I understand... This is the most practical information I've heard

Hats off to you, very understandable for a beginner trying to get a solar set up off the ground. You make me feel smart for settling on 6 volt 390 amp hr batteries in series and then paralleled for a 24 volt system for about 400$ each. I think I will by two more!

i know you prob dont even read comments with 62 thousand subs, but you make a difference. thank you for your knowledge and sharing it!

I noticed on another of your videos some one asked a question about if there was a way to know when the power comes back on after an outage. Of coarse after you are running your inverter. Here in Calif. on PG&E smart meters there is a little LED green light on the Right side of the meter in the center that flashes when the power comes back on ! I noticed by accident after a rolling black out. I'd also like to thank you for you videos, very helpful. I have system set up Similar to your battery back up. My inverter took a dump after 5 years. It Had A ground on the frame. Worked well when it was still alive. ! lol I purchased a Renogy 2000 watt inverter, needless to say the new ground fault inverters are a challenge, I had the ground hooked to the frame like the other on and it wouldn't do squat ! worked if I hooked a drill or a refrigerator to it but when I hard wired it nothing just the ground fault warning. Your video's are amazing ! Went right to the problem after watching them. Stupid ground wire ! Thanks Keep up the great job, your friend, dan

Great comparison! This is very useful information. Thank you for sharing your results.

Glad to have you back

Finally some explanations on RU-vid from someone who actually knows what he is talking about. Look forward to more videos! Would be great if you could explain what some of the components actually do that you point out in your tear downs.

awesome unbiased comparison im off grid and the rhetoric about this is daunting a problem i have with my agm is percent of charge. you only have what the voltage is to go by

Wow! Exactly what I was looking for! Now I am convinced that if I were to go solar/wind (off grid), I'd jump on those huge heavy Trojan's in a heartbeat. Just being 6 volts each, helps in balancing and if one pukes, you're not throwing away 5 good cells as w/a 12 volt battery. I really wish there were more options for 2 volt single cell FLA! Ya, more bulky due to packaging, but now we have even more control, and probably a bit lighter (per cell) than one huge 6 volt unit. Nice work!

Really good video, looking forward to part 2

DUDE! You're back! I missed your videos. Welcome back.

Thanks for another great video. Can't wait for part 2 as my home battery bank is up for replacement!

Welcome Back to RU-vid! BEdtime. Will watch later, lol

Really enjoyed your systematic approach. Thank you.

This is eye popping analysis. Thank you for clarifying and changing my understanding. Saved me tons of $$$

Was waiting for your video. So informative. Thanks keep up the great work

In the charge discharge cycles I found that even cheap Lithium allowed approx 4 times the usable energy as the solar charging window for me was around 4 to 5 hours and that would fully charge the lithium but only 20 t0 30 percent of my AGMs...

Love the lead info. I'm anticipating more rejuvenation videos. How much and what sort of over-volting and heat abuse is helpful in getting more life from a lead battery? How should we conceptualize the voltage swings during charging? That info is gold. Thanks for sharing. Re this video: Battleborn includes a charge controller so your cost comparison is not apples to apples. I disagree with the way you are conceptualizing cycle life. You have your mindset in the charts, not in the battery. All else being equal, from a lead battery's perspective, its death clock ticks when it is sitting around at less than fully charged, which is 21ish hours per day. A LiFePO4 cell has its life counter ticking when it is abused at temperature extremes especially at the ends of SoC. Lithium could not care less about sitting around half charged, which is good because that is what they are going to do in an off grid installation. A lithium battery, if kept at proper temperatures, might blow the doors off of its rated cycle life. I'm not saying that you are definitely incorrect on cycle life, but your view seems shaded by your investment in lead. Given a graph of how long each chemistry is held at different SoCs in a typical off grid install and Lithium will likely win. The advantage of lead is for back-up because it likes to stay fully charged. Off grid might "want" to be fully charged but that ship sails every evening at sunset. Respect lithium's fussy temperature requirements and they will last a long time. I have a $20 LiFePO4 solar light which has been cycled daily for about a decade and counting. Occasionally charged on bright, sub zero days too . It's still going anyway. A quality cell, properly cared for? Don't be so certain that it will not out live you. Also, the posts here pointing out that lead chemistries die, but lithium fades away, are real. A lead at 80% is a time bomb. A lithium at 60% keeps on squeaking and rattling and limping along.

Your videos are so informative. Keep up the good work.

excellent content! I am only beginning to learn about solar systems and battery types but I have never heard these arguments, and justified with data too! very refreshing to hear a fair comparison.

I was using 4 massive 100+ pound telecomm AGM batteries for 5 years (still in use for my battery pack spot welder). But this year I switched to Model S modules and I absolutely love them for home storage. Nearly impossible to get appreciable sag out of them in a 3p configuration and the TSLA BMS is rock solid. Let's do some more inverter torture tests as the market is flush with new players since your last video.

Love the vids. Keep them up!

I fully agree, and anticipated, that lithium ion batteries' primary (sole?) benefit is weight savings--certainly useful regarding electric cars and weed whackers. A friend who owns a Tesla confirmed the guidance he received that 20%-80% is the sweet spot for maintaining his batteries. What surprised me is the apparent advantage of flooded cell vs. AGM. Why the heck are we upcharged for AGM batteries for our cars, and why are they touted as the "premium" choice? Always enjoy your videos--keep 'em coming!

Thanks for all this data.

thanks for all your projects and info. Do you any experience with any of the carbon foam batteries?

Thanx for making more videos. I enjoy the same things u do. A lot of people on here if u rubbed their brain cells together at a rapid rate, would achieve near absolute zero. Im sure yours would keep my hands warm. Thanx again.

Anecdotal comment on Lithium Ion. I'm still rocking an iPhone 4. From like 2012. I'm not some tech luddite (else why would I be here) but for various reasons I just haven't gotten around to replacing it. I still get about 3 days standby. And to be honest I've not noticed a decrease in battery life. But then so very few apps (aside from Gmail and the web browser and Kindle) work that I suppose that's why. Love that you're back and appreciate the content.

Very well done, I am interested in the follow up videos.

Battleborn costs 4x more than building a DIY LiFePO4 pack with high quality cells that can provide 3000+ full cycles. Also, the battleborn is extremely heavy compared to aluminum cased prismatic cell packs. Battleborn is not good for weight comparison. You can make a 12.8V (4S)280Ah LiFePO4 pack with 5000 cycles (at solar use c rates), BMS included, for $500. LiFePO4 is cheaper and lasts much longer than lead acid. And it's more efficient. Which means less money spent on solar panels. I would conclude that lithium is much cheaper than lead acid. Not drop in solutions, but diy packs. (or a sok battery) and anecdotally, I have had lead acid batteries fail often. And I maintained them. I have never had a lithium battery fail. That's from living off-grid for 9 years. Also, the safety of LiFePO4 is better than lead acid. No harmful gases that require ventilation. BMS makes the LiFePO4 battery fool proof. Ocpd, lvd and hvd, that the lead acid battery do not have. Also, the coulombic efficiency difference and usable capacity should be considered. This difference alone make LiFePO4 light years ahead of lead acid. I made a long video where I show my numbers if you want. It's called lithium is cheaper than lead acid. I substantiate my claim with data as well

Excellent topic. Unscripted is more natural. I would love to have a forklift battery for off grid energy storage.

I agree on the cycle life for flooded lead acid at 80%. At my last job we had electric forklifts. Each had an almost 3000lb battery in them, which doubled as a counterweight. They were run down that hard every day, and lasted about 5 years before needing replacement.

That was a good analysis. I do think lithium will get better and cheaper, but right now flooded lead acid is still the way to go. As long as you maintain them such as adding distilled water they will last a long time. One plus for lithium is that they can't spill, so they are suitable in vehicles. AGM might be ok for a vehicle but at that price it may almost be worth spending more on lithium as space will matter more too. But one downside of lithium is the more complicated electronics needed. The Battleborn has that all built in, but if you want to make a larger battery bank from cells you have more to worry about to make sure you get it right. Lithium is also harder to buy. I don't really see lot of places, at least in Canada, where you can buy the cells. Basically, at this point if building a system I would go with flooded acid, and when they die, lithium will probably be cheaper and easier to get at that point and be worth revisiting. We still use flooded acid in telecom, and I'm sure when the price is right they will start switching to lithium, but lithium is more complicated to setup. With flooded acid you put all the cells in series and set a constant float voltage and they are happy. In a backup application it's harder to start tracking current going into each cell and altering the voltage, because the load is running at same time too.

I really appreciated seeing a breakdown of the numbers for all the different scenarios. will you being going over the differences in "usable voltage ranges" in part 2? I know some 12 volt electronics don't operate well (or at all) below 11ish volts. also, will lithium batteries have a longer service life in scenarios when the charging solution is sometimes unable to replace the bulk of capacity used immediately? (say in a solar setup when the seasons change and you get frequent periods of cloud cover etc)

Very useful, thanks.

So nice to see you alive and kicking. Would have been nice if you had left a note :-/ I am also messing around with both Li-ion and AGM,, my AGM bank is old USP batteries and on there 15Year,, I have 24 of them so really want to squeeze all the life out of them. Any chance you would know how to improve on the gel,, it´s probably getting a bit dry,, can it be dissolved in distilled water, and make the battery last another year.

I switched to lithium 2 years ago the biggest difference is voltage drop on agm when you put a load on agm the volts go low and shuts of inverter it doesn't do that with lithium plus I pay a third the price as battle born I make my own

Chose lead acid, and went for flooded, as those at least can easily be inspected and refilled as needed, plus I had limited ability to change float voltage, aside from moving them outside to allow them to run cooler than in the UPS. 18 months along and they are surviving.

This is really interesting. I have been following you for years and glad you have decided to post new videos again ore often. I have one comment so far, you stated Lithium Iron Phosphate batteries do not like to be fully charged when being stored long term. I have heard this same thing from several sources. However (and especially since you are using their battery) I contacted BattleBorn and they told me to store their battery fully charged. Yes, I was surprised by that answer as well. Fell free to confirm this. Can there be something "different" about the BB over other Lithium Iron Phosphate batteries. I would not think so and that is why I found this statement from them surprising. Comment?

I’m certainly looking to make lead acid batteries to save money; this helps ty. Really lithium is just better for a battery wall but there’s always a shelf design that could work for lead acid

I’ve been going back and forth for weeks on what chemistry of battery I wanted to go with… I decided to go with lithium because I wanted to try it, and it was by far the cheapest option. I got 200ah prismatic cells and built my own battery for less than half of the cost of flooded. I’m crossing my fingers that it’ll be reliable.

You definitely don't save money going with lithium, but you save sanity. At least, in a RV/Van setting with primarily solar and only occasional fast charges from shore power. Obviously in a traditional off-grid house/cabin, your use case would differ significantly. I was willing to pay the premium to have the flexibility and reliability. (And I do recognize that I was paying more for that.)

Keep in mind that the batteries he's showing are the highest end ones you can get, and there are perfectly fine AGM and lithium batteries that less than $200 per kwh, they might not be as high a quality, but they will still be perfectly fine and reliable, at least if it's not being used for industrial use where every extra cycle can more than make up for the extra cost.

Yay .... very well done :)

Could you speak on NiMH prius style of batteries at some time?

Can you do a vid on iron nickel battery?, not much information out there. Like your vids keep it up.

I watched your video and thought you are a great tubing blogger. Are you interested in doing a review of pure sine wave inverters?

Hello thank you for this video I thought it was absolutely amazing. How do I determine what size of inverter do I need for my home. I think it will be 15000+W for a 7k square ft house. Thanks in advance.

Hi... I love watching your videos. I have a very odd question. I am living in Italy and the cost per KWH are getting out of hand. I was thinking of getting a solar system..... ok till now nothing special as of a question. My father lives next door in an attached home and was thinking of sharing my solar system with my dads house with an ats switch without having 2 set ups. Is this even possible or am I better off with 2 solar systems? If I have opt for 2 systems is there some way we can share a huge battey instead of having 2 separate ones?

I’ve used a lead acid battery in my van with my solar for five years with no problem I make sure I don’t drain it more than halfway and I’ve only put water in it three times

My mate brought 50 Lead Acid Deep Cycles used in submarines. 20 years later he still has to dump power into this emersion heater :)

Since I would not be moving them, I would not be concerned about the weight of a battery (except maybe delivery charges) as long as it had endurance for off-grid storage.

2 years on - Hybrid Grid-connected solar systems designed to use every last milliwatt rather than export it are getting common, even charging batteries late at night on cheap tariffs for use later, or even just to be sold back to the grid at a profit. Chuck electric cars into the pot! the choice gets harder. - but great video :) - where have you gone?

What about the charging curve of the led acid? It takes hours to charge a led acid bank over 80% SOC to 100%. In a daily cycle that's impossible. Lithium goes to 100% at 1c.

I'm fairly new to solar, but went with agm batteries as they are stored indoors. I truly wish I had just bit the bullet and went with Lithium batteries. I'm in western MA and not getting much sun light here in the fall season, I'm sure even less in winter. The agm batteries just do not charge fast enough and discharge very quickly. Sometimes only drawing 1-3 amps out of an 800ah bank shuts down the inverter within hours. I don't have any confidence in the agm batteries at all at this point and have2 x 200ah lithium on the way. In comparison I have a small 300w lithium solar generator that seems to out last the agms. On paper maybe agm looks good, but in my area or maybe it's my system... they do not have any stamina.

I am curious if you have ever looked into NiFe battery technology? I certainly recognize that was not the point of this video and I'm not saying that you should have included it, but I'm just curious if you have ever looked into that technology?

Zooms 200ah battery is currently $690 with a $45 off coupon bringing to to $645 plus tax with free shipping on Amazon- compared to the selected battleborn as priced in this video you get 2.94x the watts per dollar as listed on the spreadsheet, so if you utilized it to an 80% depth is discharge it is almost identical to the FLA. Pricing on zooms as of December 2021. I also intend to have this as a standby system for power outages so I’ll keep the 48v bank float voltage at about 50% of battery capacity to maximize battery life while in “cold storage” and if there is a power outage I’ll then start drawing power from a 2,100 watt PV array running 78dc/27 amps into a 3k GroWatt inverter/charge controller/ all in one unit.

I have a 4 8D deep cycle for my off-grid system I like the abuse lead acid flooded seem to hold up to the best. it is backbreaking work to swap them out every 5 years tho

Did I understand you to say that the depth of discharge on FLA does not effect cycle life? I have found quite the opposite to be true. I may have misunderstood you. I have found that in a off grid solar application FLA batteries typically are at a partial state of charge for many days in a row here in The Pacific North Wet. Sulfation is a real issue at partial SOC. It is a non issue with lithium. FLA also has an ever increasing resistance to taking a charge. When my L-16 batteries were new they took about 10% more energy to recharge than I took out. This drastically changes as time goes by. When my batteries were 5 years old it too 20% more. So far with Lithium ion NMC my batteries take a charge so fast I have the efficiency setting on my battery monitor set at 99%.

I really love that you are back. We need more people with there world based in facts and data and less in opinions and hear say. I have been thinking the same as you regarding DOD ad lifespan. I run 24 x OPzS1500 (1700 Ah) 2 volt cells. When I dived into the data on the cells I concludes the same as you describe. DOD does not matter on how much energy you can pass through the battery before end of life. Here are my calculations on a OPzS1500 cell: From data: 1000 cycles ved 90% DOD 1500 cycles ved 60% DOD 3000 cycles ved 30% DOD 4500 cycles ved 20% DOD Complete energy in and out before end of life: 90% DOD: 1000*0,9*1700*2=3060000 Wh=3060kWh 60% DOD: 1500*0,6*1700*2=3060000 Wh=3060kWh 30% DOD: 3000*0,3*1700*2=3060000 Wh=3060kWh 20% DOD: 4500*0,2*1700*2=3060000 Wh=3060kWh

thanks

Found your videos very interesting & wondered if you’d come across Lithium Titanate 🤔

With NEC 2020 as long as the Inverter is UL9540 and compatible with Lead Acid.... does that mean the combination of said inverter with any Lead acid storage battery would be approved?

Would it be right to compare the round-trip efficiency of the batteries here? I was under the impression that discharging a lead acid at anything like 1c would severely diminish the capacity?

Could you possibly touch on charging efficiencies/times of each battery type ?

🤔… very interesting!, finally !, somebody who isn’t bullshitting , well done sir , your a legend!!!👍🏾

The flooded acid battery Abby's is how many years you still revive it and it still be good AGM and lithium-ion when is dead it is dead nothing else you could do about it

I went for AGM lead carbon (top brand) at 4 years old, the 320 ah is down to about 70ah, the system has always been connected to the same brand inverters etc and set to the suggested settings, with hindsight the batteries were way off spec 18 months ago finally now changing them because the voltage drops too low. Breaking into one battery it's virtually dried out? So it's possible we may recover some more use from them, my new "maintenance" free batteries at least have caps to unseal and check in future unlike the last lot.

So if I want a 24v system I need four of them. Yeah, that's pricey but at 220lb each we are talking 880lb of batteries! I'm not sure how I would handle that.

LiFePO4 batteries like to be stored at 100% SOC. NMC prefers 50% to 80%. LiFePO4 have 95% Coulombic efficiency. Lead acid around 70-80% depending on discharge rate. This is an important consideration for off grid solar.

A better attempt than most to do a fair comparison. One issue is that Lithium "12v" batteries are still near their early-adopter pricing. I just watched a youtuber (Freely Roaming) claim that he can buy 12v-worth of 280ah Li Iron cells for sub US$400 so only 15% of the price per KWh of your Battle Born. Despite your comments I still feel Lithium is a better bet for a battery subject to significant daily discharge - you only have to look at Tesla's recent stats on battery degradation. I was certainly surprised by your comment that Lithium is seriously affected by being charged above 80%. For max life its best to avoid 100% charge but "seriously affected" - I don't think so.

Trojan batteries are indeed good batteries and yes costly. Had them on golf cart.

Can't find part 2 :( after buying 2 battleborns because my 200 ah agm died after 2 years, this is interesting.

We need a Neil in every school 😀

Your arguments against lithium make perfect sense....within the context of a fixed home system. But lugging hundreds of pounds of lead in a tiny teardrop travel trailer like mine is not a viable option. Lithium wins hands down. And the reality is, most people use a cheap flooded battery or batteries in their RV. Which makes a lithium comparison valid.

I'm in need of some advise I live totally offgrid with only 400watt coming in I'm using 2 poor lead acid now a dealer I was going to buy 2 trogan t105 for $320 but he also has 2 reconditioned discovery agm batteries...which would be the wisest choice ?

The costs of Lithium will rapidly fall with economies of scale. This has already started happening, it is only a matter of time. The motor industry gave it a nice jump start (yeah pun intended).

What type of battery does the US Navy use in their submarines? Price is no object there, might give us a clue which is best.

Am i correct in assuming the kwh/$ is based on the cost of the batteries, not including shipping?

So are forklift batteries the best thing to use then?

I use crown CR-235 flooded batteries.

Somehow I like my AGM batteries better than any other battery out there I've had difficult discoveries and deep cycle and conventional lead acid batteries in my time and I think ATM batteries are a little better and they do last longer

Depending on the use, I think lithium ion, or lithium iron phosphate, is the better choice, if you have hydroelectric, that the batteries are only used for short surges, lead acid is fine, otherwise lead isn't my choice, it's about as scientific as a spoon, for lower cycle systems liion, for higher cycle systems, lifepo4, definitely, my lithium ion bank, will be fully cycles weekly, with normal use, I'm hoping for a minimum of 10 years, with it still useable , but low capacity, I will likely be buying LiFePo, of something else that may be available between now and then, I do have a 400 ah LIFePo bank, for lighting and other 12v needs off grid, otherwise the 24v liion battery and inverter powers everything, or the 7kw generator! Also 4500 watts of pv, and adding wind turbines and more pv,

You're lucky that you live in USA. You can buy wrecked car like chevrolet volt for around $2000, remove 12kWh battery with BMS and all the stuff you would need to use it for solar. This gives you lithium for lead acid price and they're going to last very long.

Lithium batteries don't seem to like being recharged in temperatures below 25 ° F or -4 ° C, which is important to me in Canada.

The comment about DoD at 12:30 is not supported by datasheets. For instance, FullRiver AGMs claim 5000 cycles of 10% DoD, 3000 cycles of 20% DOD, but only 500 cycles of 80% DOD. 500 x (80%/20%) is not 3000 (it's 2000). So yes, even shallow discharges wear the battery out deeper discharges do more damage (note: This is per their 2 hour test so I imagine the 80% DoD is at a higher discharge current meaning hotter batteries)

FYI lead acid batteries can be used for decades if you know how to recondition them. I know guys using the same deep cycle marine batteries since the late 80s.

Wow. Awesome analysis! So why are Tesla building Powerwalls from a zillion little 18650 cells?

Well on lithium iron phosphate the damage at fully charged or fully discharged is relative but not that big of a deal even if you do and it's more like the top 10% less so on the bottom end but

what voltage would a 35ah battery after drawing 35 amps for one hour?

What's about voltage sag on lights and computers

Early or Late adopter of lithium, but no one can deny the energy density of lithium. Everyone uses lithium batteries, cell phones, cameras, laptops, drones and etc, all use lithium batteries. It will take time to get cheaper direct replacement batteries for lead acid batteries replacement. Solar industry using batteries is really small, majority of people are only grid tied, no batteries. Agreed on fire risk, but if you produce power there is always a fire risk. Never put any Grid power source in your house. Put it outside and away in a separate cabinet or shed. Never use lithium batteries without a BMS.

7:45 - "empirical units" was an oddly appropriate misstatement :-)

My greater question are: 1. Does lithium batteries perform better than AGM or Gel during high discharge rates? 2. If I go for Lithium is it then recommended to keep my battery at 90-95% state of charge & not go below 25% DoD? 3. Looking at prices in Africa & warranty, AGM & Gel are at maximum 2yrs, but generally at 1year, Lithium is never at 5yrs plus and truthfully getting a manufacturer to honor these is clutching at straws. 4. Price of lithium (Pylontech US2500), is about US$1.250 & 200ah x 4 batteries is US$1,400 (which give me circa 200ah in a 24v system at 50% discharge). That extra $150 is something & excludes labor & installation which is another US$240. 5. Making sure batteries are correctly installed in series & parallel to ensure good balancing during charging and discharging is another issue. Your 2-cents would be greatly appreciated.