Replaced old lead acid batteries with LifePO4 for home power system off grid

So I finally got around to replacing my ancient 35000 watt hours of LA batteries with about 30000 watt hours of LifePO4. What a major change this is! It over doubled my usable watt hours even though the total bank has less.  With LA cells I could only use about 25-30% with the new LifePo4 I can use 60%. Voltage sag is more or less a thing of the past. With a full system load the voltage only sagged 0.1 volt with my old bank under full load it was over 1.0 volt of sag.

Simply amazing!!!

Certainly sounds like a winner. In your specific situation,  did you compile a direct cost comparison between the two battery types? I'd love to see the numbers if possible,  while still keeping the vast performance improvement in the back of my (rapidly shrinking) mind. Thanks for this post, it helps to shape  my decisions

For the combination of home energy, farmyard vehicle propulsion, and potentially future EV purchase, I continue to try to keep up with developments in solar energy and storage.  While very tempted to sink money into LiFePO4, I'm more inclined to spend only 'dabbling' amounts of cash here and wait to see where battery storage is heading.  So much change in the battery industry and with sodium ion battery technology moving quickly, that may turn out to be a less costly and more eco-friendy option in the near future.  Wife uses an electric Polaris 4X4 Ranger for farm chores and we are sticking with lead acid for the time being, but I will likely test LiFePO4's in my electric golf cart which also is a farmyard 'go-fer' vehicle. As we reside not far from the Canadian border in the northern Plains (USA), I was very encouraged by a bar-stool discussion this past week with a gal from Germany.  She was mentioning her family farm in a mid-central location of that country where she had helped her father install a solar system that is grid-tied, yet supplying a good portion of their home power.  Germany has a decent committment to solar and likley subsidizes these installations (??), but I'm not sure about that.  At any rate, successes in northern regions have me still leaning towards solar integration (or stand-alone?) with grid for our remaining days here.  Just seems from my limited experience so far with that technology to be extremely under-utilized at this point.

Rico Loma wrote:Certainly sounds like a winner. In your specific situation,  did you compile a direct cost comparison between the two battery types? I'd love to see the numbers if possible,  while still keeping the vast performance improvement in the back of my (rapidly shrinking) mind. Thanks for this post, it helps to shape  my decisions

No when I bought these last year my thinking was if I treat them right they would be the last batteries for home power I'll ever need to buy as they will in all likely hood out live me! They were rated for 8000 full cycles or roughly 22 years. Then after much research I had also determined that keeping the battery cells between 20 and 80 percent would double and maybe even triple the lifespan. So now we are talking 16,000-24,000 cycles or days. Well there are 365 days in a year and 16,000 divided by 365 that's roughly 43.5 years and I feel I'll be lucky if I live another 25-30 years....  These are Eve 280AH cells and I have 32 of them in a 16s2p arrangement. I also got them on sale with free shipping for under $4,000. To me that's a no brainer as $4,000 would barely pay a power bill for 3 years for a small extremely efficient house.

I purchased them from the 18650 battery store.

You hit the 16 d nail on the head. That was exactly the type of thinking I hoped for, so thanks Larry

I have 1500+-ah of series/parallel 24 volt L-16 type lead acid US Batteries. No grid here anywhere close.
Looking at Battle Born's website, for American tech, I would likely need about 15,000USD worth of heated batteries, to replace them. Mine cost, in 2023, about 2600USD through Oasis Montana, no sales tax, picked them up in Missoula, no freight.
LA batteries, for all their apparent shortcoming are:
Stone
Axe
Simple.
....and pretty dang heavy.
Been around for well over a hundred years. I'm not sure I want a battery that takes it's own brain to function, even if that brain is American made.
We leave our home 4-6 weeks in the early winter, the temps inside get down to about 10F.  Therefore the self heating batteries. Our winter sun is actually decent. My snow covered yard opens to the south, our lake freezes/snows over. One big reflector. Solar panels work better in the cold.
You could spend less for LiFePo I'm sure. But if you told me you believe the circuitry and safety features of some cut rate Chineese battery you bought on TEMU/AliBaba/Amazon, for which you will have NO recourse in 2-4 years, were equivalent to the units sold by a Nevada based company, I would say my belief is you are delusional. In my mind because of complexity and 'newness' of tech, the lithium is not yet close to proven.
Go to the Battle Born website and look at the list of tests and compliances they subject their batteries to and provide the same data for the batteries you seem to want to recommend to me.
I may or may not not get 3000 cycles to death a LiFePo battery seems to promise, but I never run my batteries to less than 70%, and the 4v lead beasts these batteries replaced lasted about 30 years. I don't kid myself that these batteries are the equivalent of the 4V KWatts we had, but I also could apparently replace my US Batteries like 5-6 times before the cost breakeven for lithium is approached.
My only caution for a high capacity LA like these is to mind the charge rate they like for bulk charging. These batteries like almost 40A of charge to begin.
300W panels are cheap, charge controllers and cabling are not, doing that on a budget is tough, possibly not having to panel up is a plus for lithium. Some of the current charge controllers or control/inverter options no longer support three stage LA charging, something else to consider.
Battery prices in Canada are quite high. I can buy in the States and pay the 10% duty and come out money ahead, even with currency conversion.
When your lithium batteries are 15 years old you can tell me how wonderful they are/have been.
I'll be waiting/listening.

Tommy Bolin wrote:I have 1500+-ah of series/parallel 24 volt L-16 type lead acid US Batteries. No grid here anywhere close.
Looking at Battle Born's website, for American tech, I would likely need about 15,000USD worth of heated batteries, to replace them. Mine cost, in 2023, about 2600USD through Oasis Montana, no sales tax, picked them up in Missoula, no freight.
LA batteries, for all their apparent shortcoming are:
Stone
Axe
Simple.
....and pretty dang heavy.
Been around for well over a hundred years. I'm not sure I want a battery that takes it's own brain to function, even if that brain is American made.
We leave our home 4-6 weeks in the early winter, the temps inside get down to about 10F.  Therefore the self heating batteries. Our winter sun is actually decent. My snow covered yard opens to the south, our lake freezes/snows over. One big reflector. Solar panels work better in the cold.
You could spend less for LiFePo I'm sure. But if you told me you believe the circuitry and safety features of some cut rate Chineese battery you bought on TEMU/AliBaba/Amazon, for which you will have NO recourse in 2-4 years, were equivalent to the units sold by a Nevada based company, I would say my belief is you are delusional. In my mind because of complexity and 'newness' of tech, the lithium is not yet close to proven.
Go to the Battle Born website and look at the list of tests and compliances they subject their batteries to and provide the same data for the batteries you seem to want to recommend to me.
I may or may not not get 3000 cycles to death a LiFePo battery seems to promise, but I never run my batteries to less than 70%, and the 4v lead beasts these batteries replaced lasted about 30 years. I don't kid myself that these batteries are the equivalent of the 4V KWatts we had, but I also could apparently replace my US Batteries like 5-6 times before the cost breakeven for lithium is approached.
My only caution for a high capacity LA like these is to mind the charge rate they like for bulk charging. These batteries like almost 40A of charge to begin.
300W panels are cheap, charge controllers and cabling are not, doing that on a budget is tough, possibly not having to panel up is a plus for lithium. Some of the current charge controllers or control/inverter options no longer support three stage LA charging, something else to consider.
Battery prices in Canada are quite high. I can buy in the States and pay the 10% duty and come out money ahead, even with currency conversion.
When your lithium batteries are 15 years old you can tell me how wonderful they are/have been.
I'll be waiting/listening.

If we are all still around in 15-30 years I'll be happy to.

I built my system from parts so I can also replace parts as needed IE: the BMS / brain if it goes bad

It got down to about 20f last night and I never insulated or heated the batteries. Lost power about 2:30am took till about noon to get the cells warmed up to about 35f or 2c and got power back online. Spent the better part of the day after that wrapping the cells with heat tape for pipes and put insulation under and over , still need to go back and insulate the sides. Used 30 feet of heat tape with a 90w draw. It has it's own thermostat on at 35 off at 50 if I remember correctly.

Larry, that is an interesting problem to have.
I have heard of it but I dont live where it gets that cold.
Is there some system to ensure they do not chill down?

larry kidd wrote:It got down to about 20f last night and I never insulated or heated the batteries. Lost power about 2:30am took till about noon to get the cells warmed up to about 35f or 2c and got power back online. Spent the better part of the day after that wrapping the cells with heat tape for pipes and put insulation under and over , still need to go back and insulate the sides. Used 30 feet of heat tape with a 90w draw. It has it's own thermostat on at 35 off at 50 if I remember correctly.

That's good to know. I thought lithium batteries would just not charge at low temps. I didn't know discharging would be affected as well. My batteries are in the same insulated enclosure as my inverter and it seems like the inverter puts off enough heat to keep the battery above warm.

larry kidd wrote:It got down to about 20f last night and I never insulated or heated the batteries. Lost power about 2:30am took till about noon to get the cells warmed up to about 35f or 2c and got power back online. Spent the better part of the day after that wrapping the cells with heat tape for pipes and put insulation under and over , still need to go back and insulate the sides. Used 30 feet of heat tape with a 90w draw. It has it's own thermostat on at 35 off at 50 if I remember correctly.

Living where we do in the central US just below the Canadian border, an experience like this is what causes me to hesitate on diving into LiFePO4.  I probably will anyway and just keep the investment small to modest.  Wife is still tooling around the farmyard with recent ~10 degree F using lead-acid batteries in a Polaris Ranger EV and we are grateful for the robustness of the time-tested tech, even with the known power deficits of these batteries in cold weather.

There was mention recently of Canada leaning more towards solid-state/sodium ion technology, partially because it may be a less expensive battery to produce, but also in large part due to its greater resiliency to cold temperatures.  Still that battery too will use a battery management system (BMS) and one hopes these don't turn out to be a weak link in the technology.  Larry K, I always wondered if a seedling heating mat would be enough to prevent severe temperature drop in such situations.  CLearly if the location is too cold and the batteries unprotected, the BMS will do best to shut down the battery.  But in situations where the batteries are housed in an insulated container of sorts, a seedling mat seems to be designed to produce low temperature, low wattage heat to the item(s) sitting on the mat.  Perhaps this would be a safe solution for many out there?   Also a question for those having installed LiFePO4 batteries going back a decade or two:  Have you experienced or heard of situations where either the cells or the BMS itself failed causing need for battery or cell replacement? If the BMS goes bad and the cells are otherwise good, can the BMS be replaced (assuming a battery case whose contents can be accessed) fairly easily?  Thanks!

John Weiland wrote:

larry kidd wrote:It got down to about 20f last night and I never insulated or heated the batteries. Lost power about 2:30am took till about noon to get the cells warmed up to about 35f or 2c and got power back online. Spent the better part of the day after that wrapping the cells with heat tape for pipes and put insulation under and over , still need to go back and insulate the sides. Used 30 feet of heat tape with a 90w draw. It has it's own thermostat on at 35 off at 50 if I remember correctly.

Living where we do in the central US just below the Canadian border, an experience like this is what causes me to hesitate on diving into LiFePO4.  I probably will anyway and just keep the investment small to modest.  Wife is still tooling around the farmyard with recent ~10 degree F using lead-acid batteries in a Polaris Ranger EV and we are grateful for the robustness of the time-tested tech, even with the known power deficits of these batteries in cold weather.

There was mention recently of Canada leaning more towards solid-state/sodium ion technology, partially because it may be a less expensive battery to produce, but also in large part due to its greater resiliency to cold temperatures.  Still that battery too will use a battery management system (BMS) and one hopes these don't turn out to be a weak link in the technology.  Larry K, I always wondered if a seedling heating mat would be enough to prevent severe temperature drop in such situations.  CLearly if the location is too cold and the batteries unprotected, the BMS will do best to shut down the battery.  But in situations where the batteries are housed in an insulated container of sorts, a seedling mat seems to be designed to produce low temperature, low wattage heat to the item(s) sitting on the mat.  Perhaps this would be a safe solution for many out there?   Also a question for those having installed LiFePO4 batteries going back a decade or two:  Have you experienced or heard of situations where either the cells or the BMS itself failed causing need for battery or cell replacement? If the BMS goes bad and the cells are otherwise good, can the BMS be replaced (assuming a battery case whose contents can be accessed) fairly easily?  Thanks!

John there is Lithium and then there is lithium... Most of the server rack type assemblies are available with a built in heating mat. It is a little annoying though as it will only power up while the batteries are charging and cannot be used in an off grid discharge only scenario. I have taken to oversizing my insulating boxes by 6 inches on all sides and incorporate a 300 watt heater with a blower. Even with the extra troubles lithium is worth it. The greatest advantage is rate of charge. Traditionally you would limit your array size to match the ideal rate of charge of a lead acid battery since the rest was "wasted". Now we can oversize the array so that you can grab 100 percent of available sun on those days where the sun comes out hard for short amounts of time. Also all that extra time running a generator for absorb charging is also a thing of the past. So the little power you use heating the box is worth it. I would suggest sticking to a company that has distribution and available spare parts like all high cost tech items. I like the units that do closed looped communication with the inverter so you get a real time temp reading and balanced charging. The cheap drop in replacements without comms have not been doing well long term. As to Sodium they are starting to show up but are in their early adopter high cost unknown specs days so I'll wait for now.
Cheers,  David

I was really excited about Sodium ion until I realized the way they work all the way across the voltage. Where as most equipment is set for the small voltage range of lead acid cells. LifePO4 also uses a fairly small range L-ion uses a larger range and sodium uses almost the entire voltage from 2 past 12 on a 12 volt system. To put this further in context a lead battery at full charge 12.7V down to about 12 volts if you want any kind of battery life. While the system can go down to maybe 10 volts it will kill a lead battery quick fast and in a hurry. Look at the range on sodium to see what I'm talking about. This will require largely different equipment for sodium from lead acid.