Real world benefits of DIY LifePO4

[Zen]

At what point do I just surrender to BattleBorn and eat the cost/space of having a great battery bank?

Spent a lot of time researching different battery bank configurations as I'm ready to invest in the most expensive part of my planned system. Cost, space, and longevity/ease of maintenance are the key issues for me.

I'm aiming for a 400-600 Ah 24v system...probably will start with 200-400 Ah. Low temp cutoff is a must. I will use an all-in-one unit for MPPT, AC and charging functions. I'm pretty comfortable with all of the recommended bottom balancing and assembly, thanks to Will, so DIY LifePO4 is attractive.

But besides being very interesting and potentially fun to build and use these units...after adding BMS, low temp, all the connection and electrical parts, tools and instruments to complete, my time and frustration ...

Can I really save a lot on the battery bank in terms of space and cost by building the bank myself? Since my direct current/battery system/low-voltage experience is low, am I better off just cozying up with a 10yr warranty and effortless connections/maintenance in a BattleBorn?

Thanks much for your thoughts on this. Ready to pull the trigger but don't wanna shoot myself in the foot!

 

[BoloMKXXVIII]

My advise is buy the BattleBorn batteries for your main system. Buy all the battery you are going to need at one time. It is not a good idea to add more batteries later. As you cycle batteries they slowly loose capacity and their resistance can change. Mixing old and new will just shorten the life of some of the batteries. Try building a small battery yourself. Maybe a 20Ah, 12v battery. It is big enough to be useful but small enough to be affordable. Learn on that before you spend big money and potentially do something dangerous/costly due to lack of experience. Take what you want of this advice and ignore what you want. Your $$$

 

[Zen]

Thanks Bolo, this is great advice. I keep coming back to the BBs after speccing and adding it all up. The issue is certainly cost and I cannot afford to buy more than (2) 12v 100Ah units if I go this route. When I do decide to add more batteries, is it possible to balance the resistances out or equalize them in some way to ease the strain?

 

[BoloMKXXVIII]

BB batteries have their own BMS built into each individual battery. I understand the cost issue. The initial cost is quite high. Hopefully there won't be too many cycles before you add more batteries. I am not sure how BB would handle warranty issues when connecting old with new batteries.

 

[b.james]

Now I would send you the other way because the cost savings are huge . Look at the 50Ah cells in this section . Cheap enough . Buy a cheap $20 BMS but buy a victron small Solar controller not a cheap one . You will see why when you do it . Put it together and experiment . Thats what I did and I made some mistakes . Later though I went for a bigger system knowing what I wanted.

 

[crozza]

At what point do I just surrender to BattleBorn and eat the cost/space of having a great battery bank?

Spent a lot of time researching different battery bank configurations as I'm ready to invest in the most expensive part of my planned system. Cost, space, and longevity/ease of maintenance are the key issues for me.

I'm aiming for a 400-600 Ah 24v system...probably will start with 200-400 Ah. Low temp cutoff is a must. I will use an all-in-one unit for MPPT, AC and charging functions. I'm pretty comfortable with all of the recommended bottom balancing and assembly, thanks to Will, so DIY LifePO4 is attractive.

But besides being very interesting and potentially fun to build and use these units...after adding BMS, low temp, all the connection and electrical parts, tools and instruments to complete, my time and frustration ...

Can I really save a lot on the battery bank in terms of space and cost by building the bank myself? Since my direct current/battery system/low-voltage experience is low, am I better off just cozying up with a 10yr warranty and effortless connections/maintenance in a BattleBorn?

Thanks much for your thoughts on this. Ready to pull the trigger but don't wanna shoot myself in the foot!

I have been going through exactly this problem, as I am building a new house and costs keep on rising.

My decision has been to go with a system made by an Australian company using well known batteries etc for the house.

And in my workshop I will be building my own system. I reckon this will give me a reliable system (and worry free) for the house and I will learn a lot when building the garage one.

I have built my own system for the caravan and camper trailer but this is a bigger issue with different needs and wants.

 

[Zen]

I have been going through exactly this problem, as I am building a new house and costs keep on rising.

It's so awesome to be able to share problems and solutions with people on the other side of the world!

I opted to start "modestly" with 2 Battleborns for my mobile system, mostly because I'm inexperienced with batteries and wanted simplicity (read BMS) and reliability. I think as long as the system/batteries are reputable and you have a good monitoring system, all options are viable.

Starting the build here:

First Solar System

Super excited to energize my first solar system, at least the heart of it. I hope you all can help me verify that everything looks right, is safe and make any necessary changes or additions. 100% open to any mistakes or criticisms or if something just looks dumb. I'm new here. :) Not much is...

diysolarforum.com

 

[Rider]

I have a little different take on it. I fully agree that LiFePO4 is the way to go, but it's just way too expensive. Yes, I know all the arguments that it's cheaper in the long run. Don't care about the long run, I care about spending all that money right now up front. I can easily settle for AGM right now, and be patient to wait for the smoke to clear. Too many vendors offering too many items, many of which are just not worth the money.

The price of LiFePO4 is going to come down. Crap vendors will eventually get weeded out. Some batteries and vendors will shine. When all that happens, I'll buy lithium. Today, right now, my AGM does more than the job it needs to do at 1/4 the price for a similar lithium. Who knows? By that time, maybe there will be a whole different, better technology available.

 

[robaroni]

I have a little different take on it. I fully agree that LiFePO4 is the way to go, but it's just way too expensive. Yes, I know all the arguments that it's cheaper in the long run. Don't care about the long run, I care about spending all that money right now up front. I can easily settle for AGM right now, and be patient to wait for the smoke to clear. Too many vendors offering too many items, many of which are just not worth the money.

The price of LiFePO4 is going to come down. Crap vendors will eventually get weeded out. Some batteries and vendors will shine. When all that happens, I'll buy lithium. Today, right now, my AGM does more than the job it needs to do at 1/4 the price for a similar lithium. Who knows? By that time, maybe there will be a whole different, better technology available.

You make some very good points.
My advice to people is to build an intertie system with back up. It may look glamorous but running on batteries constantly is a bad idea if you have grid available. An intertie with back up keeps your pack charged for when you need it and sells all your excess after you supply your critical needs back to the grid. This way you batteries last a very long time.
AGM is a good battery for this, it's low maintenance and can sit for a long time with no problems.
I've gone both roots, I initially had L/A batteries and now I built a 10Kw LiFePo4 system. I'm good at this and still building the system was tough. If you don'tr have the tools and background you might find going with AGM's might fill your needs and it's a cheap, safe way to go.

 

[Zen]

I feel the same way Rider. It really is a big picture kind of thing with many personal factors involved in making many of the decisions for solar/off-grid applications. Couple that with the insane pace of tech and price shifting....I've had to bite the bullet many times in this aspect...computers, tools, tech, vehicles, etc.

Solar and battery markets are definitely at the crest of this dynamic. My application is tight space-wise, I want it to last forever (right...), mobile and modular so LifePO was a huge advantage in these respects.

Also, experience really is a huge factor. I'm not afraid of building a battery or wiring up some crazy stuff if I have access to the right info, and the time to do it. I weighed battery options for over a year starting with Tesla and going through about every possibility. Still crying over the price of Battleborns but they are beautiful. I'd like 2 more please ?

Had to quote "modestly" in my original post....nothing modest about a grand for a freakin battery...

 

[b.james]

Well like Will said with Lead acid if they last more than 3 years you are not using them . Combine that with only being able to use only 50% safely and the gas and corrosion factor and you can understand how Battleborn looks inviting.

I buy the cells from china and use cheap BMS's and Active balancers and am very pleased so far. Spent about $3000 AUD (2000 USD) on 16 cells of 100Ah(2500) ,inverter(200) and solar charger (200). BMS (30), Active balancer (30) Had the panels.

That gives me a 12 V battery equivalent of 400Ahs (I run at 24V atm)
For AGM I would need 800Ahs at least for the same useable capacity and maybe more and they might only last 3 years.

No brainer for me. (Proviso --As long as I get the cycles life proffered of at least 3000 or say 9 years)

 

[robaroni]

Well like Will said with Lead acid if they last more than 3 years you are not using them . Combine that with only being able to use only 50% safely and the gas and corrosion factor and you can understand how Battleborn looks inviting.

I buy the cells from china and use cheap BMS's and Active balancers and am very pleased so far. Spent about $3000 AUD (2000 USD) on 16 cells of 100Ah(2500) ,inverter(200) and solar charger (200). BMS (30), Active balancer (30) Had the panels.

That gives me a 12 V battery equivalent of 400Ahs (I run at 24V atm)
For AGM I would need 800Ahs at least for the same useable capacity and maybe more and they might only last 3 years.

No brainer for me. (Proviso --As long as I get the cycles life proffered of at least 3000)

This is why I think we have to classify battery applications. If you're just using batteries for backup when there are power failures in your area then Lithium's may not be the best choice. My last L/A batteries lasted 13 years, they cost me $1,600. and I got back $300 when I sold them for recycle. You can't come close to that with lithium's.
The only reason I used them in my latest power wall is because I got them dirt cheap before most people went to LiFePo4's over ions.

I'd like to see the ROI (return on investment) on Tesla power walls where people run them every night, I can't see it being a short time.

I think Will's statement has to be quantified. Sure if you're off grid L/A is a poor solution but most people aren't off grid and, again, if you don't have to run off grid you shouldn't.
Batteries are rated in cycles, an L/A can last over 2k cycles when it's just being run to 5 or 10% discharge. Toyota showed this in the Prius, they used Ni-Cads for years with good results watching the discharge levels..

 

[Rider]

Well like Will said with Lead acid if they last more than 3 years you are not using them .

I'll worry about it in 3 or more years. If it lasts that long and is still charging/discharging well, who cares if I'm using it to the full potential or not? It's doing the job. If and when it starts to fail, then I'll revisit current state-of-the-art. Everything may be different by then. And those who spent tons of money on 20-25 year batteries may just be kicking themselves for having spent so much and now all of sudden, better and cheaper is available. And while I am certainly capable of building batteries from cells, I don't want to be bothered having to wire and deal with a BMS and constantly checking charge states and top vs bottom balancing and on and on. I want a battery I can install and walk away from.

And if it lasts more than 3 years because I'm not using it, why on earth would I spend 4 times more money for more capability when I'm not using what I have?

To each their own....

 

[Zen]

Application is everything. If I was building a stationary system I'm pretty sure I'd have 4-8 back-breakers here! When I started calculating watt-hours and weight/size + moving this beast bank around + potentially heavy cycling = lithium.

 

[PHoganDive]

Batteries are rated in cycles, an L/A can last over 2k cycles when it's just being run to 5 or 10% discharge. Toyota showed this in the Prius, they used Ni-Cads for years with good results watching the discharge levels..

Ni-Cads should always be drained fully, otherwise they develop a memory effect and lose capacity. Early Prius's used NiMH batteries which don't have the memory effect.

 

[gnubie]

Everything may be different by then. And those who spent tons of money on 20-25 year batteries may just be kicking themselves for having spent so much and now all of sudden, better and cheaper is available.

There is always something better just around the corner. 5 years ago I bought an enterprise hard disk. Today's consumer grade disk prices and performance make it look like it was made from solid gold. Am I kicking myself? Nope. I needed it at the time, and it is still doing that job today.

 

[b.james]

Everything may be different by then. And those who spent tons of money on 20-25 year batteries may just be kicking themselves for having spent so much and now all of sudden, better and cheaper is available.
To each their own....

Funny I was reading about how Graphine is into its 15th aniversary and how it will get going anytime now . Man you can wait but I want my benefits now.

Graphene turns 15 on track to deliver on its promises

Scientists analyze the current graphene landscape and market forecast for graphene over the following decade.

www.sciencedaily.com

 

[robaroni]

Ni-Cads should always be drained fully, otherwise they develop a memory effect and lose capacity. Early Prius's used NiMH batteries which don't have the memory effect.

My point is that they used the batteries for a specific application and contoured them to to fit that app. Some Prius's still use NiMH although the plug-in uses Li-ion. Different batteries for different apps.

"Memory effect" is a misnomer, NiCads develop voltage depression which can be remedied by several cycles of fully charging and discharging. The big problem with NiCads is the cadmium which is an environmental disaster.