Getting quality lithium batteries on the cheap

I follow Jeff Cote out of Vancouver for most of my electrical and electronic questions and knowledge. But I also follow Will Prowse, a young guy who is self taught and has dedicated himself to helping people get into lithium and solar power on the cheap.

One product he has become enamored with are used medical lithium batteries. The batteries have turned out to be well maintained and when he has purchased them and tested them out, he has found them to still very usable. So in the link I am providing, you will notice the batteries he is using as quite small and I'm betting very light. So to replace a battery bank of 4 (whatchamacallit 31 batteries) with these smaller batteries would reduce the total amp hours available. But I thought what if you built a two level battery container, should be easily doable as the lightness of the batteries would probably be still less than the heavy 31 batteries.

Anyways on to the video, its one year old:


So I just reviewed this video thinking it was the one he posted a year ago, in which the medical used lithium batteries were a bargain. But his vlog as you can see drove up the pricing of them.

So here is a link to his video offerings, a great source of knowledge for solar equipment and lithium batteries and how to build your own systems.

https://www.youtube.com/channel/UCoj6RxIAQq8kmJme-5dnN0Q

We are changing our house bank and putting in LiFePO4 batteries by Lion Energy. They are 105 AH and we are putting in 3 of them. They aren’t cheap but the way it worked out for me they are cheaper than replacing the 4 6 volt GC batteries with 6 6 volt GC batteries. In order to fit the 6 GC batteries I would have to replace the aft A/C with a self contained unit. So not having to replace tha A/C unit made the Lithium batteries cheaper. I am moving the bank out of the engine room and in a space that used to house an icemaker. I started putting in the bus bars and fuse blocks today. I am replacing one of the stock alternators with a 120 amp Balmar dedicated to the house bank. Also putting in a Balmar SG200 SOC meter. The lithium batteries are pretty incredible. They each weigh 23 pounds. One of the things I like about the Lion Energy batteries is that the terminal posts unscrew so it leaves a flat surface that I am putting a 3/8”x3/4” copper bus bars to connect them together instead of using cables. They can be discharged to 0% but they recommend 20% with over 3500 cycles. They also come with a lifetime warranty.

For those happy to DIY, it's hard not to go past assembling ones own pack from components.

I've got 840ah @ 48v of batteries on their way for $140 per kwh or $1.80 per 12v amp hour.

The scary thing is that prices dropped again the day after I bought mine. ��

Wow 840ah at 48v Is definitly one of the larger battery banks aboard a boat I’ve ever heard of. Can you tell us more about the setup and why you decided to go so large? Also what charging setup do you have setup for it. That’s a hell of a bank to try to charge.

Jmarsh203 said:

Wow 840ah at 48v Is definitly one of the larger battery banks aboard a boat I’ve ever heard of. Can you tell us more about the setup and why you decided to go so large? Also what charging setup do you have setup for it. That’s a hell of a bank to try to charge.

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The vessel is new to me but is a converted 54' ex prawn trawler. We have two intended uses for it: if I am aboard it will be a technical dive mothership with the associated compressors, gas boosters etc; if my family is aboard it will be a coastal and open water cruiser for 2 teenagers and an admiral who has advised that it WILL have an electric galley with full sized domestic appliances.

I have some experience with diy batteries and charge systems for dive equipment have have found that lithium offers the big advantage that many problems can be engineered out with no net negative impact on space, weight, run time and now cost. Eg with my battery pack we will have no concerns running multiple high draw components at the same time, DoD can be controlled to maximize bank life, noisy recharging can be done as and when suits us and if we lose 10% capacity over the next X years, I won't even notice.

A major attraction when shopping for a vessel was a single pitch roof, which this vessel has. This enables ~5kw of solar panels. Backup will be an onboard auxiliary 240v genset and shore power (expected to be seldom used).

The current design is for 10kw of single phase inverters. This may change to 15kw of 3 phase inverters. I have some 3 phase equipment on board. At this stage I am in favour of consolidating from 12, 24, 240 & 415v to only 12 and 240v but this may change depending on my ability to source 240v drive motors to replace the 415v units. It's a work in progress.

Regards.

I’ve watched a few LiFePo4 battery tear apart videos.

What is amazing to me is that they appear to be a bunch of D cell batteries all connected together.

Gotta be honest here... That did not instill a bunch of confidence in me.

ksanders said:

I’ve watched a few LiFePo4 battery tear apart videos.

What is amazing to me is that they appear to be a bunch of D cell batteries all connected together.

Gotta be honest here... That did not instill a bunch of confidence in me.

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I can understand your concern if shoddy parts or techniques are used. However, series and paralleling cells to achieve the desired voltage and capacity is standard practice.

This my dive scooter battery built over 5 years ago. It went from 400wh NiMH to 1500wh Lithium in the same volume and weight.

rsn48 said:

I follow Jeff Cote out of Vancouver for most of my electrical and electronic questions and knowledge. But I also follow Will Prowse, a young guy who is self taught and has dedicated himself to helping people get into lithium and solar power on the cheap.
https://www.youtube.com/channel/UCoj6RxIAQq8kmJme-5dnN0Q

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Jeff Cote and Will Prowse provide a superb public service to all with their videos - think I have watched most.

This past summer we completed the overhaul Comodave has started, replaced four 6VDC Lead-Acid Golf Cart (nominal 460 Amp-Hour total) with four 114 Amp-Hour LiFePO4 (nominal 456 Amp-Hour total) which fit in the same space at less weight. We can now regularly use 80% capacity of the Lithiums vice 30-40% of the Golf Cart, so a large increase in effective capacity. Lots of fun cutting through 4/0 wire making our own cables to parallel the batteries and route through a Shunt Monitor to new circuit protection (fuses, bus bars, On/Off switches).

Also upgraded the pulley's on both engines to now accept a wide 10-rib J-Belt to power new 140-Amp Alternators managed by External Regulators and a combining computer as the Alternators simultaneously charge the new Lithium House Bank. As the Lithiums we acquired have a maximum 0.6C charge rate, and to operate the Alternators less strenuously, we programmed the "280-Amp" total Alternator output down to about 60% of max output.

Expensive - Yes. A significant amount of work - Yes. Love the result - Yes. With the House down to a nominal depleted State of Charge of around 20%, we can take the batteries back to 100% in under 2 hours of motoring. We will now almost always arrive at our next destination with fully charged House Bank. Next summer installing an Inverter - we should have "free" AC power when travelling between stops as the batteries now charge so fast.

A little more detail in a write-up I provided the majority Product Vendor (Twin Volvo TMD41A Diesels): https://electromaax.com/Projects/

Big project, lots of money but what am I missing? Yes, if space is at a premium and there is a need/desire for more capacity within that limited space, lithium makes sense, but at a huge cost and a ton of work. Trojan (and others) FLA batteries cycled to 30% last about 750 cycles. Assuming 100 overnights, a lot for most boaters, that means the battery bank will last 7 to 8 years at a replacement cost of about $120 per golf car battery. Okay, lower hour runs on successive days will not fully recharge our 932ah bank (8 GC2 Dekas, $1,000) so maybe our bank will last only five years but so what. A full recharge every three or four days mitigates that effect anyway. My two 100 amp externally regulated Balmar alternators are enough to do the job although I should have installed the 120 amp model. No need for monster alternators and associated drive belt upgrading, another $500 per engine. And never mind considering how long one anticipates keeping the boat. I suspect the next owner, in many cases, not all, will be the one to reap the long-term benefits. I am by no means a cheapskate boater but lithium, for me, does not make economic or useful sense. Same for Lifeline AGMs.

If battery maintenance, that is, watering FLAs every 2 or 3 months is difficult, that would argue for lithium batteries or AGMs.

CPD said:

Jeff Cote and Will Prowse provide a superb public service to all with their videos - think I have watched most.

This past summer we completed the overhaul Comodave has started, replaced four 6VDC Lead-Acid Golf Cart (nominal 460 Amp-Hour total) with four 114 Amp-Hour LiFePO4 (nominal 456 Amp-Hour total) which fit in the same space at less weight. We can now regularly use 80% capacity of the Lithiums vice 30-40% of the Golf Cart, so a large increase in effective capacity. Lots of fun cutting through 4/0 wire making our own cables to parallel the batteries and route through a Shunt Monitor to new circuit protection (fuses, bus bars, On/Off switches).

Also upgraded the pulley's on both engines to now accept a wide 10-rib J-Belt to power new 140-Amp Alternators managed by External Regulators and a combining computer as the Alternators simultaneously charge the new Lithium House Bank. As the Lithiums we acquired have a maximum 0.6C charge rate, and to operate the Alternators less strenuously, we programmed the "280-Amp" total Alternator output down to about 60% of max output.

Expensive - Yes. A significant amount of work - Yes. Love the result - Yes. With the House down to a nominal depleted State of Charge of around 20%, we can take the batteries back to 100% in under 2 hours of motoring. We will now almost always arrive at our next destination with fully charged House Bank. Next summer installing an Inverter - we should have "free" AC power when travelling between stops as the batteries now charge so fast.

A little more detail in a write-up I provided the majority Product Vendor (Twin Volvo TMD41A Diesels): https://electromaax.com/Projects/

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catalinajack said:

Big project, lots of money but what am I missing? Yes, if space is at a premium and there is a need/desire for more capacity within that limited space, lithium makes sense, but at a huge cost and a ton of work. Trojan (and others) FLA batteries cycled to 30% last about 750 cycles. Assuming 100 overnights, a lot for most boaters, that means the battery bank will last 7 to 8 years at a replacement cost of about $120 per golf car battery. Okay, lower hour runs on successive days will not fully recharge our 932ah bank (8 GC2 Dekas, $1,000) so maybe our bank will last only five years but so what. A full recharge every three or four days mitigates that effect anyway. My two 100 amp externally regulated Balmar alternators are enough to do the job although I should have installed the 120 amp model. No need for monster alternators and associated drive belt upgrading, another $500 per engine. And never mind considering how long one anticipates keeping the boat. I suspect the next owner, in many cases, not all, will be the one to reap the long-term benefits. I am by no means a cheapskate boater but lithium, for me, does not make economic or useful sense. Same for Lifeline AGMs.

If battery maintenance, that is, watering FLAs every 2 or 3 months is difficult, that would argue for lithium batteries or AGMs.

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It’s funny because most LiFePo4 arguments involve generator run time, and yes for a boat sitting on the hook generator run time can be decreased by adding charging capacity above what a FLA battery bank can accept.

The problem is actually doing it, IE adding charging capacity larger than a properly sized FLA bank can accept.

My boat is a great for example. I have not one but Two Victron Multiplus inverter/chargers running in parallel, (which is more than most LifePo4 folks install BTW) and I am just barely maxing out my 840 AH L16 based FLA house bank’s charge current capability.

So... If I took my exact same charging system and replaced my $1500 FLA battery bank (the one that lasted me a decade BTW) with a six or eight thousand dollar LiFePo4 battery bank my actual generator run hours would not necessarily decrease. I still have to replace every watt of energy and since I am able to maximize my charging systems capability now with my FLA bank, I would not be saving generator run time.

What I would theoretically be saving is the number of generator starts as I could run my generatyor longer than the 2 hours and 10 minutes it takes to recharge my FLA bank from 50% to 80% SOC(that is a actual, not a calculated time), but that is also kinda a fallacy, since I need my generator to cook food, run the watermaker, do laundry, etc...

I suppose that folks are replacing marginal FLA banks and marginal charging systems with systems that are properly designed to maximize charging current, along with LifePo4 battery banks.

The challenge is that they would achieve in most cases about the same generator run time results if they installed a well designed charging system and a well designed FLA battery bank.

One of the big reasons why I converted my house bank to lithium was to use my solar more effectively, not on float, and be able to add panels. The lithiums having a longer/larger usable discharge range gives more time for the sun to produce the power.

Bud

Bud said:

One of the big reasons why I converted my house bank to lithium was to use my solar more effectively, not on float, and be able to add panels. The lithiums having a longer/larger usable discharge range gives more time for the sun to produce the power.

Bud

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That is an entirely valid reason.

If you want to run on batteries overnight so that you can pick up solar energy the next day and a 50-80% utilized house bank would be too large, heavy, etc... then LiFePo4 would be a good awnser.

This illustrates just one more boating choice that must be, as it almost always is, particular to the boat and the owner intends to use it. My point in Post #9, probably not well-explained, was lithium, for lithium's sake, may not be a wise or cost-effective choice. I don't angst over depleting my FLAs below 50%. I don't often do so. As I said, if they last a year or two fewer, I don't care. But, I am a contrarian as to many things boating. Some examples:

1. I live south of Annapolis. I do not winterize my engines, or the water heater, or the water tanks. I just drain them. All are below the water line and sit in a water bath of above-freezing water. In the coldest of winter temps, as low as five degrees, the engine room has never gone below 35 degrees. If the bit of water in the tanks and raw water circuit (also drained) were to freeze, there would be no expansion damage. Yes, I know, but, but, but what if? I do drain fresh water supply lines and winterize the heads.

2. I am not a fan of Racor filter heads, especially dual Racors. I much prefer a Tony Athens sequential filtering system. Sight bowls? Pretty much useless. Just open the drain valve on a metal filter and have a look-see once in awhile. I read recently about a boater who had to install a back light on the bowl in order to see through it. Plus, they consume a lot of real estate. Use a vacuum gauge and change filters when needed.

3. Ditto for fuel polishing systems which are nothing more, wait for it, another fuel filter. IMHO, they are a waste of time and a whole bunch of plumbing. And day tanking? Why?

4. Shrink wrapping a boat for the winter. A thousand dollars or more to protect something from the elements for three or four months after it just spent eight or nine months exposed to the elements. New England, Great Lakes, the hard winter north country, perhaps, but not here.

Rant over. Woke up early and could not get back to sleep. No need for any replies and associated thread drift. I fully recognize that there are other opinions, probably many more, contrary to mine. Please do not respond in this thread.

ksanders said:

That is an entirely valid reason.

If you want to run on batteries overnight so that you can pick up solar energy the next day and a 50-80% utilized house bank would be too large, heavy, etc... then LiFePo4 would be a good awnser.

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@Comodave Post #2

One of the things I like about the Lion Energy batteries is that the terminal posts unscrew so it leaves a flat surface that I am putting a 3/8”x3/4” copper bus bars to connect them together instead of using cables.

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A word of caution: LFP large prismatic cells will thermally expand and contract during charge/discharge cycles so it is normal practice to use jumpers between the cells that are made up of multiple leaves of copper with a hump in the middle of the jumper to absorb the movement.

I have not worked with the Lion Batteries but knowing what the prismatics do thermally, I suggest that you contact Lion Energy and determine if your plan to use solid bus bars between their batteries is satisfactory.