LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[john61ct]

I think they all come from China, and Alibaba sellers ship anywhere. CALB is a decent brand I think, I think Genasun and Winston are gone?

Terry, do you know who supplies the likes of Victron and Redarc their bare cells?

[T1 Terry]

Originally Posted by john61ct

I think they all come from China, and Alibaba sellers ship anywhere. CALB is a decent brand I think, I think Genasun and Winston are gone?

Terry, do you know who supplies the likes of Victron and Redarc their bare cells?

Winston and possibly Sinopoly are the only manufacturers of LYP (lithium yttrium ferrous phosphate) cells, Sinopoly may has lost the right to the chemistry as it belonged to Winston Chung and there is bad blood between the 2 companies now, well worse that the bad blood that caused the split in the first place anyway :lol: For those that may not know the history with these two companies, the were once Thundersky, then the split and Winston Chung took his new formula with him, a big court battle, Sinopoly paid Winston an obscene amount of money thinking they had bought out his ability to manufacture, then discovered all they bought was the Thundersky brand name and the right to use the new formula.... now I see Winston sell both LYP under the Winston label and LFP under the Thundersky label, so who knows what the latest state of affairs are with them and no idea if Sinopoly still produce the LYP cells.

Jogn, no idea who supplies Redarc, I didn't even realise they were selling lithium batteries now, Enerdrive use Sinopoly cells, no idea what the deal is with Victron or even if they are manufacturing their own from the basic components, or maybe special order from A123, no idea.
Every man and his dog seem to claim they are lithium battery manufacturers these days but there really are only a handful of component manufacturers, the rest are just branded to suit a buyer

T1 Terry

[guvet]

Retailers of single cells (3.5v) in Australia?
Thanks T1

[andreas.mehlin]

Cylinder vs Prismatic for a boat?
Cylinder is cheaper?

Big difference with or without yttrium?

[john61ct]

So known actual LFP prismatic manufacturers, all from China:

CALB
A123
Winston (as Thundersky)
Sinopoly

[andreas.mehlin]

I´m planning an electric project...where I will install an 10kw electric engine to a trimaran powered by LifePO4. I will also have a dinghy with an electric OB. Both 48v. The 12v system will be powered by the same 48v bank with a 48-12v converter

I have been reading some in the thread about pros/cons of parallel vs serial batteries....and I came up with the idea of having redundancy by splitting up the bank to several banks.

It would be great if I could use the same batteries for both the ob and the inboard. Lets say I would like 20 000wh capacity. If I put that into 4 banks mounted in portable cases, I would get 5000wh in each. 16 pieces 3.2v 100Ah. Or having 1 big bank (10kwh) and 2 at 5kwh each, where the big bank will be a main bank and the two 5kwh will be portable and made possible to connect to the system

To make it practical I would install some kind of quick connectors and switches.

So...why would I do like this?
1) Redundancy (4 banks á 48v 100Ah)
2) Always a charged battery for the dinghy
3) Saves weight by not having a dedicated ob-battery.
4) Possible to take a battery to land and charge it there (when not tied up to shore power)

The trimaran is very lightweight and we expect to sail in very light winds as well...The engine will be used for: in/out marina, anchoring, calms, emergencies

Question...most LiFePo4 batteries seems to have a max discharge at 3C.
Does this mean that a 100A bank has a max discharge output at 300A?
The 10kw engine would have 208A at full throttle. So it should be fine?

Thoughts?

[john61ct]

To paraphrase from Jaws, "you're going to need a bigger bank".

Think about it, you're depleting your whole 100AH energy reserve in 15-20 minutes.

And as you get to a more realistic size, you lose portability.

Practical electric propulsion boats are heavy by definition.

[T1 Terry]

Originally Posted by guvet

Retailers of single cells (3.5v) in Australia?
Thanks T1

At the moment, Trev & Marcy @ Power by Nature in far nth Qld and EV Works in WA. We might get into it at a future date but next yr at the earliest. Need big pockets to import container loads and then somewhere to sell/use them before they become aged stock so a case of building the market first.

T1 Terry

[T1 Terry]

Originally Posted by andreas.mehlin

Cylinder vs Prismatic for a boat?
Cylinder is cheaper?

Big difference with or without yttrium?

Cylindrical cells are suited to high energy draw for the likes of electric propulsion. As a cylindrical cell is one very long pair of plates wound in a coil with a separator in between the layers it only requires a build up any where on the face of one plate that penetrates the separator and that cell is shorted. In a prismatic cell there are multiple plates inside the case, a short between any plate must be strong enough to handle the energy stored in the rest of the plates without simply arcing out and being burnt off.

The Yttrium expands the operating temp range and increases the cyl life.... by quite a bit when it comes to house battery use.

T1 Terry

[T1 Terry]

Originally Posted by andreas.mehlin

I´m planning an electric project...where I will install an 10kw electric engine to a trimaran powered by LifePO4. I will also have a dinghy with an electric OB. Both 48v. The 12v system will be powered by the same 48v bank with a 48-12v converter

I have been reading some in the thread about pros/cons of parallel vs serial batteries....and I came up with the idea of having redundancy by splitting up the bank to several banks.

It would be great if I could use the same batteries for both the ob and the inboard. Lets say I would like 20 000wh capacity. If I put that into 4 banks mounted in portable cases, I would get 5000wh in each. 16 pieces 3.2v 100Ah. Or having 1 big bank (10kwh) and 2 at 5kwh each, where the big bank will be a main bank and the two 5kwh will be portable and made possible to connect to the system

To make it practical I would install some kind of quick connectors and switches.

So...why would I do like this?
1) Redundancy (4 banks á 48v 100Ah)
2) Always a charged battery for the dinghy
3) Saves weight by not having a dedicated ob-battery.
4) Possible to take a battery to land and charge it there (when not tied up to shore power)

The trimaran is very lightweight and we expect to sail in very light winds as well...The engine will be used for: in/out marina, anchoring, calms, emergencies

Question...most LiFePo4 batteries seems to have a max discharge at 3C.
Does this mean that a 100A bank has a max discharge output at 300A?
The 10kw engine would have 208A at full throttle. So it should be fine?

Thoughts?

Divide the 10kW by the intended battery voltage to get the current down to 1C normal run and 3C absolute max load and what you suggest is quite feasible. Build the battery pack using 12v batteries(4 cells in series)
and link these together to build the voltage required for propulsion. 4 x 12v batteries for 48v, 8 x 12v batteries for 96v 12 x 12v batteries for 144v. These are the most common electric vehicle controller voltages and I'm guessing you would use the same for a propulsion motor.
This can then be reconfigured into 48v or 24v or 12v batteries depending on the system you want for house batteries. If you choose 12v you can then take one out of the string for the electric outboard.
The system would be rather complex to wire but not impossible, each battery would be charged as a 12v/24v/48v unit with the charging leads isolated from the boat metal work. The easiest would be a bank of 12v/24v/48v chargers powered by what ever AC voltage you plan to use, 110vac or 240vac.
This way you can recharge via a generator or mains or solar charging one of the battery and running an inverter from that to power the mains charger.
Each battery link would have a 3 position switch to the next battery, position 1 from positive to negative, position 0 open and position 2 positive to positive.
One hell of a project so if you go ahead, please start another thread with progress reports and to ask questions along the way, I'm sure there will be a lot of interest both on this forum and world wide.

T1 Terry

[T1 Terry]

One additional suggestion, build the outboard battery as separate unit using the same capacity cells as the main battery. This way you have a supply of spare cells for the main battery while you wait for a replacement cell to arrive.

T1 Terry

[alctel]

I'm looking at the Genasun solar controllers for lithium

Their 'CV Voltage' is 14.2 - which is bit higher than I'd like (I'd be more comfortable with 14.0) - but if that was a 'stop charging' mode that would be good, but I can't find a description on the site or in the manual what happens when it hits 14.2! Ideally it'd just stop, but in that case I can't find the voltage where it would start charging again!

Does it charge at a constant current until it hits 14.2 and then just switch to CV mode and hold it at 14.2 and reduce the current? Isn't that just a float mode that would ruin the batteries?

Anyone have any insight?

[T1 Terry]

Sorry, no info on the Genasun gear so I can't comment.... accept to say 14.2v measured at the battery terminals is very close to inviting a cell run away. If the charging passes through the unit and it measured internally rather than at the battery the real terminal voltage may be a few points lower than 14.2v, depending on the charge current and the cable size.
All our gear measures voltage at the cell terminals, both at cell level and full battery level so there is no ambiguity regarding actual battery voltage, but no 2 units measure it exactly the same anyway but generally within .1v between them, an expectable error level at battery terminal level, not acceptable at cell level though.

T1 Terry

[andreas.mehlin]

Originally Posted by john61ct

To paraphrase from Jaws, "you're going to need a bigger bank".

Think about it, you're depleting your whole 100AH energy reserve in 15-20 minutes.

And as you get to a more realistic size, you lose portability.

Practical electric propulsion boats are heavy by definition.

Well, in case I run full throttle, using 80% of the capacity in the battery, I would be able to go for 25 minutes (If the bank is 5kwh). But I can't see many occasions I would use full throttle. I would more likely use 20-50% throttle most of the time which would give 50-120 min.

But...It make more sense I would have one bigger bank at about 10-12kwh, and one or two portable banks at about 5 kwh, that can be plugged in as a main bank in case needed.

About parallel 12v battery vs serial 3.2v cells. It seems like it is less risky for the bank to have 3.2v cells serial connected incase of shorten cells or other complications.

[andreas.mehlin]

Originally Posted by T1 Terry

One additional suggestion, build the outboard battery as separate unit using the same capacity cells as the main battery. This way you have a supply of spare cells for the main battery while you wait for a replacement cell to arrive.

T1 Terry

I think the dinghy/ob battery should be somewhere around 5kwh. In case I choose to go with serial connected cells, it wouldn't work cause I would then use 16 of the 3.2v 100Ah cells for the OB, but if I go with one bigger bank as main bank, it would be something like 16 of 3.2 300/400Ah. Different cells.

Originally Posted by T1 Terry

Cylindrical cells are suited to high energy draw for the likes of electric propulsion. As a cylindrical cell is one very long pair of plates wound in a coil with a separator in between the layers it only requires a build up any where on the face of one plate that penetrates the separator and that cell is shorted. In a prismatic cell there are multiple plates inside the case, a short between any plate must be strong enough to handle the energy stored in the rest of the plates without simply arcing out and being burnt off.

The Yttrium expands the operating temp range and increases the cyl life.... by quite a bit when it comes to house battery use.

T1 Terry

So, prismatic would not be the way to go for electric propultion? But for a combination bank where it acts as main house bank most of the time? And propultion shorter periods for entering marina/anchoring/low throttle in calms/ max in emergencies?
Which has longest lifespan? The winston LiFEyPo4 (yttrium) seems to have longer lifespan than regular LifePO4.

It´s a sailing trimaran, sails in light winds, so we hope to not use the engine very much. Higher throttles will not be used very often. But the battery bank must be able to handle full throttle from time to time.