270ah DIY LiFePO4 build

[gregcope]

I taped my BMS to the side of the pack. My pack sides are GP4 1.5mm sheets to islote.

Mounted on 5mm foam off stands to give a bit of ventilation room. Taped on with strong parcel tape. It has not moved. Will dig out my post in my build thread. This all goes in a box.

Okay. My posts did not cover that bit.

 

[gregcope]

Best pictures i have… does not show the tape

 

[vas]

temp installation after a year from the getting the bank onboard
[ok, I did screw the BMS controller board next to the shunt and sorted out the cables...]

the setup last winter at home:

 

[Poey50]

Here's mine. The pack and most gubbins fit into the L-shaped moulded battery box on my Sadler.

 

[Poey50]

Here's mine. The pack and most gubbins fit into the L-shaped moulded battery box on my Sadler.

This is after rebuilding the pack over winter using the flexible busbars that gregcope recommended and using my new resistance tester to ensure all busbar to terminal connections are low resistance. Well worth the money.

 

[rotrax]

Interesting. A couple of questions.
How do you define cycles? My lead drop to no lower than 80% charged each night. I only have 450Ah in 12v money. I don't need any more even as liveaboard as we have solar, wind and water charging. This brings the cost of the batteries as well as the weight and size down in your comparison.
I have always though AGM was a poor choice for batteries. They cost more than Trojan wet cell batteries and have a shorter life. They are maintenance free but evidence suggests that they deal with partial state of charge less well than Trojan batteries. Lifeline stipulate that their AMG batteries must be fully charged at least once a week. You also can't equalise most AGM batteries. Lifeline AGM are super expensive. Most comparisons between lead and lifePo4 seem to compare expensive lead batteries with dubious quality lifePO4. If you take something like a high end lead battery system and compare with a Victron lifePO4 installation the costs are eye watering. The BMS alone is over £1000.
People need to make sure they are going the lifePO4 route for the right reasons. It isn't the be all and end all solution some people think it is

The Lifelines on our previous Island Packet were twelve years old and still performing OK. The new owner did change them as the boat was subsequently used for liveaboard. One of the 2008 OE Lifelines from our current vessel is in use in my home workshop as a slave battery. Been in NZ since January. Ten minutes ago it showed 12.4 on my multi meter. I am sure it will be useful for some time yet.

The Lifelines for the house bank - 4 X 110 AH - on our current Island Packet are seven years old. The Lifeline for the genset is OE from 2008, still working good, only gets charged from the genset alternator. The Starter battery is a Chinese spiral wound AGM that was about a pound per AH and is performing very well.

I have NEVER charged them fully at least once a week. Due to a dedicated policy of "If it aint broke, dont fix it!" I get by very well with my batteries.

Since fitting 400W of solar in May last year the only charging has been when the main engine is running or the solar. Not charged from shore power since May 12th last year.

Many instances of US owners getting long service with no trouble from Lifeline batteries on the IPhomeport.

I agree fully with your final conclusion.

 

[Kelpie]

I'm gradually reorganising my battery installation. One reason for this is to free up space for a second pack.

Question- is there any harm in laying a pack on its side? It would allow me to stack the two of them on top of each other and make for nice, neat, short wiring runs.
The first pack I built using aluminium end plates and threaded rod. There's enough compression to hold everything together but in theory if left on its side the cells would be pressing on the rod which doesn't seem ideal. I have thin stiff foam board between the cells and the rods but I'd probably want more protection than that if laying them down.
Alternatively I could sit each pack up on its end and place them side by side.
But if there's a good reason to keep them upright I will just find another way of fitting everything in.

 

[trbt]

The cells don't care about orientation.

 

[Poey50]

It always used to be the advice that prismatic cells should be stored upright, keeping the pressure release valve on top and to ensure that electrolyte covered all plates. But more recently Winston say their cells can be used in any orientation. I've also read that laid on their edge is better than on their side but really it's a grey area.

 

[geem]

It always used to be the advice that prismatic cells should be stored upright, keeping the pressure release valve on top and to ensure that electrolyte covered all plates. But more recently Winston say their cells can be used in any orientation. I've also read that laid on their edge is better than on their side but really it's a grey area.

Winston cells are in very rigid plastic cases. I don't know if this makes a difference but they are physically different to most other cells

 

[Poey50]

I've had my system for nearly three seasons. Yesterday I upgraded the 123SmartBMS firmware and had a small issue. I emailed the 123Smart support and as usual got a response within an hour. This has happened every time I contacted them. (Never ever bother with GWL support which is where I purchased!)

There isn't generally a lot of love for the 123SmartBMS. People don't like the separate boards per cell, don't like soldering on the connection to the negative terminal, and don't like the fact that the first and last cells use slightly more current to power the BlueTooth and Hall effect sensors. But it is the most affordable of the high end BMSs, it has excellent support through instructional videos, complementary relays (I use the 123Smart 120 amp relays and is very suitable for setting up a dual-bus system (separate load and charge circuits) - for my money, still the most suitable system for marine DIY installation. Dual-bus is the system that Victron use for several thousand pounds more.

The solution to the imbalance between outer and inner cells is simply to charge to full once per fortnight. Full is defined as 3.43 volts per cell (probably about 90% of absolutely full - the final 10% is left unused which helps longevity). The absorption setting of all chargers is adjusted to 13.75-13.8 volts. Charging then slows down as the cells fill allowing the 1amp passive balancer to do its work. The latest firmware shows 100% synchronisation on the monitor when all cells are above 3.43 volts and when the tail current drops to the final few amps.

I'd need to do this once per fortnight anyway to stop the state of charge of the 123 monitoring (and the BMV712) from drifting. And although mostly I stay under 80% SOC, it does seem to help LFP to do some bigger cycling periodically.

Anyway - I thought I'd stand up for the 123SmartBMS, and the excellent support. At about 1/3 of the cost of the REC Active (the premium product) it is well worth considering.

No commercial connection.

 

[Poey50]

Winston cells are in very rigid plastic cases. I don't know if this makes a difference but they are physically different to most other cells

I'm not sure how different they are inside compared to the aluminium cased prismatics. But there's no argument that they are the premium product. I keep seeing many happy customers having imported from the factory via Julia Wu. If I'd had the space and the money I would certainly have gone for Winstons.

 

[geem]

I've had my system for nearly three seasons. Yesterday I upgraded the 123SmartBMS firmware and had a small issue. I emailed the 123Smart support and as usual got a response within an hour. This has happened every time I contacted them. (Never ever bother with GWL support which is where I purchased!)

There isn't generally a lot of love for the 123SmartBMS. People don't like the separate boards per cell, don't like soldering on the connection to the negative terminal, and don't like the fact that the first and last cells use slightly more current to power the BlueTooth and Hall effect sensors. But it is the most affordable of the high end BMSs, it has excellent support through instructional videos, complementary relays (I use the 123Smart 120 amp relays and is very suitable for setting up a dual-bus system (separate load and charge circuits) - for my money, still the most suitable system for marine DIY installation. Dual-bus is the system that Victron use for several thousand pounds more.

The solution to the imbalance between outer and inner cells is simply to charge to full once per fortnight. Full is defined as 3.43 volts per cell (probably about 90% of absolutely full - the final 10% is left unused which helps longevity). The absorption setting of all chargers is adjusted to 13.75-13.8 volts. Charging then slows down as the cells fill allowing the 1amp passive balancer to do its work. The latest firmware shows 100% synchronisation on the monitor when all cells are above 3.43 volts and when the tail current drops to the final few amps.

I'd need to do this once per fortnight alway to stop the state of charge of the 123 monitoring (and the BMV712) from drifting. And although mostly I stay under 80% SOC, it does seem to help LFP to do some bigger cycling periodically.

Anyway - I thought I'd stand up for the 123SmartBMS, and the excellent support. At about 1/3 of the cost of the REC Active (the premium product) it is well worth considering.

No commercial connection.

Sounds like you have it sorted. I went for a 200A JK BMS. Still waiting for my eight CATL 280Ah to arrive in St Martin so I can sail up there and collect them. A build over the summer

 

[Kelpie]

The lack of separate load and charge circuits is probably the main downside of my very cheap and pretty cheerful JBD BMS. I'm currently running the 120A version but about to install the 200A.
I can go above 120A for a few seconds but this is probably not good for lifespan of the BMS.

As a liveaboard the simple BMS works well enough for me- if it shuts down for any reason then I know pretty much instantly, and can take action to put it back on line. For a boat left unattended you might find that your batteries have gone offline and stopped charging.

Nb- the only time my BMS has ever tripped has been for over-current, generally when getting a bit too ambitious cooking dinner.

 

[geem]

The lack of separate load and charge circuits is probably the main downside of my very cheap and pretty cheerful JBD BMS. I'm currently running the 120A version but about to install the 200A.
I can go above 120A for a few seconds but this is probably not good for lifespan of the BMS.

As a liveaboard the simple BMS works well enough for me- if it shuts down for any reason then I know pretty much instantly, and can take action to put it back on line. For a boat left unattended you might find that your batteries have gone offline and stopped charging.

Nb- the only time my BMS has ever tripped has been for over-current, generally when getting a bit too ambitious cooking dinner.

I chose the JK as it seems to get great reviews. Being a 24v boat the 200A BMS is actually 400A in 12v money so lots of headroom for high loads.
I currently have my 1750w windlass powered from the four Trojan T105RE lead domestic batteries. I may swap them over to the engine bank when we go online with lithium. We will keep our Trojans such that any trip of the BMS will be resolved by switching the Trojans back online.

 

[vas]

I chose the JK as it seems to get great reviews. Being a 24v boat the 200A BMS is actually 400A in 12v money so lots of headroom for high loads.
I currently have my 1750w windlass powered from the four Trojan T105RE lead domestic batteries. I may swap them over to the engine bank when we go online with lithium. We will keep our Trojans such that any trip of the BMS will be resolved by switching the Trojans back online.

this switching the trojans back online, how are you going to achieve it?
for the same reason 304Ah (8S) lifepo4 + 4 x T105RE, I have them all linked permanently, so if/when lifepo4 goes offline due to BMS, there's still something to take the hit immediately.
Not doing much good to the trojans keeping them at around 26.5V, but it's not bad either

V.

 

[geem]

this switching the trojans back online, how are you going to achieve it?
for the same reason 304Ah (8S) lifepo4 + 4 x T105RE, I have them all linked permanently, so if/when lifepo4 goes offline due to BMS, there's still something to take the hit immediately.
Not doing much good to the trojans keeping them at around 26.5V, but it's not bad either

V.

I am proposing to install a B2B and keep the Trojans charged permanently off the lithium. They will sit on float unless I use them.
To switch over from one bank to the other. I will simply isolate the bank I am on before energising the next bank. Solar will go to the lithium. The engine bank will also have a B2B to charge the lithium. Open to thoughts

 

[Poey50]

I am proposing to install a B2B and keep the Trojans charged permanently off the lithium. They will sit on float unless I use them.
To switch over from one bank to the other. I will simply isolate the bank I am on before energising the next bank. Solar will go to the lithium. The engine bank will also have a B2B to charge the lithium. Open to thoughts

This switch might be handy. Blue Sea Battery switch 3 position Blue Sea 11001-BSS - Marine Electricals

 

[Kelpie]

This switch might be handy. Blue Sea Battery switch 3 position Blue Sea 11001-BSS - Marine Electricals

That looks perfect. I couldn't find one, at least not at a sensible price, so I've used a pair of keyed isolators with one key between them.

 

[geem]

This switch might be handy. Blue Sea Battery switch 3 position Blue Sea 11001-BSS - Marine Electricals

They sell these here in the Caribbean in Budget marine. I will pick one up in St Martin when I go for me cells. Its a project that will take a lot of rewiring!