Merged LiFeYPO4 1000Ah Winston prismatic cells and all electric galley...

[jordanbigel]

Originally Posted by CatNewBee

After 2 years, finally installed th DS18B20 sensors outside, in the cockpit fridge, galley fridge and the freezer (was a little hesitant to drill 3.5mm holes through the isolation to get the sensor cable trough, but worked well) and tweaked the Victron Firmware further...

Now it shows the temperatures instead of an empty box when there is no AC input, otherwise shows the AC data.
Attachment 256453Attachment 256454

Could I impose on you with an off-topic question? I just installed a CerboGX 2 weeks ago, and I guess I still have much to learn. I also have the 4 temp sensors wired to useful things (alternators, genset, Multiplus case) - and I see the temps on the menu page, as you show in your screenshot on the right side.

But how did you get your graphic display, I don't know what you call it, the main graphics display which shows the colored boxes - you have a Temp box in the top left I see, but I don't get how you got it to appear there. You wrote then it appears when you are off shore power, I can see your Multi says Inverting, as does mine, but I just have an empty red box in the top left corner.

Also, I see additional info on your display like amps in addition to watts, etc.

How? What is the way?

Thanks in advance!

[CaptainRivet]

Originally Posted by CatNewBee

After 2 years, finally installed th DS18B20 sensors outside, in the cockpit fridge, galley fridge and the freezer (was a little hesitant to drill 3.5mm holes through the isolation to get the sensor cable trough, but worked well) and tweaked the Victron Firmware further...

Now it shows the temperatures instead of an empty box when there is no AC input, otherwise shows the AC data.
Attachment 256453Attachment 256454

Looks awesome

[CaptainRivet]

Originally Posted by goboatingnow

Cell balancing is never “ needed “ ie cells are not damaged by being out of balance , it’s just that you can’t extract the optimum energy from a battery where some cells are out of balance.

But it’s not damaging anything to be out of balance per se.

My experience is that besides an initial top balance to establish maximum energy storage. Fractional C discharge , fractional C charging and conservative stop voltages mean that cells don’t need cell balancing and if they do it’s about once a year.

Yes on a 12V bank you don‘t need cell balancing if
-you yearly top balance all cells and
- have matching grade A cells plus
- never charge/discharge more then 1/3 of the continuous C rate eg 1C max 0.33C.
But if the BMS does it well it will not hurt

From 24V it is a must as the deviations from the 8 cells add up and cells drift apart without balancing, which they always do in 24V. one disadvantage nobody mentions when advising to go to 24V from 12V. We operated the Lithium cells in earlier days without BMS in car audio as there was no BMS available or price was outrages that would support the currents we pulled. We weekly top balanced them manually to get around that. Same with LTO cells till today 5 or 6 LTO Yinglong cells for 16V never need a BMS, 10 or 12 for 26V always need one as cells drift apart doesn‘t matter how matched they are.

[s/v Jedi]

Originally Posted by CaptainRivet

Yes on a 12V bank you don‘t need cell balancing if
-you yearly top balance all cells and
- have matching grade A cells plus
- never charge/discharge more then 1/3 of the continuous C rate eg 1C max 0.33C.
But if the BMS does it well it will not hurt

From 24V it is a must as the deviations from the 8 cells add up and cells drift apart without balancing, which they always do in 24V. one disadvantage nobody mentions when advising to go to 24V from 12V. We operated the Lithium cells in earlier days without BMS in car audio as there was no BMS available or price was outrages that would support the currents we pulled. We weekly top balanced them manually to get around that. Same with LTO cells till today 5 or 6 LTO Yinglong cells for 16V never need a BMS, 10 or 12 for 26V always need one as cells drift apart doesn‘t matter how matched they are.

Your info is incorrect. The 8 cells in my 24V bank have a max. deviation of 8mV after 3 years cruising without any balancing. They started at 2mV deviation; I simply decided to not balance for another year, even though I am eager to try out the new active balancer I got.

[CaptainRivet]

Originally Posted by s/v Jedi

Your info is incorrect. The 8 cells in my 24V bank have a max. deviation of 8mV after 3 years cruising without any balancing. They started at 2mV deviation; I simply decided to not balance for another year, even though I am eager to try out the new active balancer I got.

Congrats you got perfect cells let me guess Winston?
which is an exception of the rule. What’s your max C rate you charge or discharge this bank?
This happens and always will that you find a small amount that are lucky or have a perfect combination installed. There is no rule without exceptions
In car audio, especially the SPL guys operate LifePo4 since 20years+ and community tried all sorts of combinations, for a long time without any BMS and paid their lessons learned…that what they discovered and my own experience confirms this.

[newhaul]

Originally Posted by CaptainRivet

Congrats you got perfect cells let me guess Winston?
which is an exception of the rule. What’s your max C rate you charge or discharge this bank?
This happens and always will that you find a small amount that are lucky or have a perfect combination installed. There is no rule without exceptions
In car audio, especially the SPL guys operate LifePo4 since 20years+ and community tried all sorts of combinations, for a long time without any BMS and paid their lessons learned…that what they discovered and my own experience confirms this.

Mine are about the same 12v 3 years and 4mV difference on one cell the 3 others are within 2mV no top balance after initial just before putting into service. No not Winston cells.

[s/v Jedi]

Originally Posted by CaptainRivet

Congrats you got perfect cells let me guess Winston?
which is an exception of the rule. What’s your max C rate you charge or discharge this bank?
This happens and always will that you find a small amount that are lucky or have a perfect combination installed. There is no rule without exceptions
In car audio, especially the SPL guys operate LifePo4 since 20years+ and community tried all sorts of combinations, for a long time without any BMS and paid their lessons learned…that what they discovered and my own experience confirms this.

Well, yes, Winston. But all quality cells should be like that, only with 2nd hand cells or very low quality problems are occurring more often.

But in a 8S series string, when you put 1 Ah in cell 1, you also put exactly 1 Ah in each of the other 7 cells, so it’s not surprising that they stay balanced.

[Battery Balance]

May I ask Newhaul and s/v Jedi, when you measure delta, what is the voltage?
As long as you measure below 3.45 V, you will never have much delta, not even when heavy imbalance. Captainrivet is correct, when 8 cells, the delta will be amplified.
Please report delta at 3.55 V i.e. when battery is fully charged and voltage increases to charger settings.

[newhaul]

Originally Posted by Battery Balance

May I ask Newhaul and s/v Jedi, when you measure delta, what is the voltage?
As long as you measure below 3.45 V, you will never have much delta, not even when heavy imbalance. Captainrivet is correct, when 8 cells, the delta will be amplified.
Please report delta at 3.55 V i.e. when battery is fully charged and voltage increases to charger settings.

Let's see iirc it was cell1) 3.63. Cell2) 3.65. Cell3 ) 3.62. Cell4 ) 3.65.

That good enough? And I charge my 250ah bank with 200 watts solar via MPPT. and my average daily is between 20 and 25 ah .
Average 8 amps out to bank start with 4 amps by 7 am and up to 10 by 9 so fully charged by noon .
Use the excess production to run my rice cooker in the early afternoon.

This is from the charge controller app and battery capacity is not accurate. That's what my gauge and shunt are for .
Notice at the 13.4 outage I have a near 3 amp load out to my furnace so percentage is not accurate .

[Simi 60]

Our EVE 280 8 cell bank
We have 3 of them totalling 840ah @ 24v
0.003v difference

[CaptainRivet]

Originally Posted by newhaul

Let's see iirc it was cell1) 3.63. Cell2) 3.65. Cell3 ) 3.62. Cell4 ) 3.65.

That good enough? And I charge my 250ah bank with 200 watts solar via MPPT. and my average daily is between 20 and 25 ah .
Average 8 amps out to bank start with 4 amps by 7 am and up to 10 by 9 so fully charged by noon .
Use the excess production to run my rice cooker in the early afternoon.

This is from the charge controller app and battery capacity is not accurate. That's what my gauge and shunt are for .
Notice at the 13.4 outage I have a near 3 amp load out to my furnace so percentage is not accurate .

You chage them to 3,65V as end off charge parameter? No room for error...
Thats no real charge and discharge 20AH from a 250AH bank and 200W charge....thats like trickle charging and discharging the LifePo4 bank like a lead...
Thats a minimal load even grade C would stay in balance witout balancer. And you do in fact an long absorption charge from 3.35 till 3.65V with tis low amps which equals to daily a top balance.

Discharge it regularly with 130A and charge with 120A and you will see them drifting apart quickly.

[CaptainRivet]

Originally Posted by Simi 60

Our EVE 280 8 cell bank
We have 3 of them totalling 840ah @ 24v
0.003v difference

3 banks with 24V with 3 BMS that don't communicate with each other and no balancing?

[s/v Jedi]

I measure as follows: I charge my battery to 99% (depending on solar production, it varies from 97% - 100%), then disconnect the battery, let it rest for 1 hour, then measure at the cell terminals with a 0.1mV accurate multimeter.

When you order Winston cells from Julia Yu, you get sequential serial numbers and they are really well matched. That said, my battery is 10.5kWh using 8x 400Ah cells in series and I regularly (every day) run inverters running 4-5kW loads so 0.5C is a daily occurrence.

[Simi 60]

Originally Posted by CaptainRivet

3 banks with 24V with 3 BMS that don't communicate with each other

Why do they need to communicate with each other?
They are looking after those 8 cells, not the other 16

and no balancing?

They do if needed, if we get the bank to 100% (only saw it while commissioning on shore power) in the final few minutes of charging the cells get slightly out of whack, but as soon as the charging is stopped they are back to equal soon after.

[CaptainRivet]

Originally Posted by Battery Balance

May I ask Newhaul and s/v Jedi, when you measure delta, what is the voltage?
As long as you measure below 3.45 V, you will never have much delta, not even when heavy imbalance. Captainrivet is correct, when 8 cells, the delta will be amplified.
Please report delta at 3.55 V i.e. when battery is fully charged and voltage increases to charger settings.

Thanks. Additional the loads/Charge currents need to be significant to see the differences.
Significant means 30% of their continous C Rate. 1C fo a 250AH bank is 250A,significant means 80A continous charge/discharge.

Winston are state of the art cells, they aren't lifepo4 and have 2 C. Because of this you don't see thm drifting as deviation are very low, 30% of 2C with a 400AH bank is 270A continous as signifcant load./charge current. And this current they will hardly see in the average installation.