Are The AGM Worth 2X The price Of PB?

[vtomanov]

Originally Posted by stefano_ita

Thanks, wich brand?

How did you regoulate the alternator battery charger? wich brand?4 cells and 15, 2 v max charging voltage? (3.8v x 4cells, 90% max recharge for long lasting)

--- STARTER ---
I use this one for starter battery :

EV-Power | Lithium Battery LiFePO4 (12V/20Ah)

on my boat & 2 cars & 1 motorbike nc 700 X- boat engine is Volvo 2003 - 28hp, car 1 is 2500cc Turbo-Diesel , car 2 is 2200cc HDI , motorbike 4 x

EV-Power | WINA LiFePO4 Power 3.2V/8Ah aluminium case

---- HOUSE ----
for house batteries on the boat I use 8x this for house bank : 2 sub-banks by 4 - one bank close to bow thruster and one in the original battery space - the bow thruster gets power from the house bank.

EV-Power | WB-LYP160AHA LiFeYPO4 (3.2V/160Ah WIDE)

---- CHARGING ----

Solar 250W with MPPT, Wind 400W - MPPT

Shore - generic retro( non smart) charger - 12V - 6A/12A

Engine - 50A alternator - max voltage goes to 14.4

---- Protection -----

Low voltage for house only (Victron_ set to min 11.5

No upper voltage protector at this stage

Thinking for installing a arduino based simple upper/lower voltage protector for the starter battery juts to make sure that I will not ruin my starter battery and will be unable to start if some of the charges fail and produce huge voltage or cable fail can consume the battery in full and get it under 11.5.. - but currently I'm just careful and the Victorn has a buzzed which will notify me for high voltage also..

[stefano_ita]

Originally Posted by vtomanov

--- STARTER ---
I use this one for starter battery :

EV-Power | Lithium Battery LiFePO4 (12V/20Ah)

on my boat & 2 cars & 1 motorbike nc 700 X- boat engine is Volvo 2003 - 28hp, car 1 is 2500cc Turbo-Diesel , car 2 is 2200cc HDI , motorbike 4 x

EV-Power | WINA LiFePO4 Power 3.2V/8Ah aluminium case

---- HOUSE ----
for house batteries on the boat I use 8x this for house bank : 2 sub-banks by 4 - one bank close to bow thruster and one in the original battery space - the bow thruster gets power from the house bank.

EV-Power | WB-LYP160AHA LiFeYPO4 (3.2V/160Ah WIDE)

---- CHARGING ----

Solar 250W with MPPT, Wind 400W - MPPT

Shore - generic retro( non smart) charger - 12V - 6A/12A

Engine - 50A alternator - max voltage goes to 14.4

---- Protection -----

Low voltage for house only (Victron_ set to min 11.5

No upper voltage protector at this stage

Thinking for installing a arduino based simple upper/lower voltage protector for the starter battery juts to make sure that I will not ruin my starter battery and will be unable to start if some of the charges fail and produce huge voltage or cable fail can consume the battery in full and get it under 11.5.. - but currently I'm just careful and the Victorn has a buzzed which will notify me for high voltage also..

Thank you very much for your exaustive post

[mcarling]

Originally Posted by stefano_ita

Thanks, wich brand?

I've used a variety of cylindrical and prismatic LiFePO4 batteries from various manufacturers. My latest project is using 120 CALB CAM72 cells.

Originally Posted by stefano_ita

How did you regoulate the alternator battery charger? wich brand?4 cells and 15, 2 v max charging voltage? (3.8v x 4cells, 90% max recharge for long lasting)

No!!! Charging at 3.8V per cell will damage your cells. I have not had any problems charging at 3.45V per cell but now I'm charging at 3.40V per cell. At these voltages, I can leave them connected to an MPPT charger (or any other charging source) indefinitely without any detrimental effects. I'm probably only getting 95% to 98% of max possible charge, but I'm happy with that. I have a strong preference for simple solutions.

On most boats, it should be possible to install enough solar panels to provide for all electrical loads (except for electric propulsion, heating, and air conditioning). Even electric cooking should not be a problem. (I like not having propane onboard, with its associated hassles and dangers.)

[stefano_ita]

Originally Posted by mcarling

I've used a variety of cylindrical and prismatic LiFePO4 batteries from various manufacturers. My latest project is using 120 CALB CAM72 cells.


No!!! Charging at 3.8V per cell will damage your cells. I have not had any problems charging at 3.45V per cell but now I'm charging at 3.40V per cell. At these voltages, I can leave them connected to an MPPT charger (or any other charging source) indefinitely without any detrimental effects. I'm probably only getting 95% to 98% of max possible charge, but I'm happy with that. I have a strong preference for simple solutions.

On most boats, it should be possible to install enough solar panels to provide for all electrical loads (except for electric propulsion, heating, and air conditioning). Even electric cooking should not be a problem. (I like not having propane onboard, with its associated hassles and dangers.)

Thanks for the answer

I think exactly the same about propane

Yes sorry got confused

Do you have an ordinary alternatore voltage regulator just setted to 3,45 x n. of cells? No some particular regulator for lithium battery?

TY

[mcarling]

Originally Posted by stefano_ita

Do you have an ordinary alternatore voltage regulator just setted to 3,45 x n. of cells? No some particular regulator for lithium battery?

This is a controversial topic. It's really a question of risk/reliability/money. Any reliable voltage regulator set to 3.40V to 3.45V per cell (13.6V to 13.8V for a nominal 12V system) should be fine. I don't have enough data about the reliability of various voltage regulators to be able to recommend one for you -- even I had precise knowledge of your willingness to spend money to avoid risk.

Especially if one has multiple charging sources, I recommend using a high voltage condition (HVC) relay to disconnect all charging sources from a LiFePO4 bank at 3.50V per cell.

[vtomanov]

Originally Posted by mcarling

This is a controversial topic. It's really a question of risk/reliability/money. Any reliable voltage regulator set to 3.40V to 3.45V per cell (13.6V to 13.8V for a nominal 12V system) should be fine. I don't have enough data about the reliability of various voltage regulators to be able to recommend one for you -- even I had precise knowledge of your willingness to spend money to avoid risk.

Especially if one has multiple charging sources, I recommend using a high voltage condition (HVC) relay to disconnect all charging sources from a LiFePO4 bank at 3.50V per cell.

I'm curious how you got to the number of 3.40 per cell ? as the documentation clearly states : 3.65?

https://en.wikipedia.org/wiki/Lithiu...sphate_battery

and Winston documentation states 2.8-3.8 with initial 4.0

EV-Power | WB-LYP60AHA LiFeYPO4 (3.2V/60Ah)

[mcarling]

Originally Posted by vtomanov

I'm curious how you got to the number of 3.40 per cell ? as the documentation clearly states : 3.65?

https://en.wikipedia.org/wiki/Lithiu...sphate_battery

and Winston documentation states 2.8-3.8 with initial 4.0

EV-Power | WB-LYP60AHA LiFeYPO4 (3.2V/60Ah)

I believe MaineSail's hypothesis that the manufacturers exaggerate the extent to which 4 LiFePO4 cells can work as drop-in replacements for 6 lead-acid cells without any change to charging infrastructure in order to facilitate sales.

I've seen hundreds of LiFePO4 cells destroyed by charging with voltages in the range of 3.55V to 3.65V per cell. I've also seen that one gets virtually the same capacity by charging to 3.40V to 3.45V per cell. The only advantages of more aggressive charging voltage are: 1) one can charge faster and 2) one can be more carefree about charging infrastructure. Faster charging is generally not an issue on boats, the way it is for electric cars. Using photovoltaic cells, there is no need to charge faster than about 0.2C so voltages higher than 3.40V or 3.45V per cell are simply not needed.

I'm a semi-retired professor so I have chatted with professors doing Lithium battery research. I've also read many peer-review journal articles on Lithium batteries. I've used LiFePO4 batteries for years, in electric bicycles, cars, and boats.

Feel free to charge at 3.65V per cell and expect to have balance issues and loss of capacity within 500 to 1000 cycles and perhaps permanently bulging or ruptured cells. Alternatively, charge at 3.40V or 3.45V per cell free from balance issues and keep something close to full capacity for 5000 to 8000 cycles. Your choice.

[vtomanov]

Originally Posted by mcarling

I believe MaineSail's hypothesis that the manufacturers exaggerate the extent to which 4 LiFePO4 cells can work as drop-in replacements for 6 lead-acid cells without any change to charging infrastructure in order to facilitate sales.

I've seen hundreds of LiFePO4 cells destroyed by charging with voltages in the range of 3.55V to 3.65V per cell. I've also seen that one gets virtually the same capacity by charging to 3.40V to 3.45V per cell. The only advantages of more aggressive charging voltage are: 1) one can charge faster and 2) one can be more carefree about charging infrastructure. Faster charging is generally not an issue on boats, the way it is for electric cars. Using photovoltaic cells, there is no need to charge faster than about 0.2C so voltages higher than 3.40V or 3.45V per cell are simply not needed.

I'm a semi-retired professor so I have chatted with professors doing Lithium battery research. I've also read many peer-review journal articles on Lithium batteries. I've used LiFePO4 batteries for years, in electric bicycles, cars, and boats.

Feel free to charge at 3.65V per cell and expect to have balance issues and loss of capacity within 500 to 1000 cycles and perhaps permanently bulging or ruptured cells. Alternatively, charge at 3.40V or 3.45V per cell free from balance issues and keep something close to full capacity for 5000 to 8000 cycles. Your choice.

I understand the manufacturer can publish higher figure ( btw the lower voltage is higher too) but wikipedia should be correct ? and wiki state 3.65

( for me is not a issue I just need to recompile my Arduino project, but still the last two years I had no issues without any protection..)

[Maine Sail]

Originally Posted by vtomanov

I understand the manufacturer can publish higher figure ( btw the lower voltage is higher too) but wikipedia should be correct ? and wiki state 3.65

The disconnect lies in interpretation of what the Chinese are saying. When the Chinese say 3.6VPC or 3.65VPC they mean charge to that voltage in CC and then STOP CHARGING once you hit that voltage. For most LFP batteries 3.6VPC - 3.65VPC is the maximum top balance voltage not a CC/CV charging voltage. Course if you are going to charge to anywhere close to that voltage you had better have some identical capacity and identical impedance matched cells. There is really no need to charge a fractional C bank of LFP cells beyond 3.45-3.5VPC. Doing so just opens you up to potential problems.....

This is not how CC/CV charging works because CC/CV charging KEEPS CHARGING after the target voltage has been attained....

Currently I have almost 750 cycles, most to 80% DOD, and have done no cell balancing beyond the initial top balance. That is how 13.8V works as a charging voltage on a LFP fractional C use bank........

[vtomanov]

I have nothing against charging at lower voltage a simple arduino project with one H-Bridge, Voltmeter, Ampermeter , arduino nano - for total abut £25 can solve easily all issues - just thinking that if the charging voltage is max 14.2 -14.4 as on my boat by default I'm able to use LiFePo4 without any additions - as I'm doing the last two years - and the capacity of the bank it was exactly as day one - although I'm not sure how many cycles I have done it may be 100 cycles only so far. I greatly enjoy the batteries as with 1h on engine I can run the watermaker for 10h - previously with wet cells this was most likely 2-3 hours on engine if I want to run the watermaker all day .. I can see now charging current of 45+ amps on my battery monitor compared to 15-20ams with the wet cells

[mcarling]

I agree completely with what Maine Sail wrote above.

I prefer the simple approach of using a charging voltage that is safe to apply indefinitely.