Charge controller recommend

It's the same as AGM except enter 14.8V instead of 14.4V and add some hydrocaps. Lead's easy, usually compatible and works great, you can just install it inexpensively and move on with yer life.

But get at least one charger that can do SG 1.275

markmoto

Sir Liamalot wrote: »

Lead acid you can cycle 100% to 20% LFP ideally 80% to 20% with periodic memory releasing cycles to 100%.

Thats what I mean, when you said in previous posts that AGM like to stay at 100% vs Lithium not of that nature. You might charge battery to 100% time to time to clear memory effect.
I don't know where you get that AGM can be discharge to 20% without being damage.
here is the chart AGM vs Lithium discharge voltage

Sir Liamalot wrote: »

However, any overcharge whatsoever is harmful. Every time the sun rises on your solar panel with a charged battery it's doing permanent damage. They do not like float charging or being held in absorption for load compensation. So they're a terrible choice for solar applications.
In fact, any application where you rely on a generator to supply power instead of a battery...ie. most of them.

For that reason victron MPPT charger Bluetooth app incl. settings for Lithium battery, + adjustment of float voltage & time.

Sir Liamalot wrote: »

Then there's temperature issues. The can't be charged in the cold. They range from being permanently damaged if charged below 10°C at a high rate to outright self-combusting if charged below 0°C.

10°C perfect charging temp. for lifepo4 battery but agree on when Battery temp. below 0°C hence good BMS comes with temperature sensor to prevent potential damage.
There no perfect battery but at list we have choice that works better for one application or another.

Here is the limitation of AGM batteries

-Low energy density - poor weight-to-energy ratio limits use to stationary and wheeled applications.
-Cannot be stored in a discharged condition - the cell voltage should never drop below 2.10V.
-Allows only a limited number of full discharge cycles - well suited for standby applications that require only occasional deep discharges.
-lead content and electrolyte make the battery environmentally unfriendly.
-Transportation restrictions on flooded lead acid - there are environmental concerns regarding spillage.
-Thermal runaway can occur if improperly charged.

Sir Liamalot wrote: »

They are exothermic, using them releases heat. If they get above 30°C they are being damaged and they will do this with heavy sustained loads and charging.

where you getting that information from?
See chart below



What about AGM?
The optimum operating temperature for the lead-acid battery is 25°C. Elevated temperature reduces longevity. As a guideline, every 8°C rise in temperature cuts the battery life in half. Good AGM, which would last for 10 years at 25°C, would only be good for 5 years if operated at 33°C. The same battery would desist after 2½ years if kept at a constant temperature of 41°C

Here is the chart

Sir Liamalot wrote: »

The lead-acid performs well on high load currents.

Disagree, what about Peukert exponent?
The faster a lead-acid battery is discharged, the less capacity it has. The effective battery capacity therefore depends on how deep you can discharge a battery, and how much energy is lost due to the speed of discharge of your battery.

Sir Liamalot wrote: »

Then there's the cost. You can buy 4 times the capacity of lead-acid than you can of LFP including BMS.

You can buy higher AH AGM batteries but the usable AH only stands at ~ 50% of that + heavy weight and space that requires.
Basic BMS with 100AH discharge cost no more than 30e
270ah lifepo4 cells cost 400e as we speak

Sir Liamalot wrote: »

How many fully working reliable systems have you built for that price?

I am not professional, I think you have deeper knowledge on the subject and I am hopping that I can learn some more : )

But prismatic cells that I have mention only couple of companies manufacturer in Asia
And I have see these cells being used by many companies incl. top brands sold for 1300-2000e as complete battery in nice shiny "professionally looking" plastic boxes.

Sir Liamalot wrote: »

Why can't you do that with lead?

When running inverter 3500w on AGM the voltage drops below usable means on lithium I have far steady voltage and be able to use more appliances same time. And chart again

markmoto

markmoto wrote: »

where you getting that information from?

10 years field experience. Empirical evidence from comparative performance testing. Practical applications. Peer collaboration and publishings by Toyota.

markmoto

Compare AGM vs LifePo4 battery









Lithium – Discharge Capacity vs Terminal Voltage


Lead Acid – Discharge Capacity vs Terminal Voltage


Usable Energy (Lead Acid)


Usable Energy (Lithium)


The recommended charge rate for large size AGM batteries is 0.2C i.e. 120A for a 600A battery consisting of paralleled 200Ah blocks.

Higher charge rates will heat up the battery (temperature compensation, voltage sensing and good ventilation are absolutely needed in such a case to prevent thermal runaway), and due to internal resistance the absorption voltage will be reached when the battery is charged at only 60% or less, resulting in a longer absorption time needed to fully charge the battery.

High rate charging will therefore not substantially reduce the charging time of a lead-acid technology battery.

By comparison a 200Ah Lithium battery can be charged with up to 500A, however the recommended charge rate for maximum cycle life is 100A (0.5C) or less. Again this shows that in both discharge and charge that Lithium is superior.




Clearly AGM batteries will need to be replaced more often than Lithium. It is worth bearing this in mind as this entails time, installation and transportation costs, which further negates the higher initial capital cost of Lithium as does the lower cost of recharging Lithium.

Flooded batteries are water-cooled I never said anything about AGMs being useful*.

My LFP I spent the day testing in an electronics workshop gain 10°C per hour at C1.

For the money and applied deratings I get better performance from lead.
I'm disinclined to continue refuting glossy internet pictures with my own data.

80% DOD for lead came from the graph I posted earlier.


*except firefly

markmoto

Sir Liamalot wrote: »

Flooded batteries are water-cooled I never said anything about AGMs being useful*.

My LFP I spent the day testing in an electronics workshop gains 10°C per hor at C1.

For the money and applied deratings I get better performance from lead.
I'm disinclined to continue refuting glossy internet pictures with my own data.

80% DOD for lead came from the graph I posted earlier.


*except firefly

Where did you buy your cells? You could end up buying grade B or not optimal performance cells as result getting wrong output.

Oh bottom..it wasn't even the right graph T-105s (FLA golf carts) are 1200 cycle batteries. Red line.

markmoto

markmoto wrote: »

Where did you buy your cells? You could end up buying grade B or not optimal performance cells as result getting wrong output.

Did you notice they were branded Chinese Aviation Lithium Battery? CAM 72...one of the best thermal designs. Aluminium case with stack spacers.


1C is aggressive.

Deligreen Genuine reseller.

markmoto

Sir Liamalot wrote: »

Did you notice they were branded Chinese Aviation Lithium Battery? CAM 72...one of the best thermal designs. Aluminium case with stack spacers.


1C is aggressive.

Deligreen Genuine reseller.

Interesting. calb cells usually more expensive. I have purchased from aliexpress Eve cells.

photosmart

Questions about lifecycle vs depth vs DOD


Lets say I discharge by batteries to 50% once (or say every 10 days for example) whereas the rest of the time I only discharge to say 70% 0 does that mean that now my batteries will only last as per the graph for 50% DOD or is it a percentage thing?


ie say 10 days at 50%dod and 355days at 70%DOD (I mean used 30% of capacity)



In other words does the degradation apply to a once off or are those graphs based on doing a certain discharge every single day

They're based on controlled cycle tests in a laboratory. The only purpose of them is to be compared to other batteries cycle tests in a laboratory.

I can show you batteries the user has killed in less than 20 cycles or ones that have been in use 5 years every day still ticking 100% and only clocking less than 200 cycles to 50%.

True story:

After using an FLA battery in a van as a 6-month annual full-time liveaboard for 5 years I ascertained from my collected data I was effectively on < cycle 180 to 30% DOD.



11300Ah Extracted



That leady battery oughta last me another 55 years so!

Batteries hardly ever meet a natural end. Users and bad chargers usually do them in way before it.
Don't worry about cycles other than to compare a purchase.

In answer to the question it's a fairly linear arrangement above 20% SOC that there's X amount of kWh you can extract from the battery before it has derated to having 80% of it's original plated capacity remaining.

Spend them however you want. eg. 1 cycle to 60% SOC = 2 cycles to 80% SOC.

markmoto

markmoto wrote: »

10°C perfect charging temp. for lifepo4 battery

Lithium plating....it's a huge problem. The electrons travel faster than the li-ions when charging in the cold and that causes irreparable cell damage.

Problem threefold. I need a 3rd party alternator regulator to derate my charge system in the cold and/or normal operation, or a battery heater which is appallingly inefficient, or the latest brainiac mentioned something about engine frickin' coolant loops...:rolleyes:
The battery is so expensive it's likely to be small so the C-rates are high by nature.
Then I need the alternator, solar, mains etc to not operate if the battery is fully charged or has been recently.


Threefold problem the second:


In order to integrate a very small and expensive battery to a 12v system, we need an expensive BMS and high-end chargers that are highly programmable to orchestrate the process.




I can get 80% from lead. I can get 80% from LiFePO4.
Lead is one third the cost (before the LiFePO4 required electronics to derate the system are factored) & double the weight.


Now if this is my SOC envelope:








Firstly: the voltage variation in 20% SOC and 80% SOC is so narrow only the top shelf chargers are accurate enough to measure this. If it hasn't got remote voltage sense terminals then it hasn't a chance.
Secondly there's effectively no bulk stage because that is triggered as being ~0.5V under absorption voltage. So instead chargers go instantly to CV absorption and my "fast charging" lifepo4 (in 20°C...which it never is) takes a full day to charge because the charger is locked in constant voltage.
If I want to use constant current instead I need to use over-voltage and tail current which limits me to chargers in the > €250 class.

If I try to operate within that aperture I get diminishing returns from memory effect because the absorption cutoff becomes a moving target.If I try to charge to 100% to avoid this I get long-term reduced cycle capacity.


All this for a fraction of the capacity lead can offer for equal expenditure.

I made a graph of that

Popular belief would have one believe
Bad < 0°C < Good



Taking my lesser camper as an example. If I threw away my FLA battery and got one under half the capacity for over twice the price, if I limit my alternator to 50% it's current output then I can use a "faster, more efficient" variant about 3 quarters of the year...where do I sign up?

PS I use the most aggressive charge rates in Winter..go figure!