Lithium & other advice/facts

[bellett65]

Now this is confusing to me. The plan is moving forward and I have done a few changes to the van to minimise power usage. Now I am at the battery stage. I have got this so far from this thread, I need to get 4 X 3.2 100a/h cells the relevant joiners. Possibly 8 cells, dependant on add on costs. That I figured out. Now as you would all know the Jayco brand use very high end equipment such as Setec and solar controllers such as TLS. All fine until you wish to deviate from the main stream. I think I have got the message that I will need a BMS. Would it be advisable to get an MPPT controller? What are the general thoughts on the Setec charging regime coping? Or would slipping in a DC/DC charger be better ? I want to get this as correct as practicable as the M.o.W.a.F. nearly had kittens when I said I was changing the fridge. Although she is very pleased we have.

Peter

ADMIN: Topic split from Lithium topic.

[T1 Terry]

Hi Peter,
The Setec is a trickle charger with a max voltage limit set at 13.8v, is that correct or am i confussing this unit with another transformer device?
What is a TLS solar regulators? do you have a link to specs etc, one for the Setec might be good as well.
I wouldn't go to a MPPT controller but you already know my views on the shame regarding this technology being suited to low voltage small capacity solar systems it rivals Dupont and the R134a scam, every one has been sucked in.
If you choose to fit a DC to DC charger it must have a proper Gel battery charging regime, max 13.8v, not the Gel battery killer charging regimes some charger manufacturers try to push on unsuspecting customers
As far as a BMS, every battery nees a BMS, it's a battery management system, but it doesn't have to be an automated high $$ item, they can be far more trouble than not using one, far more cell deaths can be directly connected to the use of a propriety BMS than any other cause, far better to use the smartest computer system we have available, the one between the ears, it has adaptive learning. You do need to monitor cell voltages (a proprietary BMS system doesn't) you do need a system to either warn you that cell voltages are too high or too low so you take the appropriate action, the next level up is for the warning system to turn something off, either the charger or the load, but that's about it. Cell balancing is done in the first cell conditioning stage, if you followed the directions you will probably never have to do it again, once every 3 mths at the very worst and a 5 min job even then. Mine have worked hard 24/7 for 18mths now (260Ah plus overnight) and are still perfectly balanced.
So,
A controller with fully adjustable voltages and stages is required as a solar controller, my recommendation is a good PWM controller.
A mains charger that has a suitable charging regime that is limited to 13.8v
If a DC to DC charger is used, it must be able to be limited to 13.8v
A cell logger and alarm to warn you things have wandered outside acceptable ranges.
Add ons that will make life easier:
A battery monitor, preferably one with an output that can switch a relay at adjustable state of charge (SOC) points
A relay system that can turn charging and loads off that can be driven by the cell logger and/or the battery monitor.
Ideally:
A controller that is also a battery monitor and capable of switching loads and charging off from all methods of charging, they are available and not all that expensive, one is Aust made, can you guess which one that is

T1 Terry

[millers.qld]

Hi Guys

Kimberley Kampers now use Lithium Iron Phosphate batteries. They reckon as a guide, if the battery is only discharged by 90% or less,the number of charging cycles expected for a Lithium battery is >1500 cycles. If the discharge is consistently less than 80% then 2000 cycles can be expected. It is impractical to warrant this as there may be occasssions where the batteries go to 100% discharge. This may not “damage” the batteries Kimberley use but it will shorten the number of cycles in their life. There is no way of monitoring this. They also state that charging efficiency is around 95% compared to conventional AGM of 60%. They also limit battery charge flow to no more than 30A. They also Do NOT use a charger that has a “desulphation” mode as this can be triggered by low battery voltage and the batteries will then be exposed to excessive voltage. The Charger is generally only 2 Stage. No more stages are needed with Lithium.
• The Voltage that the charger switches over at is different from
other Batteries and set at the charger. You will need to change
these settings for optimal charging.
• If using a 240V charger and a Solar Controller at the same time,
the devices have to be compatible or the system controlled to get
maximum power into the batteries as early as possible.

They have additional important information regarding using, charging and discharging Lithium batteries.

Hope this helps. For next unit I will be looking at using Lithium.

John

[T1 Terry]

Hi John,
I have read through the Kimberley Kampers info on the use of THEIR lithium batteries, it's not the be all and end all of knowledge relating to lithium batteries, just the ones they use. The 30 amp limits and max 2,000 cycles to 80% DoD don't exactly endear them to me, I can and do charge and discharge mine at more that 3 times that rate and the manufacturer of the cells I use say I'll get 5,000 cycles to 7,000 cycles if I limit the discharge rate to 80% DoD, they are over 18mths old now and have been running 24/7 with no signs of any problems, there are lot of other members with similar experiences so mine is not an isolated case.
Sadly, there is lot of mis-information out there, all claiming what they say is the be all and end all but all of it is conflicting, that’s why I started doing the experimenting myself, the amount of total B/S from people who where trusted names in the industry has me just a little sceptical about anything I read regarding these batteries now.

T1 Terry

[BobnBev]

Very true Terry, I came across a KK, when in the West this year and the way it was set up was to say missing a few points.
To small a battery ( 40 amph)for what was running in the Kamper plus a heep of other stuff, no where near enough solar, and the owner was told no need for a genny.
All he had was a small fold up solar, 2 small flexi panels on the small roof, and long wires from the fold up panels.
They had a anderson charger plug from the car, the guy had to run the car at night just to keep the (2)fridges running.( like 2.30 in the morning)
The owner was not very happy, it may have worked if you traveled every day, but if you stopped for a few days( like they were) not good.
He came to me when some one told him I also was useing( Lithium) LiFePo4 battery in my van. And wanted to know how it was going. He just couldnt belive that we were running 3 fridges and the volts didnt go below 13.1
When I told him what it cost me to set up with a 200 amph battery and solar, his wife had a fit, said theirs was a LOT more than that .
Im not knocking the Kamper it was well made, just the battery system was left wanting....
Bob n Bev....

[BruceS]

If Peter, the original poster, wishes to elaborate on exactly what he has now and how he would like to improve it we may get back on topic?
Over to you Bellett65 (Peter)
I think T1's reply covered a lot of it but you may have more queries?
I personally had trouble understanding this bit... """I need to get 4 X 3.2 100a/h cells """
I'm presuming that's 3.2V?

[T1 Terry]

The 3.2v is the nom. (nominal or average) operating voltage for a lithium ferrous cell. Their actual operating range is 3.4v fully charged and 2.8v fully discharged, a pack of 4 cells in series will give a battery with nom. voltage of 12.8v that has an operating range between 13.6v and 11.2v. A safe min. voltage is 3v per cell, one cell may drop to 2.8v under load but you would be pushing the friendship attempting to drag all 4 cells down to 2.8v, this would require all 4 cells to be exactly the same capacity before the discharge cycle started, more likely to pick the powerball numbers than that happening just when you wanted it. This is the reason for the cell logger and alarm, one cell only needs to be 0.5Ah less capacity than the others when the discharge cycle started and it will drop to 2.8v or lower before the 11.8v min is reached under a heavy or prolonged discharge. The cell isn't damaged at this point and as long as it's not a regular occurrence the reduction in over all life would hardly be noticeable, doing it every cycle will reduce it's life to around 1,000 cycles according to the manufacturer, I’ll take their word on that, I ain’t testing it with my batteries. How long will they last if you take it below the 2.8v every cycle, I'll let someone else do that test as well, but please let me know the results
What we do know is it's not an instant death, they will recharge and still function as house batteries, as long as the 0v isn't reached or passed and they aren't held at that very low voltage, yet to see what the long term damage was.

T1 Terry

[bellett65]

I will get as much info on the current equipment. I do have my eye on some cells branded Wiston.

Peter

[bob r]

has anyone used a c40 xantrex regulator on lithium batterys
they are fully adjustable and a good price maybe ti terry
knows some thing about them
bob

[T1 Terry]

Do you have a link to the fitting instructions PDF Bob? Some of the manufacturers ideas of fully adjustable leave a bit to be desired