Lithium battery charging

vince56 · Senior Member

Lithium battery charging

Peter_n_Margaret · Senior Member

Some people like to make Li harder than it really is.
Let's start with "Why is your solar controller NOT "Li capable"?"

I solar charge my Li battery at 14.0V. That is LESS than that typically used for AGM and is the maximum that the rest of the system will generally see.
I then float the Li at 13.5V. They don't ever "punch out" "14+ volts".
In emergencies I also direct charge it from the alternator which runs at 14.2V. No DC-DC required.
Cheers,
Peter

vince56 · Senior Member

Hi Peter and thanks for your reply.
I was under the impression that solar controllers needed to be designated as Lithium capable for proper use with those batteries.
The reason I say 14+ is that I have seen many Li chargers advertised at 14.6V

I take it from your reply that any charger lead acid or not will do the job but not charge the Li batteries to their max??

Peter_n_Margaret · Senior Member

Li has a range of voltages that they can be charged at. What does your battery manufacturer state as appropriate.
Provided the charger does not EXCEED the recommended voltages it will probably be quite satisfactory. A little low won't hurt the battery but you may not get to quite 100% SOC. - So what? - It is probably better for the battery to be a tad low. Anything over 13.5 is probably OK.

Of course, everyone who sells chargers will tell you that you need a new one.
Cheers,
Peter

Jaahn · Guru

Vince I have two 40Ahr lithium batteries which I fitted into a battery box and made some external terminals and a ciggy socket (similar to ones you can buy now). I have used it as a portable power source eg for use outside the camper/home for lights or TV or what ever, it has powered a 12V tv while staying away for a year in a house, and I use it as a jumpstarter for (other peoples) cars, and have used it as an emergency car battery to drive a dead car home a couple of times.

I do not own a "lithium charger" and I use the car or camper if necessary or my solar on the camper, set for LA charging and even a small old 4A simple car battery charger if it needs some extra charging. Mostly I just put some leads to the camper LA batteries outputs or the car battery. Now people have said they will never last by treating them casually like that ! But they are now over 10 years old and I do not notice any reduction in capacity.

When I bought them the vendor told me charging them with a car or a car type charger was a suitable voltage and it has worked OK for me. I do not worry if the voltage falls a bit as Lithium do like that. You might loose a tiny bit of capacity but so what.

Some solar battery chargers for flooded LA batteries do have a extra higher voltage that is applied occasionally to stir the acid in the flooded cells. That should be set to off or to the same voltage as the normal charging voltage like you do for sealed LA batteries.

Cheers Jaahn

PS what is your car and does it have a smart alternator ?

-- Edited by Jaahn on Friday 13th of December 2024 05:34:12 PM

vince56 · Senior Member

Hi Jaahn,
Car is a 200 LC, I have a diode fitted to boost alternator output so should be thought of as a "normal" alternator.

TimTim · Guru

RE: Lithium battery chargingt

67HR · Senior Member

Lithium battery charging

67HR · Senior Member

67HR wrote:
Query for Tim,
I have a 4ah cetex charger that I've used for the last 8 years to charge my wifes car, the AGM 680CC in my jeep and ride on batteries.
If I want to charge my new LiFePO4 12.8 v 100ah battery what battery select do I use.?
I also have an older Electro charger that I can select votages up to 13.8v
Just wondering what would be best to use as I obviously don't need to float the lithium battery.
Cheers trev.

-- Edited by 67HR on Tuesday 17th of December 2024 02:21:56 PM

Here's a pic of the old electro unit.

vince56 · Senior Member

Hi Tim,
I will have a Renogy 40amp DCDC charger MPPT.
Cheers Vince

TimTim · Guru

67HR wrote:
Query for Tim,
I have a 4ah cetex charger that I've used for the last 8 years to charge my wifes car, the AGM 680CC in my jeep and ride on batteries.
If I want to charge my new LiFePO4 12.8 v 100ah battery what battery select do I use.?
I also have an older Electro charger that I can select votages up to 13.8v
Just wondering what would be best to use as I obviously don't need to float the lithium battery.
Cheers trev.

-- Edited by 67HR on Tuesday 17th of December 2024 02:21:56 PM

Hi Trev,

No idea about your CteK unless you have a model number and many are multi stage chargers.

Your Electro is a 15A charger so it will charge much faster than your 4A Ctek. Here is the manual for it if you dont have one.

https://catalogue.electroparts.com.au/manuals/BC-1210%2C1215%2C1220.pdf?_ga=2.205896276.699246294.1734495891-1316888989.1734495891

I would set it on charger, Gel and Float at 13.5V. Do not use the Calcium setting under any circumstances.

With Gel setting it should take it up to about 14.2V so if you have a multimeter you can charge it up to see what voltage it reaches, disconnect and let it rest for a couple of hours and see if it settles at about 13.4V to 13.3V.

Good luck

Tim

-- Edited by TimTim on Wednesday 18th of December 2024 04:11:45 PM

vince56 · Senior Member

BTW Tim, what's your take on storage of Lithium batteries? I have been told best to store at a lower voltage in battery, ie, not fully charged.

Are We Lost · Guru

The VoltX manual says to discharge down to 80% state of charge for best longevity when storing. I imagine it would not make a lot of difference but they are the ones who should know.

Peter_n_Margaret · Senior Member

Are We Lost wrote:
The VoltX manual says to discharge down to 80% state of charge for best longevity when storing.

But they never actually tell you WHY.

Cheers,

Peter

Are We Lost · Guru

Advice on storing at 80% SOC is fairly common. Are you saying the manufacturers are wrong about their own products? Renogy goes into a bit more detail and proposes a lower storage value than VoltX.

Renogy: How to store Lithium Batteries

Charge Level
The state of charge is a often-overlooked yet critical factor in lithium battery storage, especially for long-term storage. Unlike some other battery types, lithium-ion batteries should neither be stored fully charged nor completely discharged. The ideal charge level for storing lithium batteries is around 40-50% of their capacity.

Storing a lithium-ion battery at full charge puts stress on its components, potentially leading to a faster loss of capacity over time. Conversely, allowing a battery to discharge completely before storage can cause irreversible damage. If you're planning long-term storage of lithium batteries, periodically check and adjust their charge levels to maintain this optimal range.

Just about any lithium product you buy now comes out of the factory only partly charged.

-- Edited by Are We Lost on Wednesday 18th of December 2024 06:42:30 PM

Radar · Guru

My question is.

What is termed as storage of a battery.

At present the caravan is parked up for 2 months, I do not think this is a long time but is it.

Peter_n_Margaret · Senior Member

Being common does not mean credible any more than having to have a special charger.
Tell us WHY. If they can not or will not, I choose to view it with suspicion.
Cheers,
Peter

Are We Lost · Guru

Radar, I agree that 2 months hardly seems an issue.

Peter, I do not claim to be any sort of expert on batteries. If the manufacturers commonly recommend something I would pay more heed to that advice than random people on the internet. So what is it that you think is wrong with their advice? And as per your earlier comment ....

But they never actually tell you WHY.

Cheers,

Peter

Peter_n_Margaret · Senior Member

For a start, I can not find any evidence that Renogy actually manufactures LiFePO4 batteries.
Can you?
Cheers,
Peter

Are We Lost · Guru

No, and you may well be correct that they are not the manufacturer. But would you agree that Renogy would have in depth knowledge on battery technology that far exceeds yours or mine?

I asked Copilot (AI). Copilot said 50-60% state of charge was best. When asked why the answer was ...
Batteries degrade over time due to chemical reactions within the cells. These reactions are accelerated when the battery is at a high or very low SOC.

Storing at 50% to 60% SOC reduces the rate of these reactions, thereby prolonging the battery's life.

Of course, the wisdom of AI is not absolute (garbage in, garbage out), but the answers align with most of the manufacturer/supplier advice and make logical sense to me.

Anyway, I think it is becoming unnnecessarily pedantic over an issue where the advice is widespread. It may make little difference, although some sites say it is very important. But it seems the common expert advice is that storing LiFePO4 at 80% or lower state of charge is recommended.

Over and out.

Peter_n_Margaret · Senior Member

Renogy sell batteries. There is no way they would want their advice to be the opposite to everyone else's, so they may just choose to follow the flock?
Why then is the advice for Li different to that of any LA battery?
Cheers,
Peter

TimTim · Guru

vince56 wrote:
BTW Tim, what's your take on storage of Lithium batteries? I have been told best to store at a lower voltage in battery, ie, not fully charged.

Hi Vince,

Well I go against the grain on this one.

It is the cell manufacturers that are the ones that state that the cells should not be stored at 100%. The battery manufacturers and battery sellers then repeat that information and of course things get altered a little as you move down the line.

I did read the reasons why some time back but my brain can only hold so much information and I cannot remember the scientific reasons why but it is supposed to maximise the life of the battery. The same is stated about compression of the cells but I have only ever seen one battery where the cells were restrained against expansion.

My last batch of EVE cells arrived at 70% SOC so that would give you an indication of what the manufacturer considers to be storage SOC given that they take about 2 months to get to me.

With a specified lifespan of 5000 cycles (3000 for some batteries) until they drop to 80% capacity, my belief is that my travelling days will be over well and truely before they reach that level of capacity. I dont bother with worrying about storage SOC levels or length of time before it is considered storage. i just charge them up and let them sit there and just turn off the solar. I have two seperate banks and sometimes I just leave the solar charging one on float even though it is not needed.

These batteries are more robust than many will believe so whether you leave at 80%, 70% or 60% they are not going to suddenly die on you or even lose capacity at a rate that is noticeable. I will leave mine fully charged and maybe do a capacity test every few years just to check how they are going.

I wouldnt suggest or expect anyone to follow my lead but just to do what they feel comfortable with.

Good luck

Tim

Scubadoo · Veteran Member

TimTim wrote:

...
These batteries are more robust than many will believe so whether you leave at 80%, 70% or 60% they are not going to suddenly die on you or even lose capacity at a rate that is noticeable. I will leave mine fully charged and maybe do a capacity test every few years just to check how they are going.

I agree 100%.

Charge within parameters, store at 10 or 100% SOC and they are likely outlast the average RV anyway.

Far too much scaremongering from sellers and dare I say it the occasional forum poster.

Our Sinopoly 300Ah 4 cell LiFePO4 battery has survived 10 years of full-time travel powering both the motorhome and starting the 3.9l turbo diesel Canter truck engine.

At the last 5 November annual capacitity test and converted to Ah we have crashed from the original 315 to just 299. A whopping c5% loss!

At that rate I'm guessing at least another 20 years of capacity life but fully expect them to die of old age long before that but probably after me. hmm

We have never "stored" the battery. Our aim is 100% SOC every day but that only exists while the sun shines or driving.

Dick0 · Guru

I for one don't concern myself about storage recommendations. My batteries are always connected to solar whether travelling or in storage and set to "float" at 90%. If I get approx. 3000 cycles out of the batteries, I probably won't see the day when the batteries will need replacing. If you are worried about battery storage charge the batteries then isolate them from charge and loads and they will sit there happily until your next travels.

landy · Guru

Hi all I realize this thread is a few months old now but I originally followed it with interest and I am hoping I can hope on the end of it and enlist your help. My set up at the moment is two 100 AH lead acid batteries in the Land Rover with the start Battery protected buy a relay and a second two 105 AH lead acid batteries in the caravan being charged by a combination of the cars alternator via an Anderson plug ( no DC-DC charger ) and two 150 watt solar panels, being that we prefer to free camp we hardly ever use the 240 volt charger which is a Mean Well PB 300 or 360 I cant read the model and it has been well hidden away in one of the lower cupboards. Also the solar charger has no name on it but is claimed to be 30 Amp.
What I am thinking of doing is replacing the vans Batteries with either one or two lithium in the simplest way possible and the original thread has got me wondering if I can just swap them out with the lead acid. I cannot see any way of making adjustments on the 240 charger and would not have a clue of how to go about resetting the solar charging as no book came with the van see pics below any help would be much appreciated.
Cheers Landy

-- Edited by landy on Friday 25th of April 2025 10:20:32 PM

Peter_n_Margaret · Senior Member

You must be sure that there is no "equalising" charge sequence from any charger.
It would also be useful to know the bulk and float charge voltages and anything about the Li battery BMSs.

Cheers,
Peter

TimTim · Guru

Your 240V charger is a 3 stage charger and is very capable of charging LiFePO4. Whilst LiFePO4 can be charged to 14.6 some battery manufacturers will set the BMS so they are charged slightly lower. Your charger can be set to 14.0V or 14.4V but there is very little power between 14.4 and 14.6V.

Here is your manual.

https://www.meanwell-web.com/content/files/pdfs/productPdfs/MW/PB-360P/PB-360-Manual-E.pdf

Your solar controller is in all probability a generic earlier model 3 stage PWM controller which although will charge LiFePO4 it will probably not be to 14.6V. I have attached a link to a similar model with the difference being the USB ports. There are later models out that claim to be MPPT controllers but they are fake.

Scrolling through the menu may show that it does not have a equalisation mode and in that case it will work for you but probably not fully charge your batteries. I would suggest though that as you are spending decent money on LiFePO4 you may want to invest in an MPPT controller. You will need to ensure that it is one with load terminals to minimise any alterations.

https://www.ebay.co.uk/itm/156334097353?

Unless you are planning on adding additional solar panels then a 20A controller would suffice. The Victron 20A Smart Solar comes with load terminals but the larger ones dont.

The Smart Solar has Bluetooth.

https://www.ebay.com.au/itm/127005829583?

With the above controller you will just need to disconnect the six cables in the following order, being loads, solar then battery and connect back up, battery, solar then loads. Then just set your controller to the Lithium profile.

Tim

-- Edited by TimTim on Saturday 26th of April 2025 05:48:20 AM

landy · Guru

Thank you Peter and Tim for your very prompt answers . Peter I have not yet chosen a lithium battery so I am not able to supply any information on the BMSs at the moment I am afraid. When you ask about the bulk and float charges are you talking about the charging rate my current chargers are putting out or the rates of charge that the lithium battery requires ? Also I do not understand the meaning or function of "equalising" charge although you and Tim both mention it.
Tim Thank you for the links you found and supplied for me. I notice in the Mean Well manual that you kindly sent, The PB 300 recommended battery size is 60 to 100 AH and the PB 360 is 80 to 200. At the moment although I have jammed my phone shoulder depth into the bottom cupboard taking photos I have not managed to find the actual model, so does the fact that it is at present connected to 200 AH of lead acid suggest it is safe at this level or am I taking to much for granted. I will not be sure of what size Lithium to buy until I check some physical sizes to see what will fit into my battery boxes, but I am thinking 1 X 150 AH lithium should give me a lot more usable capacity than the two lead acids with a huge weight saving. possibly even a 200 AH lithium. Cheers again Dave

TimTim · Guru

Hi Dave,

Dont be too concerned about the BMS and the charging voltage. Some will cut out at 14.6V and others lower but as I said earlier there is little difference in the available power. The reason why this is done is that the cells inside can become unbalanced as they approach being fully charged. Similarly, some manufacturers will set the BMS to cut out at 10.0V and others higher for the same reason when discharging.

If you look at the link for your charging manual that I posted it explains the three stages of charging. Again you have no need to be concerned as you 240V charger is very suitable. Page 2 shows the three stages and explains how the battery is charged, Bulk or Boost (Constant current), Absorption (Constant Voltage) and Float. LiFePO4 dont actually need to be floated but I wont do into that detail here.

Equalising is a process for flooded lead acid batteries where the charger actually overcharges the battery to remove sulphation off the plates. it is not needed for LiFePO4 batteries.

Yes, I saw the recommended model depending on the battery capacity but all that it means is that one model will take a little longer to charge your battery than the other. It actually states this.

I noted the manual I posted did not actually state the charging currents whereas this manual does. It is a little confusing though with the 300 model showing a maximum current and also a continuous current whhereas the 360 model only shows the maximum current. I would suggest that the 300 model charges at 12.5A and the 360 at 24.3A.

https://www.jameco.com/Jameco/Products/ProdDS/1952409Users%20Manual.pdf?

Seeing as you rarely use the charger, and most people dont with LiFePO4, even if it was the PB-300 model it will probably suffice and if not you could always swap it out later. Either model is safe.

Do you use a large inverter and if so what size?

Tim

-- Edited by TimTim on Sunday 27th of April 2025 07:53:09 AM

landy · Guru

Hi again Tim thank you for the new link We do have a 600 watt inverter but haven't used it in years as we find a 150 watt does our needs and is more convenient as we can plug it into the many 12 volt sockets about the van and it seems to work fine. as you suggest I'm not going to worry about the model of the 240 volt charger at this stage, I have been all around it with a long handled mirror and the model is not marked any where you can see with it in situ, probably got a sticker on the side that's screwed to the Wall. biggrin

. For My next step I will start looking for a suitable battery, I see on ebay there are a number of suppliers offering 135 Ah lithium batteries that will fit into one of my battery box's and would appear to be equal in performance to my two lead acids, would this be the case ? I can always add a second one in the other box at a later date if needed Also is there any particular brand that might be worth looking out for, time is my friend here as my goal is mainly weight reduction and my lead acids are still doing an acceptable job. I have read on here several times there are some handy specials come up from time to time. Thanks again Cheers Dave.