LiFePO4 or Lead Crystal to replace AGM?

[Milton477]

After 3 years of abuse., the 2 120Ah AGM batteries in my van are showing signs of surrender.
I had always intended at some stage to go with Lithium but now there are Lead Crystal batteries muddying the water.

While it is fairly clear that Lithium batteries maintain their voltage at above 12V while being discharged all the way down to 20% SOC or thereabouts, I can't seem to find the same information about Lead Crystal. Does anyone have a comparison or can you point me on the right direction?
Apart from the price, weight differences & green credentials, there does not seem to be much difference between the 2.

Has anyone had experience with both batteries that can tell me which battery system they would choose without factoring the cost into the equation.

I don't have an integrated electrical system in my van, all charging methods are stand alone & can be connected individually or together as required. (KISS) principle. Solar can provide around 20 amps & then the D4 sends who knows how much down a 25mm2 cable to the van batteries when travelling. I have a stand alone Victron 15A battery charger for other occasions if needed.

I intend installing an inverter big enough to run the microwave for a few minutes at a time so would need the batteries to manage an 80 amp draw without the voltage collapsing below 12V for those few minutes.


Thanks in advance.

[DiscoMick]

I have read claims that LifePOs can be discharged right down without damage, but is that true?

[bee utey]

I have read claims that LifePOs can be discharged right down without damage, but is that true?

Most species of Lithium rechargeable battery are supplied with battery management systems (BMS) to prevent that sort of damage. It is not that you can't damage a cell by discharging it too deeply (you will), it's that the battery pack as is protected against deep discharge and overcharge by electronic wizardry.

[trout1105]

These lithium batteries are way too expensive at the moment So even if they are a better option they are way above my pay grade [bigwhistle]

[Homestar]

These lithium batteries are way too expensive at the moment So even if they are a better option they are way above my pay grade [bigwhistle]

If you look at what you can do with a lithium battery, they make a lot of sense but you do need the dollars up front. I currently run 2 x Fullriver 100Ah batteries - these retail for around $400 each. Given that 1 x 100Ah lithium can do the same job as these and give me a weight saving of about 45Kg all up, the around $1,300 for one makes a lot of sense. Also the charge/discharge cycles is a heap more, so actually it's on a par with good quality AGM's over all. There is then a different charger required too, so an extra expense there as well but I'm seriously considering one for my van, but yet to take the plunge.

[drivesafe]

Hi Milton, have a look at this link, it should be of some help.

Lead Crystal deep cycle batteries (https://www.aulro.com/afvb/technical-chatter/252333-lead-crystal-deep-cycle-batteries.html)

[drivesafe]

I currently run 2 x Fullriver 100Ah batteries - Given that 1 x 100Ah lithium can do the same job as these
Hi Homestar, be very careful of the claims being made about how much better lithium batteries are over lead batteries.

For instance, if you use no more than 4o% of your current 2 Fullriver batteries capacity, then a 100Ah lithium will be fine.

But if you use 50% or more, then you need a bigger lithium battery.

Again, for instance, if you set up camp for a few days and use 80% of your Fullriver battery capacity, you will need 200Ah of lithium to replace that.

But if you were planning to replace the 200Ah of Fullriver batteries with Lead Crystal batteries, you only need 160Ah of Lead Crystal batteries and depending on how you use them, you will still have more available capacity from the 160Ah of Lead Crystal batteries then you would from 200Ah of Fullriver or 200Ah of Lithium.

Again, it all depends on how you are going to use that type of battery capacity.

[trout1105]

I am quite happy to wait until these lithium batteries stop being "Trendy" and wait for the inevitable price drop.
Just like everything else that comes out as a new thing these will eventually become affordable over time [bigwhistle]

[Milton477]

Thanks guys for the replies.
Drivesafe, I was rather hoping you would reply but my biggest question is still unanswered.

If a Lithium battery maintains it's voltage above 12V for the majority vast of the time while being discharged, what does a Lead Crystal do? I can't seem to find a discharge Voltage curve for Lead Crystal. I am interested in comparing the capacities of batteries while their voltage is above 12V.

[Homestar]

Hi Homestar, be very careful of the claims being made about how much better lithium batteries are over lead batteries.

For instance, if you use no more than 4o% of your current 2 Fullriver batteries capacity, then a 100Ah lithium will be fine.

But if you use 50% or more, then you need a bigger lithium battery.

Again, for instance, if you set up camp for a few days and use 80% of your Fullriver battery capacity, you will need 200Ah of lithium to replace that.

But if you were planning to replace the 200Ah of Fullriver batteries with Lead Crystal batteries, you only need 160Ah of Lead Crystal batteries and depending on how you use them, you will still have more available capacity from the 160Ah of Lead Crystal batteries then you would from 200Ah of Fullriver or 200Ah of Lithium.

Again, it all depends on how you are going to use that type of battery capacity.

Thanks, some good points as always. I've never had the Fullrivers below around 12.2 at almost any stage (usually they stay above 12.5 as I only generally use a couple of 4 watt LED globes for a couple of hours plus a bit of TV) - I think one hot night running 2 fans through the inverter they cane down to about 12.0 (I can't ever remember them being under 12.0) but in general I look after them very well and try not to get them below 60% when I can - I don't actually need much power at all, but at times if I know I've go ts plenty I'll use a bit more - have the telly on longer, etc. I've got 300 watts of solar panels that do a pretty good job of getting them topped up each day as well, it's rare for them not to get back to 100% during the day, but at times they don't make it and then I get a bit paranoid about using power the next night. :D

I've been out for 8 nights straight and packed up at the end with full batteries so I'm not hard on them by any means.

I think 1 x 100Ah lithium would do me fine but as I said, yet to make the jump.

[Homestar]

I am quite happy to wait until these lithium batteries stop being "Trendy" and wait for the inevitable price drop.
Just like everything else that comes out as a new thing these will eventually become affordable over time [bigwhistle]

I'd like to see that happen too but it seems they are only mining just enough Lithium to meet demand - I think in a deliberate attempt to keep price up. We need to open a Lithium mine and flood the market with cheap Lithium. [biggrin]

[drivesafe]

Thanks guys for the replies.
Drivesafe, I was rather hoping you would reply but my biggest question is still unanswered.

If a Lithium battery maintains it's voltage above 12V for the majority vast of the time while being discharged, what does a Lead Crystal do? I can't seem to find a discharge Voltage curve for Lead Crystal. I am interested in comparing the capacities of batteries while their voltage is above 12V.
Hi again Milton, and Lead Crystal batteries have a very similar discharge voltage curve to lead acid batteries.


I am curious as to why this matters?

[Milton477]

Thanks Drivesafe,

I'm just trying to compare like for like. Lithium prices for a DIY system are not so far away from Lead Crystal prices as to remove Lithium from consideration. $1200 ish vs $1500 ish for 200Ah. Big weight savings, constant voltage....

[CraigE]

I'd like to see that happen too but it seems they are only mining just enough Lithium to meet demand - I think in a deliberate attempt to keep price up. We need to open a Lithium mine and flood the market with cheap Lithium. [biggrin]

There are several already. Just up the road from where I work is Galaxy, Mt Catlin Lithium. I am going to MRL's Tantalum/Lithium mine and there is at least another 1 in WA with prospects of another 2 or 3 coming on line soon. Does not mean the price will reduce drastically as being used in more and more battery applications.

[drivesafe]

Thanks Drivesafe,

I'm just trying to compare like for like. Lithium prices for a DIY system are not so far away from Lead Crystal prices as to remove Lithium from consideration. $1200 ish vs $1500 ish for 200Ah. Big weight savings, constant voltage....
Hi again Milton, and why the requirement for constant voltage?

[Homestar]

Yes, by far the biggest advantage of a Lithium is the weight saving. It's the only reason I'm looking at them. Although my van isn't overweight, it gets very close at times. Going from 2 x AGM's to a single Lithium would save me 45Kg's - a massive difference. Constant voltage isn't an issue - everything you'll run from a 12 volt system copes easily with what a lead acid does as it discharges. If you're getting them down far enough to be an issue - under 12 volts IMO, then you're not doing your battery any favours and reducing their life dramatically.

The cycle life of a Lithium is also very good and makes it quite a good proposition although I've yet to see a Lithium do many years of use yet, so I'm still not 100% sure they'll meet the claims there.

[Milton477]

Hi again Milton, and why the requirement for constant voltage?

Thanks Drivesafe.

Right now I have a pair of 120aH AGMs sitting on 12.3v with no load. Turn on some lighting & the voltage drops to 12v & then the fridge kicks in (140l Waco), or tries to. Voltage drops to sub 11.5v & the fridge turns off. Voltage recovers & the fridge tries again with the same result.

I know or realise now that the cable to the fridge is too small at 2.5 mmsq so this exacerbates the problem somewhat. My research shows Lithiums have a flat discharge curve which drops off only when they are near discharged. I believe that my current problem would not be happening if the voltage remained above 12v. Sure, I am going to upgrade the fridge cable to 6 mmsq based on what I have learned now.

I know that there are a million ways to shoot me down with my problem but I believe that a more constant voltage above 12v is better for 12v devices than 11.8v for example. I know that my caravan air suspension compressor does. Not sure how the modem & CellFi hot spot feel about sub 12v. Also, as the voltage drops, the current rises & stresses small cables & less than perfect connections as demonstrated by my fridge.

If I have to spend the money, then how should I spend it to get the best bang for buck? All features need to be considered.

[drivesafe]

Hi again Milton, and that is one hell of a voltage drop.


With a pair of 120Ah batteries sitting at 12.3v, unless your fridge is a 3 way, then yes the cable is to thin but a 3 way fridge should never be run off the house batteries anyway.


So I am ASSUMING that your fridge is a compressor type. If so, then just how long is the 2.5mm cable run between the batteries and the fridge because, even with 2.5mm2 cable, you should not be seeing anywhere near that sort of voltage drop.


Can you post up some more details because under normal operation, with 2 x 120Ah of house battery capacity, even with a few lights running, your fridge should not pull the batteries down more than 0.2v, but 0.1v would be expected.


Something seems to be wrong with your setup and fitting any type of new batteries may not fix anything.

BTW Milton, not intearested in “shooting you down”, more interested in trying to help you, which ever way you choose to go.

[djam1]

Right now I have a pair of 120aH AGMs sitting on 12.3v with no load.

AGMs sitting with no load should be 13.1 volts so as you mentioned your batteries are very tired. (I run a bank of 6x140ah Century AGMs)
80 amps drawn from a small bank of batteries < 200 ah will always see some serious voltage drop although I understand lithium do better.

[Milton477]

Thanks for the replies.
My fridge is compressor driven, not 3 way. I did the following test a few days ago, all readings off a Victron battery meter:

The batteries were fully charged when I started. No fridge involved, just lighting - all of my lights were on so the load was constant.
Time/Voltage/Current/Power consumed are shown below.

130675

Not hugely scientific but has convinced me that the batteries are toast.

[drivesafe]

Hi Milton and that is actually good info.

Are you interested in seeing if they can be revived.

If so, start by separating them and charging each one again.

Then try your load test again, on each battery while they are separated.

From that discharge data, because the batteries did not immediately go flat, you might find one one of the batteries is OK, and was carrying the faulty battery.

[Milton477]

Good suggestion Drivesafe, I'll try that thanks.

[PeterJ]

Hi, I made the leap to LiFePo4 in my van about a year ago, I did a major upgrade to the complete system. My very strong advice is that it has to be regarded as a system change, not a battery change, and along with it a paradigm change in how you utilise your electrical energy storage. LiFeP04 is just fantastic, it's ability to supply high current draw and maintain 13V while doing it for extended periods of time is the first in a long list of advantages over Sealed Lead Acid (SLA), and the paradigm change is that you have to use them differently, they are not SLA, do not use them like you use SLA. So here is the trap, there is a lot of poor information out there so do your research and make up your own mind, it is your money, and usually quite a lot of it.

Peter

[Milton477]

Hi Peter, thanks. Could you maybe expand a little on what you have said. Did you have the system fitted professionally or did you fit it yourself? Does your van have combination charger/inverter devices? Do you charge the batteries with the tug while driving? How much solar do you have & what size LiFePo4 pack did you fit?

[PeterJ]

Hi Peter, thanks. Could you maybe expand a little on what you have said. Did you have the system fitted professionally or did you fit it yourself? Does your van have combination charger/inverter devices? Do you charge the batteries with the tug while driving? How much solar do you have & what size LiFePo4 pack did you fit?

I fitted the whole system myself, 300Ah LiFeP04 battery (with BMS), Victron Energy Multiplus 3000w inverter/charger [fully programmable with dedicated voltage sensing, I can not understate how important dedicated voltage sense is] Victron Energy 100/50 solar controller, [again fully programmable] 840w solar panels [simply] and VE battery monitor, most importantly a programmable low voltage cut off protection for the battery from Intervolt. You must not rely on the battery management system cut off to provide a low voltage safety cut off point for the system, it's only there as a OMG panic stations savior.

I can be using the microwave or coffee machine (a George job) the inverter is pulling 120 to 130A, turn on the van water pump, TV, lights whatever and not so much as a micro hiccup. I do not charge from the D4, absolutely no need.

Peter

[drivesafe]

Hi Peter and the total cost was?

[Milton477]

I fitted the whole system myself, 300Ah LiFeP04 battery (with BMS), Victron Energy Multiplus 3000w inverter/charger [fully programmable with dedicated voltage sensing, I can not understate how important dedicated voltage sense is] Victron Energy 100/50 solar controller, [again fully programmable] 840w solar panels [simply] and VE battery monitor, most importantly a programmable low voltage cut off protection for the battery from Intervolt. You must not rely on the battery management system cut off to provide a low voltage safety cut off point for the system, it's only there as a OMG panic stations savior.

I can be using the microwave or coffee machine (a George job) the inverter is pulling 120 to 130A, turn on the van water pump, TV, lights whatever and not so much as a micro hiccup. I do not charge from the D4, absolutely no need.

Peter

Thanks Peter, well done building it yourself. Some food for thought there. I take it you bought the battery complete with BMS rather than assembling the battery + BMS yourself. I am considering building from scratch.

[PeterJ]

Yes the issue of cost is always the biggie, but I have some specific requirements that I wanted to accommodate and simply did not want to do the generator thing, the answer is approx $10k, remembering that a lot of that is on equipment that anyone could spec into a FLA system or for that matter Lead Crystal. I have no exposure to Lead Crystal at all so can not comment about them.

I was going to build my own battery initially, CALB cells, build my own mounting box (compression plate) and use a commercial BMS but I became aware of a "sale" that included exactly what I wanted and when I did the numbers there was not a real lot in it. There was also a bit of a time issue for me at that point and the process of top balancing the individual cells, assembly and then running base line capacity checks was going to take a while.

I did a base line check on my battery and without boring you to tears I charged it to 14.02 (no load, about 13.7 loaded) and set my cut off at 11.8V (loaded). I hooked up a 750W bar heater to the inverter and turned it on. 4 hours and 43 minutes later it hit the low voltage cut. The Victron Energy battery monitor indicated 288Ah from a nominal 300Ah capacity and when you factor in the inverter efficiency I was very happy with the result. I run much more conservative cut out ordinarily but there you go.

[Milton477]

Thanks Peter. Does the Victron Energy 100/50 solar controller charge the batteries direct or through the Multiplus?

[PeterJ]

Hi Milton, out of convenience I used the terminals on the MultiPlus as a connection point for the solar feed from the 100/50, but in hind sight it was actually a mistake because it made setting up the voltage cut relay more difficult. Oh well, next time......[bigsad]

Having read other bits of this thread again I thought you might be interested to see the graph of my capacity test. It was manual data collection every 10 minutes and not a data logger unfortunately but it was a lot of fun.[bigsmile1]

130812

[Milton477]

Is it possible to find a more beautiful discharge curve than that?

[djam1]

Peter
I agree it all looks impressive good on you
Just a question what happens in the heat? I live in a motorhome with a large bank of AGM batteries that are recharged by 1500 watt of solar
As this is my house it is all run 24 hours a day 7 days a week without much reliance on mains power,
In the summer months the battery temps can exceed 40 degrees C they are in the bins and in extreme heat there is nothing I can do about this ( I run fans as ventilation etc.
The only reason I didn't go to Lithium is their ability to cope with heat and the 20K cost of course

[PeterJ]

Hi djam1, well the environmental specs for my battery are -20 to +60 Celsius so that would cover what you are concerned about, but as you have said you have some ventilation fans in the compartment, very easy to set up on a digital thermostat so nothing to be concerned about.

Peter

[Marty90]

FWIW I was looking at a lithium battery for my Harley and the battery world rep advised against it siting the problem with heat. Reckons there's a greater risk to fires with lithium and not much you can do about it. Apparently they go up quite spectacularly. "Best you can do is drop your bike and run!"

[Homestar]

FWIW I was looking at a lithium battery for my Harley and the battery world rep advised against it siting the problem with heat. Reckons there's a greater risk to fires with lithium and not much you can do about it. Apparently they go up quite spectacularly. "Best you can do is drop your bike and run!"

Thought that was more to do with how they are charged?

[Marty90]

I don't know. Maybe as a storage battery for accessories would be ok. Told me that was the reason he doesn't use them in his race car. I suppose in a bike it's located close to all heat sources and directly under the crown jewels😱

[drivesafe]

Hi Marty and it pays to shop around for correct INFO as well as different brands.


In 2011 I was asked to test some Lithium batteries by one of the companies I deal with.


The first brand were absolute rubbish and I managed to stuff a couple of them with out really trying.


Then in 2012, after some assurances from another lithium battery manufacture, the company supplied me with a different brand and again, I carried out some pretty rugged testing with some smaller versions of this later brand.


The company then brought in a few much larger batteries for real world testing.


Only yesterday, the company informed me they are now going to market these batteries and are bringing in their first shipment of 100Ah, 200Ah and 400Ah batteries.


It will be interesting to see what prices they are going to be.


So again, Marty,shop around as there are good and bad in most products.

[djam1]

Hi djam1, well the environmental specs for my battery are -20 to +60 Celsius so that would cover what you are concerned about, but as you have said you have some ventilation fans in the compartment, very easy to set up on a digital thermostat so nothing to be concerned about.

Peter

Peter
I understood that you loose a huge amount of capacity as the temperature rises to these levels 40+ degrees.
I may be wrong its a while since I read the results of tests done

[Milton477]

Hi Marty and it pays to shop around for correct INFO as well as different brands.


In 2011 I was asked to test some Lithium batteries by one of the companies I deal with.


The first brand were absolute rubbish and I managed to stuff a couple of them with out really trying.


Then in 2012, after some assurances from another lithium battery manufacture, the company supplied me with a different brand and again, I carried out some pretty rugged testing with some smaller versions of this later brand.


The company then brought in a few much larger batteries for real world testing.


Only yesterday, the company informed me they are now going to market these batteries and are bringing in their first shipment of 100Ah, 200Ah and 400Ah batteries.


It will be interesting to see what prices they are going to be.


So again, Marty,shop around as there are good and bad in most products.

I'm listening - especially to the price part.
It would be much simpler to pop down to the Gold Coast to collect a battery than have them shipped from Perth.
Will these be individual cells or complete batteries with cell balancing & BMS built in?

[drivesafe]

Hi Milton and at this stage, I am not looking at carrying them, but once I know pricing and availability, I will post up the supplier’s contact details.

[PeterJ]

Peter
I understood that you loose a huge amount of capacity as the temperature rises to these levels 40+ degrees.
I may be wrong its a while since I read the results of tests done

Hi djam1, I have not specifically looked at charge/discharge performance at elevated temperatures, I do not expect to be operating my system outside the limits I have quoted, or actually anywhere near it. Have you actually measured the temperatures (data logged) inside your battery compartment during your typical use patterns? No idea of your specific application a thought would be insulation,ventilation and reflection (white paint) can be quite effective for reducing the effect of heat soak.

For some of the earlier comments about how safe these batteries are, have a look at these nut jobs Sinopoly Batterietest - YouTube (https://www.youtube.com/watch?v=aQs7L5LmEss&feature=youtu.be)

Peter

[drivesafe]

Will these be individual cells or complete batteries with cell balancing & BMS built in?
I was supplied with the factory data by the manufacture, when I started testing the batteries. When I get a chance, I’ll post up any relevant info.

[Milton477]

Thanks PeterJ & others who have offered the benefit of their experience & general advice.

I have just completed installing 2 x 180Ah LifePo4 batteries in my van that I have put together from scratch.
There are no multi function smart devices like DC to DC/charger inverters etc in the system. This is a KISS system.



The cells are CALB (or China Aviation Lithium Battery I believe), 180Ah, 3.5V.
Cells are arranged in 2 banks of 4 cells in series & then paralleled to produce 2 x 180Ah = 360Ah
I have followed PeterJ's advice with an Intervolt Low Voltage Relay to protect the system as a last line of defence with a Victron BMV 600s Battery Meter responsible for managing the high & low voltage cutoff using the Low Voltage Relay's override function in the first instance.
Individual cell voltages will be monitored by a CellLog8S when they arrive from Amazon.
I am not doing any form of cell balancing at this stage.
Charging is via 400W of solar to a Victron 100/30 Controller, from the D4, by means of a portable 15A battery charger or a combination of any of the sources.
The inverter is an ebay 3300/6600W, have to see how it goes as it is a tenth of the cost of the big brands.


Total cost was around $3000 but I did already have the BMV 600 & the Solar Controller installed on the AGM batteries.
Cable is expensive, I bought a roll (25m) of yellow 25mm2 tri rated or panel wire off RS Australia for $90. Yellow is cheaper than the same size red or black, go figure. The cable needs to be soft, not like house wire.
I already had a cheap ebay hydraulic lug crimper suitable for the uninsulated lugs needed on the cables.

At the outset I did lots of reading & asked around a bit. Lots of hype, wailing & gnashing of teeth about poofteenths of a volt over 13.8V & under 12.0V vs longevity etc. which you have to wade through. There are also hidden agendas & products & the corresponding mis information that try to lead you in another direction. Then there are the quiet ones who sit there in smug Lithium silence with their coffee machines, microwaves & aircons powered off LifePo4's & don't say very much. These are the people with the real practical advice.

The obligatory Pics:

Battery Isolators,
Inverter Isolator,
Low Voltage Relay.
132614


2 X battery banks, one on the wheel arch where the AGM's sat
& the other other on the floor under the bed step.
132615132616