LiFePO4 Lithium Battery Vs AGM for House Bank "Pros" and "Cons"

[coopec]

Well yes AGM is better and lithium is better still.
Deep cycle flooded lead acid is much cheaper than AGM though, and I don't think AGM necessarily wins in life cycle cost.

IMHO if you can afford AGM you can afford Lithium, depending on how many bells and whistles you want to incorporate.

Maybe I should have used Deep cycle flooded lead acid batteries then, but it's done now. Listening to you guys I am becoming more and more certain my next batteries will be lithium (probably built by myself if they are better and cheaper)

Thanks

 

[coopec]

There are some compromises in my system. At the moment I can only charge from solar. I have nothing in place to handle disconnects- the power would just trip off. But I only have it powering the fridge and inverter anyway, not critical equipment. However these are far and away the largest loads (I cook electrically via the inverter) so there's little incentive to shift the other, smaller, loads (e.g. cabin lights) across to the lithium.

I was wondering about how you would charge the lithium battery. Can't the normal alternator charge the lithium battery? Do you agree with this guy (from the GreyNomads forum)who seems to know what he is talking about?

"Charging Lithium batteries is completely different to lead acid variations.
Lithium require a charger specifically designed for them, that supplies both a constant voltage and specific current from start to finish, and when the battery gets to a specific terminal voltage then the charger must completely shut off.
You must not float/trickle charge lithium batteries as they do not self discharge like lead acid and you will over-charge them.
Lithium battery voltages don't vary based on charge state. They deliver the full charge voltage from full charge until approx. 98% discharged so you must monitor your consumption because they do not like being completely discharged to 0 volts.
MPPT controllers cannot be used on Lithium batteries.
DC to DC chargers must have a specific lithium setting. All the mainstream units don't work for lithium.
AC to DC chargers must have a specific lithium setting."

How can i run AGM and Lithium Ion batteries together on solar. - The Grey Nomads Forum

 

[sailaboutvic]

I was wondering about how you would charge the lithium battery. Can't the normal alternator charge the lithium battery? Do you agree with this guy (from the GreyNomads forum)who seems to know what he is talking about?

"Charging Lithium batteries is completely different to lead acid variations.
Lithium require a charger specifically designed for them, that supplies both a constant voltage and specific current from start to finish, and when the battery gets to a specific terminal voltage then the charger must completely shut off.
You must not float/trickle charge lithium batteries as they do not self discharge like lead acid and you will over-charge them.
Lithium battery voltages don't vary based on charge state. They deliver the full charge voltage from full charge until approx. 98% discharged so you must monitor your consumption because they do not like being completely discharged to 0 volts.
MPPT controllers cannot be used on Lithium batteries.
DC to DC chargers must have a specific lithium setting. All the mainstream units don't work for lithium.
AC to DC chargers must have a specific lithium setting."

How can i run AGM and Lithium Ion batteries together on solar. - The Grey Nomads Forum

I don't pretend to be any expert on lithium,
Both the banks I built my mate and mine are going strong and working 24/7 every day for the last 9 months .
Lots written on lithium and I suggest you read although it's quite a long threat the one here on lithium started by poey50, there some good stuff from people here who has build their own banks .
There also links to Rod site sadly he not too well ,
.
I not sure who Grey Nomads is , but just by the bit you posted I not sure I agree with his comment .
For a start you can use MPPT with lithium many hundreds people do, that just alone get me wonder if he knows what he talking about .
Then he talks about , ( you can discharge them to 98% ) ,
well not if you want to get any long term use out of them .
You be pushing it at 90% and personally I wouldnt want to go down to 80 % ,
If you have a good size bank you would never need to go that low .
He is right they don't like to float but with most mppt a " float " setting is needed which is why many have this setting low so in reality the batteries never reach a voltages where the lithium are 100% and on float , as in the same as LA .
As a example mine are charge to 13.8v then drop to 13.5v

 

[coopec]

Benefits and challenges with using lithium batteries on board | Nordkyn Design

What a great article! (It will be permanently in my online library for future reference)?

Now that I've read the following I am not going to switch to lithium batteries with any sense of urgency.

"Those who primarily need reserve capacity, because the boat is used randomly and infrequently, should generally stick to some form of lead-acid chemistry with correct maintenance charging. It is the best option: simpler, cheaper and long lasting. This also applies to engine starting batteries, which spend their lives full".

Thank you for that.

 

[noelex]

Yes, you certainly can use MPPT controllers.

The difference between MPPT controllers and non MPPT (sometimes called PWM regulators) is simply the voltage conversion and tracking ability that is designed to extract the maximum power from the panels.

The most important part when selecting a controller for lithium is an adjustable and versatile battery management algorithm. For some lithium batteries communication with the BMS may also be helpful. These features are separate from the solar panel management, so may or may not be incorporated on both MPPT and PWM controllers.

 

[Kelpie]

I was wondering about how you would charge the lithium battery. Can't the normal alternator charge the lithium battery?

I charge mine from solar. I'm not really interested in alternator charging because as a liveaboard I try only to move when it's good sailing conditions, so I don't aim to put in that many engine hours.*
Also my lithium only, currently, powers the fridge and the cooking. I will at some point move the cabin lights and the 12v phone charging sockets over as well.

I do have a B2B charger but haven't installed it yet. And anyway if I get short on power I can just switch to gas cooking, makes much more sense than running the engine just to charge the batteries.

*that's the intention, reality may vary! But at far it's been sunny enough that despite having to motor more than I would like, I haven't needed to supplement the solar power with alternator charging.

 

[SandyP]

One super thing I like about lithium (generally) is how quickly they can charge, and particularly that I dont have to worry about part charging them (actually they prefer this). Ideal when I'll only be running the engine for short trips, giving them a bit of a topup

Also, voltages do vary according to charge state (maybe some batteries dont, mine do), so I know when to recharge

 

[Poey50]

I was wondering about how you would charge the lithium battery. Can't the normal alternator charge the lithium battery? Do you agree with this guy (from the GreyNomads forum)who seems to know what he is talking about?

"Charging Lithium batteries is completely different to lead acid variations.
Lithium require a charger specifically designed for them, that supplies both a constant voltage and specific current from start to finish, and when the battery gets to a specific terminal voltage then the charger must completely shut off.
You must not float/trickle charge lithium batteries as they do not self discharge like lead acid and you will over-charge them.
Lithium battery voltages don't vary based on charge state. They deliver the full charge voltage from full charge until approx. 98% discharged so you must monitor your consumption because they do not like being completely discharged to 0 volts.
MPPT controllers cannot be used on Lithium batteries.
DC to DC chargers must have a specific lithium setting. All the mainstream units don't work for lithium.
AC to DC chargers must have a specific lithium setting."

How can i run AGM and Lithium Ion batteries together on solar. - The Grey Nomads Forum

Mostly correct but some errors in my view.

"Charging Lithium batteries is completely different to lead acid variations.
Yes.

Lithium require a charger specifically designed for them, that supplies both a constant voltage and specific current from start to finish, and when the battery gets to a specific terminal voltage then the charger must completely shut off.
LFP is mostly all bulk charging as stated here but a short period at absorption may be required by some systems to balance the cells. There should be no float (or a float setting of 13.3 volts or below which is effectively no float), no equalisation, no temperature compensation. Target voltages for ending bulk are generally lower than for lead acid. Many people, myself included, use 13.8 volts. The first chargers with LFP specific settings were 14.6 volts or above - generally recognised now as too high.

You must not float/trickle charge lithium batteries as they do not self discharge like lead acid and you will over-charge them.
Partly correct. They do self-discharge at about 3% per month at room temperature - like lead acid - but this does not cause sulfation. In fact mid-range state of charge is preferred for a long life.

Lithium battery voltages don't vary based on charge state. They deliver the full charge voltage from full charge until approx. 98% discharged so you must monitor your consumption because they do not like being completely discharged to 0 volts.
Mostly true. The charging curve is very flat but the voltage does rise steeply near full charge and fall steeply at low charge (the upper and lower 'knees'). But to avoid the knees an accurate enough stage of charge reading is required. My BMS provides this but I have to do a full charge occasionally to reset.

MPPT controllers cannot be used on Lithium batteries.
Completely untrue as Noelex says. This may be a concern about keeping the LFP at full charge. It is a good idea to have a switch isolating the panels from the controller, as sometimes you may want to stop charging, and to have 'float' at 13.2 volts - no float at all in practice.

DC to DC chargers must have a specific lithium setting. All the mainstream units don't work for lithium.
Best to avoid specific LFP settings. They are usually too high. Both Sterling and Victron B2Bs have fully user-configurable settings and are therefore suitable.

AC to DC chargers must have a specific lithium setting."
As above.

 

[geem]

I'm all new to this. I thought AGM was better

But when I read this I am now confused

AGM batteries generally last longer than standard lead acid batteries. Because of their low self-discharge rate, AGM batteries also last longer than their flooded counterparts when not in use. A well-maintained AGM can last up to 7 years, while flooded batteries typically last around 3-5 years.6 July 2021

You need to compare true deep cycle batteries
of both types. Trojans have a typical life of about 8 years if not subject to high temperatures. AGM batteries are just a likely to fail due high temperatures as open cell. If you look at design life cycles from manufacturers you will often see AGMs do less design cycles. Forget the hype and sales blurb. Read the data

 

[coopec]

You need to compare true deep cycle batteries
of both types. Trojans have a typical life of about 8 years if not subject to high temperatures. AGM batteries are just a likely to fail due high temperatures as open cell. If you look at design life cycles from manufacturers you will often see AGMs do less design cycles. Forget the hype and sales blurb. Read the data

When I'm in the yacht tomorrow I'll take note of the Battery Model and get the specifications. I'm sure they were displayed as "Marine Deep Cycle" (But I will check)

 

[PaulRainbow]

When I'm in the yacht tomorrow I'll take note of the Battery Model and get the specifications. I'm sure they were displayed as "Marine Deep Cycle" (But I will check)

I often see descriptions like this, not saying it's the case with yours, but it's often bollox. The "marine" bit is definitely bollox.

 

[reeac]

The cabin temperatures being quoted can't be as gigh as those found under the bonnets of vehicles where the majority of batteries are located. Mind you my last big car had the battery in the boot and it was 15 years old and going strong when I sold it ( the battery, that is).

 

[geem]

The cabin temperatures being quoted can't be as gigh as those found under the bonnets of vehicles where the majority of batteries are located. Mind you my last big car had the battery in the boot and it was 15 years old and going strong when I sold it ( the battery, that is).

The cabin temperatures in the Caribbean are 24/7 365 days a year. You don't drive your car constantly so the battery cools in between. Cars in very hot climates go through batteries about every two years. Doesn't happen in UK where the average year around temperature is 15degC

 

[gregcope]

What a great article! (It will be permanently in my online library for future reference)?

Now that I've read the following I am not going to switch to lithium batteries with any sense of urgency.

"Those who primarily need reserve capacity, because the boat is used randomly and infrequently, should generally stick to some form of lead-acid chemistry with correct maintenance charging. It is the best option: simpler, cheaper and long lasting. This also applies to engine starting batteries, which spend their lives full".

Thank you for that.

For starter batteries I agree.

This paragraph is well written as it has a qualifying word like "generally".

It might be simpler if your charging sources are not configurable for LifePO4. As @Poey50 has already pointed out if you know this is a direction of travel you can buy the right kit going forward if you do not already have it. For example if you have Victron MPPT controllers these are likely to be configurable for LifePO4 that can be setup to support LifePo4 using a Storage profile. Or disconnect them when not in daily use.

However it may not be much cheaper anymore if making a DIY pack when comparing usable capacity over lifetime and that would include switching some chargers out.

It might be long lasting, however I would assume to get double (or more) the life from a LifePO4 pack compared to Pb.

nordkyndesign is very much correct that LifePo4 is a "system" rather than a "battery" and lots of other things may need to be addressed.

 

[sailaboutvic]

nordkyndesign is very much correct that LifePo4 is a "system" rather than a "battery" and lots of other things may need to be addressed.

People make lithium sound like rocket science and its not .
I didn't know what Bms was last Sept, in Oct I started reading the DIY solar forum then took up reading the forum on lithium here , at first very comfusing, you need to change this and you need to change that ,
It was made to sound as if this was going to be a very costly job,
In the end there was nothing to be change not my alternator or shore charger ,
Just some stuff added .

I want interested in aluminium casing batteries mainly because we do a lot of heavy weather sailing over the season and I didn't want to worry about them rubbing up against each other,
yes there precautions you can take line each cell with grp and so on ,
Wilson was too expensive so I when for Calbs
Dec the 16 cells arrived , 8 for my mate and 8 for me and I started to build two banks

Cut a long story short , the charging was sorted just by adding a B2B ,
The shore charger that only had LA and Gel setting was also run through the B2B that took care of that
Victron mppt can be set for what every charging rate you want so that took care of the solar charging .
The rest was just balancing the cell which took me a couple of goes , make up my own bars , added some fuses, breakers Bms job don't,
other then a quick look at my App to check how they doing , they left alone to do they job,
Mine wasn't as cheap as some here who got them from China,
my first order from China was rejected as I was in a remote country so I brought mine from gremany, I also brought my bms , B2B and 250A breaker from the same guy so in the end with discount it didn't work out too bad .

I never been great with elect but I'm more then happy with our batteries bank .

 

[gregcope]

People make lithium sound like rocket science and its not .
I didn't know what Bms was last Sept, in Oct I started reading the DIY solar forum then took up reading the forum on lithium here , at first very comfusing, you need to change this and you need to change that ,
It was made to sound as if this was going to be a very costly job,
In the end there was nothing to be change not my alternator or shore charger ,
Just some stuff added .

I want interested in aluminium casing batteries mainly because we do a lot of heavy weather sailing over the season and I didn't want to worry about them rubbing up against each other,
yes there precautions you can take line each cell with grp and so on ,
Wilson was too expensive so I when for Calbs
Dec the 16 cells arrived , 8 for my mate and 8 for me and I started to build two banks

Cut a long story short , the charging was sorted just by adding a B2B ,
The shore charger that only had LA and Gel setting was also run through the B2B that took care of that
Victron mppt can be set for what every charging rate you want so that took care of the solar charging .
The rest was just balancing the cell which took me a couple of goes , make up my own bars , added some fuses, breakers Bms job don't,
other then a quick look at my App to check how they doing , they left alone to do they job,
Mine wasn't as cheap as some here who got them from China,
my first order from China was rejected as I was in a remote country so I brought mine from gremany, I also brought my bms , B2B and 250A breaker from the same guy so in the end with discount it didn't work out too bad .

I never been great with elect but I'm more then happy with our batteries bank .

I very much agree with you.

Which cells did you get? BMS? B2B? and 250? Got links?

Very much interested in your choices.

How are your packs doing? Did you make two 12V packs or one pack from 8 cells? Or a 24v?

 

[Poey50]

People make lithium sound like rocket science and its not .

Rocket science doesn't sound like 'rocket science' to rocket scientists! It is straightforward enough exactly because they know enough. You and gregcope may have got used to how much you have learned to get to this point.

On another forum - I won't name it - there are two people who have made expensive LFP upgrades with full Victron LFP kit. One didn't know that high temperatures were a problem for LFP. The other had never heard of the degradation of capacity that comes from keeping cells at full charge. On a different other forum one person was very upset when I asked them what they would do in the event of a high voltage disconnect - they assured me it could never happen. They had never considered it. On a fourth forum someone who had proudly video-blogged their LFP installation got into desperate trouble trying to get back to New Zealand at the start of covid. Their system had been professionally installed but the BMS was isolating their battery continuously. They were stuck in the Solomon Islands with no local help and completely out of touch with the installer. Two or three people talked them through various solutions - difficult when they barely had enough charge for their phone battery. In the last month I've seen two pictures of burnt out LFP installations - neither on a boat fortunately. There are two conclusions from this. 1. I spend too much time on forums. 2. On the whole people under-think LFP rather than over-think it.

It's not rocket science if you inform yourself. If not it is at best an expensive waste of money and, at worst, a danger to life. LFP on a boat is a totally different thing to an installation in an RV or one in the shed.

 

[sailaboutvic]

I very much agree with you.

Which cells did you get? BMS? B2B? and 250? Got links?

Very much interested in your choices.

How are your packs doing? Did you make two 12V packs or one pack from 8 cells? Or a 24v?

No bull crap , I'm not someone who just because I buy something will go on how good it is if its crap .
I'm very happy with my bank and so is the other guy I build a bank for , he even runs a washing machine off his.
As I said I used 8 Calbs cells 200ah , to give me a 400ah 12v battery bank ,
B2B is a victron to be honsty its been used 2 or 3 times this year most of the time is set so it don't come on , The 750W solar doest the job nicely.
Bms is the 123 smart bms , that I'm not completely happy with , it's not that it don't do its job but if I knew then I would had went for something else, first I think it's very expensive for what it is ,
It's very open to damage if your working over it ,
I don't like the bits of wires to join each unit , a bit of a heath Robinson affair
Plus it's a passive balancer .
But as I said it does its job .
250A is the breaker , I can draw upto 250A before the whole lot switch off.
I brought them in the end from lithium power store in Germany,
I talked him I to given me a good discount so in then end I got the smart bms free ,
Probably if I brought the cells from China and the other stuff else where I could had save a couple of hundred pounds , But Michael was very help full and quick to answer any question , he even rewired the breaker.
Yes there are some stuff you need to know like charging profile. Making sure you have fuses in place and using right size wires .
But after building mine I belive anyone who can handle maintenance on boats can build their with a little bit of research .
To finish off below is the latest chart from my Bms , to day isn't a good day its been a very cloudy day not one dot of sun .
Edit
The 100% charge on the chart isn't 100% itsabout 95% , it shown 100% because the way I have it set .
My charging profile is set for 13.8v then drops to 13.5 v

 

[sailaboutvic]

Rocket science doesn't sound like 'rocket science' to rocket scientists! It is straightforward enough exactly because they know enough. You and gregcope may have got used to how much you have learned to get to this point.

On another forum - I won't name it - there are two people who have made expensive LFP upgrades with full Victron LFP kit. One didn't know that high temperatures were a problem for LFP. The other had never heard of the degradation of capacity that comes from keeping cells at full charge. On a different other forum one person was very upset when I asked them what they would do in the event of a high voltage disconnect - they assured me it could never happen. They had never considered it. On a fourth forum someone who had proudly video-blogged their LFP installation got into desperate trouble trying to get back to New Zealand at the start of covid. Their system had been professionally installed but the BMS was isolating their battery continuously. They were stuck in the Solomon Islands with no local help and completely out of touch with the installer. Two or three people talked them through various solutions - difficult when they barely had enough charge for their phone battery. In the last month I've seen two pictures of burnt out LFP installations - neither on a boat fortunately. There are two conclusions from this. 1. I spend too much time on forums. 2. On the whole people under-think LFP rather than over-think it.

It's not rocket science if you inform yourself. If not it is at best an expensive waste of money and, at worst, a danger to life. LFP on a boat is a totally different thing to an installation in an RV or one in the shed.

I agree with what you say ,
but honestly there idiots in all walk of life .
How many time have I read you should charge lithium to 14.6 and 14.8v and won't except that too high .
The point I'm making is , do your research and if your handy ( not everyone is ) There no reason you can't build your own lithium bank and use them safely.

But some people post stuff to make it sound its impossible.

 

[Poey50]

I agree with what you say ,
but honestly there idiots in all walk of life .
How many time have I read you should charge lithium to 14.6 and 14.8v and won't except that too high .
The point I'm making is , do your research and if your handy ( not everyone is ) There no reason you can't build your own lithium bank and use them safely.

But some people post stuff to make it sound its impossible.

I'm a bit puzzled as to who is making it sound impossible but, leaving that aside, I think its possible to make a good argument that the most cost-effective and suitable systems for boats are DIY builds. Expensive integrated systems like those of Victron are fabulous but there is a danger that those buying the system and the installation haven't educated themselves sufficiently, but have just thrown money. Fine until things go wrong. Worst of all, I I think, are likely to be drop-in systems using cheap LFP batteries. Those are superficially the most attractive, are heavily marketed and supported by some woefully inadequate sailing magazine articles.