Of Service to you, Professional Engineering Opinion on AGM vrs Lithium

[Supercat568]

Originally Posted by Helia 44

LATEST UPDATE AGMS VRS LITHIUM, My Professional Engineering study for my SABA 50 Cat.... I am in Australia, not selling anything, this is to help you know and understand the real issues of Lithium being cost effective. My Engineering Study is in three parts here for your benefit.

Hello Friends, here is the problem. Not money problem for me, not that LIthiums are not better, not that they are not lighter, not that they do not perform better... It is just too much of massive job, and here is an outline of why.

I (my Staff) have put in more than 500 Lithium systems up to 900 AH in mobile settings in the Outback. Trust me I am a Lithium Expert, to coin a label...

Now, Amateur Lithium installations without all the safeguards necessary, kills the Lithium batteries in about the life time of normal AGM batteries. You need to have proper charging systems in the right algorithm, solar regulators in the correct algorithm, my Victron combi Inverter Chargers would need modifications or reprogramming, you need LVD Low Voltage Disconnects so they cannot be accidentally abused, and you need the proper BMS Battery Management System for each Lithium battery so the cells all equalize or you start to devalue the system into failure. Now a lot of people that sell the Lithium can do all that, and some of the higher quality Lithium 100 AH to 200 AH batteries have the BMS on board... However, it all goes a lot deeper if you want the Lithium to last long enough to be cost effective:

I am writing this to be of Service to you my Friends, and tell you what I am doing because of it all.. Now the next layer is the engines alternators. You have to have a buffer AGM style starting battery, and then DC to DC chargers on each engine in the proper Lithium algorithm (proper charging curve for Lithium) or you grossly cut their life in half to maybe only five years like AGMs.. But then again some people get 8 years out of AGMs) Anyway besides the wiring in of DC to DC charger in the Lithium algorithm, these type of chargers cannot run all the time, they have to be ignition relay tripped to start. Still there is more: All the Lithiums that do have BMS on each battery (most quality ones that are not just gimmick sales) when you put these commonly sized 100-200 AH batteries together, the individual BMS systems are not enough. You have to have an overall BMS type system over all the batteries, called Active Balancing. It works just like the individual battery systems BMS, levelling up the charge, equalising the cells, but on the overall system. It treats all the batteries like bigger cells, and keeps them equalised in all the charging systems. Failure to have this overall Active Balancing BMS style system as well, means eventually one battery in parallel, will go down and not recover and kill the rest in a slowly failing system.

But Wait, there is more!! Heh he.. You have to also have an overall Metering system like Victron, that tells you the state of charge, but also regulates when the batteries are being charged and by how much. Without this system you would have to be an Attendant doing it all manually and that is nearly impossible. You have to have like an Enerdrive or Victron battery management meter, that trips something like Blue Sea Relay drivers, to run the LVD and all the charging systems so you do not continually charge or undercharge the system. Both again will cut the Lithium Life in half... You cannot keep charging the Lithium after it is fully charged, the overall Meter has to regulate all the charging systems or again you shorten the life of the Lithiums..

I am telling you this, because I am in the Business, and to get a 1000 AH system to run something like the Saba 50, is a massive expenditure like $18,000- $20,000 Aus in Lithium and equipment, and a week to ten days of solid work by a qualified Technician wiring everything i properly or the system will not pay off with long life... We are about 12 months backed up on Orders, I cannot pull one of my Electrical Technicians off for a week-ten days to redo my yachts whole charging systems.. After careful consideration: I am staying with AGMs

Long and the short of it, since the extra 150 kg of weight does not bother the Saba, I am thinking I am going to just stay AGM batteries. I can replace them all for about $3000 (Aus) in over 1000 AH total, like the original Varta batteries. The design of all the equipment is already there to maintain them properly. My German Varta batteries are now about six years old, and I am only doing this now because of anticipated Covid supply disruptions.. It is a pre-emptive move. My point for you is, you can buy four sets of AGM batteries for the cost of the Lithium. And while yes the Lithium outperforms, IMO in my case not worth the expense and hassle. I have an 11 kva Cummins Onan now six years old and only has 604 hours on it.. And the Lithium system has to work flawlessly to make itself cost efficient. Other than the weight factor in our case in the Outback in mobile applications it is not necessarily worth the expense.

I am thinking I am going to buy four 280 AH AGM big trawler type batteries instead. You do what is best for you. The Lithium outperforms but at several times the cost without the proper management systems I have outlined above for you, they are expensive and not going to last long enough to be cost effective. This post was in "Your Best Interests"

Skipper Owner on Saba 50 "Serenity", getting ready to live at anchor during the Covid Plague likely to get out of hand next year in Australia as Lockdowns are quit.. Lockdowns banckrupt the country, threaten to topple Governments in Australia, and the Population little affected in the 20-40 year old range start to demonstrate and protest and riot.. Just like Europe.. Australia IMO is likely to follow the Euro pattern and go grim reaper ending lockdowns..

Good luck to all of you and God Bless....

READ ON, PART TWO AND THREE OF STUDY TO FOLLOW THIS POST.....

Hi, I'm very interested in this topic and specifically marine applications. I have a lot of experience with LiPo batteries, but little tiny baby batteries compared to what you're dealing with. I posted earlier about cost reduction and looked into bigger batteries and they're coming down in price as well.
I do just want to mention one thing...there are currently at least 5 different batteries that use lithium, plus one more in development. Plus, Lithium is taken for bipolar disorder and is known to reduce suicide, so using just "lithium" in naming a battery type could be misinterpreted. LiPo is the industry standard name.

[westwon]

Wow.



Now I feel a bit silly staying awake last night thinking about changing my 2 85AH wet cells to AGM and rewiring the bank to parallel them permanently and adding a starter battery.


Thank you OP though! I love reading these technical posts, even if my boat won't ever need refits like this.


Steve

[David B]

Originally Posted by Helia 44

LATEST UPDATE AGMS VRS LITHIUM, My Professional Engineering study for my SABA 50 Cat.... I am in Australia, not selling anything, this is to help you know and understand the real issues of Lithium being cost effective. My Engineering Study is in three parts here for your benefit.


Good luck to all of you and God Bless....

READ ON, PART TWO AND THREE OF STUDY TO FOLLOW THIS POST.....

Thank you - a lot of effort in the research and putting this report together - appreciated!

I will read through when I have some spare time.

For me, the advantages of lithium are the energy density when one needs more capacity, but has nowhere to put it.
In the meantime, given a certain capacity is achievable either way, I stay with FLA as the most cost-effective.

Our bow-thruster FLA's are now 8 years old and still going strong.
Our engine generator FLA was replaced at 7 years, and that is despite it being discharged to 10.8V for 18 months (no monitoring at the time, and no charging when not running- now fixed).
Our engine and service FLA's were replaced after 3 years due to a fault that was discharging them dead flat in between monthly charges during winter storage. The replacements are now 5 years old and going strong.

My maintenance regime is a reconditioning (pulsed through smart charger) and equalisation charge at the beginning and end of the season.

For me, the cost of AGM's cannot be justified, but I am open to further comment on that.

Again, many thanks for the great article - much appreciated!

[CapnBazza]

Originally Posted by Helia 44

PART THREE OF THE THIS ENGINEERING STUDY...

COMPLETE REVERSAL.... Per the previous two posts on AGM / LITHIUM Engineering.. I am going the full big Lithium System.... Why the reversal?

On my final system design engineering study, the generator run time to get the full Boost Cycle on the AGM batteries, is just too long. Without the Boost cycle to clean the plates and do full equalisation at least every week or so they will not last that long.. So, my Covid 19 living at anchor if need be: Prep is to go the full Lithium system, as I expect it rage in Australia next year like Europe and America... I am anticipating weathering it living at anchor.. IMO We cannot afford the Lockdowns here, economic bankruptcy, social unrest and demonstrations, and Political revolt is overcoming the mandated lockdowns...

My Lithium Battery choice is the Enerdrive 300Ah Compact Pro Series Lithium Battery. This is in a powder coated case, with some higher end features, the best made IMO... Enerdrive "Top of the Line"... We have maybe 400-500 in the field in mobile settings in the Outback of Australia..

YES the Lithium will charge easier, YES the Lithium will charge faster, YES they will accept solar easier. YES, I would get about 60% more out of the Lithium in useable power.. I have proven all of that. However, as I stated in the previous two posts, it is a massive undertaking on the Saba as there would have to be massive modifications done to all the equipment and about a week to ten days for an Electrical Technician to add all the equipment, new solar regulators, new DC to DC chargers, separate starting batteries for the engines, Victron Combi Inverter charger modifications, and more. Not to do the whole job of it, would mean an early death to the Lithiums and at four times the cost not worth putting them in as not cost effective IMO.

Notes on the final Systems Engineering design: I am putting in a 3kw Victron Combi Unit, 120 amp charger, 3000 watt inverter.. I will have the 60 amp and 80 amp Victron Combi units as spares or for another project. They are not ready for the Lithium system algorithm and would conflict with each other if modified. I also have to have the Pro Compact 300 AH Lithiums BMS modified on each one, to run three of them under a general BMS sort of system called Active Balancing so they do not get out of sync..

I will be leaving one Varta Euro Pro AGM 150 AH on for each engine. They are still good, and store the other five at home on a timer charge and run them out. They are so big and the Volvo D2-75s start so easy, it is not much of a discharge on the big Varta 150s even though they are Deep Cycle and not meant for starting batteries it is not much of a jolt. And: I get some extended use out of them even though 6 years old. I would not be doing this, but they are going to lift all travel restrictions for the Christmas School Holidays in Australia so I expect the Covid-19 to come raging on here by April May our Fall down under, going into winter.. I anticipate living at anchor up in the Islands of the Great Barrier Reef, so three things will be important: Lithium, Lithium, and Lithium. It is going to be an expensive system, but I think the investment well spent and it probably will increase the value of the Saba as much or more. It will be about a $20,000 (Aus) system.

In addition to the Victron Lithium algorithm Combi unit, there will be a DC to DC charger in Lithium algorithm off each engine starting battery. These Volvo alternators are $1000 each here in Australia, and the onboard regulator is not available. In Lithium, they would probably be twice as much and also not available in Australia. Sooooo, this cost may not be there for you in the USA. But here, the starting battery is designed to be a buffer, and the DC to DC chargers will come off of that. I will also have two Epro 60 amp chargers in the Lithium algorithm as backup, wired in, to run off the Generator.

Finally there has to be the top end TPS type Victron style Battery Meter BMS installed. It will be programmed to run a couple of Blue Sea type relays to regulate the charge on and off as needed, and an LVD Low Voltage Disconnect safety system and so on. You need this system not for the readout of state of charge and so on, you need it to start and stop the charging cycle so you do not abuse the Lithiums. All in all this is a very up market system, but it is necessary or you run the Lithiums to an early demise.. The Professional Grade Lithiums 300 AH in powder coated armour cases run about $A 4000 each so you want them to last... I would hope ten years..

If you just do the average Lithium battery install without all the right BMS and Active Balancing and the rest, you would be lucky to get five years out of them. In that case you might as well stay with AGM style batteries at about 1/4 the cost, like 1/10th the cost with your stock AGM charging systems not having to be modified or replaced.

You can take this as the latest Professional advice. My Company has done maybe 500? Lithium installations in mobile units for the Outback, and we only do it properly with the latest technology. I am not for hire, not selling anything, and I hope this has been a help for you Free of Charge.

Kind regards, Skipper, Saba 50 "Serenity"...... And God Bless...

I totally agree with all your research and the consequent conclusions. I have thrown away my mobile phone to avoid the problems of batteries failing, charger cables breaking, dropping it overboard, being hacked by unscrupulous hackers and worse still, being tracked by Tech Giants. I’m in the market for a reliable Smoke Signalling Device that won’t burn down my boat if I forget to turn it off.

[T1 Terry]

Wow, long time since I've been on here, amazing how many lithium experts have sprouted out of the wood work

Hello Helia 44,
Afraid you expertise is a tad questionable. I've been doing this for over 10 yrs now, in motorhomes, caravans and river house boats and every system, and I mean every system, is still running fine and none had the old equipment thrown out and replacement equipment with "lithium" algorithms fitted in their place. Some equipment simply isn't up to the long haul full output required for lithium battery use, but that is because the manufacturer stretched the truth about current generating capabilities of their equipment. As in, a 50 amp charger suggests it can output a continuous 50 amps, but many can not, yet quality stuff can without issue.

A bit of thought and application would have you designing an interface to make any equipment work with a lithium BMS and knowledge of the requirements of lithium cells would have you building a good BMS to work with the interface modules .....

I have never had a client say they wish they had stayed with their AGM batteries, I would happily refund their money if the system was less than 6 mths old if that was the way they felt.
In fact, I have removed a system and given the client a full refund, even after they had destroyed 60% of the cells, basically because not everyone can fully understand electrical requirements yet seem to think they know better than to follow the advice given to them. For that particular client I travelled from Adelaide to Perth in an attempt to sort the problem and a few days later removed the replacement full new system I had installed because the new battery was starting to show the same signs of what had killed the first battery. He was surprised to get a full refund, but not too happy that he was now on his own to sort out a system that would survive. He had become accustomed to the flexibility a well designed lithium battery can provide and soon realised he had a serious problem now trying to find an alternative.

T1 Terry
T1 Lithium
Mannum South Australia

[goboatingnow]

I’m a retired professional engineer and I’ve worked on many Li based battery systems.

My own view is the price performance point is not there for yacht use , where energy density is NOT a particular concern. In fact it’s even hard to justify high end lead acid imho. The widespread adoption of solar has also changed the need for large bulk storage in many cases as daily recharging is now available without engine running.

In my view Li batter tech is very robust , in fact much more robust then lead acid and is far mote tolerant of abuse then lead acid. The difference is of course a mistake with Li tech is costly whereas a lead acid is peanuts by comparison

If you want an all singing self contained self controlling system , then low voltage lockouts , BMS , over charging disconnects etc etc are needed , the reality is you don’t actually need a lot of this stuff if you are prepared to follow a few rules. ( largely don’t run them dead and don’t float charge them) balancing is quite nice to have in order to maximise power but isn’t really necessary at all as the tendency is cells converge in LiFePo4 chemistry

Again I think the price point remains way to high for the benefits at present for the average yacht. No doubt this will and is changing but not there yet imho.

[T1 Terry]

Agree about the questioning about the need for a battery management system that takes care of everything for you, you could do it yourself and save the money, but then do you use your boat for leisure, rest and to enjoy being out on the water? The boat didn't come at a price point you would call economical did it? Why not spend the $$ getting a system that will continue to function without any input from you, send an alarm that identifies just what the system needs from you if a problem does arise and otherwise just does what it was meant to do for a very long time.
As far as solar on a sailboat ... ummm, maybe if the sails were solar panels that would work well, but wouldn't the shade from the sails nullify the effectiveness of solar panels? A bit like a wind turbine on a boat travelling with the wind .... not much there to drive it is there?


T1 Terry

[goboatingnow]

I run with 420 Ah bog standard lead acids, 360W of solar. The reality is the boat is virtually self contained power wise in summer.

Very hard to justify Li tech , it simply doesn’t bring anything more to the party

[aqfishing]

Not too knowledgeable on this, but interested non the less. How do capacitors fit in as a storage device? I know some systems are now using them instead of batteries.

[Pete7]

Originally Posted by T1 Terry

Why not spend the $$ getting a system that will continue to function without any input from you, send an alarm that identifies just what the system needs from you if a problem does arise and otherwise just does what it was meant to do for a very long time.
As far as solar on a sailboat ... ummm, maybe if the sails were solar panels that would work well, but wouldn't the shade from the sails nullify the effectiveness of solar panels? A bit like a wind turbine on a boat travelling with the wind .... not much there to drive it is there? T1 Terry

Alarms? what happened to the days of black batteries that just did what they said on case. Do I really want to be fretting about £2000 worth of lithium with alarms going off just as you enter harbour, or just go sailing? so I agree with Goboatingnow, interesting but not just yet. Actually, gel might be our choice next time around. Sometimes you just don't want to be the first mouse to the cheese.

Solar you say? brilliant on a small yacht without a generator. We have just upped it to 300w fixed with another 110w portable panel so we can have a small freezer, to improve the quality of life on board. We now have ice for the Gin, and that's important Spending £2000 on LFP won't give me ice, £100 on 300w of solar does. At the end of the day, LFP is just a storage medium, it doesn't create anything, other than problems. Spending money elsewhere on things that do create power does improve life on board, now just choose your poison.

[goboatingnow]

at the end of teh day , DC storage is actually a complete sunk cost, if youdo without it , you wouldnt have it at all.

Therefore the battery computation is all about $ return, unless you have an overriding constraint that skews the computation ( like energy density constraints, like in EVs etc )

so if you get 5 years out of cheap lead acids , that meet you day to day needs , versus , 10 years out of 3x the cost or 20 years out of 8-10x , you need to evaluate the " future cost of money" etc . Personally I see batteries as consumables and I plan accordingly even if over 20 years I might end up spending a little more then the initial total outlay for a more long term system.

[T1 Terry]

Originally Posted by goboatingnow

I run with 420 Ah bog standard lead acids, 360W of solar. The reality is the boat is virtually self contained power wise in summer.

Very hard to justify Li tech , it simply doesn’t bring anything more to the party

If the lead acid system does all you want, why change? Lithium is for those who aren't happy with the performance they get from lead acid batteries or are sick of being a nursemaid to them to keep them alive.
If it ain't broke, don't fix it, no point in fixing it till it's broke :lol:

T1 Terry

[T1 Terry]

Originally Posted by goboatingnow

at the end of teh day , DC storage is actually a complete sunk cost, if youdo without it , you wouldnt have it at all.

Therefore the battery computation is all about $ return, unless you have an overriding constraint that skews the computation ( like energy density constraints, like in EVs etc )

so if you get 5 years out of cheap lead acids , that meet you day to day needs , versus , 10 years out of 3x the cost or 20 years out of 8-10x , you need to evaluate the " future cost of money" etc . Personally I see batteries as consumables and I plan accordingly even if over 20 years I might end up spending a little more then the initial total outlay for a more long term system.

Interesting, can you give me an idea of the $$ value and useable capacity for the lead acid battery pack that will give you 5 yrs reliable
service and won't leave you stranded a few days out of port relying on the generator to keep the navigation equipment functioning?

T1 Terry

[Uncle Bob]

Originally Posted by T1 Terry

Interesting, can you give me an idea of the $$ value and useable capacity for the lead acid battery pack that will give you 5 yrs reliable
service and won't leave you stranded a few days out of port relying on the generator to keep the navigation equipment functioning?

T1 Terry

Terry, though not the one that you directed the question to I will chip in anyway, I have six GC2 six volt batteries as the house bank, installed going on seven years ago and still going strong, though not as good as they once were.
When purchased they set me back around $2000.00.

[David B]

Originally Posted by goboatingnow

I’m a retired professional engineer and I’ve worked on many Li based battery systems.

My own view is the price performance point is not there for yacht use , where energy density is NOT a particular concern. In fact it’s even hard to justify high end lead acid imho. The widespread adoption of solar has also changed the need for large bulk storage in many cases as daily recharging is now available without engine running.

No doubt this will and is changing but not there yet imho.

Agreed - as per my earlier post, if the energy density is otherwise achievable, then FLA is still the easiest and most cost effective - looked after, 8 years seems quite achievable with decent quality FLA from our experience, and what I hear from others.