lithium batteries or AGM

[john61ct]

Nope sure doesn't.

Takes a rational well-educated population and a political-economic system not completely dominated by the top 1% wealth and business interests.

That then allows public servants to put the welfare of the common people pretty high up their list of priorities.

[200MPH]

So, cost of my conversion as comparison to the best Pb battery apparently, the FF Carbon Foam things?

A$2400 for 300 Ah of DIY Winston Cells, that price including a Victron BP-100 to prevent undervoltage damage, which needed installing no matter what new batteries we purchased. Plus a Victron Multi charger USB/VE Bus converter box and cable.

So, that works out as about US$1800for 300 Ah capacity = 210 - 240Ah useable safe long life capacity that is easy to charge, discharge as quick or slow as you could reasonably require. This is based on using 70 - 80% of nominal capacity (which I have actually tested).

So with a FF battery of equivalent useable capacity you'd need, say 400Ah perhaps? Not sure but cant imagine it would be a 1:1 ratio of useable capacity to Li. At US500 per 100 Ah that has been quoted above, that comes out to US$2000!

I admit, we were fortunate in that our solar controller, Victron charger/inverter and wind generator all could be reprogrammed for no additional cost other than what has been stated above. Just a bit of internet research time and off you go. THe only charges source that is not controlled to my liking for the Li batteries are the two diesel (catamaran) Hitachi 80A alternators. That could be fixed with purchase and installation of some Sterling/Balmar charge controllers, but we won't go down that path yet as it does cost a bit and I don't think it's necessary for our usage.

So, if you have a bit of DIY inclination and can read, plus some luck with your exisiting charge controlling systems, then Li works out no more exensive than what is purported to be the best Pb battery (FF) going! Why wouldn't you do it?

Please note none of the above is to disrespect the FF batteries.

[john61ct]

And I doubt the Firefly are an option in Oz anyway, shipping will kill your costs, and they're way backordered keeping up with US demand.

Only caveat is LVD, and one layer only only? 100A enough?

Small system I guess, but I'd want OVD too.

I guess no worries freezing there.

Check with your insurer too. . .

[flyingfin]

Go to your local golf course and see what type of batteries they use in their carts!

[john61ct]

That has little to do with the OP topic.

Yes they would be cheaper, but likely FLA not AGM.

And often not available locally, lots of courses get batches delivered by truck.

[senormechanico]

Originally Posted by john61ct

Nope sure doesn't.

Takes a rational well-educated population and a political-economic system not completely dominated by the top 1% wealth and business interests.

That then allows public servants to put the welfare of the common people pretty high up their list of priorities.

Oh, really ! It sounds like a fairy tale to me.
Just for starters, where is there a rational well educated population?

Sorry for the thread drift, but I'm puzzled by that purported scenario.

[alctel]

Originally Posted by senormechanico

Oh, really ! It sounds like a fairy tale to me.
Just for starters, where is there a rational well educated population?

Sorry for the thread drift, but I'm puzzled by that purported scenario.

If you are trying to argue that the American system of education/healthcare is cheaper in any way then i'd take a quick look at some figures before you make a fool of yourself.

One off the top of my head - Americans pay in taxes (not including anything they pay in private healthcare) more than double than most Universal Health Care countries do for healthcare. Except the universal healthcare countries are now covered, while you still have to buy insurance in the US.

Back on topic - I am in the middle of installing lithiums, they are great - but as stated earlier there is no such thing as a dropin battery (that won't die almost immediately), so be prepared to do a lot of reading and change your entire electric system. You can get an engineered set, but that's out of the price range of most people I expect. The Carbon Foam AGMs look pretty nice, but apparently they are kinda hard to get hold of

[ErikFinn]

Pardon me and I do not mean to be picky or a smartass but was that "LiFeYPO4" supposed to be LiFePO4?
Or is there yet another new chemistry battery available that I missed?
Disclaimer: I'm a noob when it comes to lithium bats.

Originally Posted by CatNewBee

My post was related to this...

Well, I'll go the LiFeYPO4 path, so soon +1 user

BTW, My Installation will be 1000Ah LiFeYPO4 , cost estimate: 5.500€ including BMS and solenoids, so 550€/100Ah, quite close to the 500$/100Ah of the FireFly, but a lot better.

[CatNewBee]

Well, I would not let be scare mongered too much about charging re--programming and such things.

Any battery charger, that is capable to charge GEL batteries is out of the box working wit LiFePO4.

The

nominal cell voltage of the Winston Cells is:3.2V,
the allowed working range is between 2.8V-4.0V
and the recommended Charge stop Voltage for 100% is 3.65V

that translates to:

nominal: 12.8V
range: 11.2...16V
Charge stopp: 14.6V

What does that mean?

Well any IUoU GEL charger has a drop off at 14.4V, that is OK and safe for Li, Voltages below 11.2V can easily be either programmed on a Battery monitor or you simply use the UVP signal of your favorite BMS.

The Alternator regulator usually are set for Lead Acid batteries and drop off at 14.2V, so no problem for Lithium. The only one thing you have to take care about is to NOT configure equalization (15.2V) on lead acid programs, this is the only risk with old chargers. Usually you can turn off this step, it is dangerous for AGM / GEL anyway.

As a safety feature you have the BMS OVP signal you can use to drop the charging sources in question.

To make it short: any decent charger, that do not damage GEL or AGM batteries can be used for LiFeYPO4 without modification. You can tweak however this programs by disabling the temperature sensors and the absorption phase, that is quite long on GEL, but it is harmless for the LiFeYPO4 cells, because it is limited to 14.4V that translates to 3.6V cell voltage, well below the stop charge limit of 3.65V and it is healthier for the cells, they like to not stay always at 100% SOC, so this is a perfect match.

Using solar with a GEL charge characteristic keeps the battery the whole day at 95% and supplies the devices on board by solar power all day long.

The float phase of the charger set to GEL is 13.6..13.8V what translates to a cell voltage of 3.4V, that is perfectly in the operation range of the cells and causes no harm whatsoever.

The protection functions of the BMS will never kick in when using regular charging mechanisms except for equalizer programs for wet batteries (recondition function), but charger with that feature always have the means to turn it off - it would destroy any VRLA battery including GEL and AGM.

To make it short:
1.) you do not need to replace your charging environment if it is suitable for GEL / AGM1.
2.) dangerous charging sources can be handled by the BMS (OVP switch off)
3.) Deep discharge can be handled by the BMS UVP signal and/or by any programmable battery monitor system using either on SoC value or on a voltage limit set to slightly higher than 11.2V (e.g. @11.6V) Victron BMV702/712 is great for that purpose.

There are BMS modules out there (e.g. ECS LiPro) with a wider range : OVP: 3.9V UVP: 2.8 with delay, 2.6V immediately shut down, but I would use more conservative values to extend the battery life (SoC normal use >30% with 10% emergency reserve by manual override) vs. use the whole capacity down to 20% SoC. This Balancer / BMS modules would even accept a recond programm up to 15.6V, what I assume to dangerous for the cells (despite they are able to swallow for short time up to 4V/cell according to the spec). For a 1000Ah pack that means usable capacity 700Ah + 100Ah emergency reserve.

More important is the balancing of the cells to prevent them drift away, but this you need to do anyway and it is part of a reasonable BMS. Once you have one, you can drop in the LiFeYPO4 as replacement of any GEL installation without modifications.

[mickt243]

Originally Posted by ErikFinn

Pardon me and I do not mean to be picky or a smartass but was that "LiFeYPO4" supposed to be LiFePO4?
Or is there yet another new chemistry battery available that I missed?
Disclaimer: I'm a noob when it comes to lithium bats.

There are several variations on LiFePO4 chemistry....

LiFeYPO4 adds yttrium to the mix

LiFeMnPO4 is another, where manganese is added

[CatNewBee]

There are several advantages of Yttrium (LiFeYPO4 vs. LiFePO4) that makes the battery be chargeable in freezing environment (extends the temperature range) and also less Lithium is used, so the battery is considered safer (thermal runoff's and possibility of fire).


The LiFeYPO4 are a little more expensive, but seem to be more widely used in DIY projects (the yellow cells from Winston Thundersky) compared to the blue or black LiFePO4 as single cells - however LiFePO4 are broadly used in drop in solutions with internal BMS (Vision, Victron LFP, Super-B...), because they are cheaper in mass production.

I have not seen / used this type of cells (LiFeMnPO4) yet, so I cannot comment on them, according to the spec, they are also very safe toward fire / explosion. AFAIK they are more sensitive to high currents (charge / discharge) than the LiFeYPO4 and also the later are available up to 1000Ah blocks, the limit on LiFeMnPO4 was 400Ah.

The LiFePO4 / LiFeMnPO4 should not be charged in temperatures below 0°C, while LiFeYPO4 can be charged down to -35°C

[n2climbing]

We put three 300aH Relion LiFePO4 batteries on Cat's Meow in March. Happy so far. The install was done by Just Catamarans in Dania Beach, FL. They are one of very few US dealers for Relion. Raf Escobar at Just Cats is very knowledgeable/experienced.

Best Lithium-ion Batteries | Li-ion Battery Packs | RELiON

Catamaran specialists and Outremer dealers | JUST CATAMARANS

[200MPH]

In reply to CatNewBee.

Of course you can drop in your LFP pack and it will run on GEL/AGM 14.2 - 14.4V charge settings. It will work as will all your other parameters you've laid out.

Here's a tale to tell. I've been doing some experimenting with some smaller LFP batteries for work (remote data logging boxes that need to keep running with a 24V supply when some idiot pulls the AC power lead out.) We will try run two small K2 branded 6.4Ah 12.8V packs in series to get our 24V minimum we need to power our instrumentation. So far, so what. Well, the major battery supplier we use also supplied a 'suitable' charger for them. On arrival, turns out it was a 2A 29V power supply, that when tested, actually supplies 29.2V, which when divided by 2 (to give you a 12V pack equivalent) is 14.6V! So I've charged and discharged these packs a few times using desktop laboratory power supply and also the supplied charger.

Now, pay attention, here comes the worrying part.
After top balancing the cells pretty well with both on a lab power supply at around 28V they were connected together and partially discharged. Then hooked up to the 29.2V charger. Well, I set the voltage data logger going and left them to charge while I grabbed some lunch for 30 mins. When I got back one pack was around 15.6V and the other was 13.6V! Which when added together of course makes 29.2V. This happens very quickly, in a few minutes. What looks like two batteries (or cells if you like) that are well balanced around 14V each, very quickly become unbalanced to the point of battery damage nearly. If you log the voltage during charge of a LFP battery, they go linearly up nicely until maybe 13.7V for a 4 cell 12.8V nominal pack. But past there they kick upwards, and go nearly vertical in voltage curve for very little extra charge input. So although it looks like you have a lot of headroom above 3.65V per cell before you get to the damage region of 4V per cell, the reality is that it can happen very quickly and in my experience with small batteries huge voltage unbalances happening.

Now of course you'll say this is what the BMS balancing resistors are for and all will be well. Well, yes it will, all things going to plan and they all function as intended.

But why go up there at all in terms of voltage, when your pack is fully charged at no more than 3.45 - 3.5 V per cell (or 13.8-14V for a 4 cell pack). No balancing issues to worry about and you are very close to the linear part of the charging curve. I know, people don't want to change chargers etc. But you may be lucky like me and be able to program your existing chargers! Or consider upgrading your chargers while your're at it. A solar controller that is fully programmable (ours is a Plasmatronics Dingo) is not expensive at all. Granted, a big inverter/charger unit is not cheap if you need to change, but you could always trick the charger into reducing volts if you got creative. Like tweaking the battery temperature feedback signal (if it has one) so that it thinks battery is 50 deg and reduces the absorbtion voltage down to 14V or so. This is something I could pursue with my Hitachi 80A alternators. They have a thermistor that reduces set voltage with increasing temperature. So by replacing the thermistor with a set value resistor of the appropriate value, pretty sure the alternator regulators could be fooled into providing a bit under 14V instead of the 14.5V they aim for.

The reverse of the above applies to the end of discharge also. Don't go there and everything is sweet more or less.

Anyways, just my 2c worth based on some real testing of LFP cells with various charge parameters tried on my desk for work. I'm a little more cautious with my yacht pack - it cost a lot more!

But on topic, I stand by my claim above that changing over from AGM to LFP house batteries makes financial sense here and now, when you count $ per cycle. Plus all the other benefits of LFP. Of course, if you're selling the yacht in a year to two, it won't make strict financial sense.

Anyways, you pays your money and you takes your chances. The OP has more than enough info now to take their chances!

[john61ct]

Yes, the advice and specs CatNewBee presents in post #54 should be completely ignored, anyone following that advice will be sacrificing many many years of usage, hundreds maybe thousands of cycles.

Basically in agreement with vendor recommendations, which have been proven wrong, at least for House usage.

See post #30 above for a summary of current best practices, and follow the links posted at the bottom for further details. Also treat anything from Maine Sail as gospel.

And your use of lithium will stand a much better chance of paying off financially.

[CatNewBee]

Hi John,

no problem at all, if you have a proper BMS, that balances the cells / keeps them all the time balanced on charge and discharge. The bms also - even if not balancing properly - monitors each single cell and will drop the load or the charger (or both) in case one single cell goes rogue. So the Voltage of 14.4V does not cause harm at all.

Not to balance or to balance only once per month is a bad advice anyway.

also you not just charge or discharge the bank, you typically have running systems all the time. It is a bad idea to disconnect all charging sources and cycle the battery unnecessarily. This indeed will shorten the life expectance significantly - much more than staying on float (12.6V) or even on recombination voltage (14.3...14.4V) of a GEL program when the cells are in balance.

Hi 200MPH:

for your problem, you should either balance over all cells simultaneously or use a 12V-12V balancer, so the blocks are in balance to each other. This is also a good practise for 24V systems built by 12V battery blocks. I have a UPS with 24V (2 12V AGM Bats in series), they die after 12 months because they run out of balance, I replaced them 3 times, then I add a 12V-12V mid-balancer and now they run for 3 years flawlessly. It's a small cheep unit with 3 wires.