Lithium batteries - are they worth it?

[TernVI]

thanks for all the info presented, one quick Q which I cannot seem to find a reasonable answer on my (admittedly quick) search.

Would the drop in combos eventually work with normal LA settings (like deep discharge Trojans which I now have) or would they need new chargers?
I'm asking as I have a Victron Multiplus (combo charger inverter) a Victron MPPT 100/30 solar AND a Sterling Pro-digital advanced alternator regulator.
If I have to replace all of them it's definitely a no go and I'll stick to Trojans T105REs. I'm not alone in this multicharger situation, so hope it would work!

any pointers welcomed

V.

All these digital controlled chargers 'ought' to be reprogrammable to suit any battery chemistry.
They are essentially programmable voltage/current controlled converters.
Whether it's in the manufacturer's interest to give away or sell suitable new firmware instead of flogging new chargers to people keen to spend a lot on batteries might be a different question.

If there's no monitoring of the actual battery current e.g. by a battery monitor shunt, then that might be needed.

 

[vas]

All these digital controlled chargers 'ought' to be reprogrammable to suit any battery chemistry.
They are essentially programmable voltage/current controlled converters.
Whether it's in the manufacturer's interest to give away or sell suitable new firmware instead of flogging new chargers to people keen to spend a lot on batteries might be a different question.

If there's no monitoring of the actual battery current e.g. by a battery monitor shunt, then that might be needed.

thanks, both Victrons are fully configurable on absorption and float voltage, times on each stage, A etc. Not too sure about the Sterling (no s/w to connect to it and alter settings, just a couple of jumpers)
BMV700 also installed, so should be fine on this respect.

cheers

V.

 

[GHA]

Can you explain what's wrong with this, please?

They're referring to lead-acid batteries, not lithium, right?

Solar regulators are generally pretty blunt instruments for charging batteries and invariable go to float far too early. They have no idea where the power is going so push a load of current out but lots of that is going into fridges and laptops etc. It takes a ***long*** time go actually get lead acid back to really fully charged. Guessing maybe 90% of full time cruising boats full time on the hook never get there very often. Then blame the batteries.....

 

[vas]

GHA,
latest Victron MPPT firmware keeps on charging for a long time before going to float. It definitely makes a difference to the previous 1-2h and yep, float done

 

[GHA]

GHA,
latest Victron MPPT firmware keeps on charging for a long time before going to float. It definitely makes a difference to the previous 1-2h and yep, float done

I've heard the new firmware is much better but yet to update it, on mains at the mo, mine is set to 14.9v for both float and bulk, even then with 300w solar it's not a done deal to get all the way back to full with 2 x t105's based on the 'tail current' leveling out.

 

[vas]

well with 600W solar in the med, and 4XT105RE (in 24V setup) and main load being two danfoss compressors taking something like 40-50Ah during the evening/night (well lights, chargers, etc all contribute a bit), I'm down to 1A charging early in the afternoon... Obvs wouldn't be enough with three fridges taking 70Ah during the eve/night...

V.

 

[GHA]

well with 600W solar in the med, and 4XT105RE (in 24V setup) and main load being two danfoss compressors taking something like 40-50Ah during the evening/night (well lights, chargers, etc all contribute a bit), I'm down to 1A charging early in the afternoon... Obvs wouldn't be enough with three fridges taking 70Ah during the eve/night...

V.

No mast for shadows? Lucky you in that respect
I still think few full time sailing cruisers get back to really full very often, certainly not the ones I've shared a happy hour beer with in the past decade and a bit, mostly blissfully unaware they are trashing their batteries ..

 

[vas]

No mast for shadows? Lucky you in that respect
I still think few full time sailing cruisers get back to really full very often, certainly not the ones I've shared a happy hour beer with in the past decade and a bit, mostly blissfully unaware they are trashing their batteries ..

oh, there's many ways to thrash your batteries, mine are semi foobarred as I didn't realise how much water they drink and let them dry last summer, now I fill them every two-three weeks but the damage is done no matter how many times I run desulphation / equalisation etc... :-(

V.

 

[Graham376]

I still think few full time sailing cruisers get back to really full very often, certainly not the ones I've shared a happy hour beer with in the past decade and a bit, mostly blissfully unaware they are trashing their batteries ..

Why do you think that? We're within about a mile from your location and went to float at 13.30 today, roughly the usual time. Have 320W feeding 4 x T105 (2 pairs) via Smartsolar 100/30. Fridge is biggest draw at around 7 amps 24/7.

 

[Poey50]

thanks for all the info presented, one quick Q which I cannot seem to find a reasonable answer on my (admittedly quick) search.

Would the drop in combos eventually work with normal LA settings (like deep discharge Trojans which I now have) or would they need new chargers?
I'm asking as I have a Victron Multiplus (combo charger inverter) a Victron MPPT 100/30 solar AND a Sterling Pro-digital advanced alternator regulator.
If I have to replace all of them it's definitely a no go and I'll stick to Trojans T105REs. I'm not alone in this multicharger situation, so hope it would work!

any pointers welcomed

V.

The starting point in considering chargers is to know what LFP needs and what will shorten it's life. You can then work from that knowledge to decide if a particular charger is either an enabler or a slow or fast killer. In fact LFP is far simpler in its needs than lead acid and the big problem with all our clever lead acid charging systems is that mostly they are too sophisticated. LFP needs to charge to the end of its bulk voltage (more on that in a minute) hold that for a relatively short time and then stop. No long absorption, no float, no equalising, and no temperature compensation. There are quite a few dedicated LFP mains chargers who have the end of bulk at 14.6v (3.65 volts per cell). I have a cheap 20 amp one at home (actually more like 16) from Ali Express for £45. It behaves just as said above - provides constant current of 16amps up to 14.6 v, holds that voltage constant until the amps drop to about 2 amps and then switches itself off - job done. However charging regularly to 14.6v, although providing full capacity, is not quite worth it in terms of reduced longevity. LFP really is happiest around the mid-range totally unlike lead acid. I'll be using a Victron Blue Smart IP22 12/30 on the boat which has a more benign bulk charge endpoint of 14.2 volts on its LFP setting. It has a float of 13.5v. This isn't terrible but I'll switch the charger off at 14.2.

Some people have made the mistake of thinking that a charger used on an apparently gentler setting (gel for example) will be OK, not taking into account that that this setting might involve a lengthy absorption period. Rod Collins has an example in his Lithium Batteries in Boats page that I referenced above where a big investment in LFP was written off in this way.

Of the chargers you mention you should be OK with the Victron MPPT 100/30 solar (I have one to use in my system). As said LFP does not like to hang around at full charge but you can set the Victron to 13.2 float which is effectively no float at all. I don't know the Victron Combo inverter. I imagine the problem with that is you can't then have your charge and load circuits separated. The Sterling alternator lithium settings seem to be quite harsh. On my Sterling Alternator to Battery charger the LFP setting was 14.8v, for example and I gather that Sterling no longer recommend it for LFP.

So I think you are right to say that replacing chargers may well prove a sticking point for change. This is especially true for alternator charging. The simplest (but less effective method) being for the alternator to charge a dedicated start battery and for that battery to charge the LFP bank via a DC to DC charger like the Sterling B to B (which has a fully customisable range of settings) or the Victron Orion. That may be fine for a small LFP bank as long as the alternator is rated 40-50% higher than the B to B. (Lithium has little resistance to charge so will take any charge thrown at it which can burn out alternators designed for the slower work of lead acid charging, hence the extra headroom needed by the alternator). But a B2B does throw away one of the big advantages of LFP which is the ability to take a lot of current right up to full, so for that reason may people are switching to a higher output alternator like the Balmars together with external regulation such as the Balmar MC-614 to charge the LFP bank directly, with a DC to DC charger used to look after the start battery. Boats so equipped aren't going to have to rely so heavily on generators to supplement.

There are some work-arounds, more sophisticated BMSs can switch off chargers for example. Or you can buy a user-programmable voltage sensing relay to control a bigger relay for ending charge. This kind of thing for example ... V-Guard II – programmable battery monitor 12V and 24V, with LCD: Amazon.co.uk: Car & Motorbike

 

[vas]

The starting point in considering chargers is to know what LFP needs and what will shorten it's life. You can then work from that knowledge to decide if a particular charger is either an enabler or a slow or fast killer. In fact LFP is far simpler in its needs that lead acid and the big problem with all our clever lead acid charging systems is that mostly they are too sophisticated. LFP needs to charge to the end of its bulk voltage (more on that in a minute) and then stop. No (or minimal) absorption, no float, no equalising, and no temperature compensation. There are quite a few dedicated LFP mains chargers who have the end of bulk at 14.6v (3.65 volts per cell). I have a cheap 20 amp one at home (actually more like 16) from Ali Express for £45. It behaves just as said above - provides constant current of 16amps up to 14.6 v and then switches itself off - job done. However charging regularly to 14.6 while providing full capacity is not quite worth it in terms of reduced longevity. LFP really is happiest around the mid-range totally unlike lead acid. I'll be using a Victron Blue Smart IP22 12/30 on the boat which has a more benign bulk charge endpoint of 14.2 volts. It has a float of 13.5v. This isn't terrible but I'll switch the charger off at 14.2.

Some people have made the mistake of thinking that a charger used on an apparently gentler setting (gel for example) will be OK, not taking into account that that this setting might involve a lengthy absorption period. Rod Collins has an example in his Lithium Batteries in Boats page that I referenced above where a big investment in LFP was written off in this way.

Of the chargers you mention you should be OK with the Victron MPPT 100/30 solar (I have one to use in my system). As said LFP does not like to hang around at full charge but you can set the Victron to 13.2 float which is effectively no float at all. I don't know the Victron Combo inverter. I imagine the problem with that is you can't then have your charge and load circuits separated. The Sterling alternator lithium settings seem to be quite harsh. On my Alternator to Battery charger the LFP setting was 14.8v, for example.

So I think you are right to say that replacing chargers may well prove a sticking point for change. This is especially true for alternator charging. The simplest (but less effective method) being for the alternator to charge a dedicated start battery and for that battery to charge the LFP bank via a DC to DC charger like the Sterling B to B or the Victron Orion. That may be fine for a small LFP bank as long as the alternator is rated 40-50% higher than the B to B. (Lithium has little resistance to charge so will take any charge thrown at it which can burn out alternators designed for the slower work of lead acid charging, hence the extra headroom needed by the alternator). But a B2B does throw away one of the big advantages of LFP which is the ability to take a lot of current right up to full, so for that reason may people are switching to a higher output alternator like the Balmars together with external regulation such as the Balmar MC-614. Boats so equipped aren't going to have to rely so heavily on generators to supplement.

There are some work-arounds, more sophisticated BMS's can switch off chargers for example. Or you can buy a user-programmable voltage sensing relay to control a bigger relay for ending charge. This kind of thing for example ... V-Guard II – programmable battery monitor 12V and 24V, with LCD: Amazon.co.uk: Car & Motorbike

appreciate your elaborate answer, many thanks. Proves things are not that simple. TBH, 80% of my daily charge is done from the solar, 10% from the inverter charger when I turn on the geny for the watermaker (which is fully programmable as the MPPT, so no probs there) and another 10% (if that) from the alternator. Usually when I change anchorages is after lunch by which time most of the Amps are back from the solar. BTW, doesn't look like my Sterling pro digital has a lithium option (I only have AGM, GEL, LA)
Anyway, hope I can get another season from the Trojans in the state they are now and will see what the picture is going to be then. I expect prices to drop and s/w h/w to improve and be tested extensively by the early adopters :-D

cheers

V.

 

[TernVI]

thanks, both Victrons are fully configurable on absorption and float voltage, times on each stage, A etc. Not too sure about the Sterling (no s/w to connect to it and alter settings, just a couple of jumpers)
BMV700 also installed, so should be fine on this respect.

cheers

V.

I was thinking in terms of a complete new charging algorithm, rather than fiddling with the parameters in a lead-acid regime.
Absorption and float are lead-acid concepts.
You might want a whole new way of deciding when the battery is full and a whole new way of controlling the charge.
All that is do-able in software/firmware.

 

[Poey50]

appreciate your elaborate answer, many thanks. Proves things are not that simple. TBH, 80% of my daily charge is done from the solar, 10% from the inverter charger when I turn on the geny for the watermaker (which is fully programmable as the MPPT, so no probs there) and another 10% (if that) from the alternator. Usually when I change anchorages is after lunch by which time most of the Amps are back from the solar. BTW, doesn't look like my Sterling pro digital has a lithium option (I only have AGM, GEL, LA)
Anyway, hope I can get another season from the Trojans in the state they are now and will see what the picture is going to be then. I expect prices to drop and s/w h/w to improve and be tested extensively by the early adopters :-D

cheers

V.

With such high reliance on solar and such low reliance on alternator charging then I think the simpler arrangement of having the alternator charge the start battery and for a DC to DC charger to then charge LFP from the start battery might suit. One advantage of this is that in the event of a high voltage disconnect by the BMS you still have the start battery in the system so that protects your diodes from what would otherwise be a high voltage spike. Rod Collins has tested the Sterling B2B in this way and reports that it survives a sudden disconnect of the LFP.

 

[vas]

I was thinking in terms of a complete new charging algorithm, rather than fiddling with the parameters in a lead-acid regime.
Absorption and float are lead-acid concepts.
You might want a whole new way of deciding when the battery is full and a whole new way of controlling the charge.
All that is do-able in software/firmware.

true, assuming Victron develop and deliver a Lithium compatible firmware...
will wait and see I guess.

 

[vas]

With such high reliance on solar and such low reliance on alternator charging then I think the simpler arrangement of having the alternator charge the start battery and for a DC to DC charger to then charge LFP from the start battery might suit. One advantage of this is that in the event of a high voltage disconnect by the BMS you still have the start battery in the system so that protects your diodes from what would otherwise be a high voltage spike. Rod Collins has tested the Sterling B2B in this way and reports that it survives a sudden disconnect of the LFP.

good thinking, only we're talking mobo with twin engines, port does service, stbrd does starter (normal FLA truck batteries). this way, one alternator will do bugger all unless I also keep the Trojans for ballast and charge them and use a B2B to charge the lithiums how silly is that?

 

[Poey50]

good thinking, only we're talking mobo with twin engines, port does service, stbrd does starter (normal FLA truck batteries). this way, one alternator will do bugger all unless I also keep the Trojans for ballast and charge them and use a B2B to charge the lithiums how silly is that?

I think I need to refer you to a higher authority for twin engines! "Lithium Batteries on Boats" Facebook Group have some very knowledgeable people, the hem of whose garments I am only allowed to touch on special days.

 

[guardian]

Best to start here and read the whole thing and then decide if "drop-in replacements" are drop-in replacements. Spoiler alert .. they're not.

LiFePO4 Batteries On Boats - Marine How To

So what i've taken from that article amongst many things is to protect the alternator, (Sterling Power jobby) get a decent BMS, whether said battery maker has them fitted battery side and a charger bespoke to LFP? Great article BTW. Loads more research to do. Found out that maker whos link i posted earlier does do BT monitoring but after my experiences with Chinese software - not keen.

Cheers

EDIT - found out those batteries i mentioned are sold in the UK by these guys:

LiFePO4 Battery UK | Personal service | Quality Source

 

[Poey50]

So what i've taken from that article amongst many things is to protect the alternator, (Sterling Power jobby) get a decent BMS, whether said battery maker has them fitted battery side and a charger bespoke to LFP? Great article BTW. Loads more research to do. Found out that maker whos link i posted earlier does do BT monitoring but after my experiences with Chinese software - not keen.

Cheers

EDIT - found out those batteries i mentioned are sold in the UK by these guys:

LiFePO4 Battery UK | Personal service | Quality Source

I find that company to be one of the more responsible sellers of 'drop-in' batteries since they do engage with at least some of the needs for a lithium system. You do however need to do some failure planning - what-happens-if questions. These batteries have an internal BMS whose sole purpose is to protect the battery - it has no interest in protecting you. So the big question for your research is what will you do if your LFP house bank shuts down? There are some answers for this but you none as satisfactory as having separate circuits for charge and load.

But Quality Source are offering to talk through the issues and I know one of the people there who is a fellow sailor.

As an example of worst kind of marketing of 'drop-ins', SVB are a disgrace. (I won't add a link.) I rarely bother to complain about anything but was so enraged by their 'drop-in replacement' bullsh1t I wrote them this email.

"I’m writing to you to complain about your misleading promotion of drop-in replacement LiFePO4 batteries as drop-in replacement for lead acid. Your advert is misleading and dangerous in a marine environment.

A battery management system is best thought of as like a fuse on an electrical circuit. It offers catastrophic level protection only, to protect the battery from being destroyed. Fair enough if there are no big consequences - such as using it in an RV or to power up a trolling motor. In fact these would be excellent batteries for that. But there is a big difference for sailors. Let's say a sailor is motoring along and the alternator is charging the battery. It will do so very fast as there is much lower internal resistance in these batteries and no long absorption phase as in lead acid. So it would be easy to overcharge. That's OK, your supplier might say, as there is a high voltage disconnect in the BMS to protect the system. But what happens to the rest of the electrical system when the battery is suddenly removed? The high voltage spike may take out the alternator, solar chargers and all those expensive marine electronics. No mention of this is made at any point in the advertising or the manual. So there is potential for enormous risk at sea to life."

SVB sought a reply from the manufacturers which began with this classic line which I read with my head in hands -

We are not familiar with the internal resistance of Li-Ion/LiFePO4 batteries being smaller than equivalent Lead-Acid batteries. To the best of our knowledge the opposite is true.

No words....

Or possibly one ... morons.

 

[Poey50]

This is the other very popular deal that I mentioned. 280ah cells from Xuba Electronics - with Amy as main contact person. It's not a great video but you get a good look at the cells.

Unboxing and Review of the purchase process for 16 of the 280AH LiFePo4 EVE cells from Amy at Luyuan/Xuba

 

[gregcope]

Do any of those other forums for bulk buys @Poey50? As shipping is expensive it might help with costs. If i understood that video right he got 16cells for $1700 which is £
$106.25 per cell Or $425 for a 4 cell 280aH bank. Today that would be £326!