Lead carbon batteries.

[pessimist]

I'm tempted by lithium batteries, but my insurers are wary. I'm also not keen on installing b2b chargers to protect the alternators. Lead carbon appear to present a good compromise - faster charge, more cycles and better psoc performance than straight AGM. I may be worrying unnecessarily but does the faster charge acceptance present any risk to the alternators. If not these seem an excellent compromise.

 

[KeithMD]

For general awareness, can you tell us what the insurers say?
Are they wary of something like lithium batteries bursting into flames?

 

[dunedin]

For general awareness, can you tell us what the insurers say?
Are they wary of something like lithium batteries bursting into flames?

References to “Lithium batteries” are generally meaningless and unhelpful - there are various types of Lithium Ion batteries with different performance and safety characteristics.
AFAIK the Lithium Phosphate LiFePO4 batteries are generally considered most suitable for use in yachts (some car EVs now use more exotic ion types).
It will vary by insurance underwriter, but I have heard specific and credible reports of:
- some insurers not providing cover for DIY installations of LiFePO4 batteries for domestic batteries, unless inspected (or installed) by a qualified professional;
- some insurers not providing cover for LiFePO4 batteries for electric propulsion use, unless a professional factory fit in a new boat.
How common these examples are remains to be seen, so need more info.

 

[V1701]

Have a look at this video, guy's an electrician, convinced me that I'd seriously look at LC batts next time I come to replace my usual lead acids. I think he'd have picked up on any associated risks been a while since I watched it...

 

[KeithMD]

That makes me wonder, are many boat makers now offering lithium batteries as an option or even standard?

I remember Simon Baker at DazCat mentioning it, and it gets a mention in this YW review.
Dazcat 1495 boat test, a cutting edge cat – Yachting World

PBO reviews:
Lithium boat batteries: 12 of the best options tested

 

[Poey50]

That makes me wonder, are many boat makers now offering lithium batteries as an option or even standard?

I remember Simon Baker at DazCat mentioning it, and it gets a mention in this YW review.
Dazcat 1495 boat test, a cutting edge cat – Yachting World

PBO reviews:
Lithium boat batteries: 12 of the best options tested

The PBO review is wholly irresponsible in being entirely battery-focussed. No mention of charging, fusing, non-communicative BMS disconnects, alternator sizing or protection. Lithium on a boat has to be part of a well thought-through integrated system.

 

[jwilson]

Is it practical to leave the existing alternator and shorepower charger connected to an existing 200+ Ah lead acid bank (in good condition), but to have a LIPO of say 100AH feeding actual power draw, eg lights, fridge, electronics. Could a B2B charger take power from the lead-acids to top up the LIPO whenever they were over 12.x volts? Surely this would effectively give considerably more than 100AH out of the single LIPO.

If this works it looks like a sensible change-over strategy that avoids throwing away newish lead-acids. After a few years the lead-acids will get tired and you put in a second LIPO to replace them, everything in-out then to the two LIPOs.

 

[PaulRainbow]

Is it practical to leave the existing alternator and shorepower charger connected to an existing 200+ Ah lead acid bank (in good condition), but to have a LIPO of say 100AH feeding actual power draw, eg lights, fridge, electronics. Could a B2B charger take power from the lead-acids to top up the LIPO whenever they were over 12.x volts? Surely this would effectively give considerably more than 100AH out of the single LIPO.

If this works it looks like a sensible change-over strategy that avoids throwing away newish lead-acids. After a few years the lead-acids will get tired and you put in a second LIPO to replace them, everything in-out then to the two LIPOs.

No.

Stolen from post #6 "Lithium on a boat has to be part of a well thought-through integrated system. "

 

[Pete7]

John, to answer your first question, no but you might consider a hybrid system with lead acid and LifePO4 are combined. However, you need to ensure the LifePO4 isn't constantly on charge.

Question 2, you will need to consider what happens if the BMS isolates the LifePO4 batteries when the alternator is running at speed. The are ways to control this, but as Paul has said they need to be part of a complete system.

Perhaps start with watching Emily and clark's series of videos, Adding Lithium to lead Acid Batteries on You Tube as a primer.

Pete

 

[KompetentKrew]

Lead carbon … does the faster charge acceptance present any risk to the alternators.

My guess is no.

AGM can accept 0.4C for about an hour when they're reasonably well discharged and I've never heard of a problem with alternators charging them.

I have the impression that lead carbon mostly acts like AGMs which are fine with deep discharging. Victron's datasheet [PDF] doesn't mention an actual acceptance rate, though, just a lower charge voltage.

Maybe a Sterling alternator regulator would address this, in any case? I guess you'd need to check the manual (this is available for download somewhere on Sterling's site) and check its output voltages are compatible with the charging voltages listed in Victron's PDF.

 

[BabaYaga]

Lead carbon appear to present a good compromise - faster charge, more cycles and better psoc performance than straight AGM. I may be worrying unnecessarily but does the faster charge acceptance present any risk to the alternators. If not these seem an excellent compromise.

I have had a lead carbon house bank (90 Ah x 3) for a few years and my impression is that although charge acceptance may be faster, the difference to other lead acid batteries, and especially to other AGMs, is not dramatical. So I suspect your alternators will cope well, unless their capacity is already marginal with respect to the size of the bank.

 

[goeasy123]

Irrespective of your usage profile replacing LA with Lead Carbon LA reduces risk in nearly all respects. Replacing your existing LA with any configuration that includes Lithium increases risk in all but a very few cases.

Unless you want to change your usage profile (like all-electric cooking) LC will give you better utilisation and probably lower cost over more conventional LA.

LC batteries specs all look very similar in charging regimes. Leoch is typical, which is well shy of stressing the standard alternator on a Yanmar 4JH.

 

[William_H]

Back to original question will Lead carbon batteries damage my alternator. Probably not. The current out of an alternator depends on rotation speed and battery charging loads. If loads demand more current than alternator can supply then with max field current output voltage will fall. (reduces load current so balances nicely)
An alternator might get hot under heavy load and this could cause damage short term or long term. A larger capability alternator would not get so hot. But as said alternator output can only reach max at high rotation speeds. (pulley sizes) For OP an amp meter reading alternator load current would answer question regarding need for larger alternator in actual use. ol'will

 

[Mark26]

I replaced my 2 old flooded led acid 120ah batteries with a single Victron 170ah Lead Carbon AGM three years ago.

I have an old engine which is running the original 50amp alternator.

The battery has worked great and I’ve never had any alternator problems.

I also have a Victron smart shunt so I can monitor charge and discharge rates.

My electrical consumption is very low, the vast majority of it being the fridge, after a one night stop over I normally use just 20% of my batteries capacity and on the rare occasions I stay in one place for two nights, I use about 50%.

Alternator rotation speed seems to have no effect on charging rates. The highest charge rate I ever saw was 40amps from my 50 amp alternator but it’s generally nearer 25-30 amps initially, dropping off after an hour or so. The alternator works well at tickover and doesn’t put out more charge at cruising speeds.

 

[Alex_Blackwood]

Back to original question will Lead carbon batteries damage my alternator. Probably not. The current out of an alternator depends on rotation speed and battery charging loads. If loads demand more current than alternator can supply then with max field current output voltage will fall. (reduces load current so balances nicely)
An alternator might get hot under heavy load and this could cause damage short term or long term. A larger capability alternator would not get so hot. But as said alternator output can only reach max at high rotation speeds. (pulley sizes) For OP an amp meter reading alternator load current would answer question regarding need for larger alternator in actual use. ol'will

Sorry, Alternator current is not speed dependent Frequency of an alternator is. Whilst I agree that a high load (amps) can reduce the speed of the engine! High revs will not increase the output current (amps). That is solely dependent on the demand. You may have to increase the engine throttle to cope with a high load demand.

 

[geem]

Sorry, Alternator current is not speed dependent Frequency of an alternator is. Whilst I agree that a high load (amps) can reduce the speed of the engine! High revs will not increase the output current (amps). That is solely dependent on the demand. You may have to increase the engine throttle to cope with a high load demand.

Alternator speed is directly related to the available current output. If the batteries don't need the amps then the regulator won't deliver them. If you place a large load on the batteries or the batteries are well discharged the output of the alternator will increase as you raise the engine from tickover to higher revs

 

[ryanroberts]

I swapped out to 3xLeoch 110 pure carbons and haven't noticed any alternator issues. About to put a regulator on it though as it never hits a decent voltage even when fully charged.

 

[geem]

I am not sure why people think lead carbon will have any issues with alternator performance. They are lead batteries with relatively high resistance. Nothing like the same chemistry as low resistance lifePO4 technology that eats alternators for breakfast. The carbon is there to reduce the effects of sulphation. Its just a modified AGM battery thst will last longer. Thr drawback of AGM has always been that they sulphate if you don't get them to full charge everyday. The carbon addresses this problem to some extent

 

[pessimist]

References to “Lithium batteries” are generally meaningless and unhelpful - there are various types of Lithium Ion batteries with different performance and safety characteristics.
AFAIK the Lithium Phosphate LiFePO4 batteries are generally considered most suitable for use in yachts (some car EVs now use more exotic ion types).
It will vary by insurance underwriter, but I have heard specific and credible reports of:
- some insurers not providing cover for DIY installations of LiFePO4 batteries for domestic batteries, unless inspected (or installed) by a qualified professional;
- some insurers not providing cover for LiFePO4 batteries for electric propulsion use, unless a professional factory fit in a new boat.
How common these examples are remains to be seen, so need more info.

Sorry should have been more specfic , just can't imagine anyone installing anything other than LiFePO4 for marine use.

For general awareness, can you tell us what the insurers say?
Are they wary of something like lithium batteries bursting into flames?

I did post the response from my insurers some while ago but can't find it quickly. The gist was that they would have to consult the underwriters and that, in any case, the batteries would have to be retail (not built from single cells) and would have to be professionally installed.

 

[pessimist]

Thanks everyone for the replies. It would seem that I will have no problems going down my proposed route.