Battery economics?

[dgadee]

Coming near end of life of 2 * 155ah house batteries and thinking about replacement. If max from them was only ever 50% and now they are near end of life, I suppose all I now have usable in ah is around 120?

One lithium battery would give me the same output and last a lot longer. Is my thinking correct? Or is there a fundamental flaw?

 

[lpdsn]

I guess it is the future. I think you'd need to review your charging arrangements though. Li batteries need a bit more care when charging so you can't just whack the ampage in using chargers designed for lead acid batteries.

 

[bedouin]

I must admit to having thoughts along similar lines. However I see two possible concerns.

I would question how well they would cope in the rather harsh marine environment with a less than ideal charging regime.

Also my experience with Lion batteries is that they don't necessarily last that long. They are rarely performing adequately after 4 or 5 years. In contrast my current set of boat batteries are 10years old and put up with a lot of abuse and are still going strong.

 

[pmagowan]

Every time I have looked into it lead acid batteries seem to come up trumps on value for money against the fancy types. So, it generally seems that you need some other justification for fancy batteries such as space, weight, etc etc

 

[Tranona]

If by economics you mean the lowest cost over time for a given amount of power drawn then suspect that lithium is still uneconomic compared with the alternatives.

The key thing to look for is number of expected cycles, so if you are a weekend sailor then ordinary wet cell are usually satisfactory if you have a good capacity. typically 250-300AH capacity is adequate for a 30-35' cruising boat. AGM start to become viable if you want a greater number of cycles and a quick recharge time, but clearly more expensive even though potentially longer lasting than wet cell. For heavy prolonged use there is a case for batteries such as Trojans or Rolls which can give even higher number of cycles (at higher initial cost) and favoured by long term liveaboards who then tend to have the charging capacity (solar, generator perhaps) to keep them regularly charged.

So your choice depends on many factors related to your usage, charging and time horizon.

 

[lpdsn]

One lithium battery would give me the same output and last a lot longer. Is my thinking correct? Or is there a fundamental flaw?

Actually, just a thought. IIRC, you have a Dehler CWS, so you'll have the one or two hundred Amps load from time to time from the winch. I don't know how the Li battery will cope with that but probably worth your while asking the vendor.

 

[bedouin]

Actually, just a thought. IIRC, you have a Dehler CWS, so you'll have the one or two hundred Amps load from time to time from the winch. I don't know how the Li battery will cope with that but probably worth your while asking the vendor.

The one thing Li batteries do well is provide high current so they are well suited to Engine starting, winches and so on. In many applications a lithium ion battery can be fully discharged in 10-15 minutes without adverse affects - try that with Lead Acid!

 

[Stemar]

Lithium cells are far less able to give a sustained high output than lead/acid batteries. It can be done, but I'd want some clever electronics to prevent overheating if the anchor gets stuck or the engine's slow starting. Overload a L/A battery & you damage the battery, overload Lithium ion batteries and you've got a very nasty fire to deal with - just ask Boeing!

A little light reading: https://www.lithiumpros.com/crank-amp-ratings-for-lithium-batteries/

 

[dgadee]

Yes, have. Dehler cws but most power used in putting up main. That always has engine on.

I meant one lithium house battery and one small lead acid starting battery. Sorry if not clear.

 

[Sailingsaves]

Lithiums are too expensive (imo) and the need for careful charge (and discharge) is why I have not gone that route.

E.g. for maximum longevity, only discharge to 50%. So whatever the rating, one is only getting half that rating. Only charge to 90% for maximum longevity.

Oh yes, and don't charge whilst being used for maximum longevity as it 'stresses' the battery too much, thereby lessening life of battery.

They were invented as a compromise I believe (ideally for mobile 'phones) ; small, 'no' memory effect, packed a punch, not expected to last that long because people would change 'phones before battery died.

With the cheapness and reliability of good lead acids combined with the clever charging equipment at low prices I still find this the better route.

 

[bedouin]

I meant one lithium house battery and one small lead acid starting battery. Sorry if not clear.

In contrast I might consider the opposite approach

I don't think Lion stack up for the domestic bank but their very high current delivery make them more appropriate for engine starting and because of the low consumption (in AH terms) it would not be difficult to keep them charged. A 1KG battery could replace my 25kg Lead acid battery - or allow me to repurpose that as additional domestic capacity

 

[Sailingsaves]

In contrast I might consider the opposite approach

I don't think Lion stack up for the domestic bank but their very high current delivery make them more appropriate for engine starting and because of the low consumption (in AH terms) it would not be difficult to keep them charged. A 1KG battery could replace my 25kg Lead acid battery - or allow me to repurpose that as additional domestic capacity

Would one of the jump starter li-ion things do for your starter battery? I have heard good things about them for starting cars (but I don't know which brand, make etc was used).

As you say, packs a punch, used rarely and can be charged whilst sitting idle. All the safety electronics packed inside.

https://www.google.co.uk/search?q=l...h8TbAhWKKcAKHYahDBoQ_AUICigB&biw=1280&bih=669

Would one of the £60 ones be good enough I wonder?

https://www.amazon.co.uk/s/ref=nb_s...x=lithium+ion+jump,aps,180&crid=14342RODS5UML

Interesting video on this £60 - odd one:

https://www.amazon.co.uk/DBPOWER-18...1104&sr=8-3&keywords=lithium+ion+jump+starter

 

[bedouin]

Would one of the jump starter li-ion things do for your starter battery? I have heard good things about them for starting cars (but I don't know which brand, make etc was used).

As you say, packs a punch, used rarely and can be charged whilst sitting idle. All the safety electronics packed inside.

https://www.google.co.uk/search?q=l...h8TbAhWKKcAKHYahDBoQ_AUICigB&biw=1280&bih=669

Would one of the £60 ones be good enough I wonder?

https://www.amazon.co.uk/s/ref=nb_s...x=lithium+ion+jump,aps,180&crid=14342RODS5UML

Those are what I had in mind but I am not sure they are designed for regular use. They might have limited lifetime if used in that way.

However I know Lion batteries are more than capable of doing it so I am a little surprised I can't find any available commercially. Makes me wonder if there isn't another difficulty I don't know about.

 

[Tranona]

In contrast I might consider the opposite approach

I don't think Lion stack up for the domestic bank but their very high current delivery make them more appropriate for engine starting and because of the low consumption (in AH terms) it would not be difficult to keep them charged. A 1KG battery could replace my 25kg Lead acid battery - or allow me to repurpose that as additional domestic capacity

You can achieve that in part by using an AGM start battery such as a Red Flash 1100 which can be installed anywhere in any orientation so freeing up space for bigger house bank.

 

[bedouin]

You can achieve that in part by using an AGM start battery such as a Red Flash 1100 which can be installed anywhere in any orientation so freeing up space for bigger house bank.

Indeed - but even a Red Flash battery is large in comparison to a Li ion one. It is in fact quite tricky for me to mount one somewhere that keeps the cable runs short.

 

[Mikedefieslife]

Hmmm the talk here seems to be Lion batteries that practically no-one uses because as mentioned they can be a fire hazard.

Lithium Iron Phosphate LiFePo4 are an entirely different matter. These are the ones that to install if you are going lithium, but they are of course super expensive. The previous type are best left to Samsung mobile phones, Boeing planes, and RC vehicles.

 

[Sailingsaves]

Hmmm the talk here seems to be Lion batteries that practically no-one uses because as mentioned they can be a fire hazard.

Lithium Iron Phosphate LiFePo4 are an entirely different matter. These are the ones that to install if you are going lithium, but they are of course super expensive. The previous type are best left to Samsung mobile phones, Boeing planes, and RC vehicles.

LiFPo4 are great, but so is the price (for me at least).

https://www.google.co.uk/search?biw...c.1.64.psy-ab..0.2.162...0i13k1.0.qH3glU6KyxQ

I don't read newspapers, what fires occurred with Li-ion or was it Lithium polymers?

I have been tinkering with Li-ions for a few years (even some cheap non-protected ones), but have had no trouble at all.

I am going to buy a £50 Lithium ion jump starter pack, look after it, and see what is what.

 

[RichardS]

Hmmm the talk here seems to be Lion batteries that practically no-one uses because as mentioned they can be a fire hazard.

Lithium Iron Phosphate LiFePo4 are an entirely different matter. These are the ones that to install if you are going lithium, but they are of course super expensive. The previous type are best left to Samsung mobile phones, Boeing planes, and RC vehicles.

Indeed. These are the ones you need http://www.sunbeamsystem.com/en/smart-l-i-t-h-i-u-m-2/

Quick charging, high current, no special charger needed, can be discharged to zero without any deleterious effect and have a huge life cycle.

At the moment only 100Ah max but rather than 3 x 200Ah, I could use 3 x 100Ah to get the same capacity. However, they are not cheap so I'm still undecided but they can be used in parallel with lead acid so I might phase them in.

Richard

 

[lpdsn]

At the moment only 100Ah max but rather than 3 x 200Ah, I could use 3 x 100Ah to get the same capacity. However, they are not cheap so I'm still undecided but they can be used in parallel with lead acid so I might phase them in.

I look forward to getting your feedback in a few years time.

Your forum needs guinea pigs.

 

[Tranona]

Your forum needs guinea pigs.

Served up Peruvian style or turned into pate as in the Camomile Lawn?