How rapid is a liithium ion battery’s’death’?

[fredrussell]

I bought a nice condition Torqeedo 800 outboard at the weekend. Battery is the original lithium manganese one so, I would say, at least 10 years old. The battery charges to 70 or 80% or so. Torqeedo claim(ed) that it’ll do half an hour at full power - I ran it on the flubber at full whack and after 24 minutes it went into slow (get you home) mode. So not bad really for a ten year old battery.

I have to decide now whether it’s worth buying a re-cell pack (£300) when really, for my meagre needs, it’s current battery capacity is enough. Do lithium batteries fail slowly at a linear rate, or am I likely to find the next time I use it, say in two months time, it has rapidly deteriorated due to lack of regular use and charging.

I don’t mind shelling out for re-cell pack, and I bid on this Torqeedo budgeting for doing just that, but having tried it out there is more battery capacity than I expected of such an old battery.

 

[Supertramp]

I have one that is about 15 years old. The battery is about 60% of what it was when new. No sign of sudden decline, you adapt to the range left. I keep it charged and avoid storage in sub zero temperatures. Like you, if it frustrates me I will recell.

I charge it off a homemade12v socket on the boat (when motoring).

 

[Alan S]

[QUOTE="Supertramp, post: 7929309, member: 180378"
I keep it charged and avoid storage in sub zero temperatures.

Storing a lithium battery, much better to store it half charged rather than fully charged.

 

[penfold]

Decline in cell capacity does appear to be linear or close to it, but obvs with an outboard water ingress might confound that, IIRC the early ones weren't terribly well sealed. Someone did a thread recently about DIY re-cell of a battery.

 

[fredrussell]

Decline in cell capacity does appear to be linear or close to it, but obvs with an outboard water ingress might confound that, IIRC the early ones weren't terribly well sealed. Someone did a thread recently about DIY re-cell of a battery.

yep, saw that - cheers, looks straightforward enough. I think for the time being I’ll use it as is. It’s unlikely I’ll need more capacity for a few short trips ashore now and then.
I have to say, it’s a joy to use after a petrol outboard - I’m an instant convert.

 

[KompetentKrew]

I have to decide now whether it’s worth buying a re-cell pack (£300) when really, for my meagre needs, it’s current battery capacity is enough.

Keep the existing battery as long as it lasts.

It does what you want - you'll be mad as hell if you spend £300 on renewing it and then the motor dies the next week.

If you get a couple of years out of what you've got now and something then fails then there may be other more economic options.

 

[Star-Lord]

Yes

[QUOTE="Supertramp, post: 7929309, member: 180378"
I keep it charged and avoid storage in sub zero temperatures.

Storing a lithium battery, much better to store it half charged rather than fully charged.

Yes, always store half charged! Research how/when to charge also.

 

[fredrussell]

Yes

Yes, always store half charged! Research how/when to charge also.

Torqeedo can’t (or couldn’t - old model) decide on long term storage. In the manual for mine (T800) it says store at 20-40% long term, but in the manual for the T801 (the mk II) with identical battery it says 80-97% for long term storage.

 

[Supertramp]

[QUOTE="Supertramp, post: 7929309, member: 180378"
I keep it charged and avoid storage in sub zero temperatures.

Storing a lithium battery, much better to store it half charged rather than fully charged.

Good point, although I recall my Torqeedo notes say store nearly full but disconnected when leaving for several months. Mine is a relatively early one and I think the understanding and guidance have evolved.

The problem during use is that you always want it full, not part full. And I prefer to charge when the engine is running or on shore power. I understand that electric car batteries are protected from becoming too full and damaging the cells hence they can be left connected and fully charged. But possibly not a Torqeedo.

If it lasts 20 years I will be impressed, but I have a feeling the leg will expire before then.

 

[nestawayboats]

TORQEEDO HISTORY. Your Torqeedo 801 is likely to be at least 12 years old. We have a 2010 brochure which "introduces" the then-new 503/1003, with battery capacities of 300 and 400Wh respectively. The 401/801 came with 300Wh batteries... today you get 500Wh with the (new 2021) 603, and 916Wh with the new 2019 1103. Rivals Epropulsion provide a 1276Wh capacity battery with the Spirit PLUS. Things are definitely progressing.

Anyway as I recall we sold very few 401/801 series motors once the 503/1003 were available (Spring 2010); to anyone who understood it, whilst more expensive, the 1003 was a clear leap forward for both battery capacity and also more basic stuff like water resistance. For example the 801 had what I can only describe as a telephone connector for tiller communication, the 1003 used a proper waterproof connector they still use now for the 1103.

401/801s are pretty rare nowadays - largely because at one time Torqeedo offered a generous upgrade deal to trade in your 401/801 against a 503/1003 - but as other contributors to this thread indicate those that are still in circulation are still working, albeit with reduced capacity/run time.

SAFETY NOTE. Please be careful with 401/801 batteries, they were barely splashproof. And lithium cells do not like getting wet. I think safety concerns were part of the reason for Torqeedo's generous trade-in offer. The 503/1003 batteries and everything since from Torqeedo are rated IP67 ie submersible to depths of 1m for 1 hour.

ON BATTERY LIFE. As a rough guide you can expect a lithium battery to lose 3% of its capacity every year, just by existing, so a 12 year old battery that had 300Wh when new should have about 200Wh capacity now. Another factor that reduces capacity is number of charge cycles used, but as they (Torqeedo's current batteries) suggest they'll still have 80% capacity after 800 cycles it's not relevant to most leisure users. And another factor again is how they're stored, avoid extremes of temperature and charge state... the important thing is not the exact percentage, just not completely full or empty.

SUMMARY. I guess the important point is, as long as you can put up with slowly reducing capacity, and take reasonable care of them, these electric outboards with integrated lithium batteries are lasting well. Of course today's models also start life with a lot more battery capacity and better waterproofing than those of 12 years ago.

Ian
Nestaway Boats Ltd

 

[fredrussell]

Cheers Ian, much appreciated. I shall take battery housing apart and seal any likely water ingress points where possible. And I did wonder about the telephone style connector! I did consider putting a blob of silicon grease (or similar) over it where it meets the tiller arm, but I’ll see how I get on. My main gripe is the size of the thing. Later 800’s came in standard and long shaft but mine, being an early one is the one-size-fits-all long shaft size. Minor problem, obviously, as it all folds up. Other than that, cracking little outboard.