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Portable Battery Lithuim Ion NMC - 660Wh


toppy007

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Hi all

 

Just thought I'd post a battery build that I've written an instructables guide for.

 

I wanted to build a portable battery that I could charge at work and take to the boat to relive some of the usage on the boats battery system as its a little outdated and I'm not ready for the system redesign.

 

Its working nicely running all my low to medium voltage equipment and means I'm not enjoying anyone in the evening with the engine noise and smoke.

 

see the link below if your interested and your thoughts would be most appreciated  

 

https://www.instructables.com/12V-Lithium-Ion-18650-55ah-Portable-Battery/

 

 

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Thanks for sharing!

 

I've wondered about something along these lines before. Someone I know mentioned (without details) that a friend had bought a similar (but commercially made) thing for about £1000 - not cheap!

Edited by Ewan123
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5 hours ago, toppy007 said:

Hi all

 

Just thought I'd post a battery build that I've written an instructables guide for.

 

I wanted to build a portable battery that I could charge at work and take to the boat to relive some of the usage on the boats battery system as its a little outdated and I'm not ready for the system redesign.

 

Its working nicely running all my low to medium voltage equipment and means I'm not enjoying anyone in the evening with the engine noise and smoke.

 

see the link below if your interested and your thoughts would be most appreciated  

 

https://www.instructables.com/12V-Lithium-Ion-18650-55ah-Portable-Battery/

 

 

Best post of the day ?

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Nice idea and description, but I foresee issues with the spot welding of all those cells.

Not only were the instructions not clear as to the exact layout and connections, but should one cell fail there would be serious issues in finding the 'dead' one and replacing it.

Furthermore, it would be a double loss to go up from12V to 240v then back down to the charge voltage required.

Although often unavoidable, it would be beneficial to use items that have a 12v charge supply and cut out the inverter where possible. 

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23 hours ago, MarkH2159 said:

Nice idea and description, but I foresee issues with the spot welding of all those cells.

Not only were the instructions not clear as to the exact layout and connections, but should one cell fail there would be serious issues in finding the 'dead' one and replacing it.

Furthermore, it would be a double loss to go up from12V to 240v then back down to the charge voltage required.

Although often unavoidable, it would be beneficial to use items that have a 12v charge supply and cut out the inverter where possible. 

Yeah well stated, agree with all of that, I however think spot welding is required when considering its performance against the compactness and ruggedness needed for portability. but using used 18650 cell means you'll not get the cycle life of new cells. but then at 80p a cell from a supplier you trust and a good vetting cell diagnostic process is key to obtaining a balanced pack.  

 

And yes I think I could of added more detail explaining the nickle connections in the pack. I might upload a small CAD animation to highlight how the cells are combined. somehow writing it down logically seems as difficult as explaining the rules of cricket! 

 

A great resource is http://www.ebikeschool.com/how-to-build-a-diy-electric-bicycle-lithium-battery-from-18650-cells/

 

And an option to monitor individual cells can be achieved using a PCB integrated assembles(No spot welding too). Tho this is more powerwall and less portability 

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On 01/12/2020 at 15:55, toppy007 said:

 

Its working nicely running all my low to medium voltage equipment and means I'm not enjoying anyone in the evening with the engine noise and smoke.

 

 

 

 

I think this statement is a bit misleading. You are using Li-ion cells that operate at a slightly higher voltage to the LiFePO4 chemistry that most of us are using. That means when fully charged you pack will be up at 16.4V which could be a bit high for some 12V systems on a boat. Your article is aimed at feeding a victron inverter which can operate up to 17V input which is fine but I didnt see any real caution to any peeps looking to use it to supplement their 12 V electrics. You dont want to blow up your 12V kit.

You did say "This means it is important to review the appliances being served to make sure they can handle the voltage range of the 18650 cells of (12V - 16.4V)" but it could easily be missed by someone not familar with these batteries. Perhaps you should put this warning in 'bold'?

Also you mention something about your BMS but I didnt see anything about how the BMS avoids overcharging (I only skim read it! - apologies if it is there!). Hope it cuts off as the batteries get to 100% as the chemistry is not as stable as the LiFePO4 chemistry.

 

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19 minutes ago, Dr Bob said:

I think this statement is a bit misleading. You are using Li-ion cells that operate at a slightly higher voltage to the LiFePO4 chemistry that most of us are using. That means when fully charged you pack will be up at 16.4V which could be a bit high for some 12V systems on a boat. Your article is aimed at feeding a victron inverter which can operate up to 17V input which is fine but I didnt see any real caution to any peeps looking to use it to supplement their 12 V electrics. You dont want to blow up your 12V kit.

You did say "This means it is important to review the appliances being served to make sure they can handle the voltage range of the 18650 cells of (12V - 16.4V)" but it could easily be missed by someone not familar with these batteries. Perhaps you should put this warning in 'bold'?

Also you mention something about your BMS but I didnt see anything about how the BMS avoids overcharging (I only skim read it! - apologies if it is there!). Hope it cuts off as the batteries get to 100% as the chemistry is not as stable as the LiFePO4 chemistry.

 

Noted! I'll add that.

 

Maybe a voltage regulator should have be noted as well. 

 

And yes BMS needs to be for the correct cell chemistry type! 3.6-3.7v cut off and balancing. Actually the charger I've added also has a voltage cut-off pre-set.

 

I think a lot of people don't realise that lithium ion's come in so many different forms and this maybe an issue.

 

I'm a big fan of the lithium titanate. I'm sure these are the future of the electric inland waterways. well until solid-state comes into being.

 

Have you come across any boat running this chemistry? 

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@toppy007

 

Have you seen the funny Kilowatt labs "supercapacitor" scam ? 

 

It's a real giggle. Someone has done a unit which has a load of LTO cells in it, BMS etc and they are claiming that they are supercapacitors and will do a million cycles and last 45 years. 

10 year warranty (electronics based) which allows them to sell LTO then disappear before any warranty claims. 

 

If you have a bit of time and like lithium batteries I can recommend this thread 

 

https://forums.aeva.asn.au/viewtopic.php?t=5486&start=125

 

I found it very funny but then I am easily pleased to be fair. 

 

It's particularly interesting that they can do air freight because the device "does not have lithium batteries in it they are supercapacitors". 

 

A real giggle but also potentially a really good product, ironically, because LTO is high cycle life and stable. 

 

And the bloke promoting them is such a scammer it's unbelievable !!

 

Video of him here . Comedy gold !

 

https://pesn.com/news/2017/06/18/70

 

On daily cycling the product has a life of 2700 years! That's what a million cycles means! 

 

It's hilarious watching it but also slightly worrying that a lot of people seen that have been taken in by this scam. 

 

There are loads of other scams around the old energy storage chestnut but this one is one of the more amusing ones. 

 

Edited by magnetman
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3 hours ago, toppy007 said:

I think a lot of people don't realise that lithium ion's come in so many different forms and this maybe an issue.

I think most people on here quickly become aware that LiFePo4s are the safe option to use on canal boats.

 

3 hours ago, toppy007 said:

I'm a big fan of the lithium titanate. I'm sure these are the future of the electric inland waterways. well until solid-state comes into being.

 

Have you come across any boat running this chemistry? 

Never heard them mentioned. High charge rates are not relevant for canal boats (today or tomorrow) as very few peeps will be able to charge over 250A. Most of us on here are using 2nd hand LiFePO4s and they arent available on EVs in Europe. They will also likely be expensive as you will need 5 cells in series if not more!  LiFePo4s have the perfect cell voltage so work in the range 12.8-13.3V so sitting above LA's in a hybrid system......the majority of peeps putting 2nd hand Li's on their boats are using a Lead acid as a dump battery so that working voltage is ideal.

Cant see any other Li type being used for quite a time.

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I reckon LTO has a lot of potential for boats. We don't really need particularly small and light batteries. What we do need is safety and high cycle life.

 

LTO has both of these factors. 

 

For a commercial drop-in lithium battery rather than a diy system I could see LTO becoming quite common as a consumer product. 

 

It can take a high charge which also makes it potentially interesting for electric propulsion systems on boats if high power mains charging points ever appear. 

 

 

Looks pretty cool on the GWL presentation. 

 

 

 

Quick calculation let's say 48v propulsion motor. 2kw average to push boat. Possibly less if you are in a heavily locked section of canal. 

 

So that's 40 amps @48v 

 

Want 3 hours worth to get between charging stations.

 

60 of these 2.3v/40ah would be 46v/120ah.

 

1250g per unit so would weigh in the order of 75kg. Not a problem for a fixed bank in a boat. 

 

Not cheap though at £80 each. 

 

£5k of batteries, but they can upload significant charge fast (10C).

 

Unfortunately as they aren't used in cars much (car makers want to sell more cars not everlasting cars) they will probably remain an expensive product. 

 

Very nice though I reckon. 

 

It's easy to dismiss other options if you are already using an existing system but watch this space I reckon. 

 

 

If they arrr good enough for Damen...

 

https://www.motorship.com/news101/industry-news/lithium-titanium-oxide-batteries-for-marine-use

Edited by magnetman
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Not yet but interesting to read more about these on the cruisers forum.

 

A 6S will be a direct replacement for engine start battery, no need to modify alternator. Ok a bit higher voltage but that means alternator won't blow up and no high voltage cut required on the battery itself. 

 

Voltage could be a bit high for sensitive equipment so perhaps a buck converter in the domestic line or for individual items would be sensible. 

 

It looks like there might be a patent problem like there was with NiMh so they might never come down in price. Which is a shame because -IF- the 20,000 cycle life, fast charging and direct replacement for lead acid systems is true then it does seem to be an incredibly sensible thing to have on a boat...

 

There are also claims (from someone not selling them) that they can be completely discharged and recover, making a BMS unnecessary. 

 

Again that is a bold claim and awkward to verify. 

 

And they have high short term current ability so a 30ah 6S arrangement would start a diesel engine easily. 

 

It looks like a lot of the cheaper ones are ex Chinese electric buses with new wrappers so it's a buyer beware job.

 

 

As always new and rather expensive stuff like this will be subject to post purchase rationalisation issues and choice-supportive bias. 

 

https://www.cruisersforum.com/forums/f166/lto-battery-as-the-perfect-starter-bowtruster-battery-228831.html

 

 

GWL have 40ah cylinders 2.3v for euro80+vat+ shipping so for a 40ah 13.8v nominal battery it's £600+ so definitely not cheap. 

 

But it could be very very good if some of the stats are true. 

 

 

Edited by magnetman
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On 05/12/2020 at 10:01, magnetman said:

Not yet but interesting to read more about these on the cruisers forum.

 

A 6S will be a direct replacement for engine start battery, no need to modify alternator. Ok a bit higher voltage but that means alternator won't blow up and no high voltage cut required on the battery itself. 

 

Voltage could be a bit high for sensitive equipment so perhaps a buck converter in the domestic line or for individual items would be sensible. 

 

It looks like there might be a patent problem like there was with NiMh so they might never come down in price. Which is a shame because -IF- the 20,000 cycle life, fast charging and direct replacement for lead acid systems is true then it does seem to be an incredibly sensible thing to have on a boat...

 

There are also claims (from someone not selling them) that they can be completely discharged and recover, making a BMS unnecessary. 

 

Again that is a bold claim and awkward to verify. 

 

And they have high short term current ability so a 30ah 6S arrangement would start a diesel engine easily. 

 

It looks like a lot of the cheaper ones are ex Chinese electric buses with new wrappers so it's a buyer beware job.

 

 

As always new and rather expensive stuff like this will be subject to post purchase rationalisation issues and choice-supportive bias. 

 

https://www.cruisersforum.com/forums/f166/lto-battery-as-the-perfect-starter-bowtruster-battery-228831.html

 

 

GWL have 40ah cylinders 2.3v for euro80+vat+ shipping so for a 40ah 13.8v nominal battery it's £600+ so definitely not cheap. 

 

But it could be very very good if some of the stats are true. 

 

 

Magnetman, apologies for coming across very negative on the LTOs, I really should have spent time reading through what was out there on them. I agree with you that LTO's really do look interesting for canal boats BUT it looks like the cost is prohibitive.

The cruiser forum is a very good resource on info on Li batteries and has been for the last 8 years! Reading through the LTO thread it is possible to come up with some 'theoretical' observations on LTOs. My take on them is as follows:

I see 2 issues – Voltage and cost.

First Voltage. It looks like the nominal voltage of the LTO cell is around 2.0 to 2.3V and the upper charge limit is 2.8V. That means 5 cells in series would give you 11.0V-12.0V operational (over 85% of charge range suggested) or 14.0V at highest charge voltage. With 6 in series, operational voltage would be 12.0V to 13.8V with 16.4V at the highest charge voltage which is certainly enough to blow a lot of sensitive 12V electrics. The 5 cells looks too low in voltage and couldnt be used with a dump LA starter battery..

However, if we used 6 cells in series then it looks like these batteries could be charged by a normal alternator or LA charging regime and only achieve a float voltage therefore no danger of overcharging (the big problem with Li's). Think of it – your alternator getting up to 14.4V constant voltage phase would likely to only give an 80% charged LTO set up – a wild guess! All you would need is some sort of 'buck step down' device to protect the 12V systems (not a clue what that entails or costs!). The ability to charge without worrying about overcharging is very significant and could make BMSs much simpler without isolation switches etc. You wouldn't even need an LA start battery as a dump load as the LTOs would never need isolating.

This however is all theoretical. How would it work in practice? With LiFePO4s we now have 3-4 years of experience with @Tom and Bex, @MoominPapa and @peterboat all pioneering them and learning all the tricks and demands of the system. We now know how they work. LTOs would require similar pioneering support before peeps could have confidence to install. For example, if we have 6 cells in series, what if one cell fails and we end up with a lower voltage? That means overcharging could be an issue so we do need an autodisconnect and a cell voltage monitoring which may not be available for this type of technology. The barriers to operation show up on this initial leading edge use. Another issue that is mentioned in the Cruiser thread is balancing LTOs. It sound like they need balancing at the top end but if you were just going up to 14.4V then not an issue (less than 80% charged) ....but is it? What about bottom balancing. They claim to be able to go down to 0% SoC with no problems! So no bottom balancing needed.......Hmmmm?

The second issue is then cost. With a 6 in series set up, you are using 50% more cells that LiFePO4s cost and as the LTOs seem more expensive to start with then maybe you are talking twice the price for LTOs. Peeps here are looking at 2nd hand Li's to get costs around £1000 per installation rather than the £4,000 for commercial systems so a doubling of cost may be totally prohibitive. Add this to the fact that there are very few EVs based on LTOs so they are not available 2nd hand. Maybe their use on Buses may give a market for 2nd hand batteries but is that really going to happen? The cycle life of LTOs is amazing but will commercial use grow when it is almost certain that in 10 years time our batteries for EVs will be a lot different.

In summary, I would be very interested to trial LTOs on my boat if I could find 500Ahrs of capacity at a decent price (as likely as @mrsmelly buying an ecofan) and someone could convince me that I dont need an autodisconnect!

Yes. Very interesting but I think the price is too high by a long way. Good to make everyone aware of them. Let me know if you see any cheap ones!

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11 minutes ago, Dr Bob said:

Think of it – your alternator getting up to 14.4V constant voltage phase would likely to only give an 80% charged LTO set up – a wild guess! All you would need is some sort of 'buck step down' device to protect the 12V systems (not a clue what that entails or costs!)

 

Being a 'bear of little brain' when it comes to this 'lithium stuff' - if the alternator can only charge to 14.4 / 14.6 volts then the batteries will never get above this voltage, that being the case why would you need a buck step-down when the maximum voltage was only ever the same as FLA's ?

 

When charging from the mains - could you not also use a 'standard' FLA charger at 14.6v max ?

 

Sorry if its a stupid question.

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1 minute ago, Alan de Enfield said:

 

Being a 'bear of little brain' when it comes to this 'lithium stuff' - if the alternator can only charge to 14.4 / 14.6 volts then the batteries will never get above this voltage, that being the case why would you need a buck step-down when the maximum voltage was only ever the same as FLA's ?

 

When charging from the mains - could you not also use a 'standard' FLA charger at 14.6v max ?

 

Sorry if its a stupid question.

No, you are spot on. I had thought of that but got fed up typing!

If you only charge to 14.4V then no problem and it works fine with normal chargers if on an LA setting. It sounds simple.....if expensive.

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If they are a robust as they say they are electric buses will use them until they are dead because it makes commercial sense.  However if all buses and EVs go this way we would have a chance of getting them cheap enough to buy new.  I will continue with what I have, and the electric car will keep its lithium polymer setup for the foreseeable future as they are new

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