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Battery Technology.


Bob Blues
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I have been thinking of buying a Tesla Car and this has 90Kw of battery. I have also wanted to convert my boat to battery power and for some time looked at the solar boat project but was put off by the limited amount of power/cruising time.

 

So when I started looking at the Tesla 90D I was looking at the charging options. When connected to a Tesla Super Charger it will charge your 90kw battery to 80% in 20 mins and a full charge in 1 hr. Tesla’s battery packs contain thousands of lithium-ion battery cells which must be parallel charged to be able to charge that quickly. There are various charging options standard 3 Kw/11kw/22kw and the single phase and 3 phase options. So I guess there must be an intelligent option that applies the charge across multiple points of the battery instead of the main terminals.

 

From watching a video of the super charger it was charging at over 400V but the speed of charge was amazing. The other thing was the battery life and discharge capabilities. One chap had done 200,000 miles and the battery was at 96% I know people take their battery down to 10% all the time and then use the super charger to 80-90% and then down to 10% again with out any degradation. Is it possible to use this technology in a Narrow boat? I have seen the size of the battery pack and although it is very heavy I recon it would fit in. It seems like we are in the dark ages with regards to power discharging batteries to 50% so they last a long time seems so old. Tesla have a 8 year guarantee on their batteris so I guess they must be happy with their performance.

 

There is also a number of inverter options so unless I get one and strip the car down and retro fit it to the NB I’ll not know.

 

I see they have a 100Kw battery pack now. Hmmm

 

Comments?

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The LIFEPo4 batteries is aviable, cost about €100 + some per 100 Amp, are 3.2V but 3V is working Volt, (a 12V will need 4 batt)

are to find in 300-400-500-750-1000 Ah size.

the 500 weight 13 Kg, the 750 17 Kg, the 1000 27 Kg.

 

Going to 48V you need 16 in series, so 208 - 432 kg (500 - 1000 Ah)

Going to 72V you need 24 in series so 312 - 648 Kg (500 - 1000 Ah)

 

A powerful BMS is needed to balance the batteries.

 

With more then 60 V you need an qualified electrician to work on it.

 

Chargers isn't the problem, you do need somewhere to plug it in that can take the load.

I don't know the standard socket fuse in UK, here in good old Sweden it is 6-10-16-20-25-35 amp with the 3 lower ones to be found at a single phase socket

10 Ah and 230 V is 2300W

3 phase and 16 Amp and you can have 19 kW nominal, for how long I don't know.

 

A NB cruise at 3 MPH average need 2.5 kW, at 4 MPH 6 kW

So 3 hours cruising between the locks per day takes 7.5 kWh * efficiency * efficiency (out of batt - out of socket) + domestic use.

on a river at 4 mph 6 kW for every hour, at 5 mph it need 12 kW for every hour, again times the efficiency.

Edited by Dalslandia
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IMO it's the charge controller that makes things difficult in a non OEM use. Getting charge control right AND discharge control right, with all the essential battery monitoring could be rather hard. However for people who cruise in the summer solar makes a lot of sense. The high solar summer months give lots of power for cruising with just enough for weekends in spring and autumn, and the usual "leave the boat for later" power to just maintain the batteries over winter.

 

Current electric car makers are very secretive about their charge, discharge and battery monitoring electronics.

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Simple is best. Putting aside the cost issue, a big Li battery needs a lot of electronics to prevent over charge and especially over discharge. Then you will need more electronics to control the motor to propel the boat. To keep currents down to sensible levels the voltages will be high. From memory in the UK regs get a lot more difficult above about 32V.

 

All of this means that when you wake up one morning and go to run the engine and nothing happens basically there is nothing you can do other than to call out a very expensive engineer who will probably then fit some very expensive parts.

 

On top of that a second hand boat will be very hard to sell as no one will want it.

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There is groving market for BMS and is adaptable to the use in a boat, don't need tousends small batteries, those 100-1000 Ah lifepo4 is single cell,

motor controle is off the shelf too.

 

Lead crystal thecnology seems to be good too, can go deeper then AGM and wet led/acid. and don't die from being completely dis charged.

 

I think 60 volt is the limit for do it self. in EU.

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I used to work for one of the auto manufacturers and a big problem with electronics is the more sophisticated electronic devices have a life of just a few years - things like microprocessors, custom integrated circuits and sensors. Vehicle makers will then do an 'all time' buy, so buy lots of stock. Too much and it gets thrown away at 15 years and not enough and they run out. Vehicle makers will normally ensure parts for 10 years after vehicle manufacture. For things like boats, that means that replacement boards may not be available after about 10 years. It was rumoured and I think not denied that one of the organisations responsible for rail signals was buying bits on ebay to keep stuff working as old second hand parts were all that was left. But for specialist markets like boats there wont be a good supply of second hand bits and so it will mean completely new controllers and batteries every say 10 to 15 years. This will be very expensive for little benefit over a simple diesel engine.

Probably over time regulations will force lower emissions, but I will only apply the low emissions stuff as and when I have no choice.

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The LIFEPo4 batteries is aviable, cost about €100 + some per 100 Amp, are 3.2V but 3V is working Volt, (a 12V will need 4 batt)

are to find in 300-400-500-750-1000 Ah size.

the 500 weight 13 Kg, the 750 17 Kg, the 1000 27 Kg.

 

Going to 48V you need 16 in series, so 208 - 432 kg (500 - 1000 Ah)

Going to 72V you need 24 in series so 312 - 648 Kg (500 - 1000 Ah)

 

A powerful BMS is needed to balance the batteries.

 

With more then 60 V you need an qualified electrician to work on it.

 

Chargers isn't the problem, you do need somewhere to plug it in that can take the load.

I don't know the standard socket fuse in UK, here in good old Sweden it is 6-10-16-20-25-35 amp with the 3 lower ones to be found at a single phase socket

10 Ah and 230 V is 2300W

3 phase and 16 Amp and you can have 19 kW nominal, for how long I don't know.

 

A NB cruise at 3 MPH average need 2.5 kW, at 4 MPH 6 kW

So 3 hours cruising between the locks per day takes 7.5 kWh * efficiency * efficiency (out of batt - out of socket) + domestic use.

on a river at 4 mph 6 kW per hour, at 5 mph it need 12 kW per hour again times the efficiency.

 

Stop it judge.gif

 

kW per hour are very similar to amps per hour and will not be tolerated on this good forum, YOU should know better.

 

..............Dave

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Stop it judge.gif

 

kW per hour are very similar to amps per hour and will not be tolerated on this good forum, YOU should know better.

 

..............Dave

Sorry about that, amps hour per day times volts, Mr Watt was from Scotland not England, Mr. Amp was. :) or was that Mr Lucas the inventer of darkness.

 

(for the others, watt it takes to drive the boat is power - Watts, amps is like saying my engine turn out 300 torque something per hour :) )

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I used to work for one of the auto manufacturers and a big problem with electronics is the more sophisticated electronic devices have a life of just a few years - things like microprocessors, custom integrated circuits and sensors. Vehicle makers will then do an 'all time' buy, so buy lots of stock. Too much and it gets thrown away at 15 years and not enough and they run out. Vehicle makers will normally ensure parts for 10 years after vehicle manufacture. For things like boats, that means that replacement boards may not be available after about 10 years. It was rumoured and I think not denied that one of the organisations responsible for rail signals was buying bits on ebay to keep stuff working as old second hand parts were all that was left. But for specialist markets like boats there wont be a good supply of second hand bits and so it will mean completely new controllers and batteries every say 10 to 15 years. This will be very expensive for little benefit over a simple diesel engine.

Probably over time regulations will force lower emissions, but I will only apply the low emissions stuff as and when I have no choice.

 

Watt you say make very much sense to me, a diesel engine is hard to beat, economicly or service vise. problem is the politics, here the "Green" party voted for tax on energy from solar panels, they didn't know why or who or when though, that party leader also use forbidden bottom paint on her boat, in brackish waters.

 

Now they talk about forbidding all IC cars from 2030, and they close 2 of the 9 nuclear reactors 2019 and 2020. Just to charge the Swedish cars if they was all electric will take 8-9 TWh per year = one reactor of 1000 MW running one year non stop, the total Swedish electric production is about 150 TWh per year, 65 TWh nuclear, 65 TWh hydro (water) plants, 15 TWh wind, rest is bought from other countrys, and so called condense power plants, = oil fired. If all cars and trucks is electric, it will free a lot of oil for the condense plants though.

Edited by Dalslandia
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The main benefit of Lithium-based batteries in almost every other use case is weight. Everything benefits from lighter batteries, except a boat, where it might mean you need extra paving slabs under the floor. The only benefit for boaters is that you can run them down to nearly nothing and (to a greater extent than lead acid at least) you can leave the expensive electronics to take care of them the same way you do with the lithium batteries in your phone and laptop. The increased costs per kWh are currently so great that it's just not worth it though.

 

HOWEVER

 

The cost of Lithium based cells is coming down quite quickly, as demand (for cars, phones and laptops) is increasing quickly. Tesla are building what is apparently the largest building in the world (by footprint) just to make batteries in, and other manufacturers particularly in Germany and China are ramping up production. This will bring reduced costs and more availability of different battery configurations with their own management systems. The point where a battery bank of n kWh is cheaper to do with Lithium based batteries than lead acid certainly exists, I wouldn't like to say when it'll be but we're probably talking within 10-15 years.

 

I'm currently having a sailaway built with a parallel hybrid system based around a 48V wet lead acid battery bank. Research / warranty / estimates lead me to believe that this battery bank will last around 10 years before it needs replacing, and I'll be very surprised if the sensible replacement is still wet lead acid, at the moment it's the sensible choice though.

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Its certainly an interesting idea, there was a talk about the Tesla 'power wall' on here a few months ago.

I don't know the standard socket fuse in UK....


In a domestic setting, its a square pin plug/socket with a plug top fuse rated at 13amp, typically run of a 32amp ring or 16amp radial circuit. Nominal is 230vac but in practice its top end of tolerance.

In industry the 'Ceeform' sockets are common, with the majority of marinas and caravan sites providing a 16amp 230v nominal socket. There are protected by a circuit breaker per outlet.
So the maximum you will typically get for a boat is a 16amp 240vac supply, around 3.8kW I have seen 32amp outlets, but very few indeed. More commonly the outlet is derated to reduce cable costs.


I used to work for one of the auto manufacturers and a big problem with electronics is the more sophisticated electronic devices have a life of just a few years - things like microprocessors, custom integrated circuits and sensors.

...It was rumoured and I think not denied that one of the organisations responsible for rail signals was buying bits on ebay to keep stuff working as old second hand parts were all that was left....


Often we think and electronics lasting forever, certainly good lives can be had, but equally just yesterday I had a BT Openreach technician suggest that it was common for the 'Hub4' and 'Hub5' units to fail after 6-8months and getting through several in only a few years was common place and all but to expected. Shocking quality.


The main benefit of Lithium-based batteries in almost every other use case is weight. Everything benefits from lighter batteries, except a boat, where it might mean you need extra paving slabs under the floor. .....

...I'm currently having a sailaway built with a parallel hybrid system based around a 48V wet lead acid battery bank. Research / warranty / estimates lead me to believe that this battery bank will last around 10 years before it needs replacing, and I'll be very surprised if the sensible replacement is still wet lead acid, at the moment it's the sensible choice though....

 

 

How does the maximum rate of charge of of you design bank compare to say a lithium based car system? Obviously a charge time of a few hours would be a huge bonus if charging over a generator, but the tail on fully charging a lead acid with a conventional charger is huge.

 

The company I currently work for makes electric pedestrian pusher/mover units which are based on sealed lead-acid gell cells. Again, weight is a bonus as we balest the machines, but while a shorter charge can be used as an interrim step, the is a very real requirment to leave them plugged in for a charge of minimum 8-12hours duration atleast periodically (we suggest a week in noramal use) to allow the carger to complete its cycle and if nothing else equalise the cells. Easy enough if you are a bricks and motar setup, all but impossable if running from generators.

 

 

 

Daniel

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Its certainly an interesting idea, there was a talk about the Tesla 'power wall' on here a few months ago.

 

 

In a domestic setting, its a square pin plug/socket with a plug top fuse rated at 13amp, typically run of a 32amp ring or 16amp radial circuit. Nominal is 230vac but in practice its top end of tolerance.

 

In industry the 'Ceeform' sockets are common, with the majority of marinas and caravan sites providing a 16amp 230v nominal socket. There are protected by a circuit breaker per outlet.

So the maximum you will typically get for a boat is a 16amp 240vac supply, around 3.8kW I have seen 32amp outlets, but very few indeed. More commonly the outlet is derated to reduce cable costs.

 

 

Daniel

Same sockets as we use then (except for the domestic) the blue one is found in every guest harbor or marina, the red 3 phase is normally the 16 or 32 amps.

 

Saw yesterday, one asking on a forum about charge efficiency, he had some sort of car? with lead acid batteries, he used a real KWh counter that was installed in every house before the new electronic remote readable was installed, to measure the energy that did go into the charger, and in the car could read what he was getting out from the batteries, was reaching a 60% efficiency, charger + battery, using max 50% of the battery, and knowing the last bit is hardest to get in, it seems reasonable, so 70% eff. in the batteries and about 90 in the charger, next poster on the same forum had installed litium batteries and got 85-90% in the batteries, 75-80% total

Edited by Dalslandia
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Sorry about that, amps hour per day times volts, Mr Watt was from Scotland not England, Mr. Amp was. smile.png or was that Mr Lucas the inventer of darkness.

 

(for the others, watt it takes to drive the boat is power - Watts, amps is like saying my engine turn out 300 torque something per hour smile.png )

 

Nice reply, sorry for slow response but rather than foruming I am boating just now, currently on the lower South Oxford but looking forward to a week on the Thames, it should be very calm but a big diesel engine still makes me feel safer than a little 'lektrik motor.

 

...........Dave

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Nice reply, sorry for slow response but rather than foruming I am boating just now, currently on the lower South Oxford but looking forward to a week on the Thames, it should be very calm but a big diesel engine still makes me feel safer than a little 'lektrik motor.

 

...........Dave

 

Nice, here the winter is coming, this morning +8C but yesterday morning it was ice on the car windshield. so soon it will be ice on the lakes.

In Dalslandia I would like an elektrisk motor, because of the noise in the restaurant, with a serie hybrid (diesel gen set) and partly charging over night, I will save 2 litre diesel per day, so a lifepo4 batt pack will be paid back in 700 years, the first set of batteries that is.

The electric motor isn't the problem, can have it in any size,

a smaller battery like 144V 1000 amp, will cost €50.000, doing 85 trips a year for 10 years if battery last that long is about €60 per day, or €1.00 per passenger, I guess they pay that happy as an drunk sailor.

Edited by Dalslandia
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How does the maximum rate of charge of of you design bank compare to say a lithium based car system? Obviously a charge time of a few hours would be a huge bonus if charging over a generator, but the tail on fully charging a lead acid with a conventional charger is huge.

 

The company I currently work for makes electric pedestrian pusher/mover units which are based on sealed lead-acid gell cells. Again, weight is a bonus as we balest the machines, but while a shorter charge can be used as an interrim step, the is a very real requirment to leave them plugged in for a charge of minimum 8-12hours duration atleast periodically (we suggest a week in noramal use) to allow the carger to complete its cycle and if nothing else equalise the cells. Easy enough if you are a bricks and motar setup, all but impossable if running from generators.

 

It's obviously not brilliant, but again it doesn't need to be because different use cases. If you're doing a long distance drive you want your car to top to at least 80% (although they do seem to still have the long tail issue) in the time it takes you to have a pee and a burger in the service station. Equalising the cells is more of an issue, and something I was talking with the developer and supplier of the system about yesterday. The system includes a standard diesel engine that can recharge the batteries, and charging can also be done via shore power as well as solar, he recommended running the engine a fair bit in winter and/or plugging into some shore power every 2-4 weeks until the batts were saturated so the cells would equalise.

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  • 3 weeks later...

Right, well I have bought my 90D.

From all the tech information I get it looks like the best battery life is when the batteries are only charged to 80%. If its charged to 100% then they face a higher degradation.

 

Trying to see if I can get Mr Musk to invest in NB technology

 

bob

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one thing everyone seems to ignore when talking about putting lithium batteries in boats is that having them where they could potentially get wet is almost the worst thing that can be done with them (short circuiting them is the worst)

 

 

Lithium reacts intensely with water, forming lithium hydroxide and highly flammable hydrogen. The colourless solution is highly alkalic. The exothermal reactions lasts longer than the reaction of sodium and water, which is directly below lithium in the periodic chart.

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I know people take their battery down to 10% all the time and then use the super charger to 80-90% and then down to 10% again with out any degradation.

 

This is incorrect, they are just lithium batteries and will degrade quickly if quickly charged, it's not recommended to super charge them quickly unless you need to (like on a long journey)

 

You can charge to 100%, but keeping them at 100% for long periods of time isn't good for the batteries, but if you using the car you won't have this issue!

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I used to work for one of the auto manufacturers and a big problem with electronics is the more sophisticated electronic devices have a life of just a few years - things like microprocessors, custom integrated circuits and sensors. Vehicle makers will then do an 'all time' buy, so buy lots of stock. Too much and it gets thrown away at 15 years and not enough and they run out. Vehicle makers will normally ensure parts for 10 years after vehicle manufacture. For things like boats, that means that replacement boards may not be available after about 10 years. It was rumoured and I think not denied that one of the organisations responsible for rail signals was buying bits on ebay to keep stuff working as old second hand parts were all that was left. But for specialist markets like boats there wont be a good supply of second hand bits and so it will mean completely new controllers and batteries every say 10 to 15 years. This will be very expensive for little benefit over a simple diesel engine.

Probably over time regulations will force lower emissions, but I will only apply the low emissions stuff as and when I have no choice.

 

Fully agree. I've had to authorise life time buys of semiconductors for cars that have just been launched and the silicon vendor has decided to pull the plug on the technology. This is going to be one of the big negatives for electric cars - 10 years down the line one of the IGBTs (big power transistor) or a small obscure device fails and the car's scrap. They're not like the older systems where you can buy brand new parts for your Model T or MGB because any machine shop can make tham.

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Fully agree. I've had to authorise life time buys of semiconductors for cars that have just been launched and the silicon vendor has decided to pull the plug on the technology. This is going to be one of the big negatives for electric cars - 10 years down the line one of the IGBTs (big power transistor) or a small obscure device fails and the car's scrap. They're not like the older systems where you can buy brand new parts for your Model T or MGB because any machine shop can make tham.

That is the big problem with modern tech, the parts are discontinued fairly soon after introduction, so as you say the car companies do an all time buy, but that only ensures part availability for 10 years. Ten years is not enough for narrowboat use.

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Even worse is the semiconductor makers doing die shrinks to increase their yields. They sell it as making the devices faster and cheaper - what they don't realise/care is that it wrecks all of the emc/rfi work and the whole lot needs re-validating. Lots of pain & grief.

Edited by Chalky
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  • 3 weeks later...

Have been following the Tesla Forums with regards to charging the new car. I have seen many posts saying that the best course of action is to keep them below 80% as over 80 stresses the batteries.

 

Now, With regards to using this technology in a narrow boat, I don't see why you couldn't use this. The Tesla battery pack uses a heater and cooler to keep the batteries at the optimum temperature. So the same could be used in the hull of a NB.

 

I was looking at putting a Linch motor into the boat a few years ago and looked at 1000 A/h Lead acid batteries this would have given me 48KW of power charged through solar or a gen. The cost of this was about £4500 of the batteries. However, as I said in my OP I would love to go for the same technology as the Tesla. The car batteries are 16 units laid out across the floor but these could be stacked up instead of laid flat so pack them into the old engine compartment. I would try to go for a 40KW Lithium and run coolant through a pump to the boats skin tank.

 

The front motor in the 90 D puts out about 195Hp I think so I guess this work for the boat with a restriction on the motor.

 

Bob

Edited by Bob Blues
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I recently discussed the use of LIFEPo4 batteries with one of my friends who is a designer for hybrid bus power management systems, and has been for several years now. The biggest killer of lithium batteries apparently is excessive charging, by this he means charging over 80%SOC as this permanently degrades them a bit like taking lead acid below 50%. They also hate being taken below 20% charge but this apparently is not as bad as over 80%. The life span, similar to lead acid is governed by the number of cycles, it is larger than we are used to typically 2-3000 cycles 20% to 80% so that is good but they are best stored at 50-60% charge. So the great benefits of solar, topping up daily and keeping the batteries at 100% whilst the boat is not used become bad, charging during the day and then discharging overnight as normal is no problem but when returning to your mooring to go home for a few weeks you need to ensure you don't charge above 50%.

 

For those interested they currently use two banks of 30Kwatthour per bus, one to power assist the bus up hills and accelerating and the other collecting the regenerative braking energy as well as surplus output from the diesel generator to charge. They expect to switch banks about once an hour since they only charge up to 50% and run the bank down to 30%, even then the battery bank only has a life of about a year. But as the bus is normally in use 15+ hours a day and 350 days a year that is 2450 cycles. Charging higher or discharging lower shortens the life, They used to have one bank but the battery life was shorter due to the thousands of small discharges(accelerating and hills) and charges(braking) per day although the state of charge is much more consistent around 35-40%. As for a pure electric vehicle similar to the Tesla mentioned by the OP they will normally be charged overnight and run one cycle per day so as long as they are kept below 80% and above 20% they should do about 7 years on a battery bank.

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