very true, I am redesigning the roof to fold out to around 99m2 that will give around 25kw capacity up there. all to be passed by engineer tho.. the its drawn and I get I too him I will find out
Full Electric Drive Conversion of Tri-Axle Coach 21700 or prismatic? Battery cycle Testers..?
- Thread starter AkivaAld
- Start date
best of my knowledge at heart vehicle is between 0.5-1kw per Km that give a range of 200-400km at worst case scenario fully loaded 20.5T. charge times are high but with dc/dc its not bad and only going to become more common in the future.
Depending on design it may end up with more than 400kwh pack.
I am currently drawing a system that folds out with pneumatic actuators to increase roof capacity to around 99m2 with solar capacity of around 25kw (custom built by me with wafers) and have a ETFE coating on them for weather/oxygen protection.
Nah still here, off working and sourcing parts, writing a plan for the bus systems for easy engineering solution.
Yes there is a lot of cells, like 25000 or so and yes that's a lot of welding. (most likely going to set up a laser welder) made from a laser tattoo removal unit, (styropro) on YouTube demonstrated how they can cause blisters on tungsten. so they have enough power to weld steel in an inert atmosphere. This combined with my knowledge of 3d printing will allow for a module welder purged in an argo filled housing.
OffGridForGood
Catch, make or grow everything you can.
Sounds like you have been planning this out!
Hope you keep posting the progress as you go, I really would like to see this build.
Gotta have projects, why not a big bus
Hope you keep posting the progress as you go, I really would like to see this build.
Gotta have projects, why not a big bus
So got the bus on stands, ready for under chassis work, (rust prevention) paint. Air suspension work new airbags. Roof is tapped and insides 50% removed. Also have some goodies at home when I’m back. tester and some cells.. see the outcome of cycle life expectancy and go from there! Those Geb cells come down to 0.80c at the volumes I require!
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400bird
Solar Wizard
That's even worse! Just to be clear, you are proposing NMC cells (an assumption, but you said not Lifepo4) without a BMS and without cell level monitoring?
Please do more research before you burn down the bus
I've been building Li-ion battery packs for some time.
lets simplify this so I can share the concept.
Each battery Module 14.8v nominal will have a Bms, This will balance the 4s 28p module, (over, under, voltage, ect,) I'm certain you are aware of the way that works.
Lets say that there is 33 modules in series that's around 488.4V giving 68.3kwh to achieve 200kwh of battery one that equates to 3p 205kwh.
The bus will have 2 batteries at 205kwh
Each set of modules (3) is connected into a bus bar, that bus bar is then connected to the next (series)
Every one of the modules BMS has a 14.8v output 5a, these go to nothing except a relay/mosfet control board.
This custom board has relays/mosfets that are always open, each mosfet exits onto a common power (solid state low amperage low draw relay/mosfet).
When BMS is in tolerance there is no flow of energy to the Common output of the Mosfet's
Every module has single BMS has its own relay/mosfet.
That common Output of the mosfet (off when bms is normal) enters the control Solid state relay, Control Solid State Relay Is normally Open (power from key operates Positive or negative leg to energise or denergise contactor)
When the one of the 99 bms units calls fault, energy is then allowed to flow onto the common input of the Control Solid State Relay.
This then pulls the CSSR into closed mode. Removing energy from the coil in the 900v 500A contactor.
+ the system has a whole lot of diodes to stop that back flow through the Mosfets in the BMS from the 488v battery avoiding smoke bomb
To balance the 33S 14.8v string, each module will be capacity tested and matched to minimise drift, having 3p allows this to happen along the 33 string, not to mention 2 batteries so balance should be really good.
Balancing between the 33S will be done with 10 amp din mounted battery equalisers, if one pack is too high/low. It will show on the BMS of all 3 that are in Parallel. Energy will be removed, from the Control board, contactor de-energised, the 10A balancer may continue to work. BMS comes online once balance is restored by 10 amp equaliser contactor is re instated, Trusting the system will be very tight due to design, test and balance matching should avoid this happening.
Then Cell Back flow will be countered if there is a short with Nickel Cell fused busbar on the modules. This is rated at 12A for 3 seconds.
As the motor will be 400kw for short bursts, it will not exceed 1C on the batteries hence not ever drawing over 5a, I will see how costing goes but would love 600kwh to lower the load on the cells under full acceleration. See how initial costing goes.
This is probably one of the most cost effective and safest systems with an abundance of balancing in a simple way that requires non expensive parts to function like $10k bms systems rated to ludicrous voltages.
Im in the process of designing a CANBUS system for the whole bus, this will include, temperature sensors ect for the battery and will also be able to automatically pull power to the CSSR via set parameters.
Trust this clarifies the BMS
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I love it. Most people talk, you look like you are doing! When you are finished and passing my way (small farm near Barossa SA) i’d love to shout you a wood oven roast, fine red wine, and a tranquil pitstop place in return for a tour of your bus ?
pollenface
Solar Addict
A caravan parks worst nightmare, heh 
I like it!
I like it!
Drop in the bucket compared to the rest of the project $$$
Thats going to be allot of Li-ion (fire crackers) under the hood. Mark the back of the bus so I can see it and stay 50 yrds away...
yabert
Solar Enthusiast
No, this way you will pay more and you will end with an unreliable conversion or worst you will never end this conversion.
You don't seem to have the experience to design this kind of conversion, so I repeat:
Appreciate the kindness and lack of pessimism, seems there are a few sour grapes in here. So really appreciate the kindness. Akiva
400bird
Solar Wizard
I'm glad you will have some cell level protection. I'm also still 100% sure all those 12v packs are not ideal. Not a single EV manufacturer does it this way.
Love the bus im general, keep going! Just be open to input.
Love the bus im general, keep going! Just be open to input.
They would be doing a disservice to not point out the issues with your project. I find feedback good or bad is all helpful. Sometimes it can save you lots of pain.
If I was doing this build, I would go hybrid and put in a 4 cylinder diesel generator. Line the roof with panels and build out a kitchen, room, etc...
The drive would be electric but with the generator, have a smaller/safer battery pack.
Unfortunately I don’t have access to off the shelf BMS systems designed in factories by teams of engineers. The packs will be around 700mm in length and in custom 3d printed housings. Surrounded by a full steel frame. I guess you could say, rack mounted 12v packs.
Basically in a safety frame that can be lifted in and out of the bus. (Replaces diesel tank)
Most manufacturers are running modules anyway of different values.
Being safe is at the highest level on my mind with high powered packs. I have defiantly be putting effort into ensuring this will be non hazardous to anyone.
Currently designing the bms control board with eagle cad for simulations.
Kindness akiva
The whole point of the bus is to be an inspiration, to show what every one of us is capable of. That when we are aware of our actions and the consequences, we don’t need to over engineer things. I say this as most manufacturers want to be in the game, pushing batteries to the limit… in order to sell a product. Smaller batteries are not always safer… try pulling 400kw out of a 200kw pack, 2c draw. Short life cycle, excess heat. At max the motor I have can only draw 400kw for 30 seconds, before reducing power. So under 1c draw.
I have nothing to gain from burning down 10 years of income I’ve put into a house by having some shortcuts. Nor harming anyone else in the process.
But I still choose to do this build because I’m certainly capable with my skill set in which none of you actually know about.
Everything in this bus is being recycled as the conversion happens cause I actually give a shit about the planet, species and humans that are here.
Maybe instead those people can ask exactly how things are going to work before pointing fingers stating things are unsafe or dangerous.
If we love authority that much then you guys can stay there
timselectric
If I can do it, you can do it.
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If you didn't want constructive criticism. You probably came to the wrong place. If all that you were looking for was praise. Maybe it would have been better to wait and just post the finished, working project.
Most of the people here want everyone to succeed. And want to help them do it in a safe, efficient, and economical way.
Your project interests me because I have a heavy EV build planned, myself.
I'm not going to offer any advice or suggestions. As it doesn't appear to be why you are here. But I will be watching this thread for ideas that might help with mine. Whether those ideas come from your build. Or from the suggestions of others.
Good luck, and I can't wait to see how it turns out.
Most of the people here want everyone to succeed. And want to help them do it in a safe, efficient, and economical way.
Your project interests me because I have a heavy EV build planned, myself.
I'm not going to offer any advice or suggestions. As it doesn't appear to be why you are here. But I will be watching this thread for ideas that might help with mine. Whether those ideas come from your build. Or from the suggestions of others.
Good luck, and I can't wait to see how it turns out.
S
Not to mention if you don’t have access to the full bms, you only end up with heaps of modules you can’t buy a balancer for…
As for engineers, I’m sure if they were allowed they would not build cars the way they do, squeezing every ounce of energy potential out of them before they combust. It’s no wonder li ion has a bad name. 20kwh batteries and 100kw motors. With batteries that have short cycle life’s…
So you want me to trust those who are subject to extreme financial restraints on battery quantities,(price) and rely on the absurd safety systems they have created all so they can sell cheap EV vehicles to the masses. Because it’s cheaper to build a circuit board with some sensors to extract up to the fire cracker red line, than building a vehicle safely. Those are the ones you want me to trust.
I don’t need water cooled cells… cause I’m not a moron and won’t ever need to draw that amount of power out of the packs.
It’s only wankers that think they are smart that build stupid thinks like that, that cause problems and stupid legislations.
Just through sizing the battery according to the vehicle and motor combo, correct cell level balancing at cell level and modules.
Testing of cell performance, heat build up, simple multi physics simulations of bus bars on battery modules. Simple feedback loops of temperatures and simple safety cutoff limits.
There is nothing complex about building a battery.
You want me to rely on people’s misfortunes and being involved in a vehicle accident… that’s a twisted logic.
Not to mention if you don’t have access to the full bms, you only end up with heaps of modules you can’t buy a balancer for…
As for engineers, I’m sure if they were allowed they would not build cars the way they do, squeezing every ounce of energy potential out of them before they combust. It’s no wonder li ion has a bad name. 20kwh batteries and 100kw motors. With batteries that have short cycle life’s…
So you want me to trust those who are subject to extreme financial restraints on battery quantities,(price) and rely on the absurd safety systems they have created all so they can sell cheap EV vehicles to the masses. Because it’s cheaper to build a circuit board with some sensors to extract up to the fire cracker red line, than building a vehicle safely. Those are the ones you want me to trust.
I don’t need water cooled cells… cause I’m not a moron and won’t ever need to draw that amount of power out of the packs.
It’s only wankers that think they are smart that build stupid thinks like that, that cause problems and stupid legislations.
Just through sizing the battery according to the vehicle and motor combo, correct cell level balancing at cell level and modules.
Testing of cell performance, heat build up, simple multi physics simulations of bus bars on battery modules. Simple feedback loops of temperatures and simple safety cutoff limits.
There is nothing complex about building a battery.
Hey Tim, it’s not that I don’t want discussion around what I am doing.
It’s the way others approach it, rather than asking why I have chosen things a certain way.
They “tell” me how to do it, based on how they would do it. But unfortunately for them they are not the ones who are doing it. It’s not their money, skills, life experience or qualifications that are working on this project
They attempt to tell me what to do this without even having the curtesy of asking why certain things have been selected. Or the comprehension of why certain things have been chosen.
I like to call it an Agent smithing, (like the matrix). This is where with reading for about 15 minutes the decide they know every thought or route you have explored every ounce of research, that they know your background, qualifications. Then they decide they know better and more than you. So they then push the hand into the chest and say. “Everything is much better when it is all… me”
I’m certain there is sone really excellent ideas out there that may allow me to weigh up another selection that hasn’t been seen.
There is a rhyme and reason, certain formats are the way they are due to restraints on motors, bms, cost, solar charging voltages, dc/dc converters for the voltages required, all being a major factor.
DIY is about sharing projects that we can all do, safely whilst respecting the impacts they have on others. For me the concepts of this have been underway for around 2 years and most routes mentioned have been looked at.
there is a reason I have selected certain things. Availability, weight, voltage, charge voltage from solar, system size, amperage requirements. Module arrangement, balancing system.
For sound 2 years I have been checking out what is available, having quotes, learning requirements needed to complete this.
When someone who has spent 15 mins reading this post “tells” me what to do without even asking why I had decided a certain way. I’m going to be not receptive to their advice.
If they wish to have a discussion on certain aspects of the choices and then recommend something different that’s fine. I’m sure there is a lot of experience here.
Unfortunately it’s not their money that they are shelling out, so it’s easy to just tell others what to do. Maybe if they observed a little more they would see there may be solutions in what I am doing to things they have problems to.
They also don’t know my background, skillsets, what knowledge I do and do not have. To assume you know everything about someone, like a few of these people in here have and say “ you do not have the skills” after reading for 15 minutes or knowing anything about you. Is highly arrogant and egotistical, it’s very “Agent Smith”
The purpose of this build is to be economical, to share that these big projects can be done. To design not on the limit of battery technology and have no need or requirements for stupid safety systems. Respect the planet, other species and all others on the road.
Just because mass manufacturers do something one way, (with machines and lots of overheads billions of dollars of infrastructure), does not mean the task can not be completed safe and effectively by anyone.
It’s what we are all here for, sharing ideas, not bludgeoning each other with egos.
I’m open to discussion, if someone asks why I’ve chosen a certain way, I will answer. Because the information they may wish to share might have already been thought of and may not be able to work in the situations I have, due to restraints of the project.
Awesome to hear you wish for the same ideas. I have several motor company’s that have quoted me prices for combos and solo ev motors. Some of which are 3500nm monsters!
I commend your effort. I think reusing things is great.
If you realy want to make a difference, learn the science and educate others that have been brain washed. You see, most people are driven by their emotions and don't actually check the facts that are offered to them.
Example; We are told CO2 is going to destroy the planet.
Fact 1 - if CO2 levels gets below 180-200ppm plants start to die, then we all die.
Fact 2 - Perfect level is around 1400ppm. Plants thrive at the sweet spot. We are around 425ish
Fact 3 - CO2 is only a fraction of a percentage of the air, how can it affect us that much? Insulation works both directions
Fact 4 - The sun controls our temperature, not our use of buses.
If you feel your brain fighting these facts, that is normal. The mind has a hard time letting go of beliefs.
So if you really want to help the planet, keep the petro power plant in the bus and just make sure it runs clean though an electric bus probably uses the same amount of the "deadly" CO2 from further down the line.
Facts, - get some.
OffGridForGood
Catch, make or grow everything you can.
I will admit, at the beginning my first thought was - "this doner is too heavy" this idea came from following many of the ICE-EV car conversions from another forum. They go so far as to list many basic doners by 'stripped-weight' chasis less engine-transmission-gas tank, as a starting point and guide for those looking for a suitable doner ICE car. However, since following all your posts, it appears you have made a series of selections and know full well the consequences of the doner you have chosen, are prepared for the work and have a suitable budget planned, clearly not going in blindly. Like myself, I am sure many comments came from others based on similar experiences, we certainly see many well intentioned but less capable dream projects posted by some who (unlike you) are have not thought it through and do not have the budget. So, All good, I am interested to see the build, and to learn what you have in mind for the cell BMS sounds interesting.
OffGridForGood
Catch, make or grow everything you can.
LOL
look up how much (as a percentage) cyanide in your water will kill you!
look up how much lead in the air caused damage to brain development
look up how much mercury it takes to damage your cells.
if you think the exhaust isn't causing any harm, go sit in your garage with the car engine running for an hour or so and report back what you noticed.
Yes, the mind has a hard time letting go of beliefs alright.
Um, the danger of sitting in your garage with the car running is not exactly the CO2, but rather CO (and everything else), and lack of O2.
And you're also talking way higher concentration levels doing that, than he said with atmospheric levels at the ppm level. Huge difference.
But no need to derail the thread
Now consider what is really bad for this planet and you are doing better than most.
We have been distracted with chasing a ghost. Mean while, for example; herbicides and insecticides have been ignored. The point is, everyone is out chasing the CO2 boogie man while other issues get ignored. Environmentalist have been fooled in a big way.
Thats my point.
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