144Vdc EV Charger

batteries are wonderfully complex in their dynamics and it is possible to exploit those features. have done this by putting 1000V across the battery for microseconds at a time very low duty cycle at the resonant frequency of the battery and strange things happen.

but that's not what my charger is designed for. in this case, i just go for the straight up conventional solution :)
 
Will it be capable of bulk parallel output arrays?

Can I connect 5 of them in parallel amd share current effectively?
 
Any CC charger should be able to do this - the trick is when they hit the CV stage.
 
heathyoung said:
Any CC charger should be able to do this - the trick is when they hit the CV stage.


That's also what I previous had thought, until testing a handful of chargers in parallel and finding issues with current sharing that I don't understand.
 
liveforphysics, what's your thought on Lithium-Air batteries? still too far away to be worth talking about? or a big thinng that really works, coming to a supplier near you?
 
HighHopes said:
liveforphysics, what's your thought on Lithium-Air batteries? still too far away to be worth talking about? or a big thinng that really works, coming to a supplier near you?


Lithium air, while possible to yield fantastic energy densities, seems unlikely to bare useful fruit to EV's inside the next decade.

I would love to be wrong about this, but everything I've seen with respect to Lithium air testing and/or other cell designs using metallic Lithium anodes seem a long ways off from being useful outside entertaining lab techs with unexpected and occasionally exciting displays during cycling.

While it may be possible for these challenges to be solved by some clever additive or yet-untested electrolyte blend, I would not recommend holding your breath.

The good news is, EV's don't need the crazy level of energy density that is possible to achieve with Lithium Air.
 
true, but i'm really after the autonomous flying car... so... maybe they both become available at the same time
 
HighHopes said:
true, but i'm really after the autonomous flying car... so... maybe they both become available at the same time

You're looking for a higher C-rate cell than Lithium Air would be able to achieve then.

You know there are 2 projects in the bay area for flying autonomous cars, perhaps join one and apply yourself towards making the wait shorter. :)
 
ho humm.. wish i had more free time to finish the prototype. the magnetics design is next. magnetics design is an exercise in multiple variables being solved simultaneously. so it is processed iteratively. start with your analysis that shows what the average and peak currents are going to be, power level, get in the neighbourhood for the physical size of the thing. go through the many equations for determinating the perameters, keep an eye on saturation and other limitations. and optomize the losses between core & winding. iterations.

i'm working on a combat robot controller right now for a friend, so i'm occupied elsewhere, but i'll come back to this eventually. its so close now to a prototype.. if you want to jump in here and give a first pass on the magnetic design please do so!
 
wondering if anyone has a source for some good thermal grease? i'm looking for Dow Corning TC-5022 or equivalent or near to. just need one or two of those syringe dispenser types, not the kG bucket. seems this stuff is hard to find. i found a local place that supplies but its $300 min purchase and/or they only have kG buckets.
 
i actually found a source! but they wanted $83 to ship to canada. wtf!?
 
Yeah? wtf
 
http://www.tomshardware.com/answers/id-233341/dow-corning-5121-artic-silver.html
 
Yeah? wtf
have you learned nothing? :shock:
as you go up in power the smaller your margins will get. the more the little details matter.

.. maybe i confuse you. i asked the question here but it is not for this EV charger project. it is for the EV and combat robot controllers which are both pushing some serious power densities on an air cooled aluminum heatsink.

@live4physics, yes actually its my preferred to use TC-5022 but i couldn't find that one at all. so i settle for TC-5021. couldn't find that either.
in the end, i decided to purchase some PK-1 cause that's what i could get and now i hope for the best. i get nervouos for new things, i like tried and true. call me boring but i'm more happy when it works the first time :)
 
I hope you plan to lap the heat sink and the power devices + accurate torque tightening in the proper sequence if you are being that specific on thermal compound. :mrgreen:

Here is a comparison chart of pastes with some really funny ones at the end they used for comparison sake, but humor aside, over clockers go over kill on many things. I went to one event where they were using liquid nitrogen to cool the CPUs in the attempt to break clock/benchmark records.
http://www.tomshardware.com/reviews/thermal-paste-performance-benchmark,3616-18.html

If you told these guys you could hook them up with a liquid He setup, at least one of them would fork out the cash.

Btw, I understand your thought process on it, I just think you are splitting hairs based on the application.
 
i'm curious to know if i can eliminate the fan
 
at least nomex paper is cheap. i like that!
 
its almost time to re-vamp this thread. make it bi-directional, higher power.... ability to stack in parallel.
i don't know about the DC voltage though. this project was for 144Vdc because i thought it would be hard to make and to fit a 400V DIY pack from re-cycled leaf or chevy volt. 2 years later, wondering if that's still the case... maybe 400V pack is a lot easier to make now?
 
HighHopes said:
its almost time to re-vamp this thread. make it bi-directional, higher power.... ability to stack in parallel.
i don't know about the DC voltage though. this project was for 144Vdc because i thought it would be hard to make and to fit a 400V DIY pack from re-cycled leaf or chevy volt. 2 years later, wondering if that's still the case... maybe 400V pack is a lot easier to make now?

The leaf is fully charged right around 400v.

Most OEM EVs are ~ 360-380v nominal
 
400V for the win.

And the age-old question... does size matter? Of course in the context of choosing the switching frequency. 20khz to avoid noise... 200khz to make it lightweight?

Glad to hear this thread might come back in 2018.
 
very likely the switching freqency will be >=100khz because this sort of application requires a lot of power magnetics and you want to keep that small. once the design is done for 400V output (for example) you'll have all the math and capability to spin the design in a modular way to get any output DC you want. most use 400V ok.. but there could be others that prefer 144V.
 
Come on isolated!!! :mrgreen:
 
Yep, with no isolation in the only can be a DIY'er charger. With isolation it has a shot at being a volume production product if power density and cost are right.

I personally love the topology Arlin is exploring using just a PFC stage switch driving a transformer and synchronous rectification output. It should also run bi-directional and be isolated. Fewer power conversion stages is how to win efficiency.


Arlo1 said:
Come on isolated!!! :mrgreen:
 
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