best bit I’ve found: http://www.ti.com/product/BQ51052B/datasheet
this is a cheap receiver and includes all the details needed to charge lithium to 4.2 at 1.5 amps! simple and tiny at like 3mm x 2mm. now to figure out how to plug it together.
@Hummie omg I think you are getting closer to this! I hope there are all the required parts… so we would not need to (you personally, as first tester)… fiddle with coils, wires and capacitors and other stuff!
I read that forum where guys (or seems to be 1-2 of them) made their diy coils… but ohboyh how many questions they had about the working principles of this tech! They were able to get a somewhat crude model… working at like 10-18% efficiency…
But you have to understand one thing : These guys are just going after the distance… not the power…
We are going after a power… since we can somewhat adjust what distance we will use to charge our boards!
I can actually show some crude graphs of what others, sometimes in ‘‘laboratory enviroment’’ achieves… and this is without taking into consideration, the New Zealander company, which seems to be working on this for 9yrs already!.. They got 100-150w units working… some of them are qute bulky for our needs… but non the less - they work at the required power levels we would need!
Im living with 80 charger for 192wh, so with 100-200w there should be enough power to charge decentlhy! When I will be able I will probably make a charging chart for newbeginners! This is somewhat easier than to make … battery chart with all the finnicky details batteries have in common!
id be happy to use this last chip and charge at 60 watts as long as i add a huge battery.
hoping to be spoon fed now what to do with the chip. This will be much easier than trying to reinvent the wheel though
http://www.ti.com/lit/ds/symlink/bq51050b.pdf
data sheet for it
I took a look at the chip!
I think it just needs a coil as in input… sort of like that…
Did you check one my documents I sent? There was some shematics info about Qi chargers and how they work… some answers might be in that document!..
1.5Amps per chip did not sound bad at all!
I assume with some extra cooling these chips could be run to their max rating!
Otherwise, for conservative purposes we should be running them at ~1A or so probably.
Plus, we have to look up if all coils are fine for this… some are rated only till 500ma.
If, we get 1A per cell group, then depending on how many cells in parallel, we would probably get around 0.33A per cell (3P pack), If we run 4P then it would be a bit worse…And this is one 1A capable coil per cell group… now we need to multiply this probably by the count of how many cells in serial we got (6-10S)…
If we had a chance to get 2A from single coil, then we could get the same power for 2 cell groups at once. So half less coils we would need to charge the batteries!
I just imagine how this would look like from charging perspective, if did get that 1A of power, at the receiving coil.
we’re not just connecting coils to cells this is pretty much plug and play stuff. if you look at the last link i posted if one inductance charger is attached to each cell it will effectively be a balancer. won’t have all the functions of a bms and all that safety but good enough for me.
there/s a chat forum that the texas instruments people have and I should get over there and maybe get it figured but i think it’s gunna be easy and there’s a matching part intended for this part.
just need to do the source side and break up the 120ac into…cant find it on the sheet but not a problem
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We will get to resonant circuits, dont worry! I think @Hummie is on the way to find everything commerically already made, we just need to put it all together…
I agree that building resonant circuit might not be as easy… but for some easy tests, it looks like signal generator can also be used! It just need to be able to ouput high enough frequency… with high enough power, I believe…
from what i read resonant is kind of a gimmick and it’s simply inductive but with better frequency coupling. nothing really different. plain old inductive up close for high power is good and this stuff already made by the pros has all the safety and testing needed and cheap i think. I’m still on the plan
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Hope it makes things little bit more clear for you.
@devin, this went too far from the original topic, for this reason, I deleted my posts, you should do the same and let’s talk about this in a PM ( which I sent you btw ).
your theory is already on the site many times I think. how bout leaving it in your thread so we can keep this to the topic
you can have induction without a core though. all the ones I posted don’t have one. I’ll give you my theory when I come up with one.
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i think you could get the 4.2 after the rectifier but lithium charging for safety needs a switch from cc to cv and a shut off of some sort I believe and that’s a complication that has to be added.
they use pure copper or close to it. the better the conductor the better for an inductor I’d think and it’s a layering of the magnetic field. the core adds more comlexity in the process. I think you can get much greater permeability and a much stronger magnetic field per amp with mu metal. it saturates quickly as well but as far as greatest magnetic field build able it’s top. maybe it’s chemical structure reveals why but …how bout what to do to put the parts necessary to get the board charged?
yes it would shut off. but theres more things that lithium needs with the cc cv i believe and going straight to the cell is bad for the batteries. the cc cv thing they like. I wish I could omit and simplify…but that chip is an all in one it seems.
i’m looking up the cc and cv thing now to see what the hell it’s about really but it seems mainly so the current isn’t too high,but dont think that would be a problem to begin with since the induction coils will only transmit 1.5 amps. but the “transformer” and rectifier need not be bulky or big. And bms break often.