lutful... of ideasPremium
|reply to elios |
Re: PSU's and DC-DC convters or Is There An EE In The House!?
said by elios:I actually said that in my first response when I thought you were trying to rapid charge packs at 40A.
well the thing is more then 5C change rates will damage the packs so no point in charging over 4C really ... almost no one charges at over 4C its just not good for the packs
FYI some electric cars and military gear safely charge lithium polymer packs at 10C and some UAVs/drones (not that different than your RC helis) are actually rapid charged at 20C. That is possible because they implement proper per-cell safety monitoring and true CC-CV algorithm.
However, the system I imagined would definitely have adjustable constant current which could be set for example between 0.1C to 10C for each pack based on its electrical specs and application needs.
said by elios:Yes ... but X independent smart charger modules can be packaged more easily in an enclosure with 120V/240V switchable AC input and internal bus that could distribute upto 30A. System controller could ensure maximum 15A@120V or 30A@240V current draw for all active chargers.
needing 2kw+ of power to run the thing the really limit is the power coming out of your wall
Anyway, I found 2 off-the-shelf LT automotive chips (used by Mitsubishi) which could be used for the RC industry. Each independent charger module could handle upto 12S packs at 50.4V/20A with these chips and total system cost for 8 pack solution should be less than single monster parallel balance charger with required accessories.
the check the cell chemistry on the fast charge cars there not Lipo they are using Li-Fe/A123 which you CAN charge an insane rates
we use Li-Fe for things like TX, RX and ignition packs
the trade off is Li-Fe weighs more and has lower per cell voltage
not ideal for flight packs
there just isnt a need for that kind of a charger
when with a 40amp charger you can do 6 packs at once
even bird that needs 2 at time thats 3 flight
12 packs and you can fly back to back all day long
and with the Powerlab you can link up to 16 of them lol to run of the setting of 1 IF you REALLY need that much
your avg RC guy rarely needs more then a 20amp to 30 amp charger
and the guys wanting setups like me are few and at the top end of the hobby
lutful... of ideasPremium
said by elios:Many production hybrid cars have been switching over to lithium polymer since Hyundai did it back in 2008:
check the cell chemistry on the fast charge cars there not Lipo they are using Li-Fe/A123 which you CAN charge an insane rates
The Elantra LPI HEV will be the first car in the world to use lithium polymer rechargeable batteries ... significant advantages over lithiumion batteries including higher energy density, lower manufacturing costs, being more robust to physical damage and they can also take more chargedischarge cycles ...
said by elios:Powerlab appears to be the end of innovation for RC folks.
... with the Powerlab you can link up to 16 of them lol to run of the setting of 1 IF you REALLY need that much
Anyway, your original problem is solved by a multi-phase DC-DC boost converter: more phases = more current @ constant voltage.
it pretty much is untill we get a new battery type any way
|reply to lutful |
got my stuff in and setup
PSU is putting out 25.5v so should be good to go
only tested up to 30amps on the charger so far but looks good