[astrand]

I'm working on electric motorcycles and smaller EVs that use 125-150V batteries. From what I can find out, the CHAdeMO and CCS DC quick charge systems have a low voltage cutoffs of 200V and 250V, respectively. If this is the case, is there some convenient way of charging my batteries with these systems? A high power DC to DC converter? An on-board charger that accepts the DC quick charge? It would be great to keep the 100A + charging ability, if the batteries could handle it.

Difficult to recommend any particular solution without knowing more about the vehicles. For example, if you are already planning for a high power onboard charger, choosing one which accepts DC input sounds like a good idea. But otherwise, a non-isolated buck converter is probably as good as it gets wrt price and performance.

I suppose there's no way to reconfigure the battery pack for example into two strings that could be paralell during drive (125-150 V) and serial during charge?

Br,
Peter

 

[electro wrks]

Would a smaller version of something like this be on the right track?:http://www.ushybrid.com/documents/PDF/BDC2.pdf

Isolated? Non-isolated OK? Bidirectional?

 

[Kevin Sharpe]

the CHAdeMO and CCS DC quick charge systems have a low voltage cutoffs of 200V and 250V, respectively.

I would verify those figures in the 'real' world before undertaking any design.

Damien and Colin discovered that some CHAdeMO chargers did not meet the specifications with regards to low voltage operation;

 

[electro wrks]

God bless Damian, but listening to he and Jack Rickard drone on makes watching paint dry and batteries charge a real pleasure by comparison! He does confirm the info I have re the 200V lower limit some EVSE stations have in spite of the 50-500V CHAdeMO design specs. Zero motorcycles ran into this issue with their ~100V systems when they offered CHAdeMO charging as an option on their bikes. They quickly dropped the option.

Damian does briefly mention, with no follow up, "stacked-up Vicors [DC to DCs]" as an option for dealing with the too high a voltage cut-off problem. Unfortunately, there's no convenient way to add cells(as Damian does) and otherwise raise the voltage with the smaller vehicles I'm working on. Any other ideas out there?

 

[electro wrks]

Could these incredibly compact Tesla Gen2 10kW battery chargers handle a DC input? If so, two of them with their wide 50- 430VDC and 45A(90A total for two) outputs might work in my applications:http://www.ebay.com/itm/162561595701?item=162561595701&viewitem=&vxp=mtr

I have no idea how they might be tied to CHAdeMO or CCS inputs for this to work. Any ideas? At the very least, they could be plugged into separate circuit Nema 14-50 outlets at RV sites and residences for almost the same charging rate. And, possibly multiple J1772 plug inputs.

P.S.Should have known Damian is working on these chargers:https://www.youtube.com/watch?v=LqJ7HhS65po