Hi Matthew hope your ship is running well.
you are spot on as usual Just one important factor the motor in question is rated at 9kw at an 180 amp input. The pack/charger combination seems to have been at its limit given the response to additional throttle.
With that motor I don't think you would have to go far into its performance curve to exceed the capability of any commercially available charger.
Also, near flat batteries do not necessarily have lower current levels. If the throttle setting is maintained there is a point where as the pack voltage goes over the falls (last 10-15% of discharge) the current output can rise dramatically.
In the situation of a near flat battery, being charged, being required to supply a greater motor input, it is likely the battery voltage would collapse as the short term current rose. I wonder if the charger was shutting off due to a too low battery voltage?
Cheers Andrew
On 15/06/12 08:12, Michael Mccomb wrote:
>
>
> i just saying that it is very unlikely the charger could put out
> enough current to run the motor.... so if the motor is using 30amps
> at 48v and the charger can only supply 10amps at 48v the 20amp deficit
> will drag the battery down more slowly than without the charger but it
> will definitely still drag it down..... if you down powered the
> motor to consume only as many amps as the 48v charger can provide then
> you would attain a steady state with no battery discharging
>
But also, the charger might not like it and shut down, thinking there
is a battery fault, or it may overheat when it finds it has to run at
full output for longer than it otherwise would if charging a battery.
Really probably the only people who can answer definitively are the
manufacture of the charger.
It's quite clear from discussions here on this list that some popular
chargers definitely will NOT like 'series hybrid' operation - either
over heating or thinking there is a battery fault.
In many 'UPS' situations it's normal for the charger to be charging
the batteries while the batteries are under load. (90%+ of the computer
UPS unit's out there for example). So any charger designed for such an
'industrial' environment will cope. But a charger designed for an EV
won't have that sort of need. Very few EVs can be charged and used at
the same time.
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