Mixing Chargers On a DC Bus (In Parallel Of Course)

WITH DIFFERENT CURRENT RATINGS?
7.4.1

You know by now that two chargers with the same voltage rating can always be connected in parallel. They may or may not share load current. If they have different current ratings, they certainly won’t share the current equally.

In SCR/SCRF chargers, you can have proportional load sharing using the forced load sharing option. In the AT charger, it’s OK to have parallel chargers with different current ratings, but you can’t use load sharing at all. The AT control circuit simply won’t allow it.

USING DIFFERENT CHARGER MODELS?
7.4.2

Users sometimes ask “Can I put an AT charger in parallel with an SCR/SCRF charger?” Yes, if they’re the same voltage rating. But they won’t get anywhere near load sharing. There is no way to force load sharing between different charger models.

FROM DIFFERENT MANUFACTURERS?
7.4.3

We knew this would come up. You want to use brand L on the same bus with an AT? We don’t see any reason it won’t work, but frankly, we haven’t tested it. The only foreseeable problem is that changes in load current demand might cause some instability due to differences in transient response between the two chargers, and/or differences in the charger output transfer characteristics.

Instructor

William K. Bennett

Former VP/Chief Engineer

HindlePower, Inc.

About this Instructor

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