Paul, many, many years ago I discovered that instead of purchasing a battery powered arranger keyboard, the best and least expensive option was to purchase in inexpensive DC/AC inverter. Than you just connect it to your car battery and you can still use your best 110AC powered gear. Thus one is available at Home Depot for $85.
Gary

Edited by travlin'easy (06/18/19 12:01 PM)
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PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!
K+E=W (Knowledge Plus Experience = Wisdom.)