My bow thruster says 12 V on the motor but there are 2 12 v batteries hooked up in series (24 v). Why is that? The reason I asked is today I turned on the bow thruster and got a red light but no thrust . One battery test 13+ volts but the second one (also attached to the bow thruster) was pretty dead (6 v)...so I'll replace both batteries if necessary but why are there 2 12 v batteries if the bow thruster is 12 v?
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