Have two 871 Detroits on my boat and will move in this direction
I can not make sense of your configuration please let us know what is in each sell to complete the battery.
A 3 sell battery that I remember if my memory serve me well was as follow,
+,N,+,N,+,N, -,-,-,N,+,N.+,N,+.
BUT I never figured out the (N) plates are they bonded and lead to ground?
Absolutely a fine piece of work how many liters do you expect.
Regards
Shellback