I guess every one with a $.75 chip and a $3.00 case wants to be in the SOC (state of charge ) business.
the Victon folks seem to be the latest entry,shunt sensing and fairly cheep.
$164 single bank, $206 for dual at Jamestown.
Reading Home Power mag , a great source for real info on most alternate energy concepts , the number of Deep Cycle battery MFg seems to grow daily.
Most are LA , and are priced up with Surettes , but some deals can be found.