Electronic circuit design for 12V battery balancing

I am looking for an electronic design using 'minimalistic components' to improve battery balancing. The circuit will be embedded inside the battery with not more than one communication cable between the batteries. 1. The balancing should work both series and parallel connected batteries / battery strings. 2. The battery current has built in sensors for current and voltage. 3. The cable used should be of standard type. It should be able to communicate between batteries and also transfer small currents between the batteries. 4. The circuit should be able to pick up information of the battery bank (12V), process the information internally and regulate the power flow in/out of the battery to 'actively' balance the battery bank. 5. No external controller should be used. 6. The balancer should use in any battery combination of series and parallel. 7. One additional cable between the batteries (preferably RJ45) should be enough. 8. Each battery would have two ports for making the connection. The connection topology should be daisy chain. 9. The target price of such additional component is $2 per battery (excluding ports). 10. The target size of the such PCB is 3cm x 2cm. The function of the balancer should be similar to 3305 (please check 2 files enclosed). However, this should be fit inside each battery and the batteries should communicate with each other (wired or preferably wirelessly). The existing cables connected between batteries should be able to transfer charge between the batteries - batteries with excess charge to transfer the current into battery with low charge.