I installed a Cell-Log8S on the center battery box cell # 47 (the most negative) to #41.

Cell-Log8

That is 7 batteries. The Cell-Log will monitor voltage only, not amps in, amps out or temperature.

It will do some things that the Elithon would not.
Store a log of the monitored cells see http://saturn.lynnautorepair.com/node/519
Display the live voltages in digital or bar graph
High volt alarm
Low volt alarm
Difference from high and low alarm (delta)
Time elapsed alarm

The Cell-Log will only show 2 to 8 batteries.
Made by SHENZHEN JUNSI ELECTRONIC CO.,LTD

I paid $46 for the CellLog 8S and $9 for the 9 pin cable pigtail. Both item were purchased on eBay.

Specifications are:
*Lithium (LiPo/LiIo/LiFe) battery cell count: 2 – 8 series
*Pack voltage range: 4.0 – 43.0VDC (USB can provide lower voltage 1.0V)
*Alarm pack voltage range: 0.1 – 43.0VDC
*Cell voltage range: 1.3 – 4.9VDC
*Alarm cell voltage range: 1.3 – 4.9VDC
*Voltage display resolution: 1mV
*Current loading of test: 8mA
*Maximum voltage for alarm port: 50VDC
*Current drain for alarm port: <500mA
*Log Files storage: 16Mbit (43 hours@2 seconds logging interval)
*Sample logging time interval: 0.5 – 60 seconds
*PC Connect: USB port
*Weight: 18g
*Dimensions (L X W X D): 62X39X12mm (2.44″ X 1.53″ X 0.47″)
*PC software compatible with Logview at http://www.logview.info
See the manual at http://www.hillrc.com/UploadFiles/CellLog_8S.pdf