The shc35 and shc60 use the same battery pack-- it was a custom made pack of enercell 2 volt dry cells wired in series to make two 12volt banks-- if you ever took one apart you would see two rows of 6 cells each wired as a separate bank with a heating element run between them (the heating element maintained the battery pack above freezing when used in sub-zero temps)...... The internal circuitry of the heater is wired in a series/parallel configuration-- on startup, the two banks are in series to drive the glow plug--- after warm-up, the system switches to parallel mode for charging. The heaters have an on-board thermo electric generator which charges the battery as it runs essentially allowing endless operation in theory (in reality, you would have to shut it down after about 12-15 hours max to permit refueling (assuming you run the 5 gallon jerry can)......
The battery is big bucks from hunter engineering (now known as hdt technologies)...... You can find the abs black plastic case for the battery pack online as they are a commercial off the shelf (COTS) part. MCM electronics had them when I built two packs for my heaters a few years back. All you would need then are 12 enercell 2 volt 10amp dry cells (cost about $15ea.), a silicone embedded 12volt strip heating element (also found at MCM electronics-- or at least they were there when I built mine-- cost about $12), the appropriate molex conector (I cheated and used some connectors I had lying around), a fuse holder, and a good potting compound to hold everything in place and seal it up. Figure about $200-$225 to build your own.
As a side note, almost all the electronic parts on the shc35 and shc60 are COTS-- the only exception being the board in the remote wired control head (the IC on it is proprietary). Another little known fact is that most of the electronic components will interchange between the shc35 and shc60 to include the control head-- Hunter spec'd different part numbers for the control heads between the two but that was just due to the extra tones the shc60 could generate when troubleshooting which are explained on an extra data tag affixed to the control heads issued with the shc60. Otherwise the heads are identical and will readily interchange.
PM me if you have any additional questions or want to talk values-- the prices on these things are all over the place and can be high if you don't know what to look for......
Z
