RE: Eletronic engine syncronizer **SUPPORT **
Reply now to using Lion/Lipo for glow drivers....
Glow driver circuits are very simple. If you use a single cell NiMh or NiCd then it is a simple on off switch. If you want to use a higher voltage battery like a single cell lipo or 4 cell NiXX the you have to have a regulator to drop the voltage. The other option I have been thinking about is a high speed current limiter but that is too deep for a forum discussion.
So here is the problem with a higher voltage battery at 4amps. A linear regulator is going to burn/convert the voltage drop x amps as heat. So 4 Amps from a 4.0V battery delivering 1.5V is a 2.5V drop at 4 AMPs. That is 2.5 x 4 which is 10 Watts. A TO-220 can only dissapate about 1.5W without sinking. A LM317 I think can only go up to 3A. Most are 1.5A. You should look at the LM338 which can go to 5A but at 5A with a 4.0V input and a 1.5V output you are going to have to convert 2.5V x 4A = 10Watts to heat. That is going to require a massive heat sink and fan. Even worse about 75% of your battery will be used to produce heat rather than light the glow plug.
The right way to do it is with a high frequency switching regulator that can run at >80% efficency.
Proabably too expensive for TwinSync glow drivers (i.e. ~$100 per pair rather than $50 per pair)...I am working with TBM to come out with so low cost high freq switching regulators but most guys don't understand the real value of switching versus linear regulators... this should prob be a seperate thread.