Batteries

[arnolt]

Hey guys my 1993 F350 XLT 7.3 turbo diesel truck has two 12 volt batteries. Are they both used for starting? Is one for starting and one for 12volt accessories? I do not think there are any 24 volt items on the truck. Are they in series, parallel or independent? Could I run the truck with just one 12 volt battery? I have owned old British cars that have used two 6 volt batteries to make 12 volts for starting and running. I just have never seen two 12volts in a vehicle. Any thoughts, ideas references would be appreciated.

Thanking all in advance for any help.

Arnolt

 

[u2slow]

They are in parallel... acting like one large 12v battery.

The glow-plug needs of the ford diesels make it tough to get by with a single.

 

[arnolt]

Thanks for the reply. So 12 volts but double the amps for the glow plugs.

Arnolt

 

[u2slow]

Yup...

Its not the GP's that need both batts, so much as the starter still needs a lot of amps *after* the initial glow plug draw.

 

[IDIBRONCO]

Yup...

Its not the GP's that need both batts, so much as the starter still needs a lot of amps *after* the initial glow plug draw.

That's a pretty good way to describe it.

 

[Greenie]

A starter needs to turn fast to start a diesel. Gasoline engines are more forgiving with a slower starter.

 

[1mouse3]

Its not the GP's that need both batts, so much as the starter still needs a lot of amps *after* the initial glow plug draw.

Yea, the higher the compression the more energy is need to turn the load. These idi's are around 20:1 and my 390 fe is around 10:1, so twice the energy is needed. Gear reduction in a starter helps some but only so much can be done in a give size. The mini start I have for the fe is slightly slower than oem but can hold can hold a steady speed through compression. Throwing glow pulgs in the mix dose not help and is like leaving the headlight on for a bit before starting.

 

[arnolt]

Thanks to all for the info. Makes sense now given the glow plug/ headlight analogy. I guess these diesels need some serious amps to turnover and start.

Arnolt