FMTV battery set up

[emmado22]

All,

I found this today, looking at the FMTV electrcial schematics.

Seems they use a total for 4 each 6TL batteries. I dont quite understand how they are wired. Can 2 of the batts be bad/low, and the truck still crank? Or do all 4 need to be good? I was told by my old maintaince NCO that the 900's use 4 batts, but only really needed 2 of them to crank up... Is that the same with the FMTV?

Anyone have any thoughts?

 

[cranetruck]

They are in series, parallel, just a confusing drawing. The bottom two are in parallel and the top two are in parallel and the two pairs in series.

There are 3 each 24 volt taps and one 12 volt, not familiar with the "tester" symbol, it usually symbolizes a fuse.

 

[emmado22]

The tester is exactly that, a tester. if it glows, the batts work.

So with that diagram, how much jucie goes to the starter? 24V, Im assuming? And if 2 of the batts were dead, would the truck still be able to start? with just 2 batts worth of 24V, instead of 4 batts worth?

 

[rmgill]

It would of course depend on how the starter was wired to the rest of the system.

 

[cranetruck]

Two batteries in series should easily handle the 300 amp or so for a starter motor, so if you pulled two "bad" batteries you could still crank the engine.

 

[halftrack]

The MTVRs use only two but the battery compartment can hold up to 4. the tm says 4 is used for extreme cold weather.