Engine/Transmission (1998.5 - 2002) Why 2 batteries?

[BSowers]

As 15w40 stated the grid heaters shut off when the starter is cranking. Is this true? How many amps DO the grid heaters suck any way?

My thought of isolating was strictly for the purpose of giving the grid heaters their own battery so they wouldn't suck down the starting/operating battery.

 

[EricBu12]

I replaced my 2 batteries for the 1700 amp Odyssey battery from Mr bob's dist. it has a warm 1700 amp rating and is sorta a deep cycle, can cycle 400 times 100% drain with no problem. It is a dry cell so cold weather doesn't affect it as much as reg wet batteries do. Wet batteries lose a 1/3 of their power when really cold thats why they have battery warmers and such.....



I have been told that this starts up in 10 deg. with no problem. If I were in a climate like -30 them I might have 2 of these.



<img src=https://www.turbodieselregister.com/user_gallery/sizeimage.php?&photoid=5420&width=2/src img>

 

[15w40]

I found the reference to the grid heaters in my ‘98 shop manual. It states that the PCM (not the ECM as I posted above) controls the grid heaters based on the intake air temperature. The PCM is programmed with a battery saving feature.



It will shut down the air heater relays if:



* the engine starter is operated during the pre-heat cycle

* the engine stalls during the post-heat cycle

* the engine starter is operated for more than 10 seconds during the post-heat cycle

* the vehicle speed is above 18 mph during the post heat cycle.



Each grid heater will draw 95 amps at 12 volts.

 

[krs]

EricBu12,

You should never have a problem using a battery with that much current - it's more than both OEM batteries supply, isn't it?



We were in stop and go traffic through Eugene, OR one night and my grid heaters kept cycling as we went for no reason that I'll accept. So I diconnected both of them and they've stayed that way for nine months now, The truck fires right up and didn't seem affected by our 20s and 30s winter nights. A code is set for each solenoid but it's not serious enough to light the 'check engine' light.

 

[EricBu12]

KRS,



Go to practical solutions and get the heater savers. It disables the heaters when the coolant temp is above 70 deg. makes the heaters work in the winter and when the engine is above 70 deg. , the heaters stay off, even if you go to a store and the engine is still warm... .