Guests - If You want access to member only forums on FM. You will gain access only when you Sign-in or Sign-Up on Fishing Minnesota.

It's easy - LOOK UPPER right menu.

Sign in to follow this  
Followers 0
lungslicer

Duramax Diesel Question?

7 posts in this topic

Can anyone tell me exactly why I have 2 batteries under the hood of my Diesel. Do both batteries actually crank the motor? What do they each do? Does anyone know of a good website to learn more about Diesel motors? Thanks guys!

Share this post


Link to post
Share on other sites

Diesel motors have much higher compression than gas, that's why there is no spark plugs.

To start a diesel motor you have the compression and speed of motor to achieve the combustion necessary, that's why 2 batteries are needed, 1 will not have enough power to spin motor fast and long enough.

They are both charged by the alternator, follow the positive cables from each battery, you'll see they are bridged.

Which truck do you have ? If you do a Google search for your brand name forum you will get a lot of results. Check which one has most poster and you'll find the best ones out there.

Share this post


Link to post
Share on other sites

To add to what Valv already said, the engines have glow-plugs which require a fair amount of power before the engine even fires, so add that plus the high compression ratio (18:1) fighting the starter and you need that extra battery for easy starting.

Share this post


Link to post
Share on other sites

Yup, one battery MIGHT do in the summer, but come cooler weather when oil viscosity throws in another factor, both are necessary for the reasons mentioned.

Believe me, if GM thought you could get by with one battery, there would be only one battery there.

Share this post


Link to post
Share on other sites

Quote:

Believe me, if GM thought you could get by with one battery, there would be only one battery there.


I'll second that! grin.gif

Share this post


Link to post
Share on other sites

[Note from admin: Please read forum policy before posting again. Thank you.]

Share this post


Link to post
Share on other sites

You always will find a 2 battery set up under a diesel way more power required to start. Not so much now but wait till Dec-Mar that 15-40 oil is stiff. You will notice a hugh difference on colder mornings if you have it plugged in but that isn't always possible. Mine started last winter one day when it was -30 and wasn't plugged in. It wasn't happy but it did start grin.gif. Your going to love that truck I sure like mine.

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.
Sign in to follow this  
Followers 0



  • Posts

    • vanwalleye
      Nice thats what I like to hear, was doing an annual trip to LOW with my buddies, but to be quite honest biggest fish I ever saw in 10 plus trips was 27 inches, I caught 3 bigger than that on the pond last year, and hey I can stay in Wright county where I live and catch 10 inch walleyes.. I don't make it up to that end of the lake ever, usually fish the south end..Bought a wheel house this year, would loke to set it up as base camp and hopefully be able to head up toward that end and do some exploring..And thanks for the input, thinking there is a lot of readers and not many writers on this site nowadays...
    • eyeguy 54
      yepper
    • icepike 1
      Lake Marion is completely iced over. Hopefully we won't get much snow and be fishing soon.
    • popriveter
      Silver lake in New Brighton is iced over. I'm going to count one week before checking thickness on my early ice spots. Could be fishing next Friday if all goes well.  
    • fishingstar
      Hey eyes one thing nice is you have reveres to help clean out your holes