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Why Do Diesel Engines Have Multiple Batteries?

Video Review

Video Transcript

in this video we’re going to be
discussing why most diesel engines
require two three four or multiple
separate sets of batteries to start or
charge their system
hey guys Josh for the add update channel
and in this video we’re going to be
discussing why most diesel engines have
more than one battery in them so if
you’re looking for the quick answer
basically diesel engines typically draw
more current in order to start them and
you need more than one battery to create
enough current to turn the starter to
crank the engine that’s the quick answer
if you want to know why that is stay
tuned and watch the rest of the video ok
so there’s gonna be different parts of
this video but the first one is yd
diesel engines require more current to
the starter in order to crank them over
well typically Diesel’s are harder
starting in general let’s take two
similar in displacement sighs engines
let’s say it Cummins five nine and a
Chevy 350 which is a 5.7 liter typically
your gas engine the 5.7 liter just needs
one battery but most trucks that are
gonna have a five nine probably gonna
have two batteries even though the
displacement is similar why is that well
there’s many reasons but the biggest one
is compression ratio so what that is is
the amount of air that enters the
combustion chamber compared to the
amount of air volume when it’s
compressed at the top of the piston
stroke gas engines are typically nine to
one ten to one diesels can be much
higher they can be fifteen sixteen
seventeen sometimes twenty to one
compression ratio and that is much
harder on the starter while you’re
starting because you’re compressing more
air into a smaller space now what other
reasons are there
well Diesel’s typically have a higher
viscosity oil which means the oil is a
thicker viscosity and especially in
quartered climates it’s harder to turn
the crankshaft to pump the oil through
your bearings while starting compared to
a gas engine which typically runs a
lighter weight oil what else while
Diesel’s can be harder starting as well
due to their fuel system depending on
the style of fuel system of course the
very old-style high pressure pumps we’re
typically easier starting than the Huey
system and electronic unit injectors
found on most of the heavier duty diesel
truck engines most newer trucks that
were gonna have a common rail system
which are very good for starting even in
cold conditions but still they have high
compression ratios typically thicker oil
heavier components a lot of reasons
they’re not only that some diesels are
gonna have cold starting or pre starting
aids now what can those be well it’s
coming glow plugs Inlet air heaters
things like that and what those are
gonna do is they’re gonna help heat up
the intake air or the combustion chamber
to help the diesel start easier and
typically these are some sort of heater
grid or a resistor type glow plug and
they drop a fair amount of current maybe
up to almost a hundred amps which a very
small car engine might draw a hundred
amps to crank but these items by
themselves might be drawing that just to
heat up the intake charge so that’s
another reason why Diesel’s might draw a
little more current than your average
gas engine while starting or before
starting I’m sure I get this comment if
I don’t make this statement not all
diesel engines have multiple batteries
in fact not all Diesel’s need multiple
batteries most car diesel engines are
fairly small and displacement and a
single battery will do but typically
once you start getting up six seven
eight liters and above you’re gonna need
additional cranking amps that doesn’t
necessarily mean you need two batteries
though now let’s discuss the battery
there’s no such thing as a diesel
battery your batteries are typically
12-volt even the ones where there’s
multiple batteries these are typically
ran in parallel which means the positive
of each battery is connected to the
positive of the other batteries or
battery and the negative of each
batteries connected to the negative or
negatives of the other batteries or
battery and this allows for each battery
to put out whatever cranking amps is
demanded of it by the starter so I’ll
get a 12-volt diesel engine start on a
single battery yes it could as long as
the cranking amp rating of the battery
is high enough so a normal let’s say at
24 a group 24 battery that’s not the
voltage that’s the group size you might
have let’s say 800 cranking amps if your
engine requires 800 cranking amps to
start this battery would work but if
your battery starts getting weak or you
have to end up cranking for an extended
period because let’s say you have a bad
injector or low fuel pressure the
battery might fail on you because it’s
even though it’s capable of putting out
enough current it doesn’t have enough
reserve capacity now let’s compare that
to a 8 D heavy-duty battery this is also
a 12-volt battery but notice the
difference in the cranking amps the amp
hours also the weight and the price is
going to be considerably higher so if
you have say a 600 cranking amp battery
in your car and your starter pulls 400
amps that’s gonna start the engine
if your diesel engine requires let’s say
800 amps and you have a 600 amp battery
the battery is not going to be able to
put out enough current to properly start
the engine now if you had 2 600 amp
batteries ran in parallel you would have
1,200 cranking amps available to you and
depending on the size of the engine and
the size of the starter that is going to
be with determines what kind of current
draw is coming out of your batteries now
most trucks are
twelve volt systems some specialty
trucks though can be 24 volt systems as
well as tour buses some RVs equipment
generators boats
those can be 24 volt systems and in
those setups they typically have to have
two batteries and the reason for that is
the 12-volt batteries are ran in series
now what is series
well series is where you basically
connect one battery to the other one
which will double the voltage of the
batteries but not increase the cranking
amp rating of the battery and I’ll show
you this little experiment to see what
I’m talking about so this little
experiment we have two D cell batteries
and they are 1.5 volts each and we’re
going to show you what happens when you
series them so each battery will be
independently one and a half volts DC
Animas or the other one as well and then
they’ll put them in series now this will
work on any DC battery you can see what
happens if you touch them together
okay just kidding so what we’ve done
here is we’ve connected the positive to
the negative the other and they’re
effectively in series so what it does is
it doubles the voltage so if you’re
running a 24 volt setup which most
diesel pickups are not gonna have a 24
volt they’re gonna be a 12 volt setup
you would need a series setup similar to
this so if you if you have to work on
heavy equipment or you hear some about
series that’s what they’re talking about
where two batteries are not connected to
increase the cranking amps they’re
connected to increase the voltage of the
system what about an RV setup where
there’s different sets of batteries and
some maybe six volt some maybe 12 volt
and they’re all in the coach let’s talk
about that well typically an RV is gonna
have chassis batteries and it’s gonna
have deep cycle house batteries so this
is a pretty typical sight on an RV the
three batteries on the right side that
are the brown darkish brown color and
the one on the ground we’re all together
and they were in something called
series-parallel whether you were using
two sets of six volts in parallel to
create a 12-volt deep cycle system and
then there’s the two on the left the
black batteries and those are your
chassis starting batteries so why would
you want deep cycle batteries in your RV
or in your boat well deep cycle
batteries are not meant for cranking
they’re meant for long-term at moderate
rates of discharge of amperage and
there’s a big difference between them
and cranking batteries typically a
cranking battery’s not meant to be
discharged all the way down to where
there’s basically very little current
potential left in the battery that’ll
damage the battery a deep cycle battery
on the other hand is not meant to put
out a lot of amps in short bursts it’s
meant to put out a moderate amount of
amps or a low amount of amps for a very
long time it can be discharged multiple
times without hurting the battery and
the difference is really the plate thick
in terms of the battery so let’s look at
some of the specs these are golf cart
batteries which a golf cart doesn’t
really start since they use an electric
motor for propulsion but you might be
using these in an RV or some other setup
where you don’t need a ton of cranking
amps for your house side of an RV but
you need a deep cycle battery because
you need a lot of amps over a long
period of time well I hope that battery
video helped explain why a diesel engine
would require more amps during starting
why these ones you might have multiple
batteries two three four or more and
what series in parallel is the
difference between the different battery
sizes a deep cycle and a normal starting
battery alright thanks for watching

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Finding the best battery for diesel trucks is not that hard because the competition is stiff and they all make great products. If you want to get the most out of your truck, you should make sure you have a good set of batteries and a good charging system.

One thing that has changed about the battery in recent years is the size. You can now find big batteries that will last for several months. This gives you more room to use your truck and be more productive. There are some things that need to be considered when choosing the right kind of battery for your diesel truck.

The size of the battery needs to be determined in relation to how long you plan on driving your truck. This is one of the key things to consider if you want to be able to do your job. A big battery will give you more power. Some smaller batteries can give you more power but will cost you a little more to run them. Make sure you find the right size of battery that is best for you. It will save you time, money and you will be able to work longer.

The type of battery that you get will be a lot different. Many companies use a Ni-Mh type battery. This kind is going to cost you less and it will give you better power. Some of these systems will charge faster than others and some are going to be easier to run.

The most important thing to think about is safety. You want to make sure you have a good charging system that can deliver high levels of power. There are some products that have been developed specifically to provide you with this kind of power. Most of these are still being developed and they are not available for sale on the open market yet. That means you will have to look into a company that sells these products and purchase them directly from them. This is also a good way to ensure that you have the best product for your diesel truck.

A good set of batteries and a good charger will help you get the most out of your diesel truck. They will help to save you time and money and you will be able to get more mileage.

Last update on 2021-04-18 / Disclaimer: as an Amazon Associate a Simply Philosophy team earns from qualifying purchases.

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Last update on 2021-04-18 / Disclaimer: as an Amazon Associate a Simply Philosophy team earns from qualifying purchases.