wiring in dual batteries...

bigwaylon

bigwaylon

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Joined
Mar 22, 2005
Location
Charlotte
what does it take?

'89 D350 CTD...only has the single battery in factory location...

seems like dual batteries for a diesel is the way to go?

are they setup in series/parallel? or wired independently with some type of throw switch?

Greg
 
They are in parallel, and stock, they don't have any type of isolator or switch. Series would get you 24V. The dual setup is the trick for a diesel with or without heaters/glow plugs/etc.
 
"most" modern diesel trucks have dual battery systems, run parrallel (pos to pos to load, neg to neg to ground)

the idea is to have the added AMPERAGE boost of the second battery to help overcome the compression of the engine when cranking and spin the engine faster in the process.

Just adding a battery will help, but to have a RELIABLE system, it is best to have MATCHING batteries (say, dual Optimas) even better would be having matching batteries from the same lot, to reduce any production variances.

( GM was pretty cheap about it, dual 770 amp Delcos, that by design were junk off the shelf)
 
so, it's as "simple" as finding a place to mount one...then wiring pos of new one to pos of current one and neg of new one to neg of current one?

with matching batteries, if possible?

Greg
 
bigwaylon said:
so, it's as "simple" as finding a place to mount one...then wiring pos of new one to pos of current one and neg of new one to neg of current one?
with matching batteries, if possible?
Greg
Click to expand...
Yup, pretty much
 
since you're after amperage...would it work to slightly drop the amps on the battery if I'm going with two?

i.e. if there's a 700A (no idea...haven't looked) in there now, could I go with dual 600A and be OK?

or do they both need to be rated at whatever the OEM battery is?

Greg
 
The more amps, the more power to turn the engine over, faster starts will be the most noticable after the change (especially cold when the glowplugs/grid heater are also working MAJOR power draw).

RPM is what you want when starting, the faster the engine turns, the more compression it makes on turn over and will light off that much quicker.

Reducing the amperage will hurt to an extent, but you are looking for a smaller package, so yeah, there will be a trade off

EDIT: dual 900's would work great, over 1500 amps is ideal
 
Blkvoodoo said:
EDIT: dual 900's would work great, over 1500 amps is ideal
Click to expand...


so dual 800's would be fine? that's ~600CCA over the stock single battery...

not trying to cheap out...but no need to buy $400 worth of 1000+ CCA Optimas if I could get a nice setup for less...

my father-in-law deliveries batteries for a living, so I'll check and see what he has in the 800-950 CCA range...

no big rush...just want it done before it gets colder...

Thanks.
Greg
 
opinions of batteries are like opinions on oil or oil/air filters for the most part.

IN MY OPINION, Delco batteries suck ass, I've have good experiances with Exide batteries and Optimas, have one of each currently. and no issues. past ones have out lasted their expected life.

primarilly, as with anything else, you get what you pay for.

Get what fits, and make sure it has a good warranty.
 
if your father in-law delivers Interstate batteries MPO is to use the Mega-Tron Plus, I believe they are about 1000 cca for $75. to $100. ea. I have had very good luck with them. just my $0.02
 
1BIGAZZBURBN said:
if your father in-law delivers Interstate batteries MPO is to use the Mega-Tron Plus, I believe they are about 1000 cca for $75. to $100. ea. I have had very good luck with them. just my $0.02
Click to expand...


thanks for the feedback...I haven't checked with him to see what he actually has access to...

Greg
 
I will say this.. since we have been working onmy Dodge we have killed a yellow top that was 750 CCA.. so i went to advance and bought a 1000CCA and I can tell the difference betwen the 750 and 1000 when they are both fully charged..

I think if i can ever get this truck to run i wil be puttin in 2 - 1000CCA
 
BRUISER said:
I will say this.. since we have been working onmy Dodge we have killed a yellow top that was 750 CCA.. so i went to advance and bought a 1000CCA and I can tell the difference betwen the 750 and 1000 when they are both fully charged..
I think if i can ever get this truck to run i wil be puttin in 2 - 1000CCA
Click to expand...


I'll let you know how mine goes...

as of now, it's got a single battery, somewhere between 1000-1100CCA (I looked the other day, but don't remember exactly)...

I guess I'll have to fab a mount for the second...

Greg
 
separate post to ask a completely newbie question...

I know when I bought a replacement for the TJ, it needed to be a 34...

is that just the physical size of the battery "container" itself?

basic question is can I buy ANY 12V 1000CCA battery, and as long is it straps down, I'm OK?

Greg
 
Yes the Group or Size code is nothing more than case standards and mounting points.

All 12v 1000cca will ahve the same specs, so to speak, but they will looka nd mount differently

I.E. told hold down vs. the indent for the gm hold down deal at the bottom,
 
1BIGAZZBURBN said:
if your father in-law delivers Interstate batteries MPO is to use the Mega-Tron Plus, I believe they are about 1000 cca for $75. to $100. ea. I have had very good luck with them. just my $0.02
Click to expand...


when I told him I wanted a ~1000CCA battery, he spouted off something about a MTP blah blah blah...

said it's what the new Dodges run...

when I said something about the Mega-Tron, he said that's what he was talking about...

so, he'll call me back tomorrow when he gets to work with a price...

my only concern is the MTP-27 that I see all over the internet is rated at 940CA and only 750CCA...

am I looking for 1600CA or 1600CCA total?

he may be talking about something else...but we'll see tomorrow..


Greg
 
battery "efficiancy" goes down as the temp drops, hence the differances in CA and CCA ( cranking amps and cold cranking amps) I beleive the temp rating is at 32* or freezing.

Considering most GM diesels run 770ca batteries (even the bigger ones, they just use more of them) I don't think you'll have much of an issue with dual 940ca's.

Toughest problem it'll have starting is in the real cold weather when the grid heaters/glow plugs are working at the same time (MAJOR power draw), but it shouldn't be an issue with fresh batteries.
 
he called me back this morning...

the MTP-27 is indeed 940/750

he also has the MTP-24 which is 1000/800 for the same price...and he says it's the battery that NASCAR uses to crank their motors, so I'm guessing it can handle the compression...;)

I just looked online, and there's a MTP-65 which is 1000/875, so I've called him back for a price on those...about the same size as the 24 (my Dodge right now has a Deka class 24 single battery rated 1100/1000), and ~7lbs heavier...

if the price is right on those, I'll get two...otherwise, the MTP-24 will probably handle everything I need...

Greg
 
cool...

ended up going with the dual MTP-65 setup...

my cost including tax was gonna be $118 for two MTP-24 batteries (1000/800) or the MTP-27 batteries (940/750)....and only a little more, $134 with tax, for the MTP-65 pair...

figure it was worth a couple bucks to know I had the max juice I could find (without going to some kind of big rig or farm tractor setup)...

2000CA and 1750CCA ought to be just fine...:D

Greg
 
Last batts we bought at Kenworth (columbia) were ~$60/each

Not sure of CA/CCA/or group though

And I picked up a pallet, Im sure that makes a difference
 
ShyHiK5 said:
Last batts we bought at Kenworth (columbia) were ~$60/each
Not sure of CA/CCA/or group though
And I picked up a pallet, Im sure that makes a difference
Click to expand...

what brand? it'd be nice to know what the ratings were, and I'm sure the pallet pricing makes a difference...

the MTP-65 batteries list for $125.95, and have a Suggested Price (on www.interstatebatteries.com) of $104.95...so I was happy with my $62.72 price before tax...



back to hooking them up...are there battery cable connectors that allow two cables to be hook to the same post? I'm guessing that's an off-the-shelf part at my local parts store?

I have to get both batteries (tomorrow) and then figure out how to mount them up before I know lengths of cables needed...but just trying to get a jump start on how to set it up...

the batteries should be able to be placed right next to each other in the location of the current single battery...

Greg
 
There are 2 options I know of for hooking up.
1) Some trucks have a trick battery connector that has a wire coming out of each end, so it looks sorta like -o- with the o being the post connector

2) What most home made set-ups use. Buy the standard replacement ends with the bolts through the compression bar and put both cables under one looks more like =o

If that makes any sense.

The KW batteries, I will check this weekend when I am at the shop again (I help out for extra $$$) but I *think* they are just labeled KenWorth, but wont swear to that. Guy I work with has ~18 trucks all run 2-5 of these batts.
 
bigwaylon said:
he also has the MTP-24 which is 1000/800 for the same price...and he says it's the battery that NASCAR uses to crank their motors,
Click to expand...

:lol: Yeah, maybe for their own personal trucks, but the racecars use a tiny ass "Reactor" battery.

He's full of it.
 
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