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First gen dual batteries?

35K views 29 replies 12 participants last post by  Beefstick 
#1 ·
Has anyone put a second battery in their first gen to help with cold starting? I wired in a second one a couple of years ago, but they seem to be giving me more trouble than its worth. Batteries getting hot, grounding problems, lights dimming and brightening with the alternator. Has anyone else had these problems, or does anyone have any ideas.:confused013:
 
#2 ·
the lights dimming is probably the grid heaters cycling while its cold. i have a buddy at nashville auto diesel college and they just studied electricity. the instructor told him you can hook up a battery in a parallel circuit and double the cranking amps but stay at 12v. if you hook them up in series it doubles volts and keeps same cranking amps. parallel is positive to positive and series is positive to negative. i was thanking about trying it myself. whta kind of problems were you having ?
 
#5 ·
Mine had a single battery as stock, but I've got a heavy truck battery with steel posts (takes lead post adaptors) and something like 1300 CCA. Never any doubt about starting anyhow with this engine, but never know when a REAL cold start may be necessary. ... :shock:
 
#6 ·
The lights dim while its running at an idle, and every once in a while my blinker will make my dash lights and radio flicker.
denman, what make is the heavy truck battery you use?
 
#19 ·
Sorry beefstick I can't see the brand without removing my electric heater around the sides, ... I will if you REALLY need it, but looking at it made me realize an error: it's 950CCA, .... the other number is CA. It's size is LWH 13"x6 1/2"x9 1/2" and pretty well fills the tray and holder. ...
 
#7 ·
I got a good quality group 31, no problems starting even after running a camper for the better part of the week, including running the electric boat motor.

But...you should figure out any possible wiring issues before blaming the batteries 100%.
 
#10 · (Edited)
thats what it says in my buddies handbook at school to about connecting batteries. it was purty neat actually reading all about it. but yes im positive that connecting parallel keeps 12voltage and doubles cranking amps
 
#11 ·
You want your batteries in parallel to double amperage with the same voltage, series doubles the voltage with the same amperage.
 
#12 ·
2nd on that



2nd on that, parallel doubles amps, series doubles volts.
I got 4 batteries setup in parallel on my 12 volt solar system.

Check your grounds and other connections, having 2 batteries shouldn't case any more problems then having one.
Have you replaced altenator/volt regulator?
 
#15 ·
dunno, if you have the batteries + to + and - to - you shouldn't have any heat problems unless one has a bad cell causing it to continuously charge (this would also cause the batteries to go flat). also you should only put new batteries in parallel, used batteries will have different characteristics and drain each other.

as for the voltage regulation thats controlled by the pcm, if your having trouble with cruise, air, or overdrive then it wont be charging the battery.
 
#16 ·
Using an old battery could be my problem. When I wired in the second one I bought one new battery and used the old one. Its been two years, but they've had problems heating, and since it's gotten cold here (-15F) they won't hold a charge at all.
 
#17 ·
I have never found a high amperage battery at a 'normal' retailer. I have had to go to a battery specialty shop and pick the biggest one that would fit. The difference between my current 1100 cca battery and the 900 cca one I had used previously is like night and day. At minus 20 C, the old battery would just barely turn the engine over. Starts were touch and go. I have not seen a temperature where the high amp battery wouldn't crank it over just fine. I rarely plug it in because I am retired, might not drive it for four or five days and am too cheap to pay the power bill. I do have other vehicles which I use for short trips when it is really cold out. I expect that if it were below minus 30 it would be best to plug in for a few hours and I expect the big battery would light it up just fine. If I ran it daily, I would probably run some lighter synthetic oil to help out.

Get a really big battery. Dual battery set-ups can be trouble, sometimes.
 
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#18 ·
I'll have to check around to see if I can find somewhere around here that sells high amperage batteries, that sounds like it is exactly what I need. I switched to duals because like you say when its cold just one with 900 cca just barely turns it over. I agree on the oil. When it gets cold I switch to 5w-40.
Thanks
 
#20 ·
Don't worry about the extra trouble denman. I found someone here in town that can get me a commercial grade 1250ca 1050cca Interstate battery for $135. So I think thats the route I'm gonna take. Otherwise I might just go to Wal-mart and get two of their Everstart 850cca and go back to my dual set up; but with two new ones this time.
Hey, thanks for the help I really appreciate it. Getting this thing to start when its cold gets pretty critical sometimes. Right now the forecast is for colder yet (high of -6F on monday) so I better get busy.

Thanks
 
#23 ·
Also if you go the one-battery route you'll have one heck of a great power point at the other battery site for boosting or powering accessories, .... :thumbsup:
 
#21 ·
Without a battery equalizer/isolator in your dual battery system, you will have charging troubles. 2 batteries in parrallel will charge at different rates. Leaving on overcharged and one undercharged. It quickly damages both batteries. The equalizer/isolator controlls charge rate in each battery individually and greatly increases thier life.
 
#24 ·
this isnt accurate. if this was the case the dual battery systems in the second gens would fail. isolator are great for isolating loads (ie house and engine batteries in rvs) however not for starting youd need a massive relay to make this work.
 
#22 ·
That makes perfect sense now. One of my batteries in my dual system was always getting hot, while the other seemed fine. That would also explain why they went bad so fast. Thanks for the info.
 
#27 ·
Dual batteries (in parallel) do not require an isolator to function properly. If this was the case every GM or Ford diesel would have charging issues, as would the 2nd gen (and newer) CTD.

You DO need 2 identical batteries (same rating and age) if you are going to run them without an isolator.

No starter solenoid should be used for a "isolator" relay. They are not designed for continuous use and will weld the contacts in a very short time. Ever see the Ford that at first wouldn't start, but after 30 minutes of trying it wouldn't stop starting?? That is because the relay overheated from the constant current flow.


I do agree that 1 big battery will be easier (and probably cheaper) to install than 2 small ones.
 
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#28 ·
does any one have any pics of dual batteries under there hoods. i just bought one new batterie and have a fairly fresh second one sitting there. i just need to decide if im going to make a new batterie tray on the passenger side by possibly moving the washer fluid container or modifying the existing tray to fit two batteries.

i ran two different bateeries both capacity and age on my old toyota diesel with out any problems. but i was reading on this post that different batteries could be trouble?

maybe i will just suck it up and buy one big batterie either way i will be starting my truck in real cold weather not plugged in.

does any one know were a good source for a big batterie is in alberta or b.c.? local parts stores didnt realy stock them
 
#30 ·
Thats what I decided to do. I ordered a group 31 Interstate battery from my local dealer (who I used to work for). When I was running dual batteries I had both of them placed sideways on the factory battery shelf, had to be careful not to let the posts touch the body (used rubber from a mudflap) and I ran a second ground cable to the block. My problem was that I used two different size batteries, purchased quite a few years apart.
 
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