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Old 12-24-2006, 02:15 PM
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dual batteries for starting

Hello! I did some searching here on the dual batteries setup, and most questions were related to running auxiliary electronics (sound systems, motor home appliances etc.).

My car's problem was always related to starting the engine. I am running a HEI, ministarter with a Delco 75Amp alternator (new from Napa). The battery is a 700 crank. amps, the biggest I could find at WalMart. I can turn the engine a few times just fine, then just click. So if the car sat a week, there is no fuel in the carb, I am most guaranteed to be stuck. A few revolutions to get fuel from the tank, then not enough juice to fire it up. I am running thick cables from the battery positive terminal directly to the starter, and a few cables for the ground (same gauge). There is no heat soaking issues

I have a Dodge diesel truck (1994) with a dual battery setup and it fires up just fine even after 5-10 minutes of cranking. So I would like to install a smaller battery in the engine compartment (I have room in the front) with the voltage sensing isolator for the sole purpose of starting the darn car. As you can tell, I am really fed up with it - I'd like it to be reliable.

Would this setup work for my purpose?
http://www.4wdsystems.com.au/html/isolators.htm

I want to use both batteries to crank the engine. Is this doable? Does the Dodge system work in tandem or one battery at a time to crank?

Your input is much appreciated. Merry Christmas to all of you!

Thanks,
Denis
'67 Camaro RS, 383, 3.73, TH350, Comp XE268, Harland Sharp rockers (1.5:1), Stealth intake, Edel. 750cfm, 9.4:1CR, 487X heads, Hooker headers, AeroFlow Chambers

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Old 12-24-2006, 04:16 PM
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You say mini starter, what kind?? As far as the battery you have ,it should be plenty with 9.4-1 comp. But you can get 1000 cranking in small package, interstate has a good product. The only problem with going for the big boy is that the more rated amps it has the more plates inside the battery. So in order for them to fit these plates in the battery case they have to be smaller,more of them but smaller. Which makes it more susceptible to vibration. Have you had the battery load tested? It is possible however unlikely to get a defective battery. With no load open circuit the battery should have 12.4 to 12.8 volts. Any lower than this indicates it needs a charge. 10 amp battery charger will take 3 or 4 hours to charge a partially discharged battery, and 7 to 8 fully discharged. No need to remove the vent covers if it has them,the caps have vents built in.Another common misconception is that a low battery can be charged by the alternator,Wrong, It will put a surface charge on the battery but when you really put a load on it it will fall on it's face.Now another thing that can cause a problem is if you have been cranking the car with a Bad battery?? It will burn the contacts in the solenoid and then it will start the dreaded Click. As far a the dodge system it is tandem. I was also wondering if when it starts acting up can you jump it with another car or charger?? I have lots of experience with starting systems and charging systems. I work as a fleet mechanic with 75 trucks (ford gmc dodge and freightliner) and a Yale 5000lb forklift. Let me know I will do all I can to help. will give you my cel # if you would like to converse on the ph about it.Brian
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Old 12-24-2006, 04:45 PM
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Thanks, Brian for the offer! I just did a 6 hour 12V 6AMP charge for the battery. The car started with a half-a-turn of the ignition key. No problem when there is gas in the carb. The voltemeter is showing over 14.4V while it is running. When it is turned off, 12.3V.

Yes, when it starts acting up, I can always jump it from a different vehicle. It is almost like I am lacking the last 50amps to start the engine :-) (ministarter is a Proform gear reducing unit).

I am just looking for some reliability like in my Dodge truck. Do you know any part numbers I can use off a diesel truck (isolator etc.) that I can slap together a dual battery setup that won't fail me in the parking lot? Any schematics I can solder together?

This battery passed the load test at the store. The customer rep already knows my face (I swapped batteries 3 times at the same WalMart for the past 2 years). I probably can pick a heavier duty battery and forget about it?

Would a red top Optima be a good choice?

With best regards,
Denis
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Old 12-24-2006, 05:00 PM
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try starting fluid, your carb may be leaking into intake, you may still have a bad ground some where, just a though
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Old 12-24-2006, 05:43 PM
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yeas ago i was long term camping/living in a 350 chevy van, and kept running the battery down listening to the radio.. We were doing reforestation and only moved the trucks once a week or so. I just put another battery in the cab and ran cables from the heaviest jumper cables i could find to wire both batteries together. I also got a solar trickle charger for the roof, and never had another drain down start.

The batteries were five or six feet apart, and no circuitry involved, just the cables.
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Old 12-24-2006, 06:30 PM
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My only concern to wire straight up, is uneven battery charging or drainage. It would be nice to wire it intelligently to distribute the load per 2 batteries while cranking.
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Old 12-24-2006, 07:17 PM
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Yeah I can come up with some thing if you want to do that.I will have to get to work and get the PN#s.But I think you will probably be better off with a red top optima.The other thing I was going to say is what model proform do you have is it the kind with a round solenoid or is it a hitachi/nipendenso stlye with the solenoid cast into the body of the starter.If you had a model number that would help. I have changed ours over to the Hitachi style. We had a proform with the round bolt on solenoid and it was crap,had it rebuilt by a quality local builder and it started to act up again with in a couple of months.(similar problem as you were having) Bought a Hitachi style and have not had any starting trouble since. about 160$$ anyway gotta go tuck kids away for santa to come..Seeya Brian
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Old 12-24-2006, 07:35 PM
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Brian, it is Proform, "Hi torque gear-reduction starter", part number 66256 (1.4 hp, 3.75:1 gear-reduction).

If you can email me at darom @ kern.ca.us the schematics (part numbers), I'd appreciate it. I am leaving overseas for 3 weeks tomorrow. Most likely I won't be able to check my email/post here, but I'd appreciate the info in advance.

With best regards!
Denis
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Old 12-24-2006, 07:54 PM
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sure thing, Hope your not going to Iraq???Will pray for you if you are!! Now the starter you have is the same one we had trouble with.I'll try to get you some PN#'s and some options. My personal E-mail is kgainey@jam.rr.com. Gonna put you in my email list...Merry Christmas Brian
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Old 12-25-2006, 06:43 PM
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your faulting the starter, considering getting a 2nd battery, but have you had a voltage drop test done to the battery? have 1 done, should hold 9.6V for 15s, but closer to 10v would be better. Wal Mart Battery's are sometimes crap.

you also say, your reading 12.3v with the engine off, with a good battery you should have 12.6 ( 2.1v per cell X 6 cells ). you may have a bad cell.
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Old 12-29-2006, 11:13 AM
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Doc here,

First , something is wrong if a STOCK motor won't crank over without all the Wiz Bang " addons...I submit you may have mechanical problems..

If not , though, you will need to use a battery Isolator for BOTH charge and discharge...

The charging system will see two unisolated battery's as a total resistance and the battery internal resistance in each will than equate to half that value..in plain terms BOTH battery's will charge to half charge and stop..leaving you with failing battery's and no start situations. (It will look at 2 low battery's as one battery)

If you go to an isolator, this malady will not be a problem. any good isolator from an RV place will suit your needs. Follow the instructions and GAUGE WIRE suggested and you should be fine.

YOU should first look at the battery cables and upgrade to a 0/0 cable or 0/1 cable and be sure the ground point (buss) is a a block bolt at or near the starter..you may just find that is the curative.

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Old 12-29-2006, 08:14 PM
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no mo wiz bang stuff

I realize that you both have valid points and Darmon and I discussed some things in private E-mails off the board. I have not talked to him a in a few days. And Yes I will blame the starter I had one. The "stock" style mini starters are "OK" but when you get ready to leave the crusin and all you get is CLICK,CLICK and and you want to it.Another thing that has not been discussed is if there could be a voltage drop to the pull in windings on the solenoid?? seen that too..... fairly easy fix for that too. I would like to see him have the starter given an AMP draw test.That usually will tell you a lot. I also Questioned the 12.3 V. That's like only about 60% charged if I remember correctly. And as far as the 2 batteries and not charging them??? I would like you to explain that further because we have vehicals that I work on every day that run 2 batts in parrallel and are 12.7 to 13.1 volts every time I check them and Yes I seperate them to check them individually. See ya Brian
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Old 12-30-2006, 01:45 AM
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Doc here,

Yes, the starter solenoid is a concern. This can be caused by under size wiring, poor contact in the neutral safety switch (corrosion) , or burned or pitted contacts in the Ignition switch itself..as well as a defective solenoid itself....

Quote:
Originally Posted by brian0605
I also Questioned the 12.3 V. That's like only about 60% charged if I remember correctly.
Unless your using a different composition plate formation and antimony base, a STANDARD H2SO4 battery at Static, at 12.3 volts is like 110% of chemical charge.

Here is an excerpt form BondBatterys: and the Link should you like to learn more about batterys:Battery Compositions

===============================================
Voltage

The voltage generated when two dissimilar metals are immersed in an electrolyte is determined by the chemical composition of each plate, and the chemistry of the electrolyte. Submersing a lead dioxide positive electrode and a pure lead negative electrode into a solution of sulfuric acid produces and electrical potential of 2.1 volts. Even if a number of positive plates are connected in parallel, and a number of negative plates are connected in parallel and both sets are immersed in an electrolyte bath, the voltage generated 2.1 volts, assuming the same materials are used. Only the current is affected by the number of plates per cell.

In an automotive battery, a group of positive plates and negative plates immersed in one electrically isolated section f sulfuric acid is called a cell. A typical automotive battery contains six separate cells electrically connected in series, so that the nominal voltage produced by the series is 12.6 volts.


Capacity Ratings

The battery was discharged at a constant rate for 20 hours, at the maximum rate that would still leave the average voltage at a minimum of 1.75 volts per cell (10.5 volts total for a 12 volt battery). The actual rating figure was determined by multiplying the battery's current output by the 20-hour discharge time. For instance, if a battery generated an average of 3.5 amperes for the 20 hours of the test, its rating would be 70 A-h. Today, two expressions of battery capacity are commonly used in the US. Cold cranking amperes (CCA) defines the battery's ability to start the vehicle under extremely cold conditions (its hardest short-term job). Reserve capacity (RC) defines the amount of time the battery can supply the vehicle's electrical needs if the alternator/charging circuit should fail.

================================================== ==


Quote:
Originally Posted by brian0605
And as far as the 2 batteries and not charging them???
It is a matter of internal resistance through the plate structure, and electrolyte..even though the battery's are in parallel, the resistance of the battery's becomes additive..What this means is, the charging system will always "Favor " the lowest charge unit..and bring that up to an Equal charge with the higher charged unit..(which may not be full charge either) Like a water level, it seeks "Equilibrium" in resistance..and See's the two battery's as a single unit..If , for instance , 50 % of charge exists on one unit and 25% exists on unit two, the charge system will bring the 2 nd unit up to 50% to match internal resistance of the first..and then shut off..It thinks the SINGLE battery is 100% charged..If you charge BOTH battery's separately, then each will receive 100% of charge and there exists no problem..This is why we employ AUTOMATIC BATTERY ISOLATORS..it does precisely that.


Quote:
Originally Posted by brian0605
I work on every day that run 2 batts in parrallel and are 12.7 to 13.1 volts every time I check them and Yes I seperate them to check them individually
Unless you are using totally different composition Plate structures , other than H2SO4 and , antimony base, 12.7 to 13.1 readings Don't add up..at least on a static battery..(see Above article) You may want to check the calibration of your test equipment..or if a meter, replace the battery's with fresh ones and recalibrate the unit.

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Old 12-30-2006, 04:35 PM
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12.66V 100%
12.45V 75%
12.24V 50%
12.06V 25%
11.89V 0%
When I reference the 12.7 to 13.1 that is the surface charge on the battery. If they are allowed to sit and stabilize for an hour or so they will be at the 12.66 volts. And as far as the two battery setup not charging the batts properly I still don't see it,and have never had a problem with the dual setup wired in parrallel. The only thing I have ever seen the Battery Isolator circuit used for is in motor homes and Big rigs. They were used to power the vehicals 12v accessories when the vehical wasn't running. The whole purpose of the isolator was to seperate the cranking circuit batts from the accessory batts so the vehical would crank should someone left something on to long, and some of the vehicals had and override switch that you could use to boost the vehical off in case something happened to the cranking batteries. The reason I say I can't see it is just the other day I had a truck cranking over a little slower than I thought it should and I brought it to the shop to check the batts and connections. When the batteries were checked one had 12.56v and the other was 10.32v. So either you arn't explaining what you are saying well enough or I am being dense??Which has been known to happen.....LOL....however I do like a good natured debate......Brian
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Old 12-31-2006, 02:00 AM
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Doc here,

I don't intend to debate the Chemical Reactions of a Cell, Since the Chemistry of a Cell made up for H2SO4 has not Changed in over almost 200 years, When Leyden was still making Electrolytic Capacitors ( Identical to a Battery Cell ) and Battery Cell Banks In fruit jars full of sulphuric Acid and two Dissimilar metal probes for batterys..A Full Charged H2SO4 Composition Cell, STATIC, is 2.1 volts...

If your seeing 13 volts..you have test equipment malfunctions OR an interfering outside source..

From Another Source:

Quote:
In any battery, the same sort of electrochemical reaction occurs so that electrons move from one pole to the other. The **--->actual metals and electrolytes used control the voltage of the battery <---**-- each different reaction has a characteristic voltage. For example, here's what happens in one cell of a car's lead-acid battery:

The cell has one plate made of lead and another plate made of lead dioxide, with a strong sulfuric acid electrolyte in which the plates are immersed.

Lead combines with SO4 to create PbSO4 plus one electron.

Lead dioxide, hydrogen ions and SO4 ions, plus electrons from the lead plate, create PbSO4 and water on the lead dioxide plate.

As the battery discharges, both plates build up PbSO4 (lead sulfate), and water builds up in the acid. The **--->characteristic voltage is about 2 volts per cell,<---** so by combining six cells you get a 12-volt battery.
Using a little Elementary School math, you can see..2.1 Volts per cell IS 12.6 Volts at 100% of charge..

SINCE the metal in the plates did not change, and the Chemical compound did not change, , it will ALWAYS achieve 2.1 Volts per cell...( If not defective) In the case of an Electrolytic capacitor, it has a "Working Voltage" set specific to the Cap ( Identical to a battery Cell) EXCEED that voltage for any amount of time, by more than 25% and the Cap heats or explodes..as well as a reverse polarity..

Isolator's are used Quite Frequently, Such as in the Area I install them, ENG's , Ambulances, Fire Trucks, (that use duel or more battery system systems ALL the time, during calls, or News Shoots, where non Isolated battery's would fail) AND they DO automatically charge whenever you operate the power plant, (provided you install the proper isolator.)

The reason is, because no matter you are running two battery's in parallel, and the voltage remains at the same level, the current is (whatever both battery's are capable of) in parallel, the INTERNAL resistance or BOTH battery's becomes additive..This has a direct effect on the charging unit of the system, more specific, the regulator..

Apply a little ohms law E=I/R..say, 12.6 volts at say, .5 ohms..you get 25 amps for ONE battery...double that and your numbers increase..as the cell charges or discharges, the resistance values change also..If two battery's in parallel , If you have say, two battery's requiring 75 amps to charge up, the the regulator looks at both battery's as a single unit of resistance..and referring back to our old Friend OHMS law, the Lower the voltage the higher the current..The regulator will shut off before Either reaches a full state of charge..because it has saturated Over the threshold of power capability. The Automatic Isolator Separates the systems NOT only at discharge BUT at Charge as well..so both get a full charge.

You can believe what you want or were told, as I said, I don't intend to labor the points..and if it works for you , will fine. The fact you say you work on a fleet of Vehicles DAILY with duel battery systems is kind of telling though..We at best only see Battery maintenance twice a year on Isolated Systems.

I've been in The Industry for better than 37 years, My first playground was My Father's Chem Lab, and Manufacturing Plant..(which at the time, before HAZMAT, was the lower floor of our residence in the early beginning,)

He Owned The Master Chemical and Battery Corp. And is (Was until his death) and Myself and Brother were involved as we grew up, The Holder's of.. United States Patent 4245015, The First H2SEO4 (Selenic Acid) Battery Cell..a Less Caustic battery cell.

Here is an abstract of that patent..
Quote:
Originally Posted by US PATENT OFFICE
Abstract: An electrolyte for lead plate storage battery comprising selenic acid (H.sub.2 SeO.sub.4) in aqueous solution at concentrations ranging from approximately 0.3 grams to approximately 4.0 grams of selenic acid per liter of electrolyte; the preferred embodiment of said electrolyte containing additional material selected from the group consisting of ferrous sulfate (FeSO.sub.4) at concentrations ranging from approximately 0.1 grams to approximately 8.0 grams per liter of electrolyte, sodium chloride (NaCl) at concentrations ranging from approximately 0.1 grams to approximately 4.0 grams per liter of electrolyte, and manganous sulfate (MnSO.sub.4) at concentrations ranging from approximately 0.005 grams to approximately 0.1 grams per liter of electrolyte.
Enough kicked around about this, Let's get around to the Poster's Original question and help him back on the road.

Doc
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