Grounding Batteries in Parrallel

Switching my (2) 6-volt series to (2) 12 volt parrallel. Is it better to ground each neg. terminal seperate or run Neg. from first battery to neg. on second battery and then ground to frame. My thinking is ground each one seperately, but want to know what others think.

Electrically speaking it does not matter which way you do it but if you ground each on by its self then if you have a poor connection then you could still have at least one battery trying to do the job. My self I would hook them both to ground on there own and also hook them to each other and that way you have them pretty much hooked up even if you get a bad connection at one point or another

IMHO the best way that will transfer the most amps is attach separate ground cables from batt - post to engine frame or starter mounting bolts and run 2 + cables from batt to solenoid.

Absolutely agree with TX Jim. There was a link, I think on here a while back, that showed where multiple batteries are hooked together, and both cables go to the load from one end of the stack, the batt. at that end is worked heavier.

Your two 6 volt batteries in series provides 12 volts. Why do you think you now need TWO 12 volt batteries? One 12 volt would be enough unless I don't understand what you're planning to accomplish.

On my 706 Farmall, I did away with the 2 6's and went with one 12. I bought the best Interstate, 12V pickup battery I could find. Since I dont use this tractor a lot, I put a solar battery maintainer on it. It sets in a shed that is open to the south. I have not had a low battery issue since I went with that set up.

Now maybe if I had stayed with the two 6's, I would have spent twice the money and admittedly If I had put a solar maintainer on it, I wouldn't have had problems either. But I have half the batter terminal ends to keep clean.

Gene

Run 4 cables, 2 hot, 2 ground and put the ground cables under a starter mounting bolt. That eliminates a lot of rusty joints between parts where the power is trying to flow when you ground them to the tractor chassis.

BTW, that how my Steiger tractors are wired factory stock.

Let's study basics. Big tractor engines suck up a lot of amps to get started. My little 90 hp 2 cycle outboard motor is spec'd at 120 amps to start and the 115 version is up to 150. These engines are around 80-100 cu in with cranking compression around 150 psig.

Obviously a 400 cu in Diesel, with compression in the 500 range will easily master 200 amperes. Simple math tells you that 200 amps from a 12v battery, when you want at least 11v at the starter, doesn't leave you much, if any room for resistance in the interconnection.

The thing sucking the amps is the starter and it gets it's amps from the batteries......soooo you have to marry the batteries to the starter, not to other things with long small wire runs.

How done? Use 00 (2ought) wiring; wire the batteries in parallel with hots to hots (12v to 12v) and colds to colds (- to -).

The battery nearest the starter gets wired to the starter( 2 very short wires) with the same wire size. Battery + to starter solenoid, - to starter housing mounting bolt at the housing with all connections bright, shiny, and tight....scrape the paint off the interconnect area to get metal on metal.

Now you are talking and if you do this, which I have done on a 4230 with a factory designed/installed 6v on the right side grounded at the engine block on that side, running one wire over to the 6v on the left side with the + terminal of that connected to the solenoid.....all with 0 AWG wire,resistance of both batteries in series, rather than in parallel as it is in my arrangement (1/4 the circuit resistance)..........totally SUCKS!!!!!

With a fresh pair of 12v batteries (I use the 31 which is a 27 with 3/8" stud terminals....that OTR truckers use....much lower resistance than the regular lead compression terminals) and the wiring hookup I mentioned, if you don't think that 6 cylinder hummer won't leap to life on the coldest days with no assist, try it.....will make a believer out of you. BTDT and never had to use ether start again.

If you are serious you will do as I said for about $200 total cost. Neat thing about buying the OTR truck batteries, being heavy duty and all, the truck dealer bought the batteries by the skid and had his own cable making capability. So batteries were $57 each and cables/lugs made up the rest and that included a double wire run of 00 from the right side to the left side of my 4230 with cab.

Try it and come back and tell us how happy you are with your decision to DO IT RIGHT.....PFFFFFT ON MOTHER DEERE AND HER ELECTRICAL DESIGNERS!!!!!!

HTH,

Mark

One comment on 12 volt starter voltage. You mentioned a 12 volt starter needs at least 11 volts. Not true. 12 volt starters are designed to work properly down to 9.5 volts. 11 volts cranking voltage is very hard to achieve with a diesel car, truck, or tractor.

This was well covered some time back READ THIS

http://www.smartgauge.co.uk/batt_con.html

John T
How to Connect Paralell Batteries

Best comment I saw on the Smart Gauge page was way at the bottom on the copyright stuff; it said "Best read on a computer of some sort"

(quoted from post at 18:30:20 01/17/12) Best comment I saw on the Smart Gauge page was way at the bottom on the copyright stuff; it said "Best read on a computer of some sort"

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Hi we always painted earth points on aircraft with blue paint

to keep them from corroding, after making sure the connection was shiny

clean and tight.

Just a thought

Alontjavascript:emoticon('')

The important thing is to get good connections. If you can get better connections one way versus the other, then that's the way to do it. Generally speaking, if you stack two ground cables under a single chassis bolt, you'll get a poorer connection than if they are separated. Also, connections at the battery tend to suffer more corrosion than elsewhere, so connecting each battery separately eliminates a potential bad connection.

I'd ground both. That being said, I went that route on my 86 Hydro several years ago. I have since switched to one LARGE 12 volt battery and get along better.

It has nothing to do with the starter per se. It's how fast you can spin the engine to develop enough cylinder heat to explode the diesel mist. The higher the voltage, the more the current and the stronger the starter is to spin the engine so it spins faster developing more cylinder heat of compression.

Mark

Because I had the mounting space and wanted to max out the starting effort and didn't want to use any starting assist chemicals. On the Steiger 4 wire OEM installation great....the more the merrier.

Like I said before, I started my 4010D with a well used single trolling trolling motor battery but it was very easy to start.....never dug into why, nor did I understand how the TM battery, with it's small plate volume could push the amps required to start the tractor. Didn't care.

The 4230D only had 3900 hrs on it when purchased and was used for estate mowing. Nothing wrong with it once I got some amps to it. I probably could have done just fine with one battery located adjacent to the starter (left side mount). Buttttt as said, I was certainly pleased with my performance when I finished the upgrade and I accomplished what I set out to do.

Mark

(quoted from post at 09:33:31 01/18/12) It has nothing to do with the starter per se. Mark

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Mark
Your statement isn't exactly correct. There are higher torque starters that will spin an engine faster same as there are higher HP engines.

I understand the relationship of higher cranking-voltage equating to faster cranking RPM. I am also privy to the concept of a diesel starting better when cranking faster. My point was and still is . . . you mentioned a minimum of 11 volts. 11 volts (or higher) at cranking is very difficult to achieve in a 12 volt system and that is why 12 volt starter motors are designed to work well down to 9.5 volts. It's also why batteries are typically load-tested at 9.5 volts, not 11 volts.

A typical brand new tractor will crank at 10-10.5 volts in warm weather and 9.5 - 10 volts in cold weather. Getting over 11 volts at cranking would be very difficult and require a huge set of batteries and cables - even in warm weather. And considering a battery loses near half it's cranking capacity at zero F, it would be even more difficult in cold weather.