Paralell Battery Wiring Revisited

A BIG THANK YOU TO TOM H,,,,,,,DOWNSOUTH,,,,AND ALL OTHERS

Good Sunday mornin to yall, Im well rested after last nights square dance woooooo hoooo

Below I tried my darnest to copy and paste Smart Gauges web page that in great detail with measurements explained the best way to wire batteries in paralell to equalize the battery current draw. BUT when I posted it in response to a question, the text posted but NOT the pictures grrrrrrrrrrrr. Of course we all agreed it will work either way the poster asked about BUT I posted YES in my opinion it makes a difference how they are wired, while others had opinions it didnt. None of us posted any actual current draw tests however using different connection methods.

PS I dont have the equipment time or patience to duplicate Smart Gauges tests showing different connections MAKES A DIFFERENCE, if anyone has the equipment to do what they did but obtained no difference in current draw regardless of connection methods, please let them know. Hey no guarantee thier test is accurate, Im ONLY the messenger but as an electrical engineer their research did make sense to me.

So thanks to Tom H and downsouth here are their efforts WHICH DOES HAVE TEXT PLUS PICTURES
explaing and showing tests results of different battery current draw using different paralell connection methods.

Tom H's post

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=ttalk&th=1067609

downsouth's post

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=ttalk&th=1067583

Thanks so much to Tom and downsouth and alllllll here, this is a great site with great people allllll willing to help

John T
Paralell Battery Wiring

No problem JohnT, happy to help. And besides, I thought it was an interesting article so I printed it out for future reference....of which I probably won't be able to find when I need it...:<D

It seems NO MATTER WHAT THE TOPIC a guy can ask a question on here and get help which is why I enjoy the site and even try to help others now n then when I can.

John T

The World Wide Web was invented to solve exactly the problem you had. Scientists needed a way to share information with each other, so they turned the internet into one giant web of hyperlinks.

Seems pretty obvious today but the guy who came up with the idea was knighted for his efforts (and no, we aren't talking about Algore):
Tim Berners Lee

Wow!!!!!!!!!
I really did not expect this to turn into such a long winded post because this is not a science project and a few minutes of run time either way is not going to make that much of a difference. I just figured if I am going to have 2 batteries I just as soon hook them up correctly to get a little extra run time and extend battery life as much as possible.

But since we are on a roll; lets kick the cat out the bag.
These batteries are for a 12v (boat) trolling motor I own.

Now we can hear how I should just scrap this perfectly good 12v trolling motor and buy a 24 or even 36 volt motor because the amp draw is so much less on these same thrust motors extending battery run time.

Heck lets take it one step further and talk about how buying the new $2000 (OUCH) Lithium marine deep cycle battery is going to save me money in the long run because they last threw so many recharge cycles. They are expect to last 10+ years and run at full thrust threw the entire charge rather than losing thrust power as the normal battery loses charge.

I left these points out of the original post because I can not see doing either at this time and know how easy it is to post suggestions when it is someone else’s money being spent. True if this motor goes bad I may upgrade to a larger volt motor just for this reason; But I can not see spending this extra cash at this time.

Thanks for the help. I learned a lot and yes that is why I love this site. Many people from many different carrier fields that can answer just about any question you may have.

You are most welcome, thanks for the feedback glad I helped.

I just dont see the Lithium Ion expense justified yet maybe years later when cost comes down, if they lasted x times longer and/or withstood x more cycles of charge n discharge MAYBE THEN but not now

Im attending a Lithium Ion seminar soon

Based on Smart Gauges research and current measurements Im confident IT DOES MAKE A DIFFERENCE how bateries are connected in paralell. Some have different opinions but offer no study or research or current measurements to rebut Smart gauge HOWEVER when they do (with proven aaascuracy and methodology and equipment) I will take a look. Still i dtn witness Smart gauges study so how we know if its right?? but it makes sense to me as an electrical engineer

best wishes

John T

The statement . . .

"a 24 or even 36 volt motor because the amp draw is so much less on these same thrust motors extending battery run time" . . . is not true.

To do the same work, a higher voltage motor draws less amps but runs on the same wattage regardless of voltage choice.

A 12 volt motor runs just as long as a 24 or 36 volt motor on the same size battery bank.

Some lets say a one 1/2 horse motor rated 12 volts is hooked to pair of 110 AH batteries hooked in parallel.

A second 1/2 horse motor rated 24 volts is hooked to pair of 110 AH batteries hooked in series.

Both will have the same run time.

Now with the issue of Ion batteries lasting longer then flooded-lead-acid? Depends how you figure it. Run time versus battery weight? Run time versus dollars spent?

I'm confused now, I have two 12 volt batteries in the Rv and I have them hooked as battery #1 with + to battery #2 + and battery #1 - to battery #2 - with the power coming from battery #1 both positive and negative to the Rv or would it be better to go to the positive post on battery #1 and the negative post on battery #2?

He (Tim Lee) didn't come up with the idea of the Internet. He expanded on the works of many others that came before him.

There was a crude form of what we now call "Internet" back in the middle 1960s - called ARPNET.

Stands for "Advanced Research Projects Agency Network". created by Larry Roberts. And even his invention was based on someone else's ideas before him. Later on in the early 70s, Bob Kahn and Vint Serf created the "TCP" protocol that enables the NET to work as we know it.

Tim Lee helped create hyper-text mark-up protocol language that many Websites use (HTML).
He did that in around 1990.

Can't give any credit to Al Gore that I know if.

The presence of the World-Wide-Web and the Internet certainly has it advantages and disadvantages - just about like any technology. We gain and lose at the same time.

Never before have people been able to post information - be it excellent or really bad - and have it travel around the world with the illusion of credibility because it's on a sort of TV screen.

Hooking directly from the NEG and POS of one battery puts less load on some of the cables. If all the cables are adequate, it really makes little difference.

If the two 12 volt batteries are in parallel, and you hook the power-demand to POS on battery 1 and the NEG on battery 2 - the power flow is more circuitous and there is more potential for voltage drop.

ABSOLUTEY YES IMHO We already hashed this over yesterday and franky most are bored to tears lol.

Look here for detailed reasons why with supporting current measurements. Other opinions may differ (saying it makes no difference) but until I see their evidence and supporting current measurements showing it makes no difference, Im going with what Smart Gauges experiments indicate as it makes sense to me, a retired electrical engineer, BUT they may be wrong, same as anyone her including myself may be wrong.

NOTE IM NOT GUARANTEEING SMART GAUGES RESULTS IM ONLYYYYYY SAYING IT MAKES ENGINEERING SENSE TO ME, BUT IM LONG RETIRED AND RUSTY ON THIS.

Its your choice, read Smart Gauges webpage, take your own current measurements, read opinions here and if anyone has taken precise current measurements that show smart guages people are all wet consider that also...

God Bless and best wishes

John T
Smart Gauges test results

I am not a electrical engineer but I will have to respecfully disagree with you.
All things being equal; Same 2 batteries; same size (thrust) motor; only differance is one is hooked up 12v and one is 24v.
The 24v motor will have a longer run time (small but still a differance) and the 24v motor will have a longer life span.
It has to do with heat generated by the motor; resistance over the wires. If you would like to prove OHMS law wrong go right ahead. We would love to hear your version.

I think that Ion batteries will be used by some for the discharge curve against available thrust power rather than battery life in years.
They provide full thrust for a longer time and then fall off quickly.
Where as regular batteries fall off from the start.

Note - to put in proper contest - I stated earlier that it "makes no difference" IF all the cables are large enough to not allow an undesired voltage drop. YES it makes a difference in regard to current flow and circuit lengths.

Since the guy that first posted this issue had a concern with extra running time (amp-hour-capacity) and not about amp-draw versus voltage drop - that is the context I answered to.

There are unique situations where a person might find it easier to hook up as the person first suggested. If he did, and wire sizes were adequate - it would work just as well.

OK we can disagree. You aren't going to convince me of any of that with Ohm's Law.

I assume we are talking about a difference a person can observe without test instruments and algorithyms.

In the real world, the resistance in the wires means absolutely NOTHING if you use the correct wire sizes, conductor material, and wire-run lengths.

If a motor is designed properly, a 12 volt makes no more heat than a 24 volt or a 600 volt motor.

You can take a four foot, one-way wire circuit and calculate a 1% voltage drop regardless if 12 volts or 200 volts.

Some people see a 24 volt system being rated at half the amp-draw and think the only half power is being used - which is ridiculous.

I agree, to use their (Smart Gauges) absolutely best connection method, it takes so many cables n connections Id fear voltage drop at any or all of them which is why Id just use their method 2 of + on one battery - on the other, which isnt all that hard or extra effort. As Ive learned soooooooooo many times NEVER SAY NEVER LOL there are always tiny exceptions, especially in engineering.

Were probably boring others to tears with all our detailed sparky chat, but hey were havin fun

John T

Fascinating. It sort of even makes sense to my old mostly mechanical type mind!
I've had a couple of trucks come with three batteries, but I get along with two, so fortunately I have nothing with more than two batteries.
For practical reasons, my newest tractor makes sense- two batteries, each with its own equal length and size pos. cable, each with its own equal length and size neg. cable. Easy to troubleshoot, maintain, and replace. No more of these very special one application only cables with two ends molded onto them.

Berners-Lee invented the World Wide Web, which (as you correctly stated) is not the Internet.

Al Gore was one of several in Congress who contributed to making ARPANET into the publicly available Internet we know today. He deserves some credit, but maybe not as much as he thought he deserved.