charging battery ?

[34PackardRoadsta]

Do you mean you found an Optima at our Coop? And if so, are there really two versions? When I bought mine, they only offered the red top 800 CCA.

[327]

No it's not an Optima and after I got there the moron had told me the wrong size and it was too big to fit! So I guess I'll just order the Optima like I should have.

[Guest 39Super8]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Speedster</div><div class="ubbcode-body">

But since 327's battery is located under seat, there's no need for this type cover in their '34.

</div></div>

My battery is under the seat as well. I just really liked the ease of installation. I was able to use the correct hold down, and the whole setup is really great looking.

What has really impressed me, is one PI region did the battery case and top, and correct positive and negative cables. Another PI region did the battery tray and hold down. No doubt, I could fabricate this stuff, but I couldn’t beat the craftsmanship and certainly saved precious time doing one stop shopping. Besides, it’s supporting fellow Packard organizations.

Anyway, you are right, this is an under the seat deal and is well hidden. One thing is for sure, the optima battery is not going to spew acid, and lasts a long time.

[1935Packard]

I have a quick and maybe totally naive question about the two Optimas in parallel discharging into each other. The guy who worked on my Packard put in two Optimas in parallel; he suggested that it was helpful because a v-12 could use the extra cranking amps. I'm curious how they could discharge into each other, though; if the two positives and the two negatives are connected to each other, and equally charged, where is the current going? Or is the idea that slight differences in their charge will lower the more charged battery to that of the lower one? I'm interested in part because I have had the need to recharge from time to time, although I thought it was mostly because I have been driving at night a lot with newer high-current halogen bulbs.

[Guest imported_Speedster]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 1935Packard</div><div class="ubbcode-body"> is the idea that slight differences in their charge will lower the more charged battery to that of the lower one? </div></div>

Yes, They are never exactly equal in charge so the higher charged one is always discharging thru the lower charged one.

And the rate of discharge gets Worse as the batteries get Older.

I don't know how long it takes to completely discharge them but it's fairly quickly, if they are not recharged by generator or charger.

[Guest 39Super8]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Speedster</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 1935Packard</div><div class="ubbcode-body"> is the idea that slight differences in their charge will lower the more charged battery to that of the lower one? </div></div>

Yes, They are never exactly equal in charge so the higher charged one is always discharging thru the lower charged one.

And the rate of discharge gets Worse as the batteries get Older.

I don't know how long it takes to completely discharge them but it's fairly quickly, if they are not recharged by generator or charger. </div></div>

Speedster, is this a situation you have experienced specifically with the Optima?

I have an antique Mack semi with four batteries in parallel and they have never self-discharged faster than a normal single battery. Many batteries are in parallel from flashlight batteries to just about every battery in heavy equipment. Some parallel, some series, and some series / parallel. If this is a situation specifically with Optima batteries I will not be replacing the lead/acid batteries in the Mack with Optimas.

[Guest imported_Speedster]

My only personal experience with parallel batteries is with Optimas, and they definitely stopped discharging after disconnecting one of them. I've never tried it with any other type battery.

But I was told by another Electronics Engineer that I was correct and that it's the same with any batteries in parallel. And it seems logical that would happen to any batteries, not only Optimas.

How fast they discharge depends on the condition of the batteries and how often they are recharged.

I've never seen a flashlight with batteries in parallel, only in series.

There's no discharge problem with them in Series, for higher voltages.

[Guest jjohnb]

My local Advanced Auto ordered an Optima for me to have as a back-up last week. I ordered it late Sat night in the store and picked it up Sun morning (next day)! They also dropped the price to $150 for me since I am in a couple car clubs (they discount for car club members). I also have a John Deere battery in the battery box of my '29 626 which has just under 1000 CCAs (looks more original than the Optima). I am at work and don't know the model number but can post it tonight if you would like. I can't fit a commercial battery in the battery box, only a standard size car battery. If you can fit a commercial battery you can find some (including some John Deere batts) that have 1100 or 1200 CCAs and high reserve capacity.

[Guest imported_Speedster]

I just had a thought. It may be that More than 2 batteries in parallel will discharge much more Slowly than 2 batteries in parallel will.

(example: 4 batteries), since the weakest would have 3 others to draw current from, instead of just the one. Therefore each individual battery would have less current drain, over a given about of time.

So, the more batteries you have in parallel, the more time it would take to discharge any of them.

[Owen_Dyneto]

Four six-volt lead-acid batteries in series/parallel giving 12 volts was a very common arrangement on heavy duty trucks and construction equipment for many years, as was two 6-volt batteries in parallel, giving 6 volts and 2x amperage. I'm not aware of any problems with such arrangements.

[Guest imported_Speedster]

I've found that One Optima can sit for at least 6 months (usually more) without recharging and hold a good charge, but with them in parallel they were discharging in less than a month, to a level that would not crank the engine.

I hope everyone realizes that I'm Not talking about an overnight discharge or something like that, with them in parallel.

[Guest 39Super8]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Speedster</div><div class="ubbcode-body">I've found that One Optima can sit for at least 6 months (usually more) without recharging and hold a good charge, but with them in parallel they were discharging in less than a month, to a level that would not crank the engine.

I hope everyone realizes that I'm Not talking about an overnight discharge or something like that, with them in parallel. </div></div>

You know, a good friend of mine collects antique greyhound coaches. He runs Optima’s’ in series / parallel and has not had the good luck I have had with my regular lead/acid batteries in parallel. I wonder if there is something strange with optima’s in particular.

The thing is, each cell is its own little battery with 2.1 to 2.2 volts per cell. They should discharge at the same rate once the difference in charge per cell has balanced, regardless of how are connected in series or parallel.

Interesting topic, I will ask my bus friend a few more questions.

The link to the tar toppers web page is great! They are practically in my back yard here in Phoenix.

[Guest imported_Speedster]

I did an experiment to determine how much current drain there was with 2 Optimas in parallel.

I used 2 fully charged 12.volts and put a calibrated current meter between positive terminals and with negative terminals connect with a jumper cable.

I connected them about 12 hours ago. When they were first connected I was getting only 6.2 milli-amps drain and this morning it has changed to 8.4 milli-amps. Which is much less current than I expected and much less change than I expected. I'll leave them connected a few more days to see if there is any more change.

It's difficult to see how only 7.mills or so could completely discharge them in a few weeks, but they certainly were. Maybe 6.volt batteries will discharge at a higher rate but that doesn't seem logical.

I don't have 2 conventional lead batteries to test, or I would do the same with them. My wife won't let me take the one out of her car, for some reason. LOL

[34PackardRoadsta]

Rick,

The red top 6V optima has a 50 amp hour capacity (as measured for C/20). So, that would, at an 8.4 milliamp rate, give you approximately 5900 hours before the battery would be 'dead'. That is a very slow self discharge, and about what I would expect from a spiral cell battery. Gel, AGM and spiral cell batteries really shouldn't self-discharge, either in parallel or series, if properly charged and maintained. I sort of wonder if you had a bad battery with an internal short.

Tom

[Guest simplyconnected]

Interesting discussion, but let’s do some math:

Let's use sixty milliamps, which is ten times more discharge than your six milliamps, and a 50-amp/hour battery. (I want a conservatively small battery. I’m sure yours has much more capacity.)

.06 amps/hr into 50amps/hr = 833 hours / 24 = 34 days. (Ten times that would be nearly a year.)

Lead-acid batteries form and drop sediment which accumulates on the bottom of your battery causing short circuits between the individual cells. New batteries have no sediment, so they hold a charge for many months (if kept at 70-deg.F). Charging your new battery once every 30-45 days is a practical idea. An older battery needs more frequent charge cycles.

Optima batteries wrap their cells like toilet paper (like a capacitor), which gives each cell a round appearance. They work exactly the same but they save space. Connecting batteries in parallel has no affect on discharge, unless one cell begins to severly short.

Consider, when your generator/alternator charges, the voltage is well above the battery voltage. After the battery is fully charged, and you turn your car off, the voltage slowly creeps down to a ‘leveling’ voltage (either 6 or 12-volts). Is it discharging? If it weren’t, you battery would remain at 7.2-volts (or 13.5) which is the charging voltage. So, some discharge is normal, then it levels off.

Your 6-volt starter will require an 800cca battery. Let’s do the math, 800amps x 6 volts = 4,800 watts (746 watts = one horse power). A 12-volt system uses a 500cca battery which delivers (500x12=) 6,000 watts! Nearly half-again the power of the 6-v system, using a smaller battery. That’s why 12-v starters sound more healthy starting the same engine.

I like the cut-off switch, but I laugh at the keyed security model. If anyone wrapped bare wires around the lugs a few times, there goes the security. Remember, every connection poses resistance; the fewer the better. - Dave Dare

[Guest imported_Speedster]

Sorry but you guys don't seem to understand what I'm talking about. My experiment verified that they ARE discharging.

When in parallel, One battery is Discharging into the Other battery. I don't know how to say it simpler than that. Any time there is current flowing with nothing else connected to them, then that is a Discharging battery.

There definitely IS a discharge flow of current, so over a month or so there is enough to run the batteries Down.

Both 6.volt batteries were Good (both discharged), since I continued to use them seprately with no problems and this test was done with different 12.volt batteries and both times there IS a current drain.

And It looks like the longer they remain in parallel the greater the amount of discharge, since the current drain is now up to 11.6 milliamps, so it's going up. The discharge probably started out so low since both batteries had been recently recharged. I think, If one had a lower charge then the current drain would have been much higher.

That will be the next part of my experiment, having one battery with lower charge than the other, to verify that the drain will be greater.

You can believe what you want to, but I KNOW they will dischage more than normal when in Parallel.

I will try to locate 2 normal lead batteries to do the same test and see how they compare. I have 2 but they are in cars that I don't want to remove them from.

[Guest simplyconnected]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: simplyconnected</div><div class="ubbcode-body">Connecting batteries in parallel has no affect on discharge, unless one cell begins to severly short.</div></div>

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Speedster</div><div class="ubbcode-body">When in parallel, One battery is Discharging into the Other battery. I don't know how to say it simpler than that. Any time there is current flowing with nothing else connected to them, then that is a Discharging battery.</div></div>

Then, you have a cell (or two) that is shorting and it is dragging the good battery down with it. A completed electrical path makes perfect sense and is easy to find. Check for one of the cells gassing off more than the others, OR, use a liquid battery tester (hydrometer) to check specific gravity differences. That will show a low cell voltage.

I did the 'battery in the trunk' deal for my son when he attended Northern Michigan U., on Lake Superior. I put a starter-relay and a diode between both batteries. The diode makes sure the alt charges both batteries, and the relay connected the batteries together, only for starting. Hint: Connect your relay switch circuit to the auxiliary battery.)

One time he was late for two finals. In his rush, he forgot to turn off his headlights, but he didn't have time to go back to the car. Sure enough, dead batt. With a flick of a switch, he was back in business. Up there, stuck in the woods, a dead battery can cause very serious consequences.

Dave

[Guest imported_Speedster]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: simplyconnected</div><div class="ubbcode-body">

I put a starter-relay and a diode between both batteries. The diode makes sure the alt charges both batteries, and the relay connected the batteries together, only for starting. Hint: Connect your relay switch circuit to the auxiliary battery.)</div></div>

That's a great idea, Dave

The diode and relay would also keep them from discharging into each other.

[Guest simplyconnected]

If you have a battery that is discharging, go get a new battery. There's no point in paralleling more batteries to it. Your generator is running overtime, trying to keep up and robbing HP. Your gas savings alone will pay for the new battery.

You can do the relay & diode circuit, just use a real big diode(s). I never measured charging amps, but my 55-amp alternator labors in the winter time.

On the 12-volt system, I ran two (pos & neg) #4-AWG THHN copper wires to the trunk batt just to safely handle starting current. A 6-volt system will need #0-AWG copper.

If you need help with the auxiliary battery circuit, let me know. - Dave Dare

[Guest imported_Speedster]

Dave,

Please read my pervious posts, they will explain why both 6.volt batteries were discharging into each other in parallel, they were both good batteries.

I later found that I really didn't need to parallel 2 Optimas, since they are so strong and don't discharge when setting a long time the way normal lead batteries do. Only 1 does the job very well. Since the 6.volt Optimas are so small, I first thought they would not hold a charge well, but they do, if using only one.

Presently I don't have any batteries in parallel in any of my cars.

Before that I only had experience with normal 6.volt lead batteries that were not as good, so thought I would parallel 2 Optimas, since 2 would fit in the '29s battery-box and try it, but it didn't work.

If I ever have the need to parallel 2 batteries in the future I will certainly use your idea of a high-current diode and a solenoid-relay, which I have, to keep them from discharging. Thanks for the tip.

[Guest JT]

Parallel battery connections are used in many applications without discharge problems unless the batteries used are of different ages, manufacturers or have internal problems (cell shorting). Connecting 2 good batteries fully charged in parallel should not increase the discharge rate.

[mrpushbutton]

I have used the 6V Optima batteries and I really like them.

Most of the 6v lead-acid batteries available today are made principally for the agriculturial or material handling markets and don't have the CCAs that a car wants. The Optima batteries have the CCAs in spades!

One word of warning though: install a heavy duty disconnect switch like the Cole-Hersee unit (avoid the green-knob 12V type) and use (shut the battery off) it every time you park the car, even if only overnight. The Optimas don't like deep cycling, and something as trivial as a glove box light will kill one dead if left on.

[Guest imported_Speedster]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JT</div><div class="ubbcode-body">Parallel battery connections are used in many applications without discharge problems unless the batteries used are of different ages, manufacturers or have internal problems (cell shorting). Connecting 2 good batteries fully charged in parallel should not increase the discharge rate.

</div></div>

Sorry, But I Just Proved that They Do Discharge, when in parallel!

Fully charged batteries discharge at a slower rate than unequally charged batteries, but they All discharge when in parallel. And the longer they stay connected in parallel the More the current drain Increases.

Connect 2 rechargeable batteries of any equal size together, with an accurate low-current Amp-meter, and you will see what I'm talking about. There's always current flow between them.

[Guest JT]

I think you've probably proven you have one battery that is weak. Maybe after charging batteries fully you could have a load test done on each battery to find the weak one.

[Guest imported_Speedster]

No, I've done this with 3 sets of batteries now.

First with 2 New 6.volt Optimas, (That's when I first saw the probem.)

Then a discharge Test, with Good 12.volt Optimas.

Then with 12.volt gel-cels, to verify they would discharge also.

This parallel current discharge is Very low, with good batteries, and if parallel batteries were being used in a vehicle that is driven a least every few days, this would Not be a problem. It's only when the vehicle or batteries sit for months without being recharged is when it really becomes a problem.

[Guest simplyconnected]

All batteries discharge if left alone. It's called 'shelf life.' Rechargeables have the worst shelf life. Lead-acid batteries by design, require fully-charged storage, or the plate sponge will degrade. Six months without topping off is far too long, for any rechargeable.

I agree with JT. We parallel every kind of battery (and power supply) with great success. More paralleled batteries output more capacity (coulombs of electrons).

Two batteries at the same voltage equal zero flow between them. Current can only flow if there is a difference in voltage. (That's why your gen/alt pumps out more volts than your battery rating.)

Check your battery voltage under a load. (I wrote Speedster a long PM about this.) You may be surprised to find one battery is lower. and pulling the good ones down with it. - Dave Dare

[Guest imported_Speedster]

Do the test Yourself, with 2 batteries in parallel, you will see that I'm Correct. 2 batteries in parallel are Never Exactly Equal in charge, there's always some difference. That difference, it may be very small or a great amount, is what causes the discharge.

That's the last I'm saying on the subject.

I am going to do the test with normal lead-acid batteries tho, when I can locate 2 known good ones, to see if there is any difference in results, if anyone else is interested let me know.

[R W Burgess]

Rick, I have four 950 CCA batteries in all of my big trucks. They can set for 2-3 months at a time without discharging, although it'll take 2-3 days of hard running to fully recharge them. On the other hand, one weak battery can pull the other 3 down overnight, until it won't start the next day. When you find the weak battery, you can unhook it, do a little charging and the other 3 will operate the vehicle until one or more of those bite the dust. I never throw (Sorry Dave,recycle ) old good batteries away. I generally replace a complete 4 battery set, but keep the good ones as backups. They are good for starting old pickups or for helping out a friend with a cheap replacement battery to get his through hard times.

Wayne

[Guest imported_Speedster]

Thanks, Wayne

4 batteries in parallel will discharge at a much slower rate than just 2 will, since the weaker of the 4 has 3 others to draw current from, not just 1, to keep them all charged longer. So your Info agrees with my discharge-test results.

[Tom M]

I wonder if you all got a good charge out of this post rotlmsao

[Guest imported_Speedster]

I can't say it was Better than sex, but it's been fun.

[Tom M]

Rick,

You know that word is over rated

I tell thou this was a very informative thread. I wonder if my battery is still good. It has been sitting on a battery tender o for over 2 years now.

[Guest imported_Speedster]

A trickle-charger definitely helps.

Slow charging doesn't do the internal damage to the battery the way fast High-current chargeing can.

[Guest simplyconnected]

Then, how fast does your altersparken charge yer battree?