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running LEDs 12 or 24 V

4.6K views 93 replies 18 participants last post by  VShooter  
#1 ·
Is there an advantage in running a battery setup with 2 12V batteries in parallel or is series for a 24V circuit. Are they brighter 24V? i know they use less amps 24V but also use more V so is there a battery life differance one way or another?
 
#42 ·
My point is power consumed will be the same whether you run leds on 24 volts or 12 volts. If the power consumed from the batteries is the same-12 or 24 volts-battery discharge rates will be the same 12 or 24 volt. Same discharge rate=same run time.
 
#43 ·
Yea I can see that I'm saying a 12v bat. With a 30 amp hr will run say 244 mins. So series it up with one one same battery does the run time double? So that a four battery 24v will last twice as long as a two battery?
 
#49 ·
Since we are now talkin apples and oranges,beendare,......I know a thing or 2 bout them:
Oranges is way more better cause if you ain't got nothin
ta drink,an you eat one,you ain't thursty no more.
Also you can use the juice from the Orange peelins to get stains out and clean stuff.

But come to think bout it,I like me some apples pretty good too?

Not sure on wire size OBG,used old stuff layin round.
 
#51 ·
and that Peukert was a friend of mine.............Couldn't shoot worth a dang.....

Am i reading this chart wrong or what? View attachment 18461
I think you are probably reading it right but not taking into consideration that it takes two 12 volt batteries in series to make 24 volts.
 
#52 ·
So whats your guys opinion, I got a 14 ft boat with batteries in back and led's in front. wire 24 volt or 12 volt? I'm thinkin just go 24 so I can save money on wire. cause from what you guys have been saying thats really the only advantage right?
 
#53 ·
If these charts and my methodology are correct, there should be a clear advantage to 24V.

Assume you have a 240 watt demand which is 20 amps at 12volts and 10 amps at 24volts

taking from the chart above; a 27tm gives you 207 min @ 20A, and 515 @ 10A
Connect 2 of these batteries in parallel [12V pulling 20A] gives you 2 x 207 =414 min
Connect 2 in series [24Vpulling 10A] = 515 minutes......................a 24% increase
 
#56 ·
It's actually a confusing question with a simple answer. Had me scratching my head and thinking twice when the discharge rate issue was brought up some time back.
 
#57 ·
Beendare you are correct. because one battery doesnt produce 10 amps and the other 10 amps, they both produce 20amps in parallel and are subject to peukerts LAW.
If your theory was correct the chart would show batteries having higher capacity(2 batteries in parallel) they would not suffer from lower reserve capacity, but they do at higher amps.
I think their is a lack of understanding how capacitance effects a lead acid battery, this isnt simple ohms law here.
 
#59 ·
If that were correct 2 batteries in parallel would have the same run time as a single battery-load being equal. imo
 
#58 ·
Easy enough to find out. Someone needs to hook up some leds and run them 12 and 24. Figuring that the low voltage cut off will favor the 24 volt set-up, 20 amps @ 12 volts worth of leds should run about 2 hrs longer @ 24 volts on two standard group 27 deep cycles if you guys are right. I don't see it happening but have been wrong once or twice before.lol
 
#60 ·
If you parallel them their capacity doubles, same potential driving them but twice as "big" of cells. All of which have a chemical reaction to produce 20 amps out of every 2v cell in the the 12 or 24v system. Cant confuse capacity with discharge rate.
As far as testing, it would be very difficult to guarantee the batteries in the exact same condition, same electrolyte levels, etc etc.
For the record I do think manuf. are over cautious with their ratings and deratings, a cover their a$$ thing I think.
 
#61 ·
If it were only a few minutes difference in run time I would agree that testing would be hard. Since it's almost 2 hours difference testing would be easy imo.
 
#62 ·
OK ,this is bugging me....

I called the tech line for US Battery and posed the question to them "any advantage time wise hooking it up in series 24v or parallel 12v?"

He basically said what OBG is saying- you have a finite amount of storage and it works out to be the same either way. He said you have to think of the parallel setup as 2- 12v batteries each drawing 10a [in my 10a at 24 and 20 at 12example]- not 20a total. So there is no 'added time" wiring at 24v.

A couple other comments I found interesting;

He said you cannot think of battery power as linear. He gave the example of drawing a lot of current cranking your car over for 2 minutes straight- battery poops out. So drawing very high amps consistently is not how these batteries work.

He also said there are more problems with parallel installs than series....didn't really get into the "Why"
 
#63 ·
I called the tech line for US Battery and posed the question to them "any advantage time wise hooking it up in series 24v or parallel 12v?"

He basically said what OBG is saying- you have a finite amount of storage and it works out to be the same either way. He said you have to think of the parallel setup as 2- 12v batteries each drawing 10a [in my 10a at 24 and 20 at 12example]- not 20a total. So there is no 'added time" wiring at 24v.

A couple other comments I found interesting;

He said you cannot think of battery power as linear. He gave the example of drawing a lot of current cranking your car over for 2 minutes straight- battery poops out. So drawing very high amps consistently is not how these batteries work.

He also said there are more problems with parallel installs than series....didn't really get into the "Why"
"He said you cannot think of battery power as linear. He gave the example of drawing a lot of current cranking your car over for 2 minutes straight- battery poops out. So drawing very high amps consistently is not how these batteries work."
The chart shows this.

"He also said there are more problems with parallel installs than series....didn't really get into the "Why""
I think wiring in parallel like the picture will take care of a lot of the "parallel" isssues.
Image
 
#64 ·
All this technical talk makes my head feel like I been shootin rite next to the genny all nite.
24 v more better with more lites.
Oranges more better den apples.
Flounders is more better den stingerays.
A ticket to the game is more better than a ticket from the man.
Coming home smellin like fish at daylight more better den smellin da perfum.
all the above,i guarontee.
 
#65 · (Edited)
I just spoke to the same tech, he said you talked to him, I had a good talk I kinda pushed on the why;). So I will fully eat crow, each battery, IF WIRED PROPERLY, will provide 10 amps or close to it depending on each circuits resistance/condition. And peukerts is not applicable, I apologize.
But I was not incorrect that a 24v will provide more run time, the tech went on to list the many advantages that make 24v more efficient and provide longer run time,as well as longer battery life that were pointed out earlier in the thread, such as parallel cells will discharge in non-use if uneven.
 
#67 ·
Well if you were correct and 24 volts will provide more run time why eat crow? There is no such thing as kinda right or kinda wrong. If in the led scenario mentioned by the OP the led's will run noticeably longer on 2 batteries in series than in parallel share the info as to why. I'm always open to learn stuff. For real-not being a butthead just truly curious.
 
#68 · (Edited)
Im eating crow because I used peukerts as my main reason for 24v being more efficient. I knew the difference was not as large as the chart. As I stated the tech pointed out, and I did earlier, the big issue is with paralleling cells, if one is weak all are weak, and the stronger is burdened with evening out the parallel circuit. In series it does not effect other batteries it just lowers its %. Batteries wear out, it is inherent, as is the rate at which they do so, they actually do so from the second they are manufactured.
Basically twice as many amps equals higher losses from a finite source so its likely paralleled batteries will be uneven. Also charging paralleled batteries can cause issues, such as overcharging one cell or not enough on others.
As I said early, there are many advantages to higher voltage all things equal. If it were not minnkota wouldnt use 36v on the 101 and they would just tell you to parallel 3 batteries, and it isnt JUST wire size.
So again I apologize for pushing peukerts in the particular scenario, and stand by my position 24v is superior to 12v here.
 
#69 ·
Hopefull the original poster got his questions answered. If not---well at least he got a lot of interesting reading.
 
#74 ·
If you guys want to believe paralleling your batteries making all your batteries as weak as the weakest battery means same run time as series circuit without this flaw, well I guess I should get some stock in a battery company. They say ignorance is bliss, but I just dont see it. lol
 
#75 ·
Seems to me a weak battery would affect parallel and series. If that makes me ignorant I'm happy to be ignorant.
Image
 
#76 · (Edited)
That diagram has absolutely nothing to do with capacitance or a batteries point in it life cycle, Both do effect the total voltage in both systems, its just one has a negative effect, in parallel, the moment they electrically connected in parallel, the battery with more capacitance will start send amps to the lower battery as it not is electrically the same potential lowering the overall capacitance. In series the battery capacitance is simply added to each other so there is NO loss trying to become one battery. THAT is why 24v will run longer, provide longer battery life, and have less losses.
Interesting how you bring up losses in electrical systems sometimes but then basically wants to ignore them at other times.
 
#77 ·
I don't wants to ignore anything. Since now we have a stronger and a weaker battery in parallel with the stonger battery charging the weaker battery is that electricity lost? Or does the weaker battery become stronger? Sorry, I realize I'm ignorant but I'm not seeing anything here that will make the OP's led's run noticeably longer with his batteries in series.

As an afterthought running them as long as they will burn on 2 batteries in series probably will favor the 24 volt system since the low of the led driver's operating voltage range will be reached later in the 24 volt system's batteries' discharge cycle. Other side of the coin draining the batteries until the are completely dead isn't conductive to long battery life so getting those few extra minutes probably wouldn't be a good idea imo.