Single 12V 150AH Battery or Doube 12V 75AH?

What's the cost of one 12v 150 AH compared to two 12V 75 Ah batteries. Then there's the problem of mounting two batteries, extra cables, extra weight, extra space, extra extra, etc.

I 150AH battery, if you please.

The only advantage to using two batts I can think of offhand is the ability to charge them simultaneously, using two chargers, in less time than the single larger one. Of course this doesn't mention the extra expense. Then there's weight distribution. Is this a factor? What kind of trolley? Most of us can do anything with almost nothing but we do love information.

In our Corrugator machine, there is a spare "Cartridge Trolley" which has a spare cartridge of our Single Facer unit. When operator need to change the cartridge, they move the trolley to the unit and then.....

In this trolley, there is a DC motor which is powered through Battery 12V 150AH which we want to change because of problem. So that was my question that which is the good practice/beneficial to install a single 12V 150AH or a double 12V 75AH. Space is no problem.

Single 12V 150AH for many reasons.

Since all (including me) agree that one 150AH is better with the data given so far by you, let me start a new line of thought.

If the motor consumes 150A, the battery with enable it to run for one hour. Is this needed? Will half an hour do? If yes, would it not be better to have redundancy ?

Sealed or flooded battery are rated for 10 hours rate of discharge, meaning thereby that if current drawn from the battery is sufficient for battery to last for 10 hours, then ONLY 150 AH CAPACITY can be extracted. But if current is more than the time duration reduces DISPROPORTIONATELY. If battery is discharged at 150 A, then this is equivalent to discharging at 1 hour & it might probably survive for approx. 20 mins. or so.

I too agree that single 150 Ah battery is a better choice. Charging two or more batteries in parallel will result in uneven charging ( howsoever small it may be initially but mismatch will increase with age ) since no two battery cells behave 100% identically.

Nice to know.

i have a APC UPS for my PC. The max consumption of my PC is supposed to be 300VA. This APC gives me 15 minutes of backup. This duration depends on the battery does it not? If i wanted a 1-hr backup, i would ask for a higher AH battery from APC? Thanks in advance for your clarification...

Yes !

It is right that the backup time depends upon AH of the battery.

But for that time it should be calculated on its discharge rate at which it is specified; ie

If rated for 1/10 rate then the maximum load should not exceed it otherwise backup time may be much less than expected.

Though the amp hour rating would be the same you have to look at other factors of the batteries. Surface area of the plates limit the max amount of output current. The totals here may not be the same.

With out the full load amps of the motor and the full specs of the batteries it's difficult to answer.

With a single battery, you have only 6 cells. Two batteries means 12 cells with an increase in failure rate of any one cell. Less cells is better. A single cell failure affects all other cells. This is in additiona to all the other comments.

I agree, avoid paralleling batteries like the plague, it is bad enough having to parallel the plates in a single cell, although at least they are all probably from the same batch. Cheers, Geoff Thomas.

I am not telling you this is the answer to your question but in motor homes, the preferred setup of the coach (not the engine-starting) battery is to have 2, 6 volt deep discharge batteries. I have two 220 AH 6-volt batteries (at a 20 hour discharge rate) from Trojan, the people who make many of the golf cart batteries.

These are kept charged by a 3-stage charger that can be programmed for the type of battery and it also modifies the charge according to battery temperature. Using this charger, the batteries last about 5 years if they aren't cycled too many times.

Even better, if you can afford it, is a saturated mat (AGM) battery because they require zero maintenance and can be positioned even upside down. They are expensive but last longer, about 7 years or a bit more. I have one in my car that was in the motor home that is now 8 years old and going strong.

Instead use 2x 6V 150AH in series.

ItgGives a chance to replace one if the other goes bad.

More over batteries in parallel connection are not recommended [Power sources also]

if equal or proprtional sharing is not ascertained.

Some people prefer single battery and some double, lets wait for a post of any battery expert. Conclusion is yet pending.

OK .

Just wait.

Hi Signode, I am a battery expert, I have been designing supplying and installing renewable energy systems for over 2 decades, and as the batteries are the weakest component in these systems, have made it a special area of study to the point that they are not the weakest component in the systems I put in. The reason most batteries fail is due to the situation that if one plate in a cell is smaller or larger than the rest, it will either overcharge or undercharge, either way it will fail faster than the rest, and when it fails, that cell will be smaller than all the others, so will signal to the charging source that it is fully charged before the rest of the cells by upping the total voltage. Then, the other cells will not quite finish charging so start to sulphate in patches and that sulphation will become permanent, damaging those cells to a greater or lesser degree, leading to more uneven plates in those cells, and spiralling sulphation throughout the battery, leading to reduction in capacity and internal cell damage with loss of plate material quite often as well. Of course when two batteries are in parallel, the situation is so much worse as the weaker batter will damage and finally destroy the other battery, which will then destroy it in turn as the dead battery will up the voltage so the charging source doesn't fully charge the working battery. Try and use Tubular Positive batteries, (http://www.iig.com.au/wind/batteries.html) use a variable voltage charger so you can change the different charge times for the different stages of the charging process - I recently solved a battery problem on a remote Island by increasing the length of the absorption stage for example, preferably use flooded rather than sealed batteries as you can burn off the sulphation by increasing the equalisation and float voltages as appropriate, whereas with sealed batteries if you start them gassing they lose their acid, forming voids inside that reduce capacity. Batteries are quite a science, and there is no "smart" charger as good as an informed human. Cheers, Geoff Thomas.

A good description if the plate or cells are not within tight limits.

Just to add:

The effect of Reverse-Charge of a cell may occur when deep discharged.

This is common in Sealed lead acid batteries. I have found more than 90% of battery failure due to Revese charged cells.

GA. I too work for a battery manufacturing company, I do not know much in-depth chemistry. I am battery manufacturing equipment maintenance personal.