General battery question

[Sideoftheroad]

Just in general for any battery if a battery has multiple cells and is ran in a series does the battery drain 1 cell at a time? If the battery is ran in parallel does all cells drain at the same time?

[Rosie1965]

A battery such as ours with multiple cells is tied together internally in a series. Each cell produces 2 volts, therefore draining all cells equally. If you have 2 batteries wired parallel you have the same voltage as 1 but drain them both equally.

If you could use an example it might be easier to explain.

[aharbi]

Yep, what Rosie1965 said. Good answer.

[Flyinfool]

Yep

The shorter answer is;

It does not matter if the cells are in series or parallel, batteries always all drain at the same time.

[darthandy]

Yep

The shorter answer is;

It does not matter if the cells are in series or parallel, batteries always all drain at the same time.

 

Yeah and usually just before you really need to use the bike ... that damn Mr. Murphy!!

 

Andy

[MikeWa]

As a side note. If one cell is drained more than the others it is a bad cell indicating the need for a new battery.

[Rosie1965]

Another side note:

If you have 2 batteries wired parallel and 1 of them is bad, it will drain your good battery to an equal voltage. Therefore if you are replacing a battery in a parallel system, it's best to change both at the same time.

[playboy]

I'm sure someone will correct me if I'm mistaken but two batteries wired in series will double the voltage. 12v + 12v = 24v

[Freebird]

You are correct. Years ago when I worked for a power plant, a lot of our high voltage motors use 120V DC control. We had emergency battery backup for those control circuits. 60 LARGE 2 volt batteries wired in series to provide 120V DC backup power.

[Flyinfool]

You are correct

[Sideoftheroad]

For my particular question I am referring to lipo batteries used by r/c modelers. I was trying to figure out how long a battery will last. I have a formula that is on a website that discusses lipo batteries. I thought I had it figured out except for 1 part. My assumption was that based on their formula was on how quickly it would last would be based on per cell. My thought was just multiply the formula answer by how many cells the battery has and that is how long the battery should last. I was wrong. Thanks for the info guys

[TwoStars]

In that case you're dealing with charge capacity (Amp-hours). The charge capacity divided by the current will give you the time to discharge. Multiple cells (in series) won't change the charge capacity but will increase the voltage of the battery (like Freebird's example). The higher voltage might cause the circuit to draw more current which would shorten the discharge time. Keep in mind the voltage drops as the battery discharges, sharply at the end, so you may not get use of the full charge capacity.

[Flyinfool]

If the batteries are in parallel then you keep the same voltage and you do get more run time.

 

With LiPos you are better off just getting a bigger pack than trying to make wire harnesses to hook them up in parallel.