On-board Battery Charger

[propster]

On Charley's point, because you've helped me with this before also - the advantage is that two fully charged batteries hooked in parallel will have more than twice the run time of two fully charged single batteries run separately, because they will discharge more slowly than the individual batteries will, is that right?

[marine_man]

Yes, that's mostly correct.

However, you're statement:

two fully charged batteries hooked in parallel will have more than twice the run time of two fully charged single batteries run separately

Is going a bit far. You will get slightly more than two separate batteries, but not "more than twice" the total run time of two separate batteries.

marine_man

[Charley]

Marine man- I have a 24v system. I was trying to help propster get more run time.

[propster]

I understood that 2 batts in parallel would be considerably more run time than 1 battery individually. However, if it is also not at least somewhat greater than the sum of the run times of the two batts separately (which is what I meant by more than 2x), then is it realistically an advantage to run them in parallel vs just changing over to the fresh battery? Unless there may be some other mechanical advantage, such as more power for the same run time or something like that.

[marine_man]

It would be greater than the run times of two batteries individually.

But, it will not be "more than twice the run time of two fully charged single batteries run separately"

There is a run time advantage to the parallel setup, just not 2X.

marine_man

[propster]

I hate to beat a dead horse, but now you've really piqued my interest. I used to pride myself on my math, but I'm getting old and now I question it! If you get 6 hours on batt 1, and 6 hrs on batt 2, are you saying you won't get 12 hours plus from the both of them hooked in parallel? That is what I meant by 2X or more. If not, what is the advantage of running them in parallel? Because if I can get more total time from them separately, I'll just spin off the wing nuts and change over when the first goes down.

[Charley]

I'm kinda thinking the same propster.

[marine_man]

You should get 12 - 14 hours out of two batteries that would run 6 hours per battery separately.

Sorry for the confusion...

marine_man

[Charley]

So then you would get about twice the life.

[Ralph Wiggum]

One battery = 6 hours

One battery + one battery, run separately but consecutively = 12 hours

Two batteries, hooked together = 12-14 hours

Let's put this one to bed!

[Charley]

Sorry ralph but I was getting cofused the more it on.

[Ralph Wiggum]

Sorry ralph but I was getting cofused the more it on.

It's okay. Never hurts to be certain.