SLA Battery Question

[threephase03]

Hi Everyone.

I have a 24V load that takes around 3.2A for approximately 25-30min then 0.5-1A for another 45min.

The question is....  I want to buy two 12V SLA Batteries and run them in series what sort of issues could
I face with this type of application?

I have a feeling there might be a discharge rate problem
Issues with charging them back again and again. (Wouldn't be a daily use maybe twice a week)

Link to what i want to buy
https://www.jaycar.com.au/12v-9ah-sla-battery/p/SB2487?pos=9&queryId=aa8d8b3a70a7afd7c1a1e95ef57b547d&sort=relevance

Thanks for any input/help

TIA

 

[T3sl4co1l]

If the units are identical, there's no problem.

What do you think they do internally? (12V is 6 cells in series)

Tim

[threephase03]

Im worried about the longevity of the application. I know it will work. But is it a to simple idea and im failing to see something?

[BradC]

It'll be fine, but don't expect those Jaycar batteries to last when you cycle them that hard.

Something like a Vision FM or CSB GP series would likely last longer. The big trick to SLA longevity is charging them correctly.

[threephase03]

Thanks for the advice ill check them out. Much appreciated.

I was thinking about using one of those car trickle chargers.

 

[T3sl4co1l]

And not over discharge; going under 50% is bad for lead acid.

Tim

[BrokenYugo]

Balance/equalization charges are just part of life with lead acid.

[threephase03]

Thanks for everyone's input. I've got a 24V battery charge indicator, thinking about installing it on the battery box so I can check during use.

Guess I'm hoping when it indicates its close to flat it isn't below the 50% min level mentioned

[Circlotron]

You could always charge them with two independent 12V chargers at the same time. 13.65V @ 20 deg C. More readily available than 24V chargers and less likelihood of cell voltage imbalance because of a shorter string of cells.

[NiHaoMike]

Might want to consider 6S lithium ion instead, similar cost to sealed lead acid (particularly for small packs) but lasts a lot longer.

[threephase03]

Yeah thats what I was thinking, I already have one for my car as it sits there a bit now with all the stuff happening now days

[SmallCog]

One of the instruments we use draws 16A for 3 seconds once an hour. Power is provided by a 7AHr lead acid battery and we find 3 years to be a safe service life.

As above no issues with series batteries, but if they don’t age the same one will die first. When ones dies you’ll have to replace both

*not using random jaycar batteries so can’t speak for their reliability but we find the century batteries from BSA to be exceptionally good.

[threephase03]

If I could get 10 - 15 charges out of them they will make their money back.

So ill think it will be right

Thanks for everyone's help

[tkamiya]

Why not buy a 24V SLA?  They are not as common but they do exist.