BQ25703A: is there a switching solution for 24v lead acid charging?

We don't have an integrated buck boost charger solution for charging 24V lead acid batteries.

Yes. You may have to build a switching converter in front of charger to achieve a desired voltage. And then, tag to bq24450.

Thanks. That's quite helpful.

By the way, I have read in app notes for SLA charging that a thermistor should be used to monitor temperature.

But there's no indication where the thermistor should be placed?

a) do you attach it to the battery itself?

b) does it just monitor the air temperature? In which case if the assumption is that the battery is not any hotter than the air, that means that the constant current charging phase should end quite early so that the battery has time to cool to air temperature before it gets full?

Please share the app notes. Do you have a link?
a. I would think the thermistor should be attached to the battery.
b. It should measure the battery temperature, not air.

OK thanks.

Here's an example of an app note on SLA charging, dealing with a different part BQ24650:

www.ti.com/.../slva437a.pdf

I notice the BQ24650 evaluation board has a four-layer PCB:

www.ti.com/.../sluu444a.pdf

In the layout guidelines (page 9) it says:

"2. The control stage and the power stage must be routed separately. At each layer, the signal ground and the power ground are connected only at the thermal pad."

Is a 4-layer board necessary or can a 2-layer board be satisfactory? Otherwise that would increase the cost of using this approach quite significantly...

What power level for this SLA charging? I would not recommend you using 2-layer board since you ask this question because you may face a serious thermal issue.