Is it possible to pair MPPT/PWM charger with Computer UPS? Would it prolong the UPS battery's lifespan?

[soe soe]

Umm...some students say they only get electricity 2/3 hours a day. In this case, they may need solar as well. Currently, I am thinking

- DC Boost Converter + 24Ah/45Ah battery with charger or
- DC Boost Converter + 24Ah/45Ah battery with PWM (cheaper) + Solar panel (around 100/150w) >>> the cost may exceeds a little over 70$

Expected average power consumption is about 30W.

With 2 hours of electricity a day you can charge a battery at 0.5C to 100%.

I see. Just need 12A charger for 24Ah (24A charger for 45Ah)?

 

[zanydroid]

Yes. I believe 0.8C is the recommended top these days for max lifespan of the battery. I guess it depends on cost vs how much time grid needs to be up.

12V * 24Ah * 80% / 30 watts -> 7.5 hours of runtime.

Solar panels would be good if the grid is down for longer period of time.

 

[zanydroid]

You also want to check how much electricity they can draw for their house where they live.

I've been surprised (as someone in the US) with how small the service is in other countries, and how easy it is to exceed.

 

[soe soe]

You also want to check how much electricity they can draw for their house where they live.

I've been surprised (as someone in the US) with how small the service is in other countries, and how easy it is to exceed.

For homes with single phase, we can draw from 2kW to around 7kW depending on the place and time of the day. But input voltage is not stable and drops quite a lot (even by 50% at peak hours).

 

[zanydroid]

Ah ok. I think the charger power supply would be fine with that, esp if mains power is 230V.

 

[soe soe]

Yes. I believe 0.8C is the recommended top these days for max lifespan of the battery. I guess it depends on cost vs how much time grid needs to be up.

12V * 24Ah * 80% / 30 watts -> 7.5 hours of runtime.

Solar panels would be good if the grid is down for longer period of time.

Umm... I think you are talking about LFP batteries. I'd like to go with LFP if possible. But I am not sure if I can get 24/45Ah with reasonable price. If not available, I will have to go with SLA batteries, which has less charging rate.