24 Volt Mini UPS Schematic need help

Thread Starter

ShayanFiroozi

Joined Nov 18, 2015
41
it's a mini ups , feed the load with 24 volt battery when the main is not present , and charge battery when main come back
 

Dodgydave

Joined Jun 22, 2012
8,373
A simple mains 220V ac coil relay across the supply will detect power fail, with a set of dpdt contacts to switch off the battery from charge to output will do.
 

Thread Starter

ShayanFiroozi

Joined Nov 18, 2015
41
Yes , and charge the battery when mains is available , any suggestion ? or any change should i have to make ?
 

Dodgydave

Joined Jun 22, 2012
8,373
Best to have the battery under charge constantly and take the load from the battery terminals so it keeps topped up, like in a car, then when the mains fails the battery supplies the load,

you just need to monitor the low voltage on the battery to disconnect it from being discharged too low, an op amp comparator will do that.
 

Thread Starter

ShayanFiroozi

Joined Nov 18, 2015
41
i couldn't find a good 24 volt low voltage disconnect circuit on internet,i don't wanna buy , is there any good circuit with relay ?
 
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