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DC to DC UPS (Help!) Answered


Hi i am trying to build a sort of DC TO DC ups for my modem/router, please look at the image attached for my project plan. I was able to find many charging circuits online but i cant understand what value relay and capacitor should be used. can any one help me with this project. Thanks in advance.

http://i52.tinypic.com/v2v38n.jpg

Tags:DCtoUPS

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Goodhart

7 years ago


As you can see "in this over simplified schematic" the need for a "relay" is eliminated (would be too slow anyways) BUT that the "switching circuitry" is included within the diode configuration.

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spoogeGoodhart

Reply 7 years ago

This is exactly what i needed, Thanks. Can you please tell me what transfer will go well with this circuit or I can just pick up an after market adapter to hook up with it in that case what voltage/amps should i get?

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spoogespooge

Reply 7 years ago

I forgot to add does this circuit has overcharge protection, if not how to i add that?

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Goodhartspooge

Reply 7 years ago

I don't see it in the one I supplied;  to "add" it may mean a bit of modification (but then, since that schematic IS just a basic example, it will need adjusted anyways), to accommodate something like this maybe...

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Goodhartspooge

Reply 7 years ago

It was just an example of "how" they are made; specifics would need to be worked out per each type of load and such. One thing though, the faster the switching diodes used the better it is at "picking up without dropping" too often :-)

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LargeMouthBass

7 years ago

A relay switchover setup should not actually be needed. I think you could power the modem from the battery, with the charging circuit attached all the time.

This would be somewhat akin to your cars electrical system, where the electrical loads are connected to the battery, and so is the "charger" (alternator) which keeps the battery charged, at least while the vehicle is running. If you turn off the vehicle, you can continue to power the loads, but if you deplete the battery to far you won't be able to start the vehicle again.

The charging circuit output would need to be sufficient to handle the load of the modem and still keep the battery "topped off" during normal operation.