Daisy Chaining UPS Modules

Is it possible to daisy chain the Backup Battery 12V UPS modules to get a longer run time?  Or could I connect them in parallel somehow without damaging the units?  I'm aware that connecting them in parallel could reduce the current below the trigger threshold.

NEVER do this! You can get sine wave feedback and pop a UPS.

1. Daisy-chained UPSs do not provide any extra surge protection. A UPS is designed to remove any possibility of a surge reaching the output receptacles. In the event of a surge strong enough to damage equipment, the first UPS in the chain would sacrifice itself to protect the load. This would mean that power would be removed from the second UPS in the chain, forcing the unit into battery operation.



2. Whenever connecting a second UPS to another UPS, the chance of overloading the first one is greatly increased. The number of receptacles in a UPS is restricted by the power limitations of the UPS itself. Even if the number of receptacles was increased, the overall Watt capacity of the first UPS would remain unchanged. The capability of the second UPS would be inversely affected by that of the first unit. Therefore, the overall Watt capacity of the configuration is no greater than that of the first UPS in line.



3. In most cases, daisy-chaining UPSs does not allow for extra runtime. If you are using a UPS that outputs a step-approximated sine wave when running on battery, as soon as the first UPS goes to battery operation, the second one will also do so because it will see the step-approximated sine wave as distorted or bad power. Both UPSs will discharge together and will not provide any extra runtime to the load.

I’m not talking about daisy chaining 120V AC UPS’s. I would definitely not do that.

I’m talking about the 12V DC units that are sold on this website.

Paul its the exact same thing... its a battery/inverter thats converting 120V to 12VDC you cant feed a 120V inverter with another 12V DC unit... and running them parallel will cause sine wave feed back and literally cook the battery. Strictly speaking about battery and power conversion youre not gaining anything. Having one per board would extend the run time of each board but never daisy chain batterys/UPS like this. 

It's not.  These units do not have an inverter.  They have 12VDC input and 12VDC output plugs on them.  They charge with 12VDC, provided by an external 120VAC to 12VDC adapter.  If the internal battery voltage is not a nominal 12V (which would stun me, frankly, given how simple these units are), they use a DC to DC converter on the input and output sides.

I'm not saying it is technically possible or a good idea to daisy chain these units, but I'm quite sure it's not because of the presence of any inverter.

Paul, if you connect the units in series, you can definitely use multiple units to get a longer run time, or to increase the wattage of your system.   Refer to my post with some test results.

The solution requires that the units be placed in series.  Depending on the number of units that you use, this will yield an output series voltage of 24v, 36v, 48v, etc.   The current limit will remain 2A max.   To get the voltages that you need for your devices, you will use DC-DC converters to convert the series voltage to 12V, 5V, etc. 

For example, if you use two units, and a 24-to-12 DC-DC converter that can handle a high output current, you will have a 12V 4A battery-backed supply for your system.

To assure that grounds are isolated, it's important that you use individual power supplies to charge the UPS modules.  Also, as an extra precaution, don't use power supplies that use an earth/frame ground (i.e. third prong on the plug).

That's pretty much it if you are looking for some sort of problems concerning UPS Modules and I fully agree with Duane when it comes on creating a reliable model architecture. As an network support manger from Nursing-Essays -UK multiple units can get a longer running time if you put the units in series