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IanCPS avatar image

Bluesmart in parallel with a DC power supply

I am running a 24v DC system with a 240 - 24v power supply and wish to add a Bluesmart to maintain the battery bank properly and give the system black start capability, a couple of questions: can the bluesmart operate as a power supply if the battery bank is switched off without interruption or does it drop supply then re power the loads. are there any concerns with the parallel sources, I am totally comfortable with the two supplies in parallel but the customer wants to hear it from the manufacturer

Blue Smart Charger
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2 Answers
Robert avatar image
Robert answered ·

Hello,

when the Blue Smart is first switched on it is checking for a battery, a reverse connection or a short circuit. If a heavy load is sensed the Blue Smart figures you have a short circuit and will not supply power, it will flash LEDs to show a fault.

The Blue Smart needs to sense a small load, then it will turn on a relay and can start operating as a power supply.

Once the Blue Smart no longer sees a load (batteries out of line and no load) it will go back into a mode searching for a battery. I believe this is too risky for the application.

Also, how does the power supply handle a higher voltage on its output when it is operating? how does it behave connected to the batteries when no 240V is available, does it become a load? Maybe a diode to stop feedback into the power supply is required.


Regards,

Robert Hoehne

MI Battery Engineering

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JohnC avatar image
JohnC answered ·

Hi Ian. There are a quite a number of models and sizes, so pick one out: https://www.victronenergy.com/chargers

Check with the spec sheet, but I think all the Smart varieties (probably all the others too) are listed as power-supply-capable.

Switching off the batt bank shouldn't affect loads, not to say that switching batt dc under load won't cause sparks within the switch and subsequent mV spikes on a mS scale . Shouldn't affect the Victron.

Paralleling chargers into batts is something that many thousands of people do daily. It won't hurt the chargers, which should just continue to attempt to achieve their V targets.

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