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Backup Power for base station?

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Paulie

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I'm looking to build a emergency power source for my base station. Last winter and the one prior we lost power for about 4 days.

Things to consider:

DMR radio is running 25w 13amps
want to have 48 hours on standby
:
Here is the part I can't figure out:
I plan to use this on a DMR repeater in the future and I would like the power to the repeater to be continuous in case of power loss from the main line this way the internet connection is unaffected. I can keep the batteries charged with a solar panel. Is there a way to keep one battery as a bridge between the two power sources and some kind of switch that switches between sources when power is detected on the main line?
 
Bill_G

Bill_G

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It's called an automatic power transfer switch, and they do make them for solar applications.
 
escomm

escomm

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Not to mention the DMR repeater likely has a battery revert charger and power supply already built in, if it's an XPR or SLR repeater
 
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N4KVE

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Paulie said:
DMR radio is running 25w 13amps
Click to expand...
My 45 watt XPR4550 transmitting in analog draws 13.5 amps at hi power. At 25 watts analog it's drawing 8 amps. Less in Trbo mode. GARY
 
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Paulie

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Thank you very much for this link, exactly the kind of answer I was looking for!
 
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Paulie

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N4KVE said:
My 45 watt XPR4550 transmitting in analog draws 13.5 amps at hi power. At 25 watts analog it's drawing 8 amps. Less in Trbo mode. GARY
Click to expand...

yeah but I have a few other things running off the power supply.
 
Bill_G

Bill_G

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Paulie said:
Thank you very much for this link, exactly the kind of answer I was looking for!
Click to expand...

Please notice in the Samlex spec sheet that it specifies up to 100ah battery which will not carry your load for 48 hours.
 
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thaforce

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I would think if he were using solar panels to keep the batteries charged, it wouldn't matter what the spec's on the power supply say about the battery. It probably listed such a low amp hour rating due to its charge rate. Thoughts, ideas?
 
Bill_G

Bill_G

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I think he's still thinking about the overall design. It might include PV.

The Samlex doesn't really discuss it's battery charging and maintenance. It just says it can push 4A into a 40-100ah battery, and pull 25A. I think it's depending on battery chemistry to prevent overcharging. There don't appear to be any adjustments, or limits to set. Just a straight forward little box that could have an application in a number of small jobs.

If he were to attach it to through an isolator a larger pile that gave him his 48 hours, and was primarily maintained by a PV charging system, he might be able to get away with it. He could size the PV to the batteries, and balance it to the Samlex. Still a healthy investment.

I'm thinking perhaps the Samlex with a single large battery, and without a PV system, is the best recommendation for him. He'll get some back up. He can even dry run it to see just how long it lasts, and he can address his 48hr requirement at a future date.
 
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Paulie

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Update, I contacted samlex and theforce was correct. They said if I had multiple batteries hook up together I would just need a way to charge them as the 1223 wouldn't be enough. Also I wold need to be sure no to over charge them. I ordered the samlex 1223 will be ordering the solar panels in January. Thanks for the help everyone.
 
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