Batboard

I'm working on a GMRS repeater project that calls for about 10W TPO with the repeater to run on DC only via a solar power system. I'm looking for a repeater that will run on 24V or even 48V rather than 12V. Any recommendations?

Thanks,

RD

Why not 12vdc? Are there some constraints against it?

I'm only familiar with Motorola, so I'm not sure about other brands, but the only 24vdc repeaters would be the high powered (100 watt) MTR2000 & Quantar. I know the high powered MTR will only go down to 20 watts...not sure on the Quantar but it's probably similar. So you'd be well above your desired 10 watt output.

Daniels repeaters are the way to go for solar powered sites (very low current drain), but I believe they are 12vdc as well.

I would also recomend that you look at Daniels repeaters. they are 12 volt (I doubt that you will find a low-power 24-volt repeater anywhere).

If it is a 24-volt solar system, you could look at a 24 to 12 volt converter such as this one:

http://www.ictcorporate.com/products/di ... php?id=132

You will need to keep an eye on the efficency and standby currents.

The reason for using 48V is to reduce the current drain on the batteries associated with the solar power system.

Tait has an excellent 48V repeater with an optional power saver feature. But they want an enormous price for it.

I'll check Daniels as recommended.

Thanks,

RD

I think that with a 48-volt system the only thing you're going to save on is wire size, unless the laws of
power/voltage/current have recently changed.

Skyking wrote:The reason for using 48V is to reduce the current drain on the batteries associated with the solar power system.

Tait has an excellent 48V repeater with an optional power saver feature. But they want an enormous price for it.

RD

Whether it's four 12V batteries in parallel or four 12V batteries in series, the draw is the same. You'll likely find that you can get a few less watts by staying with 12V gear since there isn't as much conversion loss getting from 48V to 12V to 9V.

Tom in D.C. wrote:I think that with a 48-volt system the only thing you're going to save on is wire size, unless the laws of
power/voltage/current have recently changed.

Yeah, really, 1 amp at 48V is not any different than 4 amps at 12V...

Yeah, really, 1 amp at 48V is not any different than 4 amps at 12V...

Until you get into battery discharge specs. Then you have to juggle load, charge, and discharge current with total pile capacity to achieve your operational goals. The battery OEM will state their product is rated 1AH, but qualify that with a 100mA load over 10hrs - you get a few minutes of service and a greatly shortened lifetime at 1A. I wish the industry would rate batteries based on what can be safely discharged in one hour, not what works out mathematically to a higher rating.

Example: the Powersonic 6V 12AH battery, according to their data sheet, will deliver 2A for 60 minutes to a terminal voltage of 5.25V with a 1000 cycle lifetime. You get 5 minutes of discharge at 12A with a 200 cycle lifetime.

This would be a 2AH battery if it were rated honestly.

Spec out the batteries properly, don't use junk, problem solved.

Not everybody is made of money. But, it is buyer beware fer sure.

Bill_G wrote:

Example: the Powersonic 6V 12AH battery, according to their data sheet, will deliver 2A for 60 minutes to a terminal voltage of 5.25V with a 1000 cycle lifetime. You get 5 minutes of discharge at 12A with a 200 cycle lifetime.

This would be a 2AH battery if it were rated honestly.

No, it would be a 12AH battery. If you cannot be bothered to read the other specifications of the battery that is not the manufacturer's fault - would you complain that a 12AH battery won't run your repeater, just because it's a 2V flooded cell battery and your repeater wants 12V?

In fact, just about ANYBODY who knows anything about specifying batteries knows you ALWAYS specify for a 0.1C rate unless you specifically allow for a higher rate.

Um, excuse me, you're harshing my mellow dude. Back off. I do know how to read specs, but I think the way batt mfgs write them out are misleading.

We're pretty far off the OP's question, so speaking as the first person who got things going off topic I'm locking the thread.