Setting up a base unit

[WSAE510]

I just purchased the Btech  GMRS 50 V2 mobile unit and I'll be putting it together

as a base station .  I have six handheld  radios as back up incase of power loss

so I'm glad to prepare for severe weather.

 

73s 

WSAE510 NH 

[LeoG]

Get a LiFePO4 battery for the base station to keep that up and running for a while.  Or put solar on it and let it self charge to keep it up and running longer.

[WSAE510]

8 hours ago, LeoG said:

Get a LiFePO4 battery for the base station to keep that up and running for a while.  Or put solar on it and let it self charge to keep it up and running longer.

I'm not as worried about it since I do have six handhelds as backups but thanks for the tip

[Socalgmrs]

4 hours ago, WSAE510 said:

I'm not as worried about it since I do have six handhelds as backups but thanks for the tip

Haha. You will be when you want to talk more than a few miles.  Battery/solar/generator  back up of some kind is essential to a base set up.  At least for me in my area, when the power goes out, due to black outs, wind, storms, ice, ect, is when I need to talk with the out side world the most.  With my 20w radio a 100ah agm battery and a good antenna I can get out 200miles in good weather.  I can for sure hit all the local repeaters reliably.  At least get an $10 adapter so you can run your hand held through the big base antenna.  A 5w hand held with some Lmr400 and a good base antenna can radiate more the 65watts.  That’s going to help much more than the ht by its self. 

[WRYZ926]

I have to agree with what the others have said. Get yourself at least a 50 AH LIPO4 battery along with a way to keep it charged up. And if done right, you can also use a solar panel setup to charge your HT batteries. Because there is a good chance that you will have to recharge them too. And having an adaptor to hook a HT to your base station antenna is also a good idea.

I know my situation is a little different since I have my amateur license and participate in Sky Warn nets. But I still have to have some type of battery backup and a way to charge my HT batteries. The closest repeaters to me are 21.5 miles away. We had a bas storm with 50 MPH + winds that kicked out power for several hours. I would not have been able to participate in the Sky Warn Net nor contacted any local family and friends without having a battery in my shack. I can't always get into the GMRS repeater with a HT and I can't get into the 70cm at all with a HT. I can normally get into the 2m repeater with a HT. But even that was difficult during that bad storm.

I have a couple of LIPO4 batteries along with a deep cycle lead acid battery. I had to hook up an inverter to charge some of my HT batteries during that storm. It was a bad one that covered a large area with tornadoes along with high shear winds. All of my spare HT's were handed out to neighbors and family. 

Moral of the story is;  One is none and two is one. Always be prepared and have plenty of backups.

[LeoG]

That's something I'm currently working on now.  Not to worried about the home base station because I have a mobile in my truck.  Plus I have a small solar system with a 3KW inverter to power 120v stuff.  But the repeater needs backup and I haven't got that done yet.  The repeater needs 12-13.2 volts so the battery along with the charger is too much for it so I need a DC-DC convertor or just build a relay system so when the power shuts off it automatically switches it to the battery.

But I don't even have the battery or charger yet so as of now it's a moot point.

[SteveShannon]

3 minutes ago, LeoG said:

That's something I'm currently working on now.  Not to worried about the home base station because I have a mobile in my truck.  Plus I have a small solar system with a 3KW inverter to power 120v stuff.  But the repeater needs backup and I haven't got that done yet.  The repeater needs 12-13.2 volts so the battery along with the charger is too much for it so I need a DC-DC convertor or just build a relay system so when the power shuts off it automatically switches it to the battery.

But I don't even have the battery or charger yet so as of now it's a moot point.

Your voltage is close enough you just need a voltage regulator, not a dc-dc converter.

[nokones]

And if you use a Lithium battery you will need the appropriate Lithium Battery charging system for maintaining the battery properly.

[LeoG]

33 minutes ago, SteveShannon said:

Your voltage is close enough you just need a voltage regulator, not a dc-dc converter.

The DC-DC converter is essentially a voltage regulator +.  Takes in 8-17v and outputs 10-15v.  Has the advantage of boosting a lower voltage to required voltage.  Main problem is the 14.4v charging the battery is way out of spec for the repeater.  Most car regulators are 13.8v or more.  Not usual to find something that puts out a true 12 volts these days.

[LeoG]

1 hour ago, SteveShannon said:

Your voltage is close enough you just need a voltage regulator, not a dc-dc converter.

Do you have a suggestion for a regulator?

[SteveShannon]

16 minutes ago, LeoG said:

Do you have a suggestion for a regulator?

For a range of 14.4 vdc in and 12.0 +/-0.5 vdc out?  How much peak current do you guess? Also, what type of battery?  For lead acid something like this might be everything you need:

https://www.dxengineering.com/parts/wmt-58403-1046?seid=dxese1&gclid=Cj0KCQjw9Km3BhDjARIsAGUb4nyW7YSRHOOjCy1OcM9SCYZ074KAnDL2RJZPhS-6XOWi7AQkuLw4WnoaApUTEALw_wcB
 

But if you already have a charger, there’s no point in paying for that circuitry again.

[LeoG]

Gonna be a LiFePO4 battery so that won't work for me, thanks for the link.  I looked around for a relay but all I've found have a 40 amp rating on the NO contact and only 3 amps on the NC contact.  Was planning on plugging the coil in and as long as there was power the relay would be closed cutting off the battery power through the contacts.  And as soon as AC power died so would the relay connecting the battery to the repeater.  12-15 amps is what the repeater draws on transmit.

[BoxCar]

5 hours ago, WRYZ926 said:

I have to agree with what the others have said. Get yourself at least a 50 AH LIPO4 battery along with a way to keep it charged up. And if done right, you can also use a solar panel setup to charge your HT batteries. Because there is a good chance that you will have to recharge them too. And having an adaptor to hook a HT to your base station antenna is also a good idea. 

Moral of the story is;  One is none and two is one. Always be prepared and have plenty of backups.

A 50 AH battery is overkill. Use the 80/20 rule that 80% of the on time is receive only. Calculate the amps used for an hour of on time and multiply that by the expected number of hours of operation. That will give you the size (in AH) battery needed. The excess power supplied by the solar system deep charges the battery providing even more operating cushion.

[SteveShannon]

1 hour ago, LeoG said:

Gonna be a LiFePO4 battery so that won't work for me, thanks for the link.  I looked around for a relay but all I've found have a 40 amp rating on the NO contact and only 3 amps on the NC contact.  Was planning on plugging the coil in and as long as there was power the relay would be closed cutting off the battery power through the contacts.  And as soon as AC power died so would the relay connecting the battery to the repeater.  12-15 amps is what the repeater draws on transmit.

I'll keep looking. Do you live in an area where the battery temperature might drop to +40°F?

[LeoG]

2 minutes ago, SteveShannon said:

I'll keep looking. Do you live in an area where the battery temperature might drop to +40°F?

The battery will be in my shop.  Although it's on the side that I don't heat often because it's storage.  I've seen it go below freezing one year but besides that I think it doesn't go much lower than the 39º that I've seen.  It's right next to a room that never goes below 60º and if I have to I can put it there and run cables through the wall.  But I'd rather not.

[WRYZ926]

44 minutes ago, BoxCar said:

A 50 AH battery is overkill. Use the 80/20 rule that 80% of the on time is receive only. Calculate the amps used for an hour of on time and multiply that by the expected number of hours of operation. That will give you the size (in AH) battery needed. The excess power supplied by the solar system deep charges the battery providing even more operating cushion.

I will generally agree with you on that. It does depend on the situation though. In my situation participating in a Sky Warn Net, I will be transmitting more often.

[LeoG]

Rule of thumb is to have 3 days reserve when it comes to solar.  I myself would start out with 100Ah LiFePO4 battery and see how that works in the next emergency.  Hopefully it'll sit there unused for years.

[AdmiralCochrane]

A 90-341 type relay is a 2 pole double throw relay with a 120v coil with each contact rated for 15 amps. If you use both poles you are 15x2 amps.

It is the second most common relay in HVAC/R work ... the most common being the 90-340, same relay with 24v coil