Batboard

I have a Ford Expedition with a 850 CCA primary battery. I need the XTL 5000 to do 50 watts and VRS 750 to do 2 watts and stay on for at least 5 hours after the truck is off. I know what you guys are going to say, run lower wattage, well that is not an option out here in the mountains where everything is far and few in between. The only place I can add a 2nd battery is in the trunk. My question is if any of you have a {cheaper} way to go other then buying a $900 professional emergency vehicle charging system.

123 wrote:I have a Ford Expedition with a 850 CCA primary battery. I need the XTL 5000 to do 50 watts and VRS 750 to do 2 watts and stay on for at least 5 hours after the truck is off. I know what you guys are going to say, run lower wattage, well that is not an option out here in the mountains where everything is far and few in between. The only place I can add a 2nd battery is in the trunk. My question is if any of you have a {cheaper} way to go other then buying a $900 professional emergency vehicle charging system.

How much transmitting are you going to be doing?

I'd recommend a better battery under the hood for starters, and probably best bet to have a second battery.

I run a couple PAC-RT style units (well, SVR200 and VRS750) out in the car, one is hooked up to a 50 watt mobile and know I can't TX with 50 watts for long in my Focus without the CDM mobile bonking out. 25 watts is fine, even after 8 hours of operation but with very little TX on the mobile side (the SVR on the other hand is frequently transmitting).

I have the highest and best battery recommended and sold over the counter for my truck. I can not fit a bigger battery in the engine comp. if that is what you are asking.

TX will be about 10% in 5 hours time slot. I cant go any lower then 50 watts due to the terrain and distance of the repeaters.

And FYI what I want to do is not use the primary battery for the radio at all, I want a 2nd battery, just didnt know if there was a cheaper way of keeping the 2nd battery charged.

VRS tx will be about 50% in a 5 hour time slot.

Kussmaul Auto Isolator - about $150. 1/0ga. cable battery-->solenoid and solenoid-->auxbatt.

Will look into it thanks.

I have used these dual battery control systems before and they work very well. The best is they will not leave you stranded on some mountain road without being able to start your truck. The worst you can do is kill the auxiliary battery with your crossband repeater if you do not recharge the battery in time. If you want to get really fancy you could build a voltage alarm that transmits a tone on the radio channel to let you know that the repeater is about to shutdown and you need to recharge.

This is an automatic dual battery control kit:

http://www.painlessperformance.com/webc ... ield=40120

and this is a manual switch dual battery control kit:

http://www.painlessperformance.com/webc ... ield=40103


Bill

In my Expedition I run a 110 Moto APX with a SVR200 mobile repeater set for 1w. When in the mobile repeat mode the radio automaticly switches down to 55 watts. To keep th battery charged I run a Honda 2kw suitcase generator to the on board installed battery charger in the truck. Our other trucks run the XTL5000 or Astro Spectras with 2watt VRS. We use the same charging set up on them as well. The Hondas run a long time on very little fuel and are super quiet.

As mentioned an auto activating solenoid between two batteries would be the best option. I'm looking at something similar for a cig-socket in the boot of my sedan (Ford Fairmont Ghia) used for charging handhelds, laptops, etc. I would run a 4guage positive wire from the front battery via a solenoid which would be activated/controlled by the "on" position of my ignition to the second battery and then the socket hooked to the second battery in the boot.

The solenoid using this method would make connection whilst the key is in the on position (thus car is on and running) meaning that the alternator will charge the second battery in the boot and have the batteries as a pair and then when the ignition is switched off or back to accessories only, the solenoid kicks out isolating the second battery so that the gear running off it cannot flatten the primary battery.

We have used a battery relay controlled by the alternator stator voltage. It parallels the batteries ONLY when the engine is running and the alternator is up to speed.

Will wrote:We have used a battery relay controlled by the alternator stator voltage. It parallels the batteries ONLY when the engine is running and the alternator is up to speed.

This is a great idea, was it hard to implement? How did you ensure it was alternator voltage and not battery voltage?