Batboard

I'm looking for suggestions on how to take the Saber battery apart. I want to preserve the contact surface and most of the interior space. I want to attempt to load some capacitors into it and drop it into an SVA.

its not easy. cheap batteries the bottom pops out. give it a squeeze or a hit with the hammer.

Slimbob,

Just buy a battery on ebay, don't waste your time being cheap! Saber batteries are a dime a dozen.

I'm serious. I'm building a suitcase repeater and don't want to lose the batteries or haul the extra weight.

Also... good to know.... Now I just need to find that 10-pack of them, new, never used....

Like everyone says buy a real saber pack but if you really want to do it ?

I put mine in a cold chamber, but a fridge should work or you can spray the bottom with freeze spray around the seam.

Next hit the bottom with a rubber mallet and the bottom should break apart to where you can pull the cells out.

Without a properly working battery on your Saber you are risking serious radio damage from the SVA.

Do NOT take any chances...

been there done that

The only easy way is to cut the bottom off the battery using a miter saw or a mill. then figure out how to fill the the hole

When I worked on the project I used super caps. It did not work. the sva would not sense the caps to trigger the charging circuit.

I ended up modifying the sva charging circuit and their is allot of other stuff that need to be done. it still in the box sitting on the bench.

it can be done but there is a lot of research that you are going to need to do.

if you have question on what i have done so far just ask

Jerry

Damn.

There's got to be a way to do this without cooking up a nicad pack.

SlimBob wrote:Damn.

There's got to be a way to do this without cooking up a nicad pack.

there is always a way. just think it thur. the major problem is supplying the 7.4 volts to the to the cap pack via the charging fingers and isolating the charging fingers from the main board.

you will still need to supply the 12 volts to the SVA. its not to hard to do "IF" you have some know how.

And remember what Dr.Frankmod says "Think out side the Box, and if its alive it worked"

jerrys

Right as I walked away I had an idea. I was thinking about this wrong. Instead of trying to trick the power supply, I need to emulate a battery. In other words, enough capacitance that I can keep the DC clean and filtered, without overwhelming the PA of the radio. Shunt the rest to ground. Not efficient, but between constant current and constant voltage sources, for example zeners and things driven from zeners, it should be possible to near emulate the behavior of the battery without involving an arduino.

Of course, the catch to the whole thing is that the 7.5V 1A regulator has to be kicked in so the PA has power to run from.

That's the way of thinking! Keep working on it.

jerrys

So I did it and it works. Four 10F 2.7V capacitors from eBay later, I have them installed in a off-brand battery along with some foam so the battery contacts don't fall inside. I destroyed the thermistor by accident, so I replaced it with a 10K resistor. Other batteries I had handy were showing 9.96K at room temperature. The capacitors are approximately the size of the Sub-C batteries, three wide and one on top.

The biggest challenge is making sure the "cap-batt" gets a decent charge before you put it into the drop-in charger, or into the SVA/car charger. Outside of that, that one doesn't get too long-winded. I think the math was a little wrong; I believe the Saber needs 1.1A - 2A on transmit at 7.2V to make 5W (50% efficiency or so).

Another hazard here is that the 10F caps come out to 2.5F at 7.5V, so one needs to protect the contacts when not in use because welding is more than possible.