WOW! Energizer Bunny Variable Voltage Mod

[asnider123]

PWM is a great way to go. The only reason I like a switching regulator better is because you don't have to compensate for battery fade. However, PWM is the most efficient regulation method, so not only do you have a very high capacity mod, but you are also maximizing run time with a very efficient regulator.

Not sure I understand how you handle charging. Did the unit come with that charging system or did you add it?

That's one geat thing about this unit, it came with a charging system built-in (see pictures 2 and 8 in OP) .. that's the main reason I want to work with 11-12v feeding the PWM, it is already set up for charging (even wall wart charger included). If I removed one of the 3 batts, it would probably be easier to regulate. However, the charging circuit is designed to recharge 3 batts in series, I would have to gut it and figure out another charging circuit.

Incidently, I am not grabbing the 12V as an output from the circuit board, which has a 2a limit. I am taking b+ and B- directly from the battery series, using the original circuit board only as a charger. Works great as is, however, it will be going PWM (though I don't think I am in a big hurry) just because it will be much more efficient. I love how it turned out!

 

[CraigHB]

Yea, that's very nice it came with a charger built-in, especially if it's using a balancing circuit, which it would be if the charger adapter is over 12V. Definitely want to hang on to that part. With either a switching regulator or PWM regulator, you'll get huge run time out of it. You wouldn't actually get any benefit from the 3rd battery with a linear regulator, just makes the regulator get hotter.

 

[asnider123]

Craig, I could tap off 8v by eliminating 1 of the batts, but I am concerned about the 3 not be prioperly balanced when I recharge. Is this a concern?

 

[unloaded]

With the linear reg the unit can double as a handwarmer during the winter months!

 

[CraigHB]

Craig, I could tap off 8v by eliminating 1 of the batts, but I am concerned about the 3 not be prioperly balanced when I recharge. Is this a concern?

I was actually thinking about that a bit, but I figured if you were just going to run a PWM regulator off all three batts, it wouldn't be worth mentioning. But, since you're asking...

You'll need to figure out how the batteries are charging. If the system simply charges the batts in series using two wires on the whole pack, you definitely do not want to create an imbalance by tapping off two batteries.

If the charger adapter is >12V, then it's most likely using a balancing system. In that case, the charger will properly deal with any imbalance if you are tapping off two batteries. Balancing chargers connect to the pack like a ladder so you might even be able to remove the top battery in the series without incapacitating the charger. Depends on the system. It may detect a battery missing and shut down. You could try and see if the bottom two batteries still charge with the top one removed.

In any case, I think your best bet with that is to run all three batteries. You could probably throw an OKR-T in there real quick as a stop gap until you get the PWM circuit dialed-in. The OKR-T can handle up to 14V so you're well within spec there.

 

[bstedh]

In any case, I think your best bet with that is to run all three batteries. You could probably throw an OKR-T in there real quick as a stop gap until you get the PWM circuit dialed-in. The OKR-T can handle up to 14V so you're well within spec there.

That was going to be my question... Will an OKR fit in there. If it will I may go looking for one of these just for the fact it has built in charging. Otherwise I am going to go find a good 3X18650 project box so I can run my SGV3 off of my OKR as it is currently sitting on the bench waiting to be put back into a mod.

Another question. Does it stand up on end well? That is the other thin I need it to do so that my SGV3 doesn't slowly leak into the combustion chamber if it sits on its side for too long.

 

[unloaded]

I can't say about the OKR fitting, but I can tell you it won't stand on end very well. It's pretty tall in relation to the base and thats not counting adding the scuba on top. The insides could easily be transferred into any box of your choice though. The batts and circuit could be reconfigured so you wouldn't need such a flat box. They are worth getting just for all the different ways you could use them. I've got a charger that has a car adapter with it, I'm sure I could run it off this thing for smaller batts. Might be good for a hunting or camping trip. And that is worst case scenerio if I can't find any other use for it.

Craig, I was meaning to ask you what's the difference between a switching reg and pwm? I always though they were the same just people using different names for them.

 

[asnider123]

That was going to be my question... Will an OKR fit in there. If it will I may go looking for one of these just for the fact it has built in charging. Otherwise I am going to go find a good 3X18650 project box so I can run my SGV3 off of my OKR as it is currently sitting on the bench waiting to be put back into a mod.

Another question. Does it stand up on end well? That is the other thin I need it to do so that my SGV3 doesn't slowly leak into the combustion chamber if it sits on its side for too long.

Stand on end, well, it woulda if I hadn't mounted a cool pink LED sticking out the bottom Guess I could remount the LED flush with the square hole. Sounds like a joke: can you put a round LED in a square hole? LOL

OKR .. what physical dimensions are necessary?

 

[CapeCAD]

That was going to be my question... Will an OKR fit in there. If it will I may go looking for one of these just for the fact it has built in charging. Otherwise I am going to go find a good 3X18650 project box so I can run my SGV3 off of my OKR as it is currently sitting on the bench waiting to be put back into a mod.

Another question. Does it stand up on end well? That is the other thin I need it to do so that my SGV3 doesn't slowly leak into the combustion chamber if it sits on its side for too long.

Have you looked at the OKL-T/6-W12N-C? It's an SMT version of the OKR but .48" square and only .283" high.

 

[Spliner]

I have a couple of the OKL series laying around that I have yet to make a mod with; seem to work about the same as the OKR or TI series switching regs. You can adjust them over 5.5v but you'll probably fry them over time.

 

[WillyB]

Guess we could call it The Brick LOL .. Craig, you are a master of the modding world and I always enjoy reading your posts. Wouldn't this make a fine VV PWM mod?????

And I really think it's a right handsome mod, especially cool with builtin charging Thanks man!!

HUH... Which Craig???? Can't be Craig"The Riddler"HB. Has this master ever posted even one measly, even grainy pic of the myriad of 'things' mentioned?

Please post a link...