Question on wiring/charging gell cell

D

d2admin

Administrator
I've got my 7w amp and 12v batt all neatly tucked into a RS project box. With jacks mounted on the side for Azden input and speaker, an on/off switch and the amp volume control. The speaker and Azden have hook & loop pads on them to mount to the box quickly. It's pretty slick. I'm getting ready to mount a DC power jack for charging the battery without having to open the box. Intention is to charge through this jack both at home with the wall transformer/charger, and via cigarette lighter adapter in the truck.

Now, realize, I don't know ANYTHING about what I'm doing here! I'm semi amazed that I was able to get it all soldered together this far and it all seems to work just great.

First question, regards how I'm going to wire in the DC power jack for charging the battery. My plan is to simply wire it into the same terminals that are coming off the battery to power the amp (two sets of wires soldered to the same terminals). I'd turn off the amp before charging of course, so that the circuit to the amp would be open and the "juice" would all go to the battery. Or, would it even be "okay" to plug in the cig adapter with the amp on, to run it off the cig adapter? Any problem with this? I'm just not sure if having it all "wired together" like that will hurt anything or not.

Second question. Assuming my simpleton plan above is good to go, is there any danger associated with charging the gell cell off my trucks power outlet? The battery I'm using is a 12v 2.9 amp. hour. Seems like the juice coming out of the cig adapter might be a bit strong for this little battery, without any regulation. Or is just not that big of a deal?

Thanks a whole bunch for all the help recieved so far, and any that you can provide on these questions!

- DAA
 
Somebody smarter than me will probably come along soon and sort you out for sure, but my initial thought on charging the battery from your truck is "no, I would not charge a gel cell that way"

When I was racing motorcycles we would remove the charging system and run off a gel cell, I ruined one of my very expensive batteries by "jump charging it" (with a pair of jumper cables) with the truck battery, without ever starting the trucks engine...

Your cigarette lighter gets it's juice from the voltage regulator, not directly from the battery, but I think it still delivers much more amperage than a "trickle charger" does... enough so that I would worry about damage to your gel cell.

I hope this helps,

Jeff /ubbthreads/images/graemlins/cool.gif
 
I would go to a hobby store and check out the battery chargers and take your battery with you so they can get the specs first hand. It is important that the charging rate is correct and for what type of battery you have. You will then know what type of end connector to install in your box. Radio Shack can also help you with your charging questions.
 
I might need to try a new Radio Shack /ubbthreads/images/graemlins/smile.gif . The guys there didn't have a clue about any of this when I asked. They weren't even sure which plugs went with the power jack! Had to go through the stuff they had and pick them out myself, and all they could say was "save your reciept and bring them back if they don't work...". I do know that the "correct" amp rating for charging my gell cell is about 500mA (at least, that is what the charger that came with it puts out). No idea how I'd go about regulating amp output from the truck outlet to the box though (and the guys at my local Radio Shack are even dumber than I am...).

- DAA
 
DAA-
You could charge in your truck. Batteries draw what they need, the current is not forced into them. It will however charge much faster than the wall charger so you will have to guess at the time needed and monitor the temp. Spot lights are the same way, this is nothing different. I would guess it would be fully charged in an hour (if I remember it correctly as a 12V 2.9 AH).
 
Thanks for the confirmation Paladon. I went ahead and did it as I desribed above and it seems to be working great.

- DAA
 
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