question for anyone currently using a battery tank

**garfin** · 01-16-2004, 10:34 AM

I've purchased a 12 volt 5ah battery for my tank up at radioshack and have just made the logical realization that a charging lead-acid battery can release some pretty toxic/flamible fumes. Has anyone out there had any trouble with fumes or have any suggestions as to where it should be mounted? (should it have vents leading outside?)

**shakes** · 01-16-2004, 01:23 PM

well mine isn't installed yet ... but i put one in a guy's car and he hasn't complained yet

i don't think it'll be that big of a deal from one battery and the tiny bit of charging you'll be doing. it won't loose much power at all during cranking so it won't need to charge much.

I would put it somewhere in the dash or in the engine compartment/trunk if possible ... not around any air ducts

**NightHunter** · 01-16-2004, 01:27 PM

It is best to install it under the hood(engine compartment). IF there are any fumes, I dont think you want that uder your dash or in the trunk. All though I have seen a lot of setups with batteries in the trunk, especially with audio system and cars with hydraulics. But if you can fit it under the hood, it is the best place.

**robiewp** · 01-16-2004, 01:28 PM

Unless I'm msitakein anything from radio shack would be sealed... no worries there

**sigma957** · 01-16-2004, 02:15 PM

From what I have read, no SLA battery is truly "sealed". They all have some sort of overflow valve that will vent gases if the battery is over charged or charged too rapidly. It should therefore only be charged in a ventilated area.

I have a small SLA battery that I've mounted right in the computer case. I have it isolated from the electrical system of the car by a diode, so it does not charge in the car. Every couple of weeks I take it out and connect it to a charger to top it off, but it rarely loses much charge since it is only drawn from when cranking.

**garfin** · 01-16-2004, 03:21 PM

Thanks for all of the great replies, I had not even considered putting it in the engine compartment, but that definetly sounds like the best place for a battery of this size.

**VWTronics** · 01-22-2004, 12:44 PM

Question of the day for you guy's...... if you have the battery setup up and running what did you end up using for a diode (ie. source and size) ???

**shakes** · 01-22-2004, 01:35 PM

MBR3045 or MBR6045 (i think those are the part numbers) ... search digikey.com for it

the 3045 has a lower voltage drop

**VWTronics** · 01-24-2004, 03:39 PM

Originally Posted by shakes

MBR3045 or MBR6045 (i think those are the part numbers) ... search digikey.com for it

the 3045 has a lower voltage drop

I have never used a MBR 3045 type diode before.... being that it looks like a regulator LM style regulator how do you conect to it? If any one has some pictures / drawings it would be much appriciated

T,
VWT

**shakes** · 01-24-2004, 04:24 PM

each package actually has 2 diodes in it ... the two outter pins are the annodes and the center pin is a common cathode.

so if you only need one diode you will only use the center pin and one outter pin.

you can sorta see something like this in the circuit i made here ... the center pin is bent abck and soldered to that red wire ... one of the outter pins (upper) is bent around connecting to the fuse, and one (lower) is bent conntected to the resistor. i needed both diodes for this circuit. you may only need one.

and you can get a datasheet for this diode from digikey.com ... it shows the pinout as well.