Feasibility of an on-board spare battery

J-B'ass · #1 10-12-2010, 06:28 PM

Hey, I was wondering if someone who knows a bit about electronics could comment how feasible this scheme of mine is:

To have an active bass with two battery compartments, but only using one at a time. When the first battery is used up, the circuit switches to using the other battery and a small LED lights up signalling that the battery needs changing.

I just don't want to ever go through the experience (again) of having a battery fail on a gig, even if the bass has a passive option.

So what do you think? Would this work, and how easy would it be to build? Also how much roughly might this add to the cost of a custom bass like a Sei or something?

Cheers!

4StringTheorist · #2 10-12-2010, 06:52 PM

On board battery check is certainly possible. The preamps from Audere have that as a built in feature: an LED lights up when you plug in, full brightness at first, then at a brightness modulated by the battery level, then back to full bright. The full brightness book-ends make it easy for your eye to check the level on the battery. Super easy way to know that your battery is all good.

The other advantage of that setup is that it only runs once on plug-in, and doesn't operate continually. Any battery-checking circuit is going to use up power from the battery in order to do its job. If such a circuit is running continually, ready to hot-swap the battery, you're looking at a reduced battery life due to the system.

walterw · #3 10-12-2010, 09:45 PM

you could just wire those two batteries in parallel; it will still be 9 volts, but now each battery will only drain half as fast, accomplishing the same goal of extended battery life.

or you could just do what most folks do and change the battery every few months or whatever.

J-B'ass · #4 10-18-2010, 11:13 AM

4StringTheorist that's a cool system you've mentioned. And yeah most of the world seems happy enough to change the battery every few months or so, but what I really had in mind was a system that could step in and save the day even if I completely forget to check the battery, ie even if the battery dies in the middle of the song the spare with just step right in with no audible event.
I might check this with the Bass Gallery, as I'm saving up for a Sei anyway.

Cheers guys!

FunkMetalBass · #5 10-18-2010, 12:07 PM

GuitarElectronics makes a Lo-Bat system that notifies you of a low battery. You could probably even rig up a switch to flip once the low battery light comes on.

SteveC · #6 10-18-2010, 12:12 PM

Certainly doable, but. i think the hassle and cost isn't worth it. Yeah, it sucks when your battery dies, but it doesn't take long to change it, or just change it regularly depending on your usage. In many years of playing active basses, it has happened to me once. Not. Worth the exa system in my opinion.

Kahooli · #7 10-18-2010, 12:20 PM

This isn't difficult. Give me the schematic to your bass and I'll make something to interface with it. Alternatively: I'll make something that ~should work but offer no guarantee.

darkstorm · #8 10-18-2010, 06:56 PM

Id think the auto switching part would be rather difficult or unrelaible or expensive. However a switch to change to other battery would be fairly simple and quite low cost imo.

4StringTheorist · #9 10-18-2010, 07:13 PM

Quote:

Originally Posted by J-B'ass

4StringTheorist that's a cool system you've mentioned. And yeah most of the world seems happy enough to change the battery every few months or so, but what I really had in mind was a system that could step in and save the day even if I completely forget to check the battery, ie even if the battery dies in the middle of the song the spare with just step right in with no audible event.

The Audere's LED is pretty eye-catching, especially if you plug in in a darkened room. It's almost tough to NOT see the battery's status. I've had absolutely zero worry that I'll not notice the battery getting weak now.

I'm with walterw: Go for two batteries. Go 18V if your preamp can handle it for more headroom and longer (but not quite double) battery life. Or wire them parallel and get fully double the battery life.

SnakeKappele · #10 10-18-2010, 07:22 PM

Quote:

Originally Posted by 4StringTheorist

I'm with walterw: Go for two batteries. Go 18V if your preamp can handle it for more headroom and longer (but not quite double) battery life. Or wire them parallel and get fully double the battery life.

Then he doesn't change the two batteries and they go out in the middle of a song.

4StringTheorist · #11 10-18-2010, 07:28 PM

Quote:

Originally Posted by SnakeKappele

Then he doesn't change the two batteries and they go out in the middle of a song.

Do what I do.. make a yearly (or more often with heavy gigging) bass maintenance day which includes a battery change.

Or use an active/passive switch and deal with the fact that you dropped a note or two if the preamp fritzes out. Play the rests, man!

Or, construct a breakout box that houses the battery, with a TRS cable into the bass to power the preamp. Hard to forget to change the battery when it's that in your face.

SnakeKappele · #12 10-18-2010, 07:43 PM

No lights but this should work: flip the switch one way for one battery and the other way for the other.

It is a DPDT ON-ON switch.

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SnakeKappele · #13 10-18-2010, 07:49 PM

You could also power your bass with a 9V power supply like a pedal. You just need a long enough cable and you could tape it to the output cable.

walterw · #14 10-18-2010, 09:57 PM

the thing that's getting missed here is that an alkaline battery isn't going to surprise you in the middle of the gig, sounding great one second then dying the next.

you will hear it as it begins to weaken; your sound will gradually get fuzzier and less dynamic over time. if you pay any attention to your tone, you'll have plenty of advance notice that it's time to change the battery.

darkstorm · #15 10-19-2010, 07:25 PM

Quote:

Originally Posted by walterw

the thing that's getting missed here is that an alkaline battery isn't going to surprise you in the middle of the gig, sounding great one second then dying the next.

you will hear it as it begins to weaken; your sound will gradually get fuzzier and less dynamic over time. if you pay any attention to your tone, you'll have plenty of advance notice that it's time to change the battery.

This to.

Chasarms · #16 10-19-2010, 08:05 PM

Quote:

Originally Posted by FunkMetalBass

GuitarElectronics makes a Lo-Bat system that notifies you of a low battery. You could probably even rig up a switch to flip once the low battery light comes on.

This is a very simple thing to install on an existing active system. If you have a plate or pickguard on your bass, you can expose it on the front, or for a less obvious look, the rear cover can expose it. It is as simple as drilling one hole and soldering two wires. If it is lit, change the battery.

By far, it s the easiest and best solution to your concern.