Tech: rechargeable batteries for guitars etc ?

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: Bernard
Date: 25 Feb 07 - 08:01 PM

Except my watch - it always gains! It's 1m 15s fast now...!

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: The Fooles Troupe
Date: 25 Feb 07 - 07:35 AM

That's a good point and true Bernard.

BTW, Lithium batteries cause battery powered clocks to run slow. :-)

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: Bernard
Date: 25 Feb 07 - 06:25 AM

That's true for guitars and other low-drain applications, but high-drain devices such as digital cameras suffer from a different problem. NiMH or Li-ion are really the only suitable portable power source for those.

An alkaline battery's internal resistance is such that it can't provide a sufficiently large current, so its voltage drops and the camera shuts down. This is despite there still being energy left in the battery... so if you insist upon using them, don't throw alkalines away when they fail in your camera, use them in a low power device... such as a guitar!!

;o)

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: The Fooles Troupe
Date: 23 Feb 07 - 06:38 PM

"I've never found any of my guitars being so 'hungry' as to warrant using rechargeables"

If you carefully read that table on the Wiki link - you will find that rechargeables have much less capacity per 'charge/swap cycle' than 'primary' cells (carbon-zinc, alkaline), thus you will get more 'life per charge/swap cycle'


bernard's comments on 'real voltage;' are correct.

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: Bernard
Date: 23 Feb 07 - 02:11 PM

In answer to the initial thread - it would be far simpler to change the battery connection lead for a new one with longer wires (easily obtained) than to do the mod you desire!

Add to that the potential need to swap the battery on occasions when you forgot to plug the charge lead in overnight...

I prefer to have two sets of cells for my digicam, each set labelled so the cells don't get mixed up, and a similar system with my MP3 players - one is 'solid state', the other a CD based unit.

I've never found any of my guitars being so 'hungry' as to warrant using rechargeables... but then, I'm fortunate that I can salvage batteries from the radio mics at work - they frequently come back from hire having only been used for a few minutes, but our policy is to supply a fresh set each time they go out. We end up with boxes full of 'old' batteries that haven't been used!

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: Bernard
Date: 23 Feb 07 - 01:57 PM

NiMH are the best bet... The argument about rechargeables being the 'wrong voltage' just doesn't stand up... I'll explain...

A 'battery' consists of cells connected in series - typically a '9v battery' will have 6 x 1.5v cells.

What causes the confusion is the 1.2V rating of NiMH cells compared with the 1.5V rating of alkaline cells. In fact alkaline cells only supply 1.5V during the early stages of their discharge and this drops to below 1.2V for most of their life.

NiMH batteries actually sustain a higher voltage than alkalines during the bulk of their discharge.

More can be found here.

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: Grab
Date: 23 Feb 07 - 12:51 PM

Re cell voltage, most non-rechargeable designs have a nominal voltage of 1.5V per cell, whereas most rechargeable designs (specifically NiCd and NiMH) have a nominal voltage of 1.2V per cell. You get higher voltages by putting cells in series, so a 9V battery is a series of six 1.5V cells. Since 9 is an exact multiple of 1.5, I can't imagine why battery manufacturers would choose to use only 5 cells and have it at 7.5V, especially since PP3 batteries are always specified as 9V.

For rechargeables though it ain't so simple. Some might use the same six-cell design but with rechargeable cells, but that only gets 7.2V. 8.4V needs seven cells so needs a different design, which presumably would need different tooling.

Graham.

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: s&r
Date: 23 Feb 07 - 09:36 AM

Just checked the open circuit volts on a dozen new Alkaline PP3 batteries. Lowest was 9.85V; highest was 9.92 volts


Stu

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: jeffp
Date: 22 Feb 07 - 09:08 AM

My Takamine electric-acoustic base has the battery in a compartment where the battery goes in contact-first and is held against the contacts by spring action and the compartment door. Very efficient and simple. And the whole thing has a footprint of less than 1/2 square inch. The panel with the built-in tuner and 3-band graphic equalizer and volume control is about 2x2 on the side of the guitar on the upper bout.

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: Mooh
Date: 22 Feb 07 - 09:08 AM

I'd prefer phantom power like that from the mixer to my condenser mics if I had to have onboard electronic pre-amplification. Getting the industry to settle on any kind of standard would likely only be accomplished by consumer influence...good luck getting string players to agree that much.

Peace, Mooh.

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: Grab
Date: 22 Feb 07 - 08:55 AM

You don't want the charger inside the battery. The basic law is "If It's Mains, It's Big". A better solution would be a wall-wart adaptor for recharging and a socket to connect to the charger.

Problem is though that rechargeable batteries *all* self-discharge. That means that you'll always need to recharge before a gig, else there might not be enough juice in the battery next time you pick up the instrument. Or worse, there might be enough to run during the soundcheck, but it'll die halfway through the second song.

There's also the further problem of what to do if you *do* forget to change the battery. At the moment, you can just swap it out. But if your battery is sealed inside the guitar, you'll be unable to use the guitar until you've recharged it, which will be just peachy when you realise too late that you've forgotten.

To be honest, I don't think anyone would pay for batteries sealed in the guitar. More likely is that people would pay for better quality battery holders. My Crafter (which is a cheap plywood job I got second-hand 12 years ago) has a PP3 battery holder which doesn't use a clip - instead it's spring-loaded to press the battery against the contacts. But some instrument makers still use old-style battery clips to save money, and some people still buy instruments with them because they're cheaper... :-/

The *real* solution to your problem is to buy a better battery housing and replace the one on your guitar. I should think Farnell or Rapid Electronics would have them - worth a check.

Graham.

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: Scrump
Date: 22 Feb 07 - 08:44 AM

Maybe the more expensive the guitar, the more difficult is is to change batteries.

My cheapo electro-acoustic has the 9v PP3 battery in a compartment set into the side of the guitar (i.e. on top in the playing position) and it can be swapped out dead easily. Looks bloody awful though, and probably affects the sound.

Whereas the battery in my most expensive acoustic fitted with an under saddle pickup is a bugger to change, being very inaccessible inside the body.

My 'medium' workhorse (somewhere in the middle, price-wise) has a detachable Fishman pickup so that makes it easy :)

I hate those snap-on terminals though - have you ever broken a battery or the connector by trying to prise them off? I have (luckily not in a guitar, though - yet) :-(

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: jeffp
Date: 22 Feb 07 - 08:37 AM

The original carbon-zinc and alkaline versions deliver 9 volts, while the NiCad and NiMH deliver either 7.2 or 8.4, depending on design.

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: GUEST,punkfolkrocker
Date: 22 Feb 07 - 12:59 AM

many thanks for the expert knowledge you guys are bringing here..

yeah.. a roadie.. as if..

though the mrs has quite tiny fingers better suited
for negotiating tight cramped battery compartments..

hmmm.. maybe she could be trained...???




but before i go to bed..

say a marketing consultant for one of the major corporate guitar manufacturers
presented the idea to their product design technicians..

maybe pitching it something like..

" a large percentage of potential consumers would buy more of our premium active electrics guitars
if they were factory fitted with convenient lightweight internal battery chargers
and a permanently installed economical rechargeable battery,
that would only need to be replaced every 5 years or so..

can we design and build this user friendly facility into our guitars..

if not.. why not..??

and if not now .. when..???"



well.. i still think its a reasonable proposition..

but is 21st Century battery technology not quite up to it yet..????


g'night..

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: JohnInKansas
Date: 22 Feb 07 - 12:03 AM

Can't be wrong 'cause all I said is I haven't seen them.

Take my word for it.

Trust me.

Although the batteries described at the Wiki article are loosely called 9V by some, most of the manufacturers who supply my retailers have started labeling them correctly at their actual 7.5V (nominal) output, and that's how they're sold now at most retail outlets here - where I shop.

Note also that the "cell voltages" for other kinds of cells can't really be quoted with great authority, because commercial products are doctored with mysterious potions and additives, usually with trace elements in the electrodes and "concoctions" in the electrolyte pastes to "adjust" the elemental voltages to what's wanted in the product device.

In the US, most of the battery powered pickups use the 7.5V battery, or less often sets of AA 1.5V; but once again, that's "of the ones I've seen," which is by no means a wide sampling.

The common cells sold in the US are the cylindrical AAA, AA, C, and D, all of which are nominally 1.5 volts. The 7.5V battery is a rectangular assembly of cells with "snap" terminals at one end, and they're also widely available.

A few places carry 6V (rare) and 12V "lantern batteries" with either spring terminals or threaded terminals with thumb nuts, but at about 1 LB_w each they'd be a bit heavy for inside a guitar.

Rechargeables (at retail shops) are pretty much limited to the 1.5V cells, in AA, C, and D sizes. NiCds were widely available not too long ago, but have almost disappeared from the consumer shops. A "mercury" rechargeable was available some years ago but is now prohibited in retail markets in most places.

Most "rechargeables" here now are NiMH (Nickel metal-hydride) which when doctored by the manufactureres have the advantage of more closely replicating the 1.54006 Volts of a fresh carbon zinc non-rechargeable, although I can't say how close they come without looking it up. With NiCd batteries, there often were problems of voltage mismatch in devices designed for throwaway carbon zincs (which for many years haven't really been carbon zinc), but they seem to be much less common with NiMH ones. The NiMH versions are also considered "less toxic" in the landfill, although how much less toxic can be debated.

Lithium rechargeables in standard sizes are only "theoretically available" in my area, but may be more common elsewhere.

Battery suppliers list some 300+ different "standard packages" that one can order, but the common retail market here is pretty limited.

As noted, the "special batteries" used in many rechargeable devices - again the ones I've taken apart - are commonly just stacks of "disk cells" resembling hearing aid and/or watch batteries, and appear to be mostly NiCd. If there's difficulty getting a replacement, a battery shop (or clever user) could quite easily assemble a replacement for most of them. As I generally only buy the cheap stuff, things popular with the idiots mass consumers may differ.

The devices that use Lithium batteries are an exception to DIY assembly, as I don't consider them truly "safe" even when purchased from a reputable manufacturer - the good ones are just "acceptable risk." Lithium rechargeables are used in virtually all portable computers, and in quite a few cell phones, GPS units, etc. If that's what you've got, I'd say get ONLY the manufacturer's exact replacement battery, and use ONLY the recommended charger.

Few places here stock rechargeable disk cells that would be useful for constructing your own battery, but the kind needed are used for the "clock battery" in many computers, so they shouldn't be too hard to find at your local computer shop. The last time I looked for one, they were mostly NiCd, so some compromises on voltage may be needed to replace a throwaway Carbon Zinc and get the voltage "just right." (Computer batteries are so reliable, usually, that they're seldom discussed, so manufacturers may be using another kind of battery now, as well as the NiCd ones.) It depends a lot on the voltage tolerance of the pickup, whether you'd have a good chance of being successful with a "homemade" battery.

It should also be noted that the chargers used with most rechargeable devices are intended for use only when the device isn't in use. Most of them are pretty noisy (there may be exceptions), and you probably wouldn't want them connected during play. That probably means adding a jack for easy connect/disconnect of the charger, and of course means carrying the charger along if you'll be out for a while.

The original problem statement sounds like the optimal solution might be just putting a bit longer leads on the connector(?). Or maybe getting a "roadie" to change the batteries.

John

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: The Fooles Troupe
Date: 21 Feb 07 - 11:20 PM

Technically, I suppose it's 8.4 Volts - but then we haven't had the 30 page discussion on non-recharge-ables also not having a permanent output voltage of less than 9 volts - 6 cells of 'nominally' 1.5V!

Nominally - because the voltage varies with the state of charge remaining in the battery - when it's 'flat' it will have well under 1.5V per cell!!!!

As I said earlier "Which means for us ignoramuses, that the circuit may not work correctly if it cannot run down to the lower voltage - definitely a good chance of a lower level output and perhaps more distortion at the every least."


Suck it and see - you are unlikely to damage the circuit by under-voltage. If it works, fine - but note form that Wiki link that 'recharge-ables' have far less life between recharges than nonrechargeables do for their 'natural life'. So you will need to recharge more than than you would have needed to replace the other type - and also ALL recharge-ables lose charge by a small amount every day when standing unused anyway!. So you should always have a spare rechargeable to pop in while one is being recharged.

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: GUEST,punkfolkrocker
Date: 21 Feb 07 - 10:51 PM

........anyway..

wouldn't it be so much more convenient and reliable

to just plug a guitar into the mains power supply

and leave the battery powering the active pickups/EQ

to recharge over-night..

or a least a few hours before each gig..



.. and as much as i'm reading your replies with keen interest..

i'm not very techno-smart regarding electrics theory..

so am getting a bit confused over 9v rechargeable batteries being

truly 9v or not..


[got to admit i've never bothered with rechargeables before..
only ever bulk bought standard disposables..
but now me and the mrs are trying to be more 'eco-friendly'
so i've just blown my xmas woolworths gift voucher on a bunch of rechargeable batteries]


.and.. right now in front of me, i've got a UK purchased 9v rechargeable
which i would have expected to be able to use use in most active circuit guitars;

printed on this battery is..

" 9v 140mAH... Standard charge: 14mA for 14 hours / Quick charge 28 mA for 7 hours.."


so will it be fit for its intended purpose .. or not..!!??

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: The Fooles Troupe
Date: 21 Feb 07 - 10:11 PM

Oh no!

Was John wrong!!!?


Ahhhhhhhhhhh Noooo!!!!!! Run Away! Run Away!


:-P

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: jeffp
Date: 21 Feb 07 - 09:22 PM

He didn't mention rechargeables in the statement about 7.5 vs. 9-volt.

the only standard form battery with snap-on terminals I've noticed is a 7.5V, not 9V.

In fact, he said that rechargeables don't even make 7.5.

I haven't seen rechargeables in the standard 7.5V form, although they might be available.

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: The Fooles Troupe
Date: 21 Feb 07 - 09:02 PM

oops - 7.2/8.4

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: The Fooles Troupe
Date: 21 Feb 07 - 08:50 PM

jeffp:

Technically John looks to be corect about the 7/9 Volt thingie...

'Rechargeable 9V PP3' s are actually only 7.2/8.2 volts... for NiCd/NiMH, - the '9V PP3' would technically be a carbon-zinc or alkaline non-rechargeable.

Which means for us ignoramuses, that the circut may not work correctly if it cannot run down to the lower voltage - defintiely a good chance of s lower level output and perhaps more distortion at the every least.

We have exactly the same things in Australia.

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: jeffp
Date: 21 Feb 07 - 08:15 PM

John, 9V batteries with snap-on terminals have been manufactured in the US for at least 40 years! They were used in transistor radios when I was a kid and I'm 52 now. Wikipedia has an article with a picture and reports Eveready's claim to have invented it in 1956.

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: Leadfingers
Date: 21 Feb 07 - 07:49 PM

With Fishman electrics , there is a neat pivot out bit to replace the battery ! VERY civilised !

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: Black Hawk
Date: 21 Feb 07 - 07:43 PM

P3 batteries in UK are 9v with snap-on terminals.

Used on all guitars I've seen apart from the Takamine cool-tubes which use 4 x AA 1.5v pen cells.

Subject: RE: Tech: rechargeable batteries for guitars etc ?
From: JohnInKansas
Date: 21 Feb 07 - 07:38 PM

I might be missing something on the new technology front, but the only standard form battery with snap-on terminals I've noticed is a 7.5V, not 9V. You can get a new snap with longer pigtails at Radio Shack for about $1.39 (US) if that would help.

I haven't seen rechargeables in the standard 7.5V form, although they might be available. We do have lots of "battery sellers" who claim "If we can't get it we'll build it for you," so you likely could get them to find or jury-rig something for you. Lots of the $65 phone batteries consist of about 4 (you'd need 5) 1.5V 1099(?) or 1035(?) NiCd "watch batteries" ($1.25 each?) crammed into a piece of shrink tube and then smeared with some RTV bathtub caulk to keep the wires from wiggling. Of course you'd have to find (or make) a 7.5V charger (Or a 9V if that's really what you've got.), or cannibalize a cordless phone stand for the charger - or somethin'.

John

Subject: Tech: rechargeable batteries for guitars etc ?
From: GUEST,punkfolkrocker
Date: 21 Feb 07 - 05:45 PM

ok then.. these days most new modern portable consumer products

[phones.. shavers.. mp3 players.. etc..]

are manufactured with very convenient internal battery rechargers..

so why cant mass factory produced guitars with active pickups and EQs be similarly equipped..???????


next question..

if our instruments have sufficient spare space in their battery compartments..


how easy would it be.. and what would would we need to buy

to custom fit such user convenient battery recharge circuits to our own instruments..


these questions being asked because i'm getting ****in' annoyed trying to change 9 volt battery
in a bass guitar with a battery connection lead thats way too short
to manipulate the battery contacts into the correct position to snap into place !!!!!

grrrrr!!!!!!!!