How will I know when to switch batteries?

[denti alligator]

Will it be a gradual loss of power? Or will it be sudden?

I'm not keeping track of hours, but I imagine I'm close to 100 by now, if not over. Still sounds great. But if low batteries make only subtle difference, then I won't hear it.

 

[Paul Birkeland]

You'll hear it. 

While there is a slow degradation that isn't as easy to pick up on, there's a point where the distortion gets really heavy and you'll know something is up!

You can also measure the voltage of the 9V stack and your D-cells, I think PJ has written about the limitations of the circuit in terms of voltages. 

 

[earwaxxer]

Its funny, I havent noticed a difference in sound as the battery voltage goes down. I have the chokes, so that may have something to do with it.

With the heater batteries, the sound will just stop when the voltage is too low. Not sure what voltage that is, but usually when I ck the battery after that happens, the battery is effectively 'dead'. I use rechargeable AA's. With the grid power, I use NMH packs, and they have gone as low as 16V at times and I didnt notice that they were that low. Full charge is 30V.

I have experimented with different grid voltages from 20V to 65V. I'm not sure if I heard a difference that I can put my finger on. Half of the time I think the high voltage sounds 'better', and the other half the low.

 

[Paul Joppa]

The manufacturers are careful to avoid specifying the minimum filament current on these battery tubes, though they will admit that 1.6 volts is the absolute maximum. However, a few of them show up in mil-spec versions where you can find usually a minimum filament voltage of 1.0 volts. Since the terminals are exposed on top, this is easily measured.

The simplest rule is: When either D-cell drops to 1.00 volts with the preamp on, replace all the batteries.

The circuit adapts itself to falling high voltage; I designed it to operate down to 24 volts but of course it may sound OK below that. My recommendation would be to replace the HV when it drops to 24 volts, which should normally happen about the same time as the D cells drop to 1.0. This matching of the lifetime depends a lot on the manufacturing of the particular batteries, and their storage history - and you have no control over either one. If I was using a Quickie a lot, I would probably get my supplies in bulk (Costco or Radio Shack or some place that has a high turnover rate) and calibrate the first couple sets.

You may be able to find an old-fashioned analog voltmeter and install it across the filament of one of the tubes. It won't deplete the battery noticeably. I went to Mouser, looked up analog panel meters, and the cheapest ones were around $10-$15 for 0.5mA full scale. Add a series resistor to get 1.5v full scale, and calibrate it against a decent digital meter to find the 1.0v point, and you're golden. Heck, at that price get two!

 

[Zimmer64]

Here're my 2 cents: I can run 2 sets of D-cells with one set of the 9 volts. Same result with Duracell Alkalines or rechargeable NIMH batteries.

As Doc said, the Quickie stops playing once the D's go below 1 volt. I ran the HV grid down to 10 volt and it kept playing.

Best

Mike

 

[proud indian]

Get this

http://www.ebay.com/itm/New-Rechargeable-Battery-Tester-AAA-AA-C-D-1-5V-9V-Button-Cell-Volt-Checker-/221058755022?pt=US_Battery_Testers&hash=item337820e9ce

his store is
http://stores.ebay.com/applegate1999?_trksid=p2047675.l2563

in case I got it wrong. For a couple of bucks, its a great tool, even to know if you have charged your battery's fully, or have mixed them up while changing them and do not know the charged ones from the uncharged ones. This normally happens when you drink and listen at the same time

No stress, and has made my life easy.


shreekant

 

[earwaxxer]

I also like those 'old fashioned' testers with the meter. I still have an old radio shack one. I use it all the time.

 

[4krow]

I believe that my truck automatically turns off the headlights after a few hours.


  Sorry, the smartass gene is a tuff one to fight. Eric on the other hand fights the dumbass gene....GOD!! there it goes again.

 

[earwaxxer]

Sorry Greg, I hate to be the one to tell you, but YOU were the bastard child between mom and the milkman!

 

[earwaxxer]

Back to the topic of batteries and drain etc. The interesting thing I have noticed, is that I can never assess the voltage output of my batteries by the sound. I use NMH, so the voltage does decrease gradually, compared to Lipo's. I remember some fantastic listening sessions with friends where I was surprised to find that the voltage was quite low for most of the session. I'm talking low 20's to the high teens. My peak voltage on that pack was 30v, but with good reserve power. Anyway, interesting variables with the battery power.

As far as Greg is concerned - I tread lightly there. I try to complement him as much as possible. Quite fragile you know.. He's trying though.

 

[4krow]

Since you have forced me into additional therapy sessions, I am tempted to send the additional charges your way......if a doctor can't cure you is it ok to reverse the charges?

 

[earwaxxer]

Dearest Greg - I have told you before, that there is no cure for what I have. You can waist your money on therapy if you wish. I dont recommend it though...

 

[4krow]

Have I missed something, or has no one answered the question, 'how many hours do the batteries last?'

 

[proud indian]

Back to the topic of batteries and drain etc. The interesting thing I have noticed, is that I can never assess the voltage output of my batteries by the sound. I use NMH, so the voltage does decrease gradually, compared to Lipo's. I remember some fantastic listening sessions with friends where I was surprised to find that the voltage was quite low for most of the session. I'm talking low 20's to the high teens. My peak voltage on that pack was 30v, but with good reserve power. Anyway, interesting variables with the battery power.

The 9v will lessen the volume when they need a change. If you keep you amp at a constant volume, you will notice the drop in volume. Next will be the distortion, after which you have no choice. The 1.2 on the other hand become "bland" before croaking.

shreekant

 

[Paul Joppa]

Have I missed something, or has no one answered the question, 'how many hours do the batteries last?'

It's in the archives, somewhere - there have been a few threads. The search is not always as helpful as you'd wish though.

Basically, fresh alkaline batteries that meet the manufacturer's specs will last around 150-200 hours. Most aren't that fresh, and/or the specs are a little optimistic, but you should see at least 100 hours from a set.

When they drop to 2/3 of the nominal, I say dump them. That's 1.00 volts on the D-cells, and 24v from the 9-v pack, or 6v per 9-v battery. If you built it stock, they are easy to measure. But as others have noted you can still get music out of them.

 

[proud indian]

At the end of the day,Quickie owners HAVE to buy rechargeable's....  if you change them every 75 hours and they have a 1000 cycles , then you are ok for 75000 hours !!!!!!! may have to worry more about the tubes than the battery's, and in case this is too much to handle, then the option is for a regular 110/220 pre. So the battery will drain and if you are running in on regular Duracell ( like it is shown in the pics on the site) then you will soon find that it is a rather expensive pre to maintain.

Sorry for the rant, but I think this battery thing is being beaten to death.

shreekant

 

[denti alligator]

OK, then, so can I get some recommendations for good rechargeable 9V and D s? Please. I have never used rechargeables, so I don't know what to avoid.

 

[Paul Birkeland]

I am seeing a price of $0.45 for 9-volt batteries if you buy 20 at a time, and about $1.50 for a D-cell if you buy 10-12 at a time.

That's just under $5.00 for 100 hours of listening time, or about 5 cents per hour...

The key to the Quickie is buying a batch of batteries online and not running to the grocery store or hardware store to get them.

 

[galyons]

The key to the Quickie is buying a batch of batteries online and not running to the grocery store or hardware store to get them.

But the option to run to the grocery store or hardware store to get batteries, in an "emergency" music outage, is wonderful!!!!

Cheers,
Geary 

 

[earwaxxer]

Many good points here... Alkaline batteries these days are cheap. There is no reason to panic about buying throw away batteries, especially if you buy them in bulk as stated many time before.

For those of us who have been conditioned from birth to abhor using throw away batteries, I feel rechargeables help us to sleep at night. There is also a certain satisfaction from reusing a battery. That has to be taken into account. There are probably hundreds of different approaches to replacing the 9v and 'D' cells with rechargeables.  You can go with rechargeable 'packs' or drop in rechargeable replacements for the said stock battery. I prefer packs, it allows more flexability (obsess-ability?) I just juiced my 30v 3300mah NMH pack, and it took about 10min to charge. My 'AA' rechargeables that I use for the heaters take much longer, but I have 2 sets. If I could, I would like my whole system to run off of batteries!