Using a 9v battery box

[ColletArrow]

I can't seem to find anything about this elsewhere, so I'm going to ask here directly.
Are there any disadvantage of using the older, 9v battery pack (4760c01) that took one 9v cell to run power functions receivers and motors instead of the current, 6x AAA battery pack (87513)? I know it will require a converter cable, but from my view it looks as though a 9v battery pack would be better as it is smaller (in height) and available in more colours than just DBG, so easier to hide in 4-wide MOCs and such.
Will this have lower power or current output to the motors, or discharge faster? Is it suitable for use in train MOCs, considering mine won't need to run very far or for very long? I was intending on using it with a rechargeable 9v cell or two, how often would I need to swap one out and recharge it?
I'm trying to decide whether or not buying one, and a converter cable, is a good idea. (Or I could try bashing together a PF cable and 9v battery clip perhaps, like this.)
Thanks in advance for any help!

[jtlan]

You won't be able to use the older pack with the receiver without some hacking, as the converter cable is not wired to connect power sources to the 9V/0V lines.

A 9V cell has a lower capacity than a pack of AAA cells (if only because, for the same battery chemistry, capacity is proportional to battery volume). If you run the train a lot you should expect to change 9V cells frequently. You can probably get a few hours of continuous running, depending on the load.

That said, you could also connect the 9V battery box directly to the motor -- no receiver. You won't be able to do any yard work, but you can recreate that 4.5V train experience. Kind of refreshing actually!

[ColletArrow]

Right, thanks. Seeing as my normal set-up is tiny, as in max 6 straights (including points) long or a temporary circle on the floor, I need a receiver in my trains. (Also due to this, my trains don't see a lot of continuous running ) Does this mean I would be better off splitting an extension cable and joining it with a 9v battery clip, as that would take up less space, save me buying a battery box and I would be altering the cable anyway?
Out of interest, how is the converter cable wired? I didn't see a diagram of that, but the rest of the page you linked was very helpful. Thanks again!

[Hod Carrier]

I've had some success using a PP3 9V battery on a MiniZip cable in my tiny TRAXX loco. It has enough grunt to run an SBrick controlling an L-Motor although I've not had any chance to test it's longevity on a long run or with any sort of train though, but it's certainly possible in a 4-wide body or other compact applications. Check out my Flickr album or search here for some photos if you wish.

[Duq]

It's possible to use those 9V battery boxes with PF without a hacked cable like this:

PF with old 9V by Duq, on Flickr

That's an unmodified PF extension lead between the battery box and receiver. The normal power lead on the receiver is not used.

You lose a bit of power but it works. And indeed, as has been mentioned, those batteries don't last very long...

[netlife]

It's now possible to buy rechargeable (with  a microUSB) 800mAH lithium batteries for the old 9V 'light and sound' battery boxes. Should keep the battery costs under control but haven't yet measured battery longevity in real life.

[paulmaglev]

On 3/8/2017 at 2:00 PM, Duq said:

It's possible to use those 9V battery boxes with PF without a hacked cable like this:

PF with old 9V by Duq, on Flickr

That's an unmodified PF extension lead between the battery box and receiver. The normal power lead on the receiver is not used.

You lose a bit of power but it works. And indeed, as has been mentioned, those batteries don't last very long...

This will work nicely with some of my potential plans.  My question is: how long will the battery last?

[Duq]

The not very scientific answer is: not very long ;-)