Standard AA vs. Ni-MH AA

[RobA]

Is it true that a NiMH AA only last about 9 hours in a HiMD player when a stanard AA can last to about 25 hours? I'm a little confused on this and just want to clear it up. I use the AA attachment on my RH10 and want to maximize the battery life. I'm not sure whether to use NiMH AA's or standard AA's in the attachment on rh10 to maximize battery life. Thanks for any replies.

Edited April 16, 2006 by RobA

[MDX-400]

No not really true. A 2500mAh NiMH AA, fully charged, will be close to the same as an AA alkaline. NiMH AAs have progressed quite some ways now and they're up to 2500mAh now. Any 2000mAh NiMH AA would be good really. A typical AA alkaline is around 2700mAh, with better ones (like Energizer and Duracell) being a bit over 2800mAh and the even "better" alkalines (the e^2 Titanium and the Ultra) being a little higher than that. Still alkalines can't do those rated capacities with any significant load on them (i.e. when recording for example or in digital camera applications, etc.). There is where NiMH will beat alkaline without a problem really. (There's more on this in other threads if you search.)

The only thing is that you aren't "supposed" to use a rechargeable in the AA attachement with the internal battery installed (i.e. not at the same time). There is a reason for this but I won't get into it too much (you can do a search here and on the T-Board for more info) though many people still do it anyway with no problems.

Your basic answer though: you should get decent times with a high cap. NiMH AA compared to an alkaline AA.

[RobA]

Thanks for the quick reply, just checked my nimh double AA batteries, they are 2300mAH. But I do use it at the same time with the regular nimh gumstick. I'll do a search on it. I hope it is not causing any damage to the player.

[RobA]

Okay, I've done a few searches and have some mixed feeling. Some posts say that a "backwards charge" takes effect and screws up the unit. Others say it works perfectly fine. Apparently when a AA is attached it is supposed to charge the nimh gumstick as it loses power, thus extending the battery life. But with nimh AA's attached, the gumstick attempts to charge to AA and shortens battery life, is this correct? Should I just stick with regular AA's instead of my 2300mAH NiMH AA's when the gumstick is attached? I don't want to cause any damage to the unit and I want optimum battery life. But it would be nice to just be able to use rechargable AA's.

[greenmachine]

The relatively high capacity of alkalines is rated under modest current consumption (maybe 1/10 or even 1/20 C). When used with high current draining devices (Hi-MD can reach reach higher peaks), the usable capacity will be significantly lower. Rechargeables on the other hand can handle high current peaks better and thus might outperform Alkalines. Drawback, among others is a relaitvely high self-discharge, which is a non-issue if used regularly.

I'd be interested about the reasons why not to use two rechargeables at once as well. What's the difference to using to using gumstick + alkaline? I would suppose the latter combination could in theory give more problems because of different voltages (1.2 vs. 1.5V), not?

[1kyle]

The relatively high capacity of alkalines is rated under modest current consumption (maybe 1/10 or even 1/20 C). When used with high current draining devices (Hi-MD can reach reach higher peaks), the usable capacity will be significantly lower. Rechargeables on the other hand can handle high current peaks better and thus might outperform Alkalines. Drawback, among others is a relaitvely high self-discharge, which is a non-issue if used regularly.

I'd be interested about the reasons why not to use two rechargeables at once as well. What's the difference to using to using gumstick + alkaline? I would suppose the latter combination could in theory give more problems because of different voltages (1.2 vs. 1.5V), not?

It all goes back to OHMS LAW (Power consumption in WATTS = Current in amps * Voltage in volts).

For the same power consumption in watts if the voltage is slightly lower (1.2 vs 1.5) the battery will have to supply more AMPS. This means it will drain slightly quicker.

The device won't have any problem using 1.2V vs 1.5V but for a given power capacity it will of course discharge quicker as it has to supply more power.

For those who've ever been in the US -- that's why it's difficult to find electric kettles

a 3 Killowatt electric kettle in Europe @ 220 volts will draw 3,000 / 220 amps = 13.5 (probably need 15 Amp fuse

In the USA if you can find one it would need 3,000 / 110 or nearly 30 Amps. The size of the wire would have to be HUGE as well to avoid heat loss in the wire.

This is no "Conspiracy theory". Merely simple physics.

Cheers

-K

[RobA]

It all goes back to OHMS LAW (Power consumption in WATTS = Current in amps * Voltage in volts).

For the same power consumption in watts if the voltage is slightly lower (1.2 vs 1.5) the battery will have to supply more AMPS. This means it will drain slightly quicker.

The device won't have any problem using 1.2V vs 1.5V but for a given power capacity it will of course discharge quicker as it has to supply more power.

For those who've ever been in the US -- that's why it's difficult to find electric kettles

a 3 Killowatt electric kettle in Europe @ 220 volts will draw 3,000 / 220 amps = 13.5 (probably need 15 Amp fuse

In the USA if you can find one it would need 3,000 / 110 or nearly 30 Amps. The size of the wire would have to be HUGE as well to avoid heat loss in the wire.

This is no "Conspiracy theory". Merely simple physics.

Cheers

-K

Ok so let me get this straight. It is perfectly safe to use nimh gumstick + nimh AA at the same time, but will not give me as much battery life as a nimh gumstick + standard AA, correct? If that's the case, I think I will continue to use both nimh batteries, as long as it is safe for the unit, I'm sure I won't lose to much battery life.

[Mr_Bass_Man]

Ok so let me get this straight. It is perfectly safe to use nimh gumstick + nimh AA at the same time, but will not give me as much battery life as a nimh gumstick + standard AA, correct? If that's the case, I think I will continue to use both nimh batteries, as long as it is safe for the unit, I'm sure I won't lose to much battery life.

I am not sure "simple physics" explains very much as the "physics" of batteries is anything _but_ simple. Even plain old Ohm's Law doesn't tell the full story as far as the "fuse" analogy goes, as the "physics" of fuses is similarly less simple than you might at first think.

[in the UK domestic consumer plug-tops are usually rated at 13A, and often fused for that same current, however a 3kW electric kettle doesn't blow the fuse (or shouldn't anyway) - it would EVENTUALLY if run for a considerable period of time, which is (or should be) much longer than it takes to boil a kettle full of water. However if that kettle develops a fault - say the insulation in the heating element breaks down - then the fault current will be much more than 13A, and the fuse will (or should) blow very quickly.]

It is very not a good idea to make assumptions about whether or not a battery of whatever chemistry you chose is perfect for any particular applications as there is an enormous range of performance of any particular type of battery due to its age, condition, manufacturer, use, etc etc. All you can really do is follow the manufacturers' advice (be it the manufacturer of the battery, or of the equipment it is being used in), and blend it with your own experience.

And avoid, if you can "built-in" batteries, as the one built in to my beloved MZ-N10 is really giving me ever so much of a hard time ! ! ! !

Edited April 16, 2006 by Mr_Bass_Man

[MDX-400]

I'd be interested about the reasons why not to use two rechargeables at once as well. What's the difference to using to using gumstick + alkaline? I would suppose the latter combination could in theory give more problems because of different voltages (1.2 vs. 1.5V), not?

It has little to do with the voltage difference but rather exactly what you stated before. As we know alkalines cannot provide their rated capacity against higher current draws. One of the reasons for this is the cell's internal resistance. Rechargeables, like NiMH, have a much lower internal resistance IIRC, therefore their propensity to cross-charge with the internal battery (be it NiMH or Li-Ion) is much greater.

It's this cross-charging that is really the issue, from the research I've done. With an Li-Ion it is a worse situation because you are then mixing chemistries. With an NiMH gumstick it seems safer because you're just mixing types (prismatic & cylindrical).

In any event it isn't likely that you will damage the unit but rather shorten the useful life of one of the cells, more likely the prismatic (gumstick) batter. The unit could be damaged, if the internal cell vents, however (which is a possiblity depending on the direction/magnitude of current transfer between the batteries). Because then you'll have a leaking battery in your unit, lol.

Again lots of people have done it without problems and I think if you use high quality cells on both sides (Japan or US made) you should be okay. Now it's still no guarantee but safer than using some off branded made in who-knows-where battery(ies). Though personally I think it is okay with the NiMH gumstick I wouldn't use an NiMH AA in a unit that uses an internal Li-Ion cell because Li-Ion is pretty sensitive and you'll likely end up cutting its lifespan short.

[greenmachine]

Thank you for your detailed thoughts. Although it's somewhat hard to imagine, i suppose there's some truth in it.

[The Low Volta]

the Li-Ion models do not have an option for an AA-Addon so it would be very hard to mix NiMH AA's and a Li-Ion battery

[MDX-400]

the Li-Ion models do not have an option for an AA-Addon so it would be very hard to mix NiMH AA's and a Li-Ion battery

You're joking right??? Sure they do! My AM-F70 sure has an AA attachment, be it retardedly large and have to take 3 AA batteries, but it has one.

The N10 certainly has a single AA attachment and it has an internal Li-Ion.

Even my Li-Ion-Poly MZ-E95 has an AA attachemnt(uses the same one as nearly every other Sony unit, in fact).

The R50 used an internal Li-Ion and could use an add on 2AA pack IIRC.

Many Sharp Li-Ion based units can use an AA pack as well (I think my Pio PMD-MK2 has an AA pack).

I could probably keep this list going if you want, LOL.

[The Low Volta]

ah ...sorry, my limited attention span (I've only started the whole MD-stuff with a NH900) didn't make me think beyond HiMD and as the general reaction to the news of the RH1 using Li-Ion was "oh darn, then it won't have an AA-addon" I simply reckoned Li-Ion with an AA-addon was not done...

[Stuge]

ah ...sorry, my limited attention span (I've only started the whole MD-stuff with a NH900) didn't make me think beyond HiMD and as the general reaction to the news of the RH1 using Li-Ion was "oh darn, then it won't have an AA-addon" I simply reckoned Li-Ion with an AA-addon was not done...

LOL,

[1kyle]

And avoid, if you can "built-in" batteries, as the one built in to my beloved MZ-N10 is really giving me ever so much of a hard time ! ! ! !

It's really easy to remove and replace. The manual shows how to do this quite clearly. All you need is a set of those tiny "Watch Makers" screwdrivers to undo 2 tiny screws ro remove the jog dial.

The battery just disconnects from the ribbon connector.

Put a new one in and you are done.

Cheers

-K

[greenmachine]

I guess the major problem wouldn't be the procedure itself, but to find a working replacement battery (for an acceptable price / at all).

[Mr_Bass_Man]

It's really easy to remove and replace. The manual shows how to do this quite clearly. All you need is a set of those tiny "Watch Makers" screwdrivers to undo 2 tiny screws ro remove the jog dial.

The battery just disconnects from the ribbon connector.

Put a new one in and you are done.

Cheers

-K

Lummy - that's great. (p. 78 of the Operating Manual)

I saw that procedure some time ago and noted that it was aimed at when the N10 has departed this life and is ready for the scrapheap. I didn't twig the Li-Ion battery was "replaceable" in this way.

Disembowelling the machine looked pretty "terminal", though from what you say it would appear to be a simply-reversible procedure.

Where did you get your replacement battery?

Edited April 17, 2006 by Mr_Bass_Man

[Top Cat]

It's this cross-charging that is really the issue, from the research I've done. With an Li-Ion it is a worse situation because you are then mixing chemistries. With an NiMH gumstick it seems safer because you're just mixing types (prismatic & cylindrical).

The question is, are the two batteries bridged in parallel indeed?

I thought it wouldn't be very wise to bridge different batteries (an alkaline & a rechargeable) even with great internal resistance.

So may be some sort of insulating circuitry is still employed in MD devices?

[MDX-400]

^No it isn't strictly/directly in parallel. There is indeed charge control/power control circuitry in place. For your interest, if you'd like more complete details, look at a service manual for whichever unit you prefer and it will be a little more specific.

[Top Cat]

You know, they really seem to be bridged... I was surprised after looking in the RH910 service manual.

OK, now here's the dilemma: extra prismatic or AA rechargeable?

What it comes down to:

Prismatic Panasonic (Japan) 1400 mAh - $14

Prismatic GP (China) 1450 mAh - $6

Prismatic charger, however inconvenient, is already available for free (inside the recorder)

AA Panasonic (China) 2100 mAh - $3

AA Panasonic (China) 2400 mAh - $4

AA charger is $8 cheapest, minimum 2xAA charging, which is very inconvenient, to $50 (more decent, allows single AA charging with auto-off etc)

Which way would you go assuming there's 1 (on average) long (slightly longer than the standard battery life) recording on batteries per week?

[jonny mac]

You know, they really seem to be bridged... I was surprised after looking in the RH910 service manual.

OK, now here's the dilemma: extra prismatic or AA rechargeable?

What it comes down to:

Prismatic Panasonic (Japan) 1400 mAh - $14

Prismatic GP (China) 1450 mAh - $6

Prismatic charger, however inconvenient, is already available for free (inside the recorder)

AA Panasonic (China) 2100 mAh - $3

AA Panasonic (China) 2400 mAh - $4

AA charger is $8 cheapest, minimum 2xAA charging, which is very inconvenient, to $50 (more decent, allows single AA charging with auto-off etc)

Which way would you go assuming there's 1 (on average) long (slightly longer than the standard battery life) recording on batteries per week?

I haven't had any problems using a rechargeable with my NH900 but then it's rare that I use the AA pack. If you're using that many batteries it'll be cheaper to go with rechargeables.

Thi shasn't come up so far and I don't know what your recording environment is but I'm assuming it's not possible to use the mains adaptor?

[The Low Volta]

the adaptor creates a very annoying buzz/humm when recording so it is really useless... I always use my AA-addon with a 2500mAh NiMH battery when recording... never had any problem and the battery life is ok for me

[Roamer]

For festivals, I use non rechargeable Lithium. This last very long and I can do several PCM recordings (the most power hungry mode) this way with the AA pack. But that's overkill for other purposes ...

[MDX-400]

OK, now here's the dilemma: extra prismatic or AA rechargeable?

Which way would you go assuming there's 1 (on average) long (slightly longer than the standard battery life) recording on batteries per week?

It all comes down to space and convenience IMO... Personally I would try to stick with the gumstick as much as I possibly could, but if I needed the AA I'd use it too. AA becomes more sensible if you aren't confined for space (i.e. if you don't have to keep it in your pocket where the AA would be possibly uncomfortable).

Since you're going over the time you can record on the gumstick battery, using the AA in the case makes perfect sense, because then you get both. Though using just the AA might get you the time you need to.

AA rechargeables are cheaper and can be used in many other devices, so it is pretty useful to have a good NiMH charger and batteries around, other than for use with your Hi-MD unit. NiMH rechargeables are mandatory for digital cameras (other than those that use proprietary batteries that is); and, they are useful for lots of other things. As some examples, I also use them in my two receiver remotes (the touchscreen one being very power-hungry so NiMH is great there); in my wireless mouse; cordless phones (which take AA NiMHs); and wherever else it is convenient. Gumsticks on the other hand you can only use in MD units, for the most part.

[RobA]

the adaptor creates a very annoying buzz/humm when recording so it is really useless... I always use my AA-addon with a 2500mAh NiMH battery when recording... never had any problem and the battery life is ok for me

But do you use the nimh AA at the same time as when using the gumstick? I'm still cautious as do whether I should use both at once.

[Top Cat]

It all comes down to space and convenience IMO...

Well, may be sometime possibly I'll manage to invent a need in some application requiring AA's, then I'll shell out for a fancy charger etc...

In the meantime I'm almost decided to go for the $6 prismatic spare

Thanks for your input!

[BobS]

I have used rechargable batteries in the outboard case with no problems many times. After all, an alkaline AA voltage drops as it ages and at some point is 1.2 volts, just like the NiMh

[The Low Volta]

I use a GP powerbank 1450mAh gumstick so I have the original one for spare... and I always carry two fully loaded 2500mAh NiMH's... and yes I do use the prismatic one and the AA's at the same time and I have not experienced any troubles... still I'm not too careful about it either...

[MDnewuser]

How is the batterylife when comparing standard AA:s and lets say Ni-MH AA:s ?. I reguarly use Duracell M3, but now i thought of trying Ni-MH (2500 Mah) and see how they work. I have MZ-NH600 and MZ-NH700 so just AA:s no add-ons or such.

Another question, is the batterylife depending on which mode your recording in ?.

Edited April 22, 2006 by MDnewuser