Topic: 9 volt Lithium Ion battery

[spyder9]

Thanks Chuck.  T+ for the info. 

How about the UA-5 > JB3 tapers?  Any results?

[spyder9]

FWIW, I ran for three hrs with this WM 9vLi at three green lights to power my UA5 and my JB3 in wav record mode.  I missed the exact time that it went "dark" but I can say that there was very little time between two green and one.  I might estimate 5 hrs at full charge running these two devices.

+T to BC for bringing this 9v to light.

Found it.  Missed it when I was reading through the thread. 

[leegeddy]

the memorex ones are identical to the ones you buy at wallmart.  only difference is the label sticker on the top.

just got my meorex today, its only a 7.2v tho, not a 9v, but its the same battery for the most part.  and i have a car charger for it now.

went to Walmart and purchased on of the rb-270 model (9v 5400mAH). charged it overnight and measured the voltage in the morning....7.73volts.  hmmmm... strange... so i called up Initial Technology in california and spoke to a techy.  the verdict is that they're ALL "7.2v" models. they don't have one that outputs 9v contrary to their packaging claim!!

personally, the lesser voltage is not a big deal to me since i'll simply use this to run the Bumblebee JBOX.  just wanted to pass this info along.

marc

[caymanreview]

hmm, that is interesting

[SparkE!]

the memorex ones are identical to the ones you buy at wallmart.  only difference is the label sticker on the top.

just got my meorex today, its only a 7.2v tho, not a 9v, but its the same battery for the most part.  and i have a car charger for it now.

went to Walmart and purchased on of the rb-270 model (9v 5400mAH). charged it overnight and measured the voltage in the morning....7.73volts.  hmmmm... strange... so i called up Initial Technology in california and spoke to a techy.  the verdict is that they're ALL "7.2v" models. they don't have one that outputs 9v contrary to their packaging claim!!

personally, the lesser voltage is not a big deal to me since i'll simply use this to run the Bumblebee JBOX.  just wanted to pass this info along.

marc

Marc, I just bought a model rb-270 from Wal*Mart and it measures 9.08 V right out of the box.  I'll bet that they mislabeled some of them.

[leegeddy]

the memorex ones are identical to the ones you buy at wallmart.  only difference is the label sticker on the top.

just got my meorex today, its only a 7.2v tho, not a 9v, but its the same battery for the most part.  and i have a car charger for it now.

went to Walmart and purchased on of the rb-270 model (9v 5400mAH). charged it overnight and measured the voltage in the morning....7.73volts.  hmmmm... strange... so i called up Initial Technology in california and spoke to a techy.  the verdict is that they're ALL "7.2v" models. they don't have one that outputs 9v contrary to their packaging claim!!

personally, the lesser voltage is not a big deal to me since i'll simply use this to run the Bumblebee JBOX.  just wanted to pass this info along.

marc

Marc, I just bought a model rb-270 from Wal*Mart and it measures 9.08 V right out of the box.  I'll bet that they mislabeled some of them.

[spock]this is illogical, captain![/spock]

i'm baffled at the discrepancies with these batts.

marc

[SparkE!]

Has anyone actually run the charging port on this battery from a 12 V automotive system by plugging into the car's cigarette lighter jack?  I know that the AC recharger adapter is rated at 12 V @ 1A, but automotive 12 V is more like 13.8V.  It might go as high as 14.8 V while your car's alternator is recharging the battery.

Does anyone know whether the AC charging adapter provides regulated 12 V or is it just rectified and filtered AC from a step-down transformer?

It would sure be nice to be able to just plug this battery into your car's cigarette lighter jack to recharge it.

[John Kelly]

Has anyone actually run the charging port on this battery from a 12 V automotive system by plugging into the car's cigarette lighter jack?  I know that the AC recharger adapter is rated at 12 V @ 1A, but automotive 12 V is more like 13.8V.  It might go as high as 14.8 V while your car's alternator is recharging the battery.

Does anyone know whether the AC charging adapter provides regulated 12 V or is it just rectified and filtered AC from a step-down transformer?

It would sure be nice to be able to just plug this battery into your car's cigarette lighter jack to recharge it.

My memorex battery (same as the walmart, i got it off of ebay) came with a car charger that appears to provide a direct connection to the cigarette lighter - no voltage regulation or anything like that.  I haven't tried to use it yet, but since it came with the battery I assume it should work fine.

[SparkE!]

My memorex battery (same as the walmart, i got it off of ebay) came with a car charger that appears to provide a direct connection to the cigarette lighter - no voltage regulation or anything like that.  I haven't tried to use it yet, but since it came with the battery I assume it should work fine.

So, you've measured the resistance through the connectors at both ends of the cable and it appears to be just wires?  Many cigarette lighter plugs have voltage regulators built into them, but it's usually not obvious that there is.  One telltale sign is an LED that lights up when you plug the cigarette lighter plug into the 12 V socket.  Usually that means that there is a voltage regulator involved.

I know that people say that the Memorex batteries are the same as the batteries from Walmart, Initial model RB-270, but has anyone hooked their RB-270 directly up to 12 V automotive power with the car running?

The reason I'm raising the question about whether the Memorex batteries are actually same as the RB-270 is that I know how the Asian electronics market is.  Often you get different designs packaged in the same plastics.  The resulting products may be functional equivalents of each other (performing the same function with similar or at least adequate performance), but with all of the various suppliers for these batteries, my bet is that not all of them are completely identical.  If there was going to be a difference, it would most likely be in the electronics that control the charging of the batteries.  There's a very wide array of battery charging solutions for Li-ION batteries, especially in the area of fast charge controllers. Trickle charge controllers are usually just a current limiter, often not much more than a series resistor coming from some slightly higher voltage than the charge termination voltage of the battery.  I'm assuming that the RB-270 has a mid-tier charging controller since it takes 6 to 8 hours for a full charge.  That's faster than a trickle charge, but it's not exactly a quick charger either.  What's the charging time on the Memorex batteries?

[dklein]

sparke! - just checked the car adapter that came with my Memorex (batt measures 9.1v)

-no resistance
-current flows in both directions (no safety / diodes)

Also, the switching adapter that came with is 12v, 1A

So the battery pack itslef does voltage regulation along with the charge cycle routine.

[Tall Adam]

charger for memorexes is identical to the one that comes with the walmart (as are all accessories, but the car adaptor obviously). if i use one adaptor to charge both my batteries (one walmart, one memorex) then why wouldnt both work on the car charger as well.

[SparkE!]

OK, I did some lab work this afternoon.  Here's what I found:

The AC charging adapter for the RB-270 puts out exactly 12 Vdc and very little AC ripple when the output is not under any load.  When you start charging the battery, it drops to about 11.25 Vdc with about .3 Vac ripple.

The battery's unloaded output voltage drops from about 9 Vdc to about .7 Vdc when the battery charger plug is inserted into the battery.  So, the battery cannot be used while it's being charged.  That means if you are covering a festival where the music lasts for more than about 9 hours, you'll need 2 batteries and you'll need to charge one of them while you use the other one.

I'm thinking of using a 3 terminal regulator and a couple of capacitors inside a 12 V cigarette lighter plug's housing to drop the automotive 12 Vdc (actually 13.8 Vdc to 14.8 Vdc) down to real 12 Vdc.  Linear Tech's LT1086CT-12 with a couple of 10uF tantalum caps  looks like it would do the job.  It looks like the RB-270 might draw as much as 750 mA charging current.  If the input voltage was 14.8 Vdc, that'd be a little over 2 W of power that the regulator would have to dissipate.

[dklein]

what exactly are you concerned about?  Do you think it doesn't work or will generate too much heat?  The lab work is great but this isn't DIY - it's a commercially available product and we're talking about using the accessories that come with it.  I really don't think manufacturers screw around with Li-Ion batteries (like using a resistor as a charging strategy). 

And if you build your own regulator, after dropout voltage you may not have enough to charge properly depending on which car!  Confused...

[SparkE!]

What I'm concerned about is whether or not the Memorex batteries are identical to the Walmart batteries (Initial RB-270).  If they are, then I'd agree that it would make sense that a simple 12 V automotive plug to type M (5.5 x 2.1 mm) power plug adapter cable would do the trick.   However, if the Memorex batteries use a different charge controller than the Walmart batteries, then it might not be so good an idea.  The cigarette lighter adapter cable does not come with the Walmart batteries and I have already built a DIY cable for it.  I just don't know whether it's safe to use the cable yet.

On the subject of regulator dropout, that LT1086CT-12 only has a 1.5 V dropout voltage, so that allows delivery of  regulated 12 V from a 12  V automotive system whose fully charged voltage ranges between 13.8 Vdc and 14.8 Vdc, depending on whether or not the vehicle is running at the time.  When charging the Walmart battery, the AC adapter pulls down a bit to 11.25 V.  Taking into account the 1.5 V dropout voltage, that implies that unless your vehicle's battery voltage drops to less than 12.75 Vdc, using the LT1086CT-12 would be no problem.

If you are worried about the dropout voltage taking that voltage too low for the charger to work, then you have to ask about whether the Memorex cable would work on a car battery with a dead cell or that had been run down, trying to start a car.

I guess it comes down to a question as to which is worse, "overvoltaging" the battery's charging port (with unregulated automotive 12V) or undervoltaging it (when your car's battery gets low).  Or is either one a problem?  I wouldn't even raise the question if the Walmart battery was supplied with a cigarette lighter plug adapter cable.

[jk labs]

On the subject of regulator dropout, that LT1086CT-12 only has a 1.5 V dropout voltage, so that allows delivery of  regulated 12 V from a 12  V automotive system whose fully charged voltage ranges between 13.8 Vdc and 14.8 Vdc, depending on whether or not the vehicle is running at the time.  When charging the Walmart battery, the AC adapter pulls down a bit to 11.25 V.  Taking into account the 1.5 V dropout voltage, that implies that unless your vehicle's battery voltage drops to less than 12.75 Vdc, using the LT1086CT-12 would be no problem.

Not sure what vehicle or battery you have but I have yet to measure a non-running vehicle to much above 12.70 except just after charging when there is surface charge present. But that charge is gone pretty fast when you start drawing current. But a quick test would tell you in an instant what to expect. The draw is about the same as the roof lamp right?