hp50g and power bank

[Dieter]

(03-28-2017 06:44 PM)franz.b Wrote:  the best charge current is C/2 where C is the battery capacity (it means that the charge time is 2h)

Hmm.... what makes a charging current "the best" possible ?-)

(03-28-2017 06:44 PM)franz.b Wrote:  The BC700 charger maximum current is 700mA which could be insufficient in some cases (AA size batteries for example)

700 mA are C/3...C/4 for current NiMH AA-size batteries. This is just fine. If faster charging is required there are charger versions with higher currents. But... we are talking about AAA batteries here where capacities are much lower.

Dieter

[franz.b]

(03-28-2017 08:07 PM)Dieter Wrote:  

(03-28-2017 06:44 PM)franz.b Wrote:  the best charge current is C/2 where C is the battery capacity (it means that the charge time is 2h)

Hmm.... what makes a charging current "the best" possible ?-)

(03-28-2017 06:44 PM)franz.b Wrote:  The BC700 charger maximum current is 700mA which could be insufficient in some cases (AA size batteries for example)

700 mA are C/3...C/4 for current NiMH AA-size batteries. This is just fine. If faster charging is required there are charger versions with higher currents. But... we are talking about AAA batteries here where capacities are much lower.

Dieter

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[Dave Frederickson]

(03-28-2017 10:30 AM)franz.b Wrote:  Powerex MH-C9000 is one of the best

I've been very happy with my BC-700 and never heard of the MH-C9000. For around $50 the MH-C9000 offers 19 charging currents from 200mA to 2000mA and an additional "Break-In" mode.

Some reviews from 6 years ago complain about the charge cycle.
http://www.candlepowerforums.com/vb/show...ve-charger
It sounds like there was an older model without the independent -deltaV end-of-charge detection feature. Anybody have experience with this possibly newer version?

Dave

[Dieter]

(03-29-2017 03:10 PM)Dave Frederickson Wrote:  It sounds like there was an older model without the independent -deltaV end-of-charge detection feature. Anybody have experience with this possibly newer version?

I see the OP lives in Germany, here the MH C-9000 is available from elv.de. There also is a link to a PDF manual which should answer most questions regarding this charger.

The same supplier offers the BC700 in a set with four Panasonic AAA low-self-discharge batteries. The batteries are Panasonic Evoltas, I can't say much about the difference between these and the current Eneloops. In any case Panasonic usually is considered a high quality battery manufacturer.

On the other hand there are also sets consisting of a BC700 and four genuine AAA Eneloops. For instance at akkushop.de. You even get a nice battery box. ;-)

Dieter

[pier4r]

(03-30-2017 02:01 PM)Dieter Wrote:  I see the OP lives in Germany, here the MH C-9000 is available from elv.de. There also is a link to a PDF manual which should answer most questions regarding this charger.

The same supplier offers the BC700 in a set with four Panasonic AAA low-self-discharge batteries. The batteries are Panasonic Evoltas, I can't say much about the difference between these and the current Eneloops. In any case Panasonic usually is considered a high quality battery manufacturer.

On the other hand there are also sets consisting of a BC700 and four genuine AAA Eneloops. For instance at akkushop.de. You even get a nice battery box. ;-)

Diete

Thanks, anyway how do you know that I live in Germany? (Berlin)

Ah ok I googled my nickname + location and it appears quickly.

[Han]

(03-30-2017 06:17 PM)pier4r Wrote:  Thanks, anyway how do you know that I live in Germany? (Berlin)

Ah ok I googled my nickname + location and it appears quickly.

Did google provide you with this link? http://www.hpmuseum.org/forum/user-1843.html

[pier4r]

(03-30-2017 06:33 PM)Han Wrote:  Did google provide you with this link? http://www.hpmuseum.org/forum/user-1843.html

No, I wonder when I set it. With google I got twitter where I shared the location.

[Dieter]

(03-30-2017 06:17 PM)pier4r Wrote:  Thanks, anyway how do you know that I live in Germany? (Berlin)

Ah ok I googled my nickname + location and it appears quickly.

No need to google. Just log in and click on your username in this or any other thread.
You provided this info when you registered, but you may also have edited it later.

Dieter

[TravisE]

(03-29-2017 03:10 PM)Dave Frederickson Wrote:  I've been very happy with my BC-700 and never heard of the MH-C9000. For around $50 the MH-C9000 offers 19 charging currents from 200mA to 2000mA and an additional "Break-In" mode.

Some reviews from 6 years ago complain about the charge cycle.
http://www.candlepowerforums.com/vb/show...ve-charger
It sounds like there was an older model without the independent -deltaV end-of-charge detection feature. Anybody have experience with this possibly newer version?

I've used the C9000 for a number of years (mainly because it was the first charger of its type I happened to come across) and have had no real issues with charging. The complaints in that thread mainly seem to be regarding how early the charger terminates the main charge and drops to a top-up charge. As I recall, very early C9000 units had an issue with not terminating (and therefore over-charging) cells sometimes, especially when charging at a lower-than-recommended rate (which could make the delta-V signal too small for the unit to detect). To address the problem, an additional termination condition was programmed into the charging algorithm of later C9000s which causes them to terminate as soon as cell voltage rises to 1.48v. This makes it charge more conservatively and drop to top-up mode sooner than older units. But this means that to get a “full” charge, the top-up can take an additional hour or two, and this seems to be what some people complain about.

This change happened rather early in the product's life (I purchased my first C9000 in 2008, and it was already the “fixed” version), so you'd have to have a very early unit to worry about the termination problem.

If I remember correctly, current C9000s will stop charging at delta-V, at 1.48 volts, if the cells reach too high a temperature, or if the charge continues for too long (I forgot what the interval was), whichever occurs first.

In practice, I don't feel the top-up charge really makes that big of a difference, especially in a relatively undemanding device like the 50g. My only real complaint of the C9000 is that it doesn't like aged cells very much and is pretty quick to reject them as being defective if the internal resistance is getting a bit high, even if they are still healthy enough to run low-power devices like the 50g. (The analyze and discharge modes will give highly inaccurate results if the internal resistance is anything less than optimal, even at the lowest 100mA discharge rate, even if the cells work fine in a normal device that uses 100 mA.)

I've personally never used the La Crosse chargers, though I've heard many, many reports several years ago about certain models failing and (literally) melting down. Yikes.

[pier4r]

Side question.

Before buying the panasoinc eneloops I found out that I have some panasoonic AAA infinium and I wanted to test the hp50g with those inside plus a power bank of 2200 mAh.

I launched an execution that lasted almost an hour of 100% cpu, but the power bank was still full. So is it true that even when the hp50g is connected to the USB power source, the first source of energy are the batteries?

[Dieter]

(04-05-2017 07:06 AM)pier4r Wrote:  I launched an execution that lasted almost an hour of 100% cpu, but the power bank was still full. So is it true that even when the hp50g is connected to the USB power source, the first source of energy are the batteries?

I can't answer that question (although I suppose that the device switches to USB power – and that's also what I get from some usenet posts), but what's the current draw of a running 50g in the worst case? 100 mA? Less? So one hour of operation will consume not more than 5% of the mentioned 2200 mAh. Which leads to the question: how did you find out the power bank "was still full"? Does it have a battery system where you can at least approximately tell the charge level? Let alone discern subtle differences like 100%, 95% or 90%?

Dieter

[pier4r]

(04-05-2017 07:53 AM)Dieter Wrote:  I can't answer that question (although I suppose that the device switches to USB power), but what's the current draw of a 50g in the worst case? 100 mA? So one hour of operation will consume not more than 5% of the mentioned 2200 mAh. Which leads to the question: how did you find out the power bank "was still full"? Does it have a battery system where you can at least approximately tell the charge level? Let alone discern subtle differences like 100%, 95% or 90%?

Dieter

Being biased with the continous "low battery" I thought that the 50g absorbed way more current in one hour of 100% cpu. That was maybe my mistake. The powerbank approximate levels in 25% bars.

Well, I do have in the schedule longer computations, so, we will see how long it last, unless I find another bug in my program and I have to connect the 50g to the PC once again.

[Dieter]

(04-05-2017 08:01 AM)pier4r Wrote:  Being biased with the continous "low battery"

...which may be caused by the batteries you use...

(04-05-2017 08:01 AM)pier4r Wrote:  I thought that the 50g absorbed way more current in one hour of 100% cpu. That was maybe my mistake.

Facts are often helpful. ;-)
What about these ones in a comp.sys.hp48 thread? Or that one (be sure to read more than just the first posts, especially consider the one by Joe Horn).

(04-05-2017 08:01 AM)pier4r Wrote:  The powerbank approximate levels in 25% bars.

OK – no further questions. #-)

Dieter

[pier4r]

(04-05-2017 08:18 AM)Dieter Wrote:  Facts are often helpful. ;-)
What about these ones in a comp.sys.hp48 thread? Or that one (be sure to read more than just the first posts, especially consider the one by Joe Horn).

Nice threads! I'm reading them.

Oh, the reply from Joe Horn to Andreas is pretty, ehm, direct.

Ok, so with a current consumption of round about 70 mAh, assuming that the power is drawn from the USB and being conservative on the powerbank 2200 mAh, saying that only the half is available for real usage, it should last more than 11 hours.

We will see. The current iteration is 142 of 1000 and then one 1000 more has to be computed.

Side note: in small communities that revolve around a common interest one finds always those few individuals able to provide good "old" contributions that otherwise are scattered around the web (until they are loaded somewhere). Every time those contributions are dug out from the archives, the community could collect them in a sort of resource list for newcomers, otherwise all the work (and knowledge) will always be on the shoulder of those individuals. Sure, then there is a problem of "which contribution qualifies for the list of contributions?". Anyway, I started in 2013 and when I find something neat I try to remember to add it here: http://www.wiki4hp.com/doku.php?id=resou...iscussions


Update: ok with my poor charged batteries (for the batteries see here: http://i.imgur.com/ps0ek1t.jpg ) the 50g lasted round about 4 hours of 100% cpu, then stopped the computation saying "low batteries". I verified and the power bank was not used, because I could not power on the 50g with only the power bank. I checked the cable and was not totally inserted on the side of the powerbank, so now it should work with just the powerbank, although the batteries are still inside (but should not help, plus, from the threads linked by Dieter, we know that the 50g uses the USB power when this is recognized ).
With only the powerbank in a conservative estimate (only 1100 mAh usable), I would consider at least 11 hours of 100% cpu use.

update2: ok the powerbank failed. Somehow it is like the power drained by the 50g is not enough, and the powerbank stops providing it and the 50g went off). So it last for half an hour and then it closes. Trying a 10000 mAh (estimating a 5000 mAh usable) now.

update3: the 10000 mAh is holding the hp 50g open so far (it has only 2 batteries out of 4, so cannot be that the batteries are used, moreover the batteries are already recognized as exhausted). 2 hours are passed and the iteration is 387 out of 1000.

[pier4r]

Update4. The 10000 mAh holds the 50g pretty well (at least, 5 hours 100% cpu), but as soon as the 50g goes in standby, then also the powerbank goes in standby and the results are lost. 5 hours lost :cries:

So, the answer is: it seems that with cheap powerbanks that have standby modes, the 50g will eventually turn off and lose the result on the stack.

[Han]

(04-05-2017 05:59 PM)pier4r Wrote:  Update4. The 10000 mAh holds the 50g pretty well (at least, 5 hours 100% cpu), but as soon as the 50g goes in standby, then also the powerbank goes in standby and the results are lost. 5 hours lost :cries:

So, the answer is: it seems that with cheap powerbanks that have standby modes, the 50g will eventually turn off and lose the result on the stack.

Save your results with

\<< DEPTH \->LIST 'RESULTS' STO \>>

saved in the STARTOFF variable.

[TravisE]

I've done some tests of my own in the past, and in my experience, the 50g does draw power from USB when available, rather than the batteries, so plugging it into a USB power source should save the batteries (it wasn't necessary to remove the batteries; they can be left in place, and the calculator will seamlessly switch back to battery power automatically if USB power fails). However, I've had the same trouble with USB power banks. Mine also only likes to stay on and provide power when the CPU is running at 100%. I've sometimes had to plug in an extra USB device of some kind (my bank has two ports) to draw enough current to keep the bank on.

[pier4r]

While reading the general forum I found another interesting post

http://www.hpmuseum.org/forum/thread-3988.html

It seems that sometimes the 50g just drains more power than needed.

There is another confirmation that when the usb is plugged, no battery drain. I love the 50g for this, because one can exploit the technology made for Smartphones to power it, just I did not know that power banks requires a minimum of drain power to stay active.

[pier4r]

(03-27-2017 03:43 PM)Dieter Wrote:  Try quality single-use batteries first (high power alkalines, maybe even Lithiums – if approved by HP). If this works, replace both your batteries and your charger by, say, a set of Panasonic Eneloops and a BC700 charger.

Finally I bought the charger! (although BC1000 instead of BC700). Thanks for the suggestion.

[Dieter]

(08-10-2018 09:23 AM)pier4r Wrote:  Finally I bought the charger! (although BC1000 instead of BC700). Thanks for the suggestion.

The BC1000 allows additional higher charging currents for AA cells. For AAAs be sure to select the default 200 mA setting.

But that's only one half of the solution: You've got a decent charger now, but you also need good batteries. Again, I recommend Panasonic Eneloops here.

Dieter