EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: r90s on December 01, 2012, 08:56:02 am
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Hi Folks,
I had ordered an Agilent U1252B Multimeter about five weeks ago through Metrictest. I formerly (in the olden days, when dinosaurs roamed) had purchased directly all of my lab test equipment directly From Agilent (then Hewlett Packard,) Tektronix, and everyone else who's offices, or main facilities' were in the Dallas Texas “Metroplex” area. There are too many sources to name available there. I now live in a forbidden obscure corner of the world, hence my order was made through a distributor.
I was told, that even though listed as in stock on their web site, that was not in stock, and would be available for shipment in about four weeks. I decided that due to the items to be included as standard, that I would “go for it”. The items listed on the site were the standard, plus soft carry case, and the probe set was the U1160A set. This probe set was the old style (which I prefer,) very complete set. Also even though the promotion was supposed to be over, they were going to include the bluetooth adapter. All this for $418 U.S. minus 10 per cent making total charge $376 dollars.
Well, five weeks had passed when I received an email from Metrictest. It said that “we expected to receive your Agilent U1252B from Agilent today for shipment; however”, The sales person was provided an update from my Product Manager notifying him that the unit has an additional 4 week lead time due to "additional testing needed on the unit prior to shipment". In the message I was then offered the U1253B meter for the same price and it was in stock. Everything else about the order was to stay the same.
I explained that that I had done diligent procurement research and that this particular model had been ruled out primarily due to it's very short battery life because of it's OLED display, as beautiful as the display was. But, I had thought things over, and since the multimeter was to be used as a temporary bench meter replacement, and would do the deal.
I guess that I need to explain, although I wish not to talk much of personal things, that I am disabled and have had to retire. Hence the need for extraordinary research and caution on financial outlays. This factor also will preclude the use of the meter outdoors in bright sunlight, where the display is problematic.
A while after agreeing to th change in the order I noticed, on the Agilent web site, that the U1160A probe set had been discontinued and asked the Metrictest sales agent to see if that set was the one included. If not and that set was not in stock to be substituted or could not be substituted, to not let it effect the promptness of the shipment.
Later I received a message (the salesperson said later, he had worded poorly) that he was adding a U1161A probe set “at no additional discount”.
I want to cut this short as my trick back is starting to hurt from my typing position.
The salesperson meant “at no additional charge. I firmly believe that it is obvious, that an Agilent induced delay, causing the need for an order modification, made it obligatory for the distributor to jump through hoops, which they did in an admirable fashion.
If this is an example of Metrictest performance, then I highly recommend them.
Now, to get the meter to run longer, I guess I'll try a 1200ma primary NiMH. Any thoughts that anyone might have about this are invited.
So Long Folks
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Hey r90s....well, that's quite some waiting-time ;)
Just out of curiosity....what made you stay with the U1252B and not move to a Fluke or the U1272A?
I own a U1272A and a U1253B....where the U1253B is loverly when working indoor or under the car, the U1272A is great for long-term logging and troubleshooting wiring and so on. (The loud beeper can be helpful sometimes ;)).
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Well, I have had two Fluke meters in the past, and found them to be very good. I started using HP (Agilent) in the very early 1970s. I have had very good luck with their products. All of that equipment was bench lab equipment though.
Now in researching things, it appears that most of the Fluke line is still great, but lacks some features that I wanted. That is, unless you paid, what for me, was too much money. I wanted the Agilent U1252B for it's greater accuracy and it's features. I like the U1272A and if was to be using a meter in the field, then it definitely would have many pluses. So would a number of Fluke meters. I ended up in a bind on time and when there was a delay I went ahead and got the seductive U1253B.
I had hoped to reduce the battery run time problem by using a higher capacity battery. When presented with the proposition of substituting the OLED meter, I did a fast search for NiMH high capacity primary batteries. The search was too quick, for I thought I had found a battery solution, without the need to buy an extra external charger. I had made a mistake and the 1200ma battery I saw turns out to be a lithium ion type.
I typed this long winded topic earlier, to tell of the bending over backwards of the metrictest distrubitor, trying to please me.
But also to ask for help with the battery life problem. People probably got tired of reading the boring story, and they did not get to my asking for help.
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Unfortunately rechargeable 9 V NiMH batteries are a poor technical solution and Agilent have screwed up with the design of the U1253B. Their marketing managers have overruled their technical designers as often happens in large companies.
To get longer battery life you can use a rechargeable lithium ion 9 V battery instead of the NiMH battery but you must not use the built-in charger or AC adapter. Rechargeable lithium 9 V batteries come with their own dedicated charger and you must use the proper charger for the battery.
Here is an example of the kind of 9 V lithium battery that could be used:
http://www.batteryjunction.com/ipowerus-9v-500.html (http://www.batteryjunction.com/ipowerus-9v-500.html)
However, a couple of these batteries plus charger is not going to come cheap.
Alternatively you could use cheaper 9 V NiMH batteries and have a spare on standby in case one runs out.
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Well ian, there is a way to use the meter´s charger than is to use LiFe batteries instead is Lipo...(life is like other litiun battery but it does't explodes, i might say than it is a more powerful NiMH, and LiFe is also cheaper than Li-ion)
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I think the biggest problem with using rechargeables in many devices is the self-discharge of the battery. Even if you don't use the device, standard NiMH batteries will be entirely depleted in a couple of months, if not sooner. There are low self-discharge (LSD) 9V batteries available now from a few companies. I've had good luck with those made by Maha and Tenergy. The Mahas are 9.6V, however, and Agilent specifies either 7.2V or 8.4V rechargeables, so I wouldn't deviate from that. The Tenergy LSD 9V is 8.4V, so that should be fine. You can get a couple for not much money:
http://www.ebay.com/itm/2-x-Tenergy-Centura-9v-Low-Self-Discharge-NiMH-Rechargeable-Batteries-/290622906425?pt=US_Rechargeable_Batteries&hash=item43aa79a039 (http://www.ebay.com/itm/2-x-Tenergy-Centura-9v-Low-Self-Discharge-NiMH-Rechargeable-Batteries-/290622906425?pt=US_Rechargeable_Batteries&hash=item43aa79a039)
I usually don't use my handheld meters for hours at a time, so the absolute runtime is not very important to me. If you are really going to use this like a bench meter and leave it on for hours, then NiMH might be a real pain to use. Li-ion 9V batteries have 5-6X the capacity of the NiMH ones, but then you have to charge them with their specific charger. With the NiMH, you can just leave them in the meter and use the charger that comes with the meter.
I've heard of LiFe batteries, but they seem to be very uncommon in the United States. I don't have any experience with them.
I hope this gives you an idea for an option that will work for you.
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Well ian, there is a way to use the meter´s charger than is to use LiFe batteries instead is Lipo...(life is like other litiun battery but it does't explodes, i might say than it is a more powerful NiMH, and LiFe is also cheaper than Li-ion)
Don't be silly, of course you can't use LiFe batteries with a NiMH charger. They are a totally different chemistry and quite incompatible. LiFe batteries must be charged using an LiFe charger (usually a CC/CV algorithm to about 3.6 V per cell).
For the most part LiFe batteries are a less useful alternative to other lithium chemistries as they have lower energy density and higher internal resistance.
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What annoys me is that, given the very low cost of solar cells these days, manufacturers ship gear with rechargeable batteries yet don't include some solar cells on the device to:
a) recharge the batteries when the item is not in use but exposed to light.
b) eliminate the effect of self-discharge
Two of my favourite devices are:
1. the 20-year-old AM/FM radio I have with inbuilt NiCd battery and solar-recharge - yes it's *still* going after all that time and I have *never* had to replace the battery!
2. my Casio FX115 Solar-powered calculator -- also still going after decades of use and it doesn't even have a battery!
Even the AA-sized NiMH cells I use in my wireless mouse and other items around the place get popped straight into a little solar charger that sits on the windowsill in my office. By the time the mouse battery goes flat (several weeks), its replacement is fully charged from the artificial lighting at night and sunlight during the day.
Hell, imagine a multimeter that recharges the inbuilt battery just while it's sitting on the bench or in the car -- exposed to normal levels of illumination.
Convenience *and* economy!
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You Gentlemen have all been so kind, to respond to my query. I have much that I want to put into a response. But a flair-up with my trick back, and my slow typing, is not only putting a crimp in that, it has played havoc with my plains to work on a project this week end. I will try to respond a bit later.
Let me quickly ask. Has anyone put in a small, unobtrusive, high quality jack to externally power one of these meters?
:-//
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From reading the product literature the U1253B comes as standard with an external AC power adapter and charging jack. The meter comes as standard with a rechargeable battery included and has charging circuitry inside the meter for the battery.
However, there is a restriction that you should not use the meter while it is plugged into the power adapter as that would spoil the isolation of the meter. The same restriction would apply to any external power source. Handheld DMMs are designed to be used floating on battery power and not connected to any external supply while in use.
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I'm going to give it a try. I'll type a bit at a time off-line and past it in. All of the posts have been very helpful, but I am going to reply primarily to Ian at this time. I'm able to use a radio mouse on a clipboard in my lap to basically operate the computer. But as I explained typing is troublesome.
In the eighties I was moved more and more into management and my attempt now is to get back into electronics, and to do projects and repairs to keep my mind active and challenged. A couple of disasters in more recent times relieved me of the benefits of that move to management, which allowed having my on lab, and relieved of the equipment itself. So I will slowly try to re-equip myself.
Now to it. Ian, the isolation and the purity of supply power was in my consideration of a jack for external supply. I guess the easiest solution would be to build a suitably sized battery pack. That would leave isolation of the internal battery, and making sure no detrimental noise came in through the cable. I'm trying for a degree of sophistication such as not constantly removing the internal battery and reinserting it into the ridiculous nine volt style battery clip. Also I thought of a more complex approach of obtaining, or making something that is "like" part of a small true UPS. It would have no ac output and have no need of the charging circuit being capable of both powering and charging at the same time. It would only need to keep the external battery charged.
Good Grief, I had no need of a make work project. There are enough things around here to repair, including replacing the fan assembly in this laptop.
Here is a link to the battery that I mistook for a NiMH, and it's 1.2 amp capacity, in case anyone has a need. For a nine volt thats very interesting.
http://www.atbatt.com/product/21230.asp# (http://www.atbatt.com/product/21230.asp#)
I realize now that, it seems not a lot of people have this meter, and therefor have had no need to give it much thought. They may not have any desire to give the problem much consideration.
I hope the days of giving a full schematic, a real manual, and theory of operation are not over for all equipment. The quick start guide (only written material provided of an operational nature) won't let you explore a lot of features.
Well my back is going again. I'll have to rest it for a while. Again I wish I could reply to everyone, and will do so later. I can only hope they will look this over, and give any thoughts they might have.
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Here is a link to the battery that I mistook for a NiMH, and it's 1.2 amp capacity, in case anyone has a need. For a nine volt thats very interesting.
Ah yes, that's an LiSOCl2 battery. It's a non-rechargeable battery designed for long term low drain applications. Quite unsuitable for normal 9 V battery applications like this meter.
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Oh my, I'm starting to feel like a tech fossil.... Lately there just seem to be too many areas that I'm not fully up on. If I can just keep from designing something the size and shape of a B-52, when a paper clip is needed.
:-/O
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From reading the product literature the U1253B comes as standard with an external AC power adapter and charging jack. The meter comes as standard with a rechargeable battery included and has charging circuitry inside the meter for the battery.
Yes....partly right, but the U1253B uses the COM and 440mA Jack to charge (when shut off). So it is occupied anyway and you can't power it on when charging.
I think some of the Metrahit multimeter (Extra for example) have a dedicated Line socket which shuts off the batteries and runs from a plug then.
I always keep some spare 9V batteries as backup, but actually never needed it as I don't keep it running all day long but switch it off when not needed.
There are some disadvantages...of course.
What geally grinds my nerves is, that you can't change the display brightness or even shut the display off when you are logging, as the Display control is blocked then. Would be nice to save battery here when you leave your meter for logging.
I won't sit six hours in front of the display just watching digits.....
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Ah BTW: I was thinking of an 2S Lipo when it needs to run long. The U1253B will shut off when the battery reaches 6.5V. So with a nice 4000mAh 7.2V LiPo from your hobby center, you should have fun....but need a LiPo charger as well.
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Thanks a bunch all of you.
I was thinking multiple things when I made the B-52 remark. I have not had the meter long enough to really asses how much of a problem this is going to be. Such as, do the values shift much from a sleep state. I have seen, but do not recall where, some posts stating not to much of a problem with runtime for those users, and I have already jumped into designing a B-52. I am going to spend some time today learning about available battery technology, instead of the hurried search on that, that I did to make my decision to accept the meter. I wish that I was more informed on the better lines of appropriate battery products, and whom are the good dealers.
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I have used Thomas Distributing for rechargeables for over a decade, and I am very happy with them:
http://www.thomasdistributing.com/ (http://www.thomasdistributing.com/)
For the Tenergy batteries, I use All-Battery:
http://www.all-battery.com/ (http://www.all-battery.com/)
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Thanks grenert, That's very helpful. I will look at them........ I was going to do kind of a post script thing ...and had a brain fade.
Oh yes, Agilent says, that when new that you have to charge the battery run it down a fair amount, then remove and replace the battery, charge again, and do this cycle a few times to get full performance out of the battery. I haven't been through that even once yet.
But it related to one of my dislikes, and that is that type of battery clip being involved. And I agree with you Achilles, it would be nice if it retained those settings through shutdown.
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Hi Kind People
Has anyone had any experience with these batterys, they looks suitable? Would anyone know off hand of a good charger that would be more versatile as to charge different lithium ion cell types, such as AA, AAA, Etc., as well as the 9v?
http://www.all-battery.com/li-ionrechargeablebattery-30593.aspx (http://www.all-battery.com/li-ionrechargeablebattery-30593.aspx)
https://www.batterymart.com/p-r-li9600-9volt-lithium-ion-battery.html (https://www.batterymart.com/p-r-li9600-9volt-lithium-ion-battery.html)
https://www.thomasdistributing.com/iPOWER-9-Volt-520mAh-Lithium-Polymer-Rechargeable-Batteriesbr9V-Lithium-RechargeablebrOne-9-Volt-Battery_p_2989.html (https://www.thomasdistributing.com/iPOWER-9-Volt-520mAh-Lithium-Polymer-Rechargeable-Batteriesbr9V-Lithium-RechargeablebrOne-9-Volt-Battery_p_2989.html)
And this battery Hitech
https://www.gnbatteries.us/servlet/the-402/Hitech-RLI9720-LiPoly-9V/Detail (https://www.gnbatteries.us/servlet/the-402/Hitech-RLI9720-LiPoly-9V/Detail)
The stated power consumption of the U1253B is 420 mVA Maximum.
I am still looking for documentation on the Ipower battery.
The hitech has this info available. I include this as info for others.
Test procedure and its criteria shall be referred to as follows.
1C = 550mA
Full charge : 8.4V (0.5C) × 5h (25°C)
(1)
Open Circuit Voltage
Test method : Within 1 hour after full charge, measure
open circuit voltage.
Criteria : More than 8.2V.
(2)
Discharge Capacity
Test method : Within 1 hour after full charge, discharge
until final discharge voltage at 0.2C and measure the time.
Criteria : More than 300 minutes.
(3)
Charge/Discharge cycle life
Test method : Charge
Discharge
8.4V (0.5C) ~ 0.02C cut off (25°C).
1C to 6V (25°C).
This charge and discharge cycles shall be repeated.
Criteria : More than 180 minutes.
(4)
Appearance by visual shall be no defect and leakage.
It appears the two Hitech batteries have a good maximum discharge rate.
So it is down to lithium ion or lithium polymer. I wonder about each of the types advantages and disadvantages.
I just can't find any info on the electrode or electrolyte. Maybe someone knows something.
To me it looks like the lithium polymer has the advantage in, self discharge, and recharge life. Am I correct in what I think that I have found out? I guess that my reasoning is, the 720 ma battery starts out with more over a given period it will retain more. I you go use the 720 for the same amount of run time, that it won't be in as discharged state as the 600 ma battery and therefore last longer.
Oh where is my carbon-nanotube supercapacitor?
Thanks