10000hr Battery Life Bench Multimeter

[SilverSolder]

Except the Duracells would leak long before the 50K hours! 

[MBY]

Fluke 37 seems indeed to be a good contender. It need very little power and has a lot of space. The problem is availability and that 2,000 counts are about as low as you can get. I'm thinking along two different lines. A) a somewhat universal solution that anyone can cram into just any low power bench DMM or B) a solution for a affordable bench meter that is still in production and/or have high availability (such as warehouses full of NOS) that can be some sort of "standard DMM" in this context.

I hope that Fluke take note and do a updated low cost, low power battery DMM. But on the other hand, what fun is that? This is a electronics forum and the whole point is sometimes to build something yourself!

Some has suggested to build a 3D-printed case around a hand held, and that's certainly a possibility but not everyone has a 3D printer or a printer with sufficient space (mine can print max 12x12cm, in practice 11x11cm) and since the market is saturated with handhelds, we probably never can reach a consensus of which meter to use. One thing that would help is a meter with a ribbon or flex cable to the LCD, but that is probably very unusual today.

I must find my old Beckmann, as its very reminiscent of Fluke 37, but not identical. I think it is this one: https://www.desmoines-classifieds.com/Madison-County-/Household-Goods-/Beckman-360-digital-multimeter-with-leads-as-is.SHTML
Only 2,000 counts but have a 20.00 ohms mode. I think it has C- or D-cells (no external power what I can remember) and run for ages and ages. But again, where is the fun in that? It doesn't need any hack to work on batteries.

[Fungus]

Fluke 37 seems indeed to be a good contender. It need very little power and has a lot of space. The problem is availability

There's not a single one on eBay right now.

Some has suggested to build a 3D-printed case around a hand held, and that's certainly a possibility

Some people have already done it, it's a lot of work though.

The best bet would be to start with something like this:

https://www.aliexpress.com/item/1005001638029456.html

But that's not a "cool" meter.   

[madires]

The idea expressed above for solar power is pretty good too if the goal is to charge or supplement the contained battery.   It is actually surprising to me that manufactures haven't gone this route with handhelds or in cases like this where the device is a "portable" bench top design.

... was also sold as Voltcraft VC260 (green rubber holster). The power supply is based on a 20F super-cap and an LT1610 boost converter. The super-cap is charged via 9-12V or mains (tiny transformer on board), both protected by a 100 Ohms fusible resistor. The 9-12V input has additionally a two-transistor voltage clamp, and there's a string of diodes to limit the charging voltage. The solar cells are just meant to support charging (the DMM won't run with them alone). That concept works well, but the DMM is crappy (cheap parts, not suited for mains). IIRC, Conrad sold the VC260 for 60 or 80 Euros (DMM, test leads and pouch). BTW, the DMM IC is an FS9721-LP3.

[MBY]

The best bet would be to start with something like this:

https://www.aliexpress.com/item/1005001638029456.html

But that's not a "cool" meter.   

Yup! But that version seems inferior to the "Vici" VC8145 or DM8145 with 80,000 counts for about the same price or less. A couple have already mentioned it in the thread and I started a new thread about modifications to this meter: https://www.eevblog.com/forum/testgear/dm8145vc8145-dmm-modifications/

To my knowledge it has been around since 2012, and it's still sold, so the availability seems good. And it's a pretty decent meter, I like it. It's reminiscent of Fluke 45 even if you of course should choose a Fluke 45 over 8145 every day of the week if you have the chance. But, unlike Fluke 45, the 8145 is actually a good contender to be battery powered. While not practical for a 10,000h battery, it's certainly practical for a battery that lasts many tens of hours on a charge.

[Fungus]

Yup! But that version seems inferior to the "Vici" VC8145 or DM8145 with 80,000 counts for about the same price or less.

I saw those but they were about 50% more expensive. 

Doesn't matter though, that's really the only sort of meter that could be a donor for this. None of the major brands make anything close.

(except maybe Uni-T)

[scopeman]

Hi Dave,

Although not a bench meter the Fluke 77 series (the older gray cased ones and the yellow case 23) would run over 1000 hours on a carbon zinc battery. All of the new ones I ever had came with a silver cased Eveready 9V CZ battery. They are still one of my favorite DMM's.

Now here is a real question. Are there any alkaline 9V batteries that don't leak? If so I have not found one yet. I have been using the Energizer Ultimate Lithium and thus far they have not leaked but AAA, AA and 9V are the only sizes I have seen. I have an old Triplett 801 TVM that uses 9V and D cells. When I store it I always remove the batteries.

Sam
W3OHM

P.S. I used a pair of Lithium Sulfuryl Chloride double D cells (60Ah total capacity) 3.9V per cell in an industrial product I designed. They worked well but the cells were close to $100.00USD each. 60Ah would run your meter for a long time!

[SilverSolder]

[...]
P.S. I used a pair of Lithium Sulfuryl Chloride double D cells (60Ah total capacity) 3.9V per cell in an industrial product I designed. They worked well but the cells were close to $100.00USD each. 60Ah would run your meter for a long time!

I wonder how much 60Ah worth of leaky Duracell batteries would cost?  May not be far off! 

[drussell]

[...]
P.S. I used a pair of Lithium Sulfuryl Chloride double D cells (60Ah total capacity) 3.9V per cell in an industrial product I designed. They worked well but the cells were close to $100.00USD each. 60Ah would run your meter for a long time!

I wonder how much 60Ah worth of leaky Duracell batteries would cost?  May not be far off! 

That might be a bit of an exaggeration.

A single, standard alkaline D cell has about 20Ah capacity at a 25ma discharge rate.  Eight ProCell PC1300s here locally is 8 x $1.34 = $10.72 CAD for 240 Wh.

[SilverSolder]

[...]
P.S. I used a pair of Lithium Sulfuryl Chloride double D cells (60Ah total capacity) 3.9V per cell in an industrial product I designed. They worked well but the cells were close to $100.00USD each. 60Ah would run your meter for a long time!

I wonder how much 60Ah worth of leaky Duracell batteries would cost?  May not be far off! 

That might be a bit of an exaggeration.

A single, standard alkaline D cell has about 20Ah capacity at a 25ma discharge rate.  Eight ProCell PC1300s here locally is 8 x $1.34 = $10.72 CAD for 240 Wh.

Are you including the price of the ruined equipment due to leaks?   

[drussell]

Are you including the price of the ruined equipment due to leaks?   

Indeed, no.... 

[David Hess]

The standard for battery life of old handheld manual ranging digital multimeters used to be 2000 hours with a 9 volt alkaline battery.  For reasons which I do not know, automatic ranging multimeters of the same era had much lower operation life but were comparable to modern meters.

[Kleinstein]

With the old metes with 2000 hours battry life (translates to many many years of normal use) chances are the battery would leak before it runs empty. With shorter battery life the chances for leaking batteries are reduced - so its a feature, not a problem. 

[drussell]

With the old metes with 2000 hours battry life (translates to many many years of normal use) chances are the battery would leak before it runs empty. With shorter battery life the chances for leaking batteries are reduced - so its a feature, not a problem. 

That is why Dave's original idea was to use some sort of chemistry that is more likely to be stable long-term than a typical consumer alkaline cell so that it was more like a permanently-installed "lifetime" battery.

[David Hess]

The only times where I have had 9 volt alkaline batteries leak, the outside case contained the leakage, and it never happened with my 2000 hour multimeters, but maybe that was because alkaline batteries back then were more reliable.

[Fungus]

Fluke 37 on eBay: https://www.ebay.com/itm/284082673373

[SilverSolder]

The only times where I have had 9 volt alkaline batteries leak, the outside case contained the leakage, and it never happened with my 2000 hour multimeters, but maybe that was because alkaline batteries back then were more reliable.

The pervasive quality problems with alkaline AA and AAA cells that I have experienced personally and many have documented in other threads here on EEVblog has made me give up on alkaline batteries altogether - they are so cheaply made now, it seems, that they are just ticking time bombs...    it may or may not be fair to the 9V variety, but why take the chance when the manufacturers (Duracell in particular, but others too) have demonstrated such a low regard for their customers?

[Kleinstein]

In a benchtop meter one should have space for a container, so that a leaking battery would not do much damage. It is just stupid to mount a battery that is prone to leaking so that the liquid would do significant damage.

9 V batteris are a little less likely to leak, but they sometimes also leak.

[David Hess]

The only times where I have had 9 volt alkaline batteries leak, the outside case contained the leakage, and it never happened with my 2000 hour multimeters, but maybe that was because alkaline batteries back then were more reliable.

The pervasive quality problems with alkaline AA and AAA cells that I have experienced personally and many have documented in other threads here on EEVblog has made me give up on alkaline batteries altogether - they are so cheaply made now, it seems, that they are just ticking time bombs...    it may or may not be fair to the 9V variety, but why take the chance when the manufacturers (Duracell in particular, but others too) have demonstrated such a low regard for their customers?

I do not really disagree since lithium 9 volt primary batteries are readily available but because of their construction, the alkaline cells in 9 volt alkaline batteries are better protected against cell leakage by the outer envelope.  My preference might be for low discharge NiMH 9 volt batteries but there are none that I trust, and I do not trust the rechargeable 9 volt lithium batteries either.

We had a discussion here not too long ago about the apparently worsening leakage of alkaline cells and it was postulated that this has to do with the removal of mercury from cell construction.