ZTS MBT-1 modified for voltage reading?

[Zenster]

I've got the ZTS MBT-1 on order but haven't received it yet.

I understand how it works, but I'd like to add the additional capability of being able to read actual voltage at the same time as getting the LED "report".

So I'm wondering if anyone has opened up a ZTS MBT-1 tester and perhaps added a couple of external jacks where a voltmeter could be attached while taking readings?

The 20% resolution of the LED's if fine for general use, but I feel that being able to read actual voltage would be a much more accurate way to match CR123 pairs and triples because we all know (now) what can happen when using mismatched CR123 lithiums.

I'm really quite fine with the 20% resolution of the tester except for the singular purpose of matching CR123's as closely as possible.

 

[tpchan]

You do understand that the ZTS units measure your batteries under a load right? Whereas a DMM just measures the voltage of your battery and doesn't tell you a thing about what the battery can do under a load. Using a volt meter is how you get into trouble with out of balance cells. Many times when cells are out of balance they will show almost the same voltage when measured with a DMM, but when measured using a ZTS unit you'll see capacity differences of 20, 40 or even 60%. This is when you "know" your cells are bad.

 

[Mr Happy]

You do understand that the ZTS units measure your batteries under a load right?

I think he does. Zenster is asking about how to measure the battery voltage while the battery is loaded by the battery tester. Maybe by connecting some external terminals on the tester to connect the voltmeter to.

But why not just use multimeter test leads with alligator clips? You could connect one to the ZTS test button and one to the probe.

 

[Zenster]

I think he does. Zenster is asking about how to measure the battery voltage while the battery is loaded by the battery tester. Maybe by connecting some external terminals on the tester to connect the voltmeter to.

But why not just use multimeter test leads with alligator clips? You could connect one to the ZTS test button and one to the probe.

Yup, you understand exactly what I'm trying to do.

Sure, I could do as you suggest and it would certainly work, but I envision two little plug-in ports (or a single RCA jack) permanently mounted on the side of the ZTS where I could just slip in the probes of my Fluke. It just sounds so.. "clean". :twothumbs

Since I don't have my ZTS yet (UPS says this Friday), what I don't know is if there is a single wire inside where I can branch off from to install those ports, or if each battery type terminal on the tester would have to be tapped into separately. That would be a bit messy of an installation.

I guess I'm going to have to be the pioneer who opens up the MBT-1 and figures it out for myself. This model is big, though. At 8" x 4.5" x 1.25", I'm hoping there's enough open space inside and on the side of the case to do as I propose.

Not to give the company a reason for making the ZTS even more expensive, it would sure be a nice "standard option" if they could make it with an RCA jack for the purpose I describe. That would be cool, to say the least, and certainly make the ZTS even that much more useful by allowing an improved resolution.

 

[louie]

The idea could be a problem. The ZTS resistor load time is variable and sometimes pretty short - maybe too short for many digital voltmeters to stabilize and give an accurate reading. The ZTS patent says they measure the voltage 50 mSec before the load is released. How they do it so fast, I don't know, as they obviously get some reading quickly to compare to their look-up table.

 

[Zenster]

The idea could be a problem.

In general, yes, but my Fluke 117 has a "Min/Max/Avg" function that can sample down to 100ms, so I'm going to experiment a little and see if that capability will get me to where I want to go.

What I'm going to do is to just put my Fluke leads between the contact points when checking a battery and just see what I get.
If the voltage reading makes sense, I'll do that again quite a few more times for different batteries and see what happens.

The ZTS itself has to be able to read a specific test voltage in order to know which LED's to trip, so it might be possible to catch that (specific) voltage externally in one way or another.

If I can't get to where I want to go with this, then I'll just use the ZTS as a general condition tester, but make up my own jig with a resistor load for the specific purpose of matching batteries.
It's just that after spending $75, it would be nice if I could rely on the ZTS to more closely match my CR123's for use in multi-cell lights.

 

[txlair]

Zenster, what did you find wrt measuring the voltage during the load test? Am considering buying the MBT1 bu do have the same concerns you expressed with matching CR123As

 

[PhotoWiz]

I think I would start out by contacting the company. I have corresponded with Dave on multiple issues and I always find his answers helpful. Now he probably isn't going to describe how to disassemble the ZTS, but you could ask whether your idea would work using a meter externally. TELL him you want to get better resolution and ask how you might do that. At least you will have his input on whether this might work.

Once you have that info, you are probably on your own for opening the case and installing the jacks.

I've noticed with older, non-LSD batteries that readings will vary from one test to another, even at the 20% level. I'm wondering how far you can go before variability from one test to the next on the same battery will exceed the resolution of your test, even for good quality cells?