I currently use a Mastech MS8268 for working with prismatics for 12V builds. Just wanting to get a straight answer as to whether or not I need a good unit like a fluke for manual top balancing and checking the resistance based on voltage?
Do I really need that extra detail is voltage? I also read that these things can become out of calibration so that is a turn off.
ta
We use Fluke meters in the shop. I have a good Meterman for my own use. We also buy a wide variety and large number of cheap ones for crude field troubleshooting. They are lost and destroyed too often to spend for quality, and the troubleshooting is very basic.
I find a variety of problems with the cheap ones. Basic accuracy. Accuracy over range. Accuracy as battery drains. Battery life. Switch quality.
The Flukes are great. My Meterman has been great. Accuracy is very good. Rugged. No failures over many years of use. It pays in the long run to spend for quality. As well as maybe getting more range and features than you currently think you need. There are good quality ones that cost less and include more features than a Fluke. Or the same features for less. It’s a tool that you may find is needed for other uses than the original one. So a few extra options and wider range can come in handy later.
When I first read the title, I thought the OP was building Lithium Iron Polonium (Po) batteries. I wondered why anyone working on highly radioactive batteries needs internet advice on the right multimeter to use… 
Perhaps he is working on his own lunar satellite like the Russians did.
Then I found out about LiFePO4 batteries. I didn’t know about that chemistry.
This makes more sense.
Unfortunately I have no advice on the multimeter problem.
So did I and my thought was, “You don’t already have a good multimeter?”
Apparently the sole world-wide supplier of Po is Russia. Perhaps things are a bit more rough and ready over there?
I don’t know where the OP is working. Po is also used in smoke detectors and we know one alternate use of those, so maybe the OP is working in his garage…
No offense to OP, it was my leap to a rash conclusion that got me off on this tangent.
So you are trying to charge each cell to the same capacity before assembling them into a battery, right? I would think the absolute calibration of the multimeter isn’t crucial here. Even if it is out of calibration, it will still read the same value for the same voltage.
More when testing the cells resistance (to keep tabs) using voltage m/ments, do I need that extra accuracy or is a basic entry level good enough?
cheers.
So is this to measure capacity of the batteries? I understand the LiFePos maintain fairly steady voltage so is this a means to estimate battery life? The usual way to test batteries that way is to check voltage with no load and then with a known resistor. I don’t know how accurate you will need that, but you don’t want to test the battery with the multimeter in resistance mode. If you try it out with a cheap multimeter and the voltage never settles down then maybe you need a better tool.
What’s “m/ments”?
I figgered it was short for measurements.
You do not need to have a current calibration certificate. Any good meter will be good enough.
You do not need to have an accurate meter. You aren’t measuring a specific point: you are measuring a point on a curve. Look at the graph for your cells. A little bit up or a little bit down on the curve isn’t going to change anything. You are only trying to to (1) match the cells, and (2) not go to far.
You can ‘not go to far’ just by noting the accuracy of your meter, and the shape of the curve, and not going too far.
If you have an old mid-price meter, you should double the quoted inaccuracy. This is just a rule of thumb: a meter that is good to 1% will eventually drift 1%. Except on good meters, the last digit is +/1 or worse: look at the paper you got with the meter. If they could make it better than the last digit for the same price, they would have added extra digits. If you use a $5 meter… if it’s stable, you can still use it to equalize the cells, just don’t go past the knee if there is one.
You aren’t trying to match the cells to infinite precision: they aren’t that kind of cell, they don’t match to more than the accuracy guoted for the cell voltage specification, and it doesn’t even matter if they are exactly matched anyway: all you’re trying to do is save money by using fewer cells: the manufacturers understand that if you want to store more power, you can buy more cells.
I’m an electrical engineer with electronic hobbies (amateur radio, musical instruments, automotive interests) and I have never been able to justify the cost of a Fluke DMM. I use some Fluke gear at work, great stuff, but the meter I use at home is actually the one our teacher recommended at my very first Electronics 101 in community college. He organized a group mail order buy for the class and I think the final cost was $27 in about 1996-7. No autorange, no arc flash rating, 2000 lousy divisions.
Incredibly, they still offer these meters. It’s the Elenco M-1700. There are some cosmetic changes to the graphics and mine never had the boot but it’s the same meter. It has served me well through community college, university, homeownership and DIY projects, hobby pursuits, repairing devices for friends and family. I doubt I’ve changed the battery more than 4 or 5 times and those were usually after I’d left it on for two months in the tool bag. It can never be called a great multimeter but it’s certainly a good one.
A piece of electronic gear that gives solid service for 25+ years is at least verging on greatness.