they don't make LSD 9V. Or they don't advertise it well.
Sure they do, I have a pile of them, maybe they don't advertise it well, but typically the package will say something like "pre-charged" or "ready to use". Most NiMH batteries currently made are LSD, it isn't a special thing you have to search for anymore.
I've used a 6 cell D-cell battery holder for cheap isolated powering of 9V equipment for long periods. You can get them on eBay or Amazon for about $5.
There are 4 advantages to doing this.
1) Alkaline D-cells are relatively cheap.
2) They can be used for lot's of other household things, like flashlights, toys, etc. So won't go to waste before they are depleted.
3) Being external, if they leak they will not destroy your meter.
4) They pack a lot of energy. They will likely power a UT61E for many, many months.
D-cells are very much running out of favor in many cases. If not careful you may end up with an AA size cell with extra spacer to make it fit the old form factor. An alkaline AA tends to last not as long as a class D dry cell though. Not many new toys / tools use the D-size - it is more like going obsolete: low power devices usually don't need that much capacity and higher power devices tend to use rechargibles.
Even with just an external battery, this makes it tricky to keep the isolation barrier with an extra cable / connector.
I just use alkaline 9 volt batteries. They last for years so rechargeable batteries do not make a lot of sense.
A multimeter consumes a few mA of current, so you could easily have a super tiny voltage doubler circuit on a lithium battery produce around 6-7.5v from 3.7v .. 4.2v
Early Texas Instruments calculators had 1 or 2 AA NiCd battery packs with a small boost converter to produce 9 volts.
D-cells are very much running out of favor in many cases. If not careful you may end up with an AA size cell with extra spacer to make it fit the old form factor. An alkaline AA tends to last not as long as a class D dry cell though. Not many new toys / tools use the D-size - it is more like going obsolete: low power devices usually don't need that much capacity and higher power devices tend to use rechargibles.
Even with just an external battery, this makes it tricky to keep the isolation barrier with an extra cable / connector.
I try to buy things that only use rechargeable, D or C cells as much as possible. I just hate spending the price of a D cell on a AAA and those 9V batteries are outrageous for the amount of energy in them. TV remotes suck.
I guess if the OP is logging data in a CAT IV OR CAT III environment, then isolation might be a thing. Otherwise I'm not sure having a couple of thin wires coming out the back of the meter represents a huge risk.
9V batteries are my favorite small alkaline, they rarely leak because they have a double casing. NiMH has been good enough for around 15 years though that I generally consider alkaline batteries obsolete.
Unless the 9V alkaline leaks I would use it for a DMM. The 9V battery in my Fluke 87V lasts a long time. Rechargeable is very likely to be dead whenever you need to use it.
You can try this DIY solution
https://www.mydigit.cn/thread-163962-1-1.html
Solution to what?
And that is the first time in more than 60 years that I have seen the output from a power supply come out of the base of a transistor.
Unless the 9V alkaline leaks I would use it for a DMM. The 9V battery in my Fluke 87V lasts a long time. Rechargeable is very likely to be dead whenever you need to use it.
Why would it be dead? As I said earlier. I've been using rechargeable 9V batteries in my Fluke 87 for years, they work fine, the modern ones are all LSD, you can leave it in the drawer for a year and pull it out and the battery won't be dead.
Unless the 9V alkaline leaks I would use it for a DMM. The 9V battery in my Fluke 87V lasts a long time. Rechargeable is very likely to be dead whenever you need to use it.
Why would it be dead? As I said earlier. I've been using rechargeable 9V batteries in my Fluke 87 for years, they work fine, the modern ones are all LSD, you can leave it in the drawer for a year and pull it out and the battery won't be dead.
Which rechargeable 9V do you use?
Which rechargeable 9V do you use?
I have several different types, EBL, Bakth, Tenergy, Thunderbolt (Harbor Freight), and some others, all NiMH. They all seem to be pretty similar.
There may be some mistakes in the schematic diagram, but the point is that it has no switch, and it is 3.6V-4.2V boosted to 9V, which can be used instead of a 9v battery
I moved from NiMH to these about 4 years ago :
https://www.batteriesdirect.com.au/shop/product/24926/lp702235-bp1.htmlI use them in everything now. Meters, Shure wireless beltpack, toys...
I spent years fighting with NiMH and the Powerex LSD 9.6V were the best, but not a patch on these lithium units for lifetime and reliability. They are a "nominal 8.4V", and all my devices work and give me sufficient low battery warning to swap them before they cut off.