I have an Omron HEM-7113 Digital Blood Pressure Monitor. The owner’s manual says it requires 4 AAA 1.5V cells. Ever since I acquired it a month ago, I have been using Eneloop AAA cells in it. No “Low Batt” warning so far. Now my question is, will its accuracy be affected by using Eneloop rechargeables, or will I be better off using the Energizer’s “Ultimate Lithiums” (accuracy-wise) ? I have these Energizer cells on stand-by, btw. ( I have this same topic on the ‘other’ side ) Thanks
As long as the output voltage of the batteries are the same as the original, you should suffer no problems.
Eneloop are made to be the same when use in place of alkaline.
Lithium batteries usually have 3.7 volt output voltage, so they will not work in the device, give caution as if you attempt use, they could fry the device. 
Since it’s a medical aid, for peace of mind I would:
Check current draw of device using different cell chemistries, see how it might be regulated (i.e. slightly more current at lower voltage);
Perform A/B BP measurements (i.e. whilst sitting down) using both kind.
Actually I have had a single Li Ion 14500 battery and a battery blank (a fake battery the size of a regular battery) work just fine…but YMMV
It was also in a TV remote and a kids toy…NOT a device your life might be dependent upon either
make sure you don’t talk nor move during check up 
Yes this is possible if the batteries are all parallel of the source and not drawn off of each one individually.
My warning applies to use of them, instead of alkaline/nimh for all batteries, as it would overload it, but of course in your example, a “blank” battery in place of more live cells would alleviate the main worry.
But this will only work in device that takes 2xAA/AAA, since the voltage of them are about 3-4 volts.
I think it will not affect the measurements; its true the voltage of a freshly charged NIMH is lower than brand new alkalines, but after a few use, the voltage of alkalines will lower to the same level as the fresh NIMH.
The device must be regulated to work properly in all conditions of the recommended batteries, so there is no reason to have problems, except for an early low battery warning. just recharge them when this happens and you are ready to go
Yep. Battery voltage is always changing. If the monitor varied with voltage, then it's trash no matter the chemistry of the batteries used.
Energizer Ultimate Lithium are primary lithium cells at ~1.5V not Li-ion at ~3.7V.
