nuances and tricks

Nine-volt batteries, which are usually called “Krona” in Russia, are quite expensive: saline batteries cost from 60 rubles, alkaline batteries from 130 rubles. Many batteries in the Krona format have appeared on sale, allowing you to save a lot where you often have to change such batteries. But there are nuances.

NiMh batteries in the Krona format have been around for a long time. Their nominal voltage is 8.4 V (1.2 x 7), but they have a rather low capacity – 200-250 mAh and they require special chargers.

Recently, a lot of “lithium Kronas” with a built-in charger have appeared on sale – the MicroUSB or Type C connector is located right in the Krona case.

There are two types of “lithium crowns”: on one battery with a built-in voltage converter and on two batteries without a converter.

In the first case, the output of such a “Krona” is always 9 volts, but there are three problems:

1. The electronic converter creates interference due to which the devices where such a battery is located may not work correctly: radio microphones and guitars begin to make noise, multimeters may give inaccurate readings. Some manufacturers even indicate in the description of such Crowns: “Please note: Because the battery uses amplification circuit, it will cause interference in the audio equipment, and there will be little noise. If you use it on high fidelity audio equipment such as electric guitars, etc, please don’t buy!

2. Due to the converter, the voltage at the contacts of such a “Krona” is always 9 volts, so the battery discharge indicators in the devices do not work – until the last moment, a 100% charge is shown, and then an instant shutdown occurs. Accordingly, it is impossible to estimate the remaining charge level and it is impossible to predict when a shutdown will occur.

3. The voltage converter constantly consumes a little electricity, so this type of “lithium Krona” can be completely discharged in about a year of storage.

The second type of “lithium Krona” with two batteries has a lower voltage. Some manufacturers write 7.4 V (nominal lithium battery voltage 3.7V X 2), some write 8.4 V (maximum lithium battery voltage 4.2V X 2), and some do not bother and stupidly write 9 V. In fact, they are all the same, and do not think that Krona 8.4 V is better than 7.4 V.

Due to the fact that there is no converter, there will be no interference and the discharge level indicators will show it, but most likely from the very beginning they will show an incomplete battery discharge. The voltage on such “lithium crowns” drops from 8.2 to 5.6-6 volts as it discharges. The voltage on conventional alkaline batteries of this type drops from 9.7 to 5.4 V as it discharges.

The voltage of 8.4 V (the initial voltage of the “lithium Krona” without a converter) approximately corresponds to a conventional battery with a 90% remaining charge. With a remaining charge of 50%, the Lithium Crown and a conventional battery have the same voltage of 7.4 V.

For example, the UNI-T UT61E multimeter starts showing a low battery symbol when the supply voltage drops below 5.7V.

The conclusion suggests itself: “lithium Krona” without a converter is better and do not be afraid that they indicate 7.4V or 8.4V instead of 9V.

Of course (since our world is imperfect) most of the “lithium crowns” available for sale are with a converter. Batteries without a converter can be recognized by voltage (7.4 or 8.4 volts), but some manufacturers, fearing that batteries with “low voltage” will not be bought, write “9V”. In Russian stores, I managed to find the “correct” batteries of only one brand – Soshine.

On Aliexpress, “lithium crowns” without a converter are even more difficult to look for. For example, one of them has GTF the title says 9V, the description says “8.2-9V”. All this is not true, as well as the declared capacity of 650 mAh. The truth can only be found in the reviews: “350 mAh of real capacity when discharged from 8.4 to 6 V.”

By the way, about capacity. According to the results my measurements salt batteries “Krona” 6F22 have a capacity of 120-150 mAh, alkaline (alkaline) 6LR61 – 550-660 mAh (it is more correct to measure the capacity of any batteries and accumulators in milliwatt-hours, but the world, as we remember, is imperfect). Accordingly, “lithium Krona” in terms of capacity are between saline and alkaline batteries. The Chinese often write big beautiful numbers, but they have nothing to do with reality.

As I already said, most Lithium Crowns are equipped with a built-in charger, but there are models without it, which have a slightly higher capacity (such Lithium Crowns are charged through the main contacts by any charger for lithium batteries with a charge voltage of 8.4 V).

PS I ordered a “lithium Krona” without a Soshine 500 mAh 7.4V converter. As soon as I get it, I will measure its real parameters and share it.

Peace for everyone!

© 2023, Alexey Nadezhin

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