Questions tagged [nimh]

A nickel–metal hydride battery (NiMH) battery is a type of rechargeable battery. They have a better energy density than nickel–cadmium batteries (NiCd or NiCad) and have largely replaced them in many applications.

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Can a 9.6V Ni-MH battery be charged by unregulated 9V adaptor with 13.5V output?

I am analyzing this Ni-MH charger circuit: The charger is an unregulated power supply with 9 volts DC output. The original battery is unknown but it is Ni-CD and someone told me he used Ni-MH 9....
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NiMH or Li-Ion for a 5v <1A powered device for a kid?

I'm building a small device based on ESP32 and powered by a 5V power supply (looks like <1A even when speakers are playing). I want to power it on batteries and it seems that everyone does Li-Ion ...
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1 answer
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Using NiMH batteries with dumb charger designed for NiCd?

I'm attempting to revive a very old calculator that was designed to use NiCd batteries (no clue about capacity). These batteries act both as a power source but also as a voltage regulator. Charger is ...
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3 votes
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High voltage when charging NiMH battery?

So, I have a number of high-capacity, Amazon AA NiMH batteries with unknown health and charge cycles. They’ve been in use for quite sometime and continue to work well for my purposes. I have been ...
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NiMH reverse charged cells

I have a NiMH battery pack that I would like to balance (charge discharge for 3 cycles.) I am doing a low charge/discharge current of 0.5 A while the battery capacity is 5 Ah. Since the pack consists ...
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3 answers
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Is it safe to use this arrangement of charging NiMH batteries in series and then using them in parallel

I have built a solar charger that charges 6 AA NiMH rechargeable batteries in series using a constant current source at a little under C/10. That part is fine. I want to use the batteries to power a ...
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Solar charger module for two NiMH in series

I have two 2450mAh NiMH batteries to be used to power an IOT project outdoors. I would like to charge the batteries with a solar panel, 5V, 1W. I have come across this module for which specs for 2 ...
1 vote
1 answer
69 views

NiMH battery charging rate vs life

I'm looking at the product info of a NiMH AA battery brand. It says these batteries last up to 2100 recharges while charged as per IEC 61951-2 2011, but they last for only 600 times if recharged using ...
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DIY power bank with NiMH batteries

I want to do a DIY power bank with NiMH batteries, like this example... But I have 6 NiMH batteries with 2600 mAh and 1.2 V. I want to use a 18650 PCB LCD but they are designed for Li-ion 18650 ...
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Is it possible to revive a NiMH cell with low capacity

I have a bunch of 2100 mAh NiMH cells that have been lying around for many years (probably about 8 years). They still had 1.2-1.3 V when I recently took them out of the drawer, but when I tried to do ...
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NiMH battery management

This follows on from a post I made about my front door (link at bottom of this post). In essence I have a door with a 12 V motor in it, which is activated by a 12 V pulse. The power supply is only ...
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174 views

How can I charge a NiMH cell with a 5 V, 2 A adapter

How can I charge a NiMH cell (1.2 V, 600 mAh) with a 5 V, 2 A adapter? Can I use a resistor in series, and if so, what value?
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Having battery cells in parallel does increase autonomy ? (My load is a constant power load. DC/DC)

I have 4 AA alkaline cells and I'm trying to figure out which is the best cell configuration to achieve maximum autonomy with constant power load. I understand that if your load is a constant current ...
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Battery pack for very slow charging of USB device

I have a GPS device that has too small of a battery pack (300 mAh) and only lasts a month or so - I want something that can last 6 mo to a year. It can recharge from a USB connection, but only draws ...
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84 views

Do I need NiMH discharge protection when load is only LEDs

I'm powering a bunch of LEDs using 3 NiMH cells in series. I don't think I need worry about deep discharge protection as the LEDs will switch off when the voltage drops below their forward voltage. ...
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LTC4060 NiMH charger 1A

I'm designing a charger for 2 series NiMH batteries. After some research I came across the LTC4060. What I don't understand about this IC is how it is able to charge 1A over the small 0.25mm trace ...
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USB-C breakout board, using V and G with a NiMH charger am I doing this wrong?

I’m pretty new to electronics so trying to find my way around. I’ve purchased this breakout USB-C: https://www.amazon.co.uk/Chenyang-24pin-Female-Socket-Connector/dp/B00VJ944V2 And this NiMH battery ...
4 votes
2 answers
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What is the minimum safe voltage for NiMH batteries, if at all?

Is there a minimum voltage below which a NiMH battery shouldn't be discharged to? One of the contributors on this website writes 800 mV is where you definitely want to stop to avoid damage. There is ...
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What is the purpose of this thing on NiMH rechargeable batteries ? Can't figure out what this component is or its purpose

What is the purpose of this thing on NiMH rechargeable batteries? I can't figure out what this component is or what it is for. I'm trying to change the batteries in a Hoover automated vacuum cleaner. ...
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Rechargable batteries

The diagram is from a wall mounted vacuum cleaner. What can the green thing be and what could its price be so i can replace it? Can i use 7 x AA NiMh batteries with 4800mAh each at 1.2 V ? Can i redo ...
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181 views

Trickle charge an NiMH battery

I'm developing a power controller which monitors and recharges a 9.6V NiMH battery pack (8x 1.2V cells @ 3300mAh) which is used to supply power to a board when mains supply is lost. The controller is ...
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NiMH battery discharged to 0V

I have a 90's handheld CB that I'm powering using 10x1.2V NiMH cells all in series. Because these cells are rather old (at least 8 years), when I got a low voltage warning, I decided to measure all ...
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Convert Ni-Mh charger's connector from cigarette lighter to USB

I recently purchased a very basic airpump to inflate a mattress. As we will be taking this mattress to a camping trip on a motorbike, we wont have a car cig-ligther socket (12V), only USB 5V. This is ...
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Charging or replacing old battery pack without burning house down

A wealthy neighbor passed down the most awesome toy ever for us to give our son under the Christmas tree, but it's got no charger. And I have no idea if the battery pack inside works. That pack is ...
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NiMH Battery Indefinite Charging

Can I indefinitely charge NiMH batteries through a current source that limits just below the battery voltage? More specifically, the battery is a 400mAh 14.4V pack and the supply is 15V but after a ...
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Measurement of internal resistance of a battery

I found two circuits online of almost same approach to measure internal resistance of a battery. Both the methods excite the battery at 50Hz using a square wave and AC voltage drop is measured across ...
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Repair/Rebuild NiMh battery pack?

2 years ago, bought a name brand cordless VSR drill motor with a 12 V battery pack for only $20. (I realize now, it was on clearance, as Manufacturer moved to a line of 20 V interchangeables...so it ...
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2 answers
137 views

NiMH discharge protection and MCU powering

I would like to power an ESP32 devkit board with four NiMH AA batteries. The ESP32 board has an AMS1117 voltage regulator. It has a dropout voltage of 1V. The output voltage is 3.3 Volts so my ...
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Question about mixing battery sizes and quantities

Ok. I have searched everywhere and can't find a definite answer on this: My first question, Is, Can you mix 2 lithium batteries of different sizes together? (Like mixing an 18650 lithium battery with ...
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1 vote
1 answer
278 views

NiMH battery pack charging circuit using Solar panel [Help]

Recently I have been working on a NiMH battery pack (7.2V / 2100mAh) charging circuit powered by a 12V solar panel. With some research I found charging NiMH takes different forms by measuring change ...
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158 views

Replacing Nimh battery to Li-ion in hybrid cars

is it a good idea to replace a Nimh battery in hybrid car (like prius model 2012) to Li-ion battery without any problems.
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Buck converter without inductor in a NiMH charger (Zilog AN0259 application note)

After doing some reading online, it seems that you can't really build a step-down converter with only a filtering capacitor and without an inductor, because the losses occuring during charging of the ...
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1 answer
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Can I use a lithium charger for a bluetooth speaker with a NiMH battery? [closed]

I have a BlueAnt bt blast bluetooth speaker that I need a new charger for. It says DC 12V on the back by the power supply. I checked the manual and this speaker has a NiMH rechargeable battery. Can I ...
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Overvolting brushed motors by 0.2V

For RC models, I own several brushed motors which are intended to operate at 7,2V. According to my previous tests, they usually take 25 amps, 30 being the absolute maximum. To divide by two the weight ...
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3 votes
1 answer
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A voltage controlled switch for a single NiMH cell

I'm developing a small project that contains one AAA NiMH battery that is charged via USB with a MAX DS2711 IC. The output of the battery is connected to a TPS61006 to boost the ~0.9 - 1.3v cell ...
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Help needed with resistor value for charging NiMH batteries

I have an old calculator which contains 4 2/3 AA NiCd batteries in series. These batteries are very old and need replacing, so I'm going to replace them with 4 2/3 AA NiMH batteries in series, which ...
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560 views

parallel connecting 24v 1500mah NIMH battery packs and how to charge

After several of searches on the internet for information about charging NIMH batteriers, i feel the need for some clarification. I've gotten my hands on a bunch of battery packs. Each battery pack is ...
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Can I change laptop's RTC and backup battery with generic Ni-MH?

I got old laptop for a good price. After some inspection, I noticed that backup battery and RTC battery are already gone bad, and seems can't hold charge. I've checked eBay for replacements, but only ...
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Power Jack part number for YAESU FT 23R battery pack?

I am planning to design a small USB powered charger for the battery pack used with the radio YAESU FT 23R. I have been searching for the correct name / part number of the power jack connector shown in ...
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Vacuum cleaner charging works only with the original adapter - why?

I have this old robotic vacuum cleaner that I got cheap and was using for a while: https://www.youtube.com/watch?v=nvj8BmijDn4 (not my video) Now however the charging adapter broke and I've been ...
24 votes
6 answers
5k views

Why are Alkaline, NiMH, and Li-ion AA measured differently (mAh, mWh, etc)?

Looking around Amazon, it seems that different types of batteries are measured differently: Does anyone know why? Li-ion are measured in mWh 1200mWh ALTIZURE (Cheap-Os) 3200mWh Deleepow 3000mWh ...
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Why are Alkaline, NiMH, and Li-ion AA measured differently (mAh, mWh, etc)? [duplicate]

Looking around Amazon, it seems that different types of batteries are measured differently: Does anyone know why? Li-ion are measured in mWh 1200mWh Cheap-Os 3200mWh Deleepow 3000mWh AmpTorrent ...
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NiMH charging circuit using 24V

I am trying to make a charging circuit to charge 2 NiMH batteries via trickle charging with 0.015A (15mA) I have used a current regulator and basically J1 is connected to the source of 24V DC and J2 ...
1 vote
2 answers
337 views

How bad would it be for a NiMH battery or/compared to a Lithium-ion battery in a device to sit unused for years?

I have a Sonicare toothbrush which has Lithium-ion battery and a body hair trimmer that has a NiMH battery. I have charged the Sonicare once or twice without ever using it, just to stop it go to 0% ...
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3 answers
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Nickel battery balancer

TLDR: The question is about retrofitting a balancer to the Ni-MH battery of an existing appliance (that doesn't trickle charge the battery), preferably in the way that will not require frequent access ...
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How to safely replace NiCD/NiMH with Li-ion in a small electric screwdriver? [duplicate]

I'd like to repair and re-use a small Bosch electric screwdriver. It currently has a battery of 3 small AA-type rechargables (unmarked cardboard wrapping) that has almost the same occupancy volume of ...
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How can I trickle charge NiMH batteries as part of an IOT controller?

I have built an IOT motor controller board that's powered by 4 AA NiMH batteries in series. I want to use a solar panel to trickle charge the batteries, but the voltage slowly decreases even when the ...
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4 votes
2 answers
10k views

Replacing NiMH with Li ion [duplicate]

I have a rechargeable vacuum cleaner with NiMH batteries, 1800mAh and 14.4 volts, 12 cells. The charger is 18v 200mA. The batteries have now died. Can I replace the batteries with 4 cell Li-ion in ...
3 votes
3 answers
263 views

Trickle charging 10 NiMh in series with ~1 W solar panel

I have been put onto a project that needs to be powered by a small (1-2 W) solar panel trickle charging a battery pack. The product will be located on rooftops. We have reviewed similar products and ...
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Balance charging battery pack one-half at a time?

I'm trying to wrap my head around how I need to go about balancing charging a few NiMh battery packs. I'm using a HiTec x4 charger, which supports balancing charging up to 6 cells at a time. However, ...