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 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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24 views
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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65 views
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 ...
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6answers
3k 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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65 views
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
...
0
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1answer
48 views
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 ...
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2answers
119 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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3answers
75 views
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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0answers
39 views
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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3answers
220 views
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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2answers
2k 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 ...
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95 views
BQ2002, LM317 NiMH charging circuit. How to control the current output?
I have designed a charging circuit utilising the BQ2002 and LM317 for 2x 1.2V NiMH batteries, and it is to be charged using a 5V USB input, I need the output current to be between 550 mA and 1A. I ...
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2answers
83 views
Trickle charging 10NiMh in series with ~1W solar panel
I have been put onto a project that needs to be powered by a small (1-2W) solar panel trickle charging a battery pack. The product will be located on rooftops. We have reviewed similar products and ...
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1answer
65 views
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, ...
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2answers
600 views
5V output on AAA Ni-Mh battery charger?
I bought a cheap Ni-Mh battery charger from Aliexpress to charge my rechargeable AA and AAA 1.2V batteries but before I plug them in, I checked the voltage on the charger terminals and it is reading ...
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2answers
203 views
DC Motor PWM Circuit Implementation
I'm a little new to this, so bear with me:
I am working on a hobby-related project that involves the operation of two DC motors in parallel, powered by a NiMH battery. (Crappy circuit diagram ...
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1answer
636 views
What is the miminum voltage for series NiMH pack?
Suppose a pack of 8 AA NiMH cells are serially attached and its known NiMH cells should not go below 900mV per cell.
Does this really mean the pack should not be discharged past 7.2v?
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388 views
Do NiMH demand balancing?
Is it fine to charge a pile of 8 2 Ah AA NiMH @ 11.6 V 0.5 A serially? They are from the same packaging and were bought only for use as an 8x pack - they were not used for anything else. Im not sure ...
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1answer
252 views
Step-up converter with Vin, Vout, GND
I want to use pololu step-up converter https://www.pololu.com/product/2836
in order to power a 5V device with two Ni-Mh batteries (1.3V each). It has only Vin, Vout and GND connectors. I've checked ...
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1answer
84 views
What would be a good replacement for a set of HR6 batteries?
I need to change this OEM set of batteries1 because they are not holding a charge any longer. I am not familiar with rechargeable batteries.
My understanding is that I should be able to swap the OEM ...
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2answers
169 views
Can I replace a NIMH rechargeable pack with a resistor if I only want to run plugged in?
My kids have a pair of IKEA night lights ("spoka") where the internal battery packs have died. I'm debating replacing the batteries (3x AAA NIMH, marked 3.6V so in series) and have looked at this ...
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1answer
35 views
Charging NiMHs: about current fluctuation tolerance
While trying to make a DIY charging system on my bicycle -based on the hub dynamo- I have seen in action that Li-Ion batteries (typical 18650 ones) do not like charging current fluctuation at all. ...
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1answer
893 views
Algorithm to know NiMH battery level
Background
I have a device with a NiMH battery. This is a portable device, so I need to know how much battery I have left at all times.
To achieve this, I want to map the battery voltage to a ...
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2answers
100 views
USB NiMH charger keeps drawing same power forever?
If my USB charger for AA/AAA NiMH batteries by BTY charges a NiMH battery, the current (ampèrage) of charge only depends on the USB input voltage (usually 5V) and the battery manufacturer (input ...
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2answers
44 views
Can I power a DC fan from li ion to nimh?
I have a mini DC fan with a 2.5mm DC connector connected to a li ion battery provided by the manufacturer.
The li iom battery pack have 4 speeds switch from 3.5V(1.3W) to 7.4V(8W).
The question is ...
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1answer
166 views
DS2715 NI-MH Charge Controller Help
I am attempting to design a system that charges a 6 cell 1800 mAh NIMH R/C car battery wirelessly with the DS2715 charge controller by Maxim. I am trying to modify their linear charging design for a 6 ...
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1answer
72 views
Safe to replace just some cells in a NiMH battery pack?
The battery pack of my Roomba is made of 12 sub-C NiMH 1.2v cells; two of them are down to around 0.5v, and the Roomba won't work.
Can I replace just these two cells with brand-new ones? Will this be ...
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3answers
8k views
Can I charge a NiCd battery with a NiMH charger?
I have an old NiCd RC battery pack. It was not used for at least ten years but when I tried to charge it with the old charger I was suprised to see it still had some capacity.
Now I just went and ...
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1answer
261 views
NiMH Batteries and Fuel Gauge
I'm currently trying to figure out the best way to make use of my gas gauge LTC2943-1 in conjunction with my pack of NiMH batteries. I am aware that voltage alone is not a sufficient measure of the ...
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Any deleterious effect from very strong, close magnets on NiMH cells over time?
This question probably isn't a perfect fit for this SE, but I did find this question: Will placing a strong magnet near my electric skateboard Li-Ion Battery pack damage or discharge it?
This is a ...
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3answers
584 views
Can NiMH batteries charge at cold temperatures?
While I am aware of the risk associated with charging Li-ion below 0 °C and that
the charge acceptance for a NiMH battery decreases with rising temperature,
I am finding conflicting information ...
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1answer
59 views
Replacing 10 AAA NiMH 1.2A batteries with 6, 9v Lithium 1.2A batteries
A vacuum that ran on 10 AAA NiMH batteries in series (15.6v at 1.2A) is nearly dead.
I attempted to replace with 6, EBL 9v 1.2A batteries Lithium... bought off a the internet. I connected them such ...
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1answer
93 views
Ebike battery not charging after cell change from Ni-Cd to high capacity Ni-MH
I recently replaced the cells in my ebike which consisted of 20 Ni-CD Size D (1.2V) 4,000mAh with 20 Ni-Mh Size D (1.2V) 10,000mAh batteries.
Before installation, I charged up each battery to ensure ...
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2answers
752 views
Can a diode prevent backwards current flow from a constant current source?
I'm trying to make a AA battery replacement battery for a vintage computer because its actual battery has gone bad. Its of the NiMH type and I'm pretty sure those are charged with a constant current. ...
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1answer
50 views
Ni-Mh batteries, low capacity better performance?
When we take appart cordless things like drills, vacuum cleaners, telephones..., they often use small capacity (like 700 mAh) Ni-Mh cells. I've always thought that it was because of cost reduction, ...
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1answer
820 views
How to make Li-Ion mimic NiMH voltages
I'm trying to replace the old NiMH Roomba battery with a bunch of 18650s recycled from old laptops. Lucky enough Roomba uses 12s NiMH battery, that operates in voltage range 12-18V, and has quite ...
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1answer
104 views
Why do different batteries of the same voltage have different results and which battery would i choose?
I want a power a homemade robot that uses an arduino and 4 small dc motors and a few sensors. Ive used pp3 energizer 9v batteries to power it in the past and they worked well, i used 9v again after ...
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1answer
43 views
multiple Nimh vs dry cell
Greetings.
I have this problem. I have a telephone that requires 3 AAA cells. I installed 3 AAA dry cells. it works good. LCD display is very sharp and bright.
But then i thought. one day that the ...
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1answer
49 views
Protect device from losing power when to much current is drawn
I use an EVX 3014 RC ESC (BEC provides 5V & 1.5amps) and I'm worried that to much of the current will be drawn to the motors that not enough of it will be available to the raspberry pi computer (...
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1answer
1k views
Charging 6 NiMH batteries in series via solar
I'm currently working on a project in which a Atmega328 is powered by 6AA NiMH batteries in series (7.5v, 2000MaH). It is in sleep mode most of the time, except to turn a servo a couple times a day, ...
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1answer
2k views
Is it ok to use a 10 years old set of NiMH rechargeable AA batteries? [closed]
I've just found my 10 year old pack of rechargeable NiMH AA and AAA batteries. The AAA ones are completely blown with a dark powder all over their positive terminals. The AA ones look fine when ...
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2answers
2k views
Balancing NiMh batteries in series over a long term
I'd like to place two NiMh batteries in series to drive a string of single LEDs. I can charge them simply at C/20 or so and the output will be intermittant so the batteries will never reach half ...
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1answer
819 views
Mosfet is getting hot in switching circuit
I've built a NiMh battery charger (6-cell battery, 7.2v, 3000Mah) using DS2715.
Input is 12v.
Here is the schematic:
For Q1 I used IRF9540N
For Q3 I used IRLB8721PbF
L1 is a 47uF ferrite choke
R7 (...
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1answer
363 views
NiMh switch-mode charger for 6-cell NiMh
I've built a charger for my batter (NiMh 6-cell 7.2v) using MAX712 IC.
The problem I'm facing is that it's in a linear mode which requires either a huge heatsink or a heatsink with a fan (9W). See ...
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2answers
1k views
MAX712 charging circuit - diode gets too hot
I've built a charger for my 7.2v 3000mAh battery using MAX712 IC.
Here is the datasheet:
http://pdfserv.maximintegrated.com/en/ds/1666.pdf
This is the schematic of my charger:
It's almost a ...
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2answers
203 views
Crude LM7809 9V NiMH charger
I want to charge my 9V NiMH cell with a LM7809. The problem is that I want to limit the current output to 20mA or 30mA. How can I limit the current output from that voltage regulator with simple ...
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2answers
561 views
do mAh on batteries (for home-use - nerf) make a difference? [duplicate]
I was wondering if the mAh on an battery pack is important or relevant, so you would recognize a difference?
Little bit Off-Topic:
I've read a lot about "Nerf voltage mods" where modders change the ...
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1answer
124 views
Questions on rechargeable battery pack configuration and calculations
I'm looking at making a battery pack for a medical device (CPAP) that would allow its use while camping. I'll tell you what I need and then what I'm planning.
What I need:
24v at 3.75 amps DC ...
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2answers
1k views
Recharging NiMH cells after long period (18 months) of self discharge
I have seen information supplied with branded NiMH cells (e.g. Duracell) saying "do not leave cells for more than 6 months without recharging."
I have some AA size cells which were fully charged ...
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1answer
573 views
Parallel battery supply
I want to parallel connect 4 x AA NiMH batteries rated each at 1.2V, along with 4 x 1N4001 simple diodes to prevent unwanted current flow (recharging) between batteries. The electric circuit is:
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