battery monitor

Started by RichD in sci.electronics.design1 year ago 5 replies

I wear an armband FM radio when I go out running, probably the last man on earth with one. It's digital tuning, with a battery charge...

I wear an armband FM radio when I go out running, probably the last man on earth with one. It's digital tuning, with a battery charge display, two AAA batteries. The display blinks when it's supposedly near empty. However, I continue to operate it until dead, and it lasts another half hour. Is it so difficult to design an accurate cheap battery charge monitor, or are alkaline bat...


How to charge a 6V Gel Cell

Started by Anonymous in sci.electronics.design5 years ago 7 replies

How to charge a Gel Cell 6V 4.5Ah. I have an electric fence charger (fencer) for livestock. It has a solar panel to charge the 6V 4.5Ah Gel...

How to charge a Gel Cell 6V 4.5Ah. I have an electric fence charger (fencer) for livestock. It has a solar panel to charge the 6V 4.5Ah Gel Cell. But this fencer has not been used for several years, so the battery is completely discharged. It's likely I'll need to replace the battery, but whether the battery is completely discharged, or brand new, I was told the battery should be pre-char...


LiIon Battery Shelf Life?

Started by Jim Thompson in sci.electronics.design4 years ago 9 replies

Just had to replace the LiIon battery on my (non-smart) LG VN251 cellphone. I was pondering availability of replacement batteries in the...

Just had to replace the LiIon battery on my (non-smart) LG VN251 cellphone. I was pondering availability of replacement batteries in the future and was wondering... what IS the shelf life of an LiIon battery? ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations ...


Rating battery for intermittent drain

Started by Mike Stern in sci.electronics.design8 years ago 9 replies

I am designing a compact signal generator to be powered by a 9V alkaline battery. It consists of a transistor (not op amp) phase...

I am designing a compact signal generator to be powered by a 9V alkaline battery. It consists of a transistor (not op amp) phase shift oscillator and emitter follower. The output is a square or sinewave at 60Hz. Draws 12mA. Given that the drain is not continuous, due to the waveform's duty cycle, how do I estimate the total operating time in hours, assuming the battery will provide 500mAH?...


Rechargable battery in small sealed container

Started by Chris B in sci.electronics.design6 years ago 4 replies

Hi - does anyone have experience or know some issues around making a water proof device that contains a rechargeable LiPol battery? Charging...

Hi - does anyone have experience or know some issues around making a water proof device that contains a rechargeable LiPol battery? Charging would be done through a waterproof USB port. Can these types of batteries be in a air tight container? Can any type of rechargeable battery be in an air tight container? Thanks so much, Chris


Error message on GPIB program, Help

Started by amdx in sci.electronics.design6 years ago 33 replies

Hi all, Recap- I had the low Cmos Clock Lithium Battery in a computer. I received a Cmos Clock Lithium Battery from China, had some question...

Hi all, Recap- I had the low Cmos Clock Lithium Battery in a computer. I received a Cmos Clock Lithium Battery from China, had some question about the date code. I installed the Cmos Clock Lithium Battery and had the same message low CMOS battery. I order a new one from Mouser and the computer now works properly. Now I'm onto making the computer control some HP equipment via GPIB, whi...


Li-ion Battery Packs

Started by rickman in sci.electronics.design3 years ago 23 replies

I'm interested in making a 12 volt lighting system that will draw around 200 to 300 mA. This battery should power it adequately if I can...

I'm interested in making a 12 volt lighting system that will draw around 200 to 300 mA. This battery should power it adequately if I can believe the 1800 mAHr spec. The listing claims it includes "Internet[sic] circuit for multiple protection design can prevent the battery from over-recharging or over-discharging,over-current,short-circuit protection etc." http://www.ebay.com/itm/1222...


OT: How to avoid smartphone battery damage from always being plugged in and topped off

Started by John Doe in sci.electronics.design1 month ago 33 replies

Ima try using a lower power USB wall adapter. Was using 2 A at 5 V. Will try a 1 A at 5 V adapter. The battery was getting quite warm,...

Ima try using a lower power USB wall adapter. Was using 2 A at 5 V. Will try a 1 A at 5 V adapter. The battery was getting quite warm, apparently every time the smartphone felt the need to recharge it, hopefully not due to overcharging. Now, with the 1 A USB adapter, seems the battery is cool even though it's charging. Won't mess with it if it doesn't get warm again. Being able to sp...


UPS External Battery

Started by BeeJ in sci.electronics.design7 years ago 5 replies

I have several UPS units. One has a connector for an external 12V battery. I am thinking of hooking up a deep discharge marine battery to...

I have several UPS units. One has a connector for an external 12V battery. I am thinking of hooking up a deep discharge marine battery to the UPS. Is there any thing to watch out for? What current rating wiring should I use? The biggest UPS is 900VA. Also, can a connector mate be found or should I just solder or attach a lug to the contacts? Suggestions please. The UPS is signali...


Lead Acid Car Battery

Started by Anonymous in sci.electronics.design1 year ago 28 replies

I'm charging the battery on a vehicle that has been sitting for a while and it was down to zip voltage. I put a power supply on it and ran up the...

I'm charging the battery on a vehicle that has been sitting for a while and it was down to zip voltage. I put a power supply on it and ran up the voltage until the current was at 2 amps. As I watched the battery voltage dropped and the current rose! I double checked all the polarities and it's wired up right and the ground on the vehicle is disconnected. The charging started a


Using cordless drill battery as stun gun?

Started by John Doe in sci.electronics.design2 years ago 27 replies

I am not planning to do so, just curious... Using a five amp hour 18 V (20 V Max) battery. At 1 million V, that would be somewhere around 3...

I am not planning to do so, just curious... Using a five amp hour 18 V (20 V Max) battery. At 1 million V, that would be somewhere around 3 A for one second? Sounds like a LOT of energy. Thanks.


Measuring LiPo cell charge level

Started by Tim Wescott in sci.electronics.design5 years ago 12 replies

AFAIK, with pretty much every other battery chemistry out there, if you leave a cell sitting for long enough, and measure it with a high enough...

AFAIK, with pretty much every other battery chemistry out there, if you leave a cell sitting for long enough, and measure it with a high enough impedance meter, it'll read full voltage -- even if it's "dead" by any other measure. (That's why decent battery testers test the battery under rated load, and look for voltage drop). Is this situation the same with LiPo cells? I've heard co...


Golf cart battery charge regulation

Started by Laurie Forti in sci.electronics.design9 years ago 57 replies

I have a friend who is a mechanic at a golf course in New Hampshire, and he has to deal with the golf carts. He claims that the golfers abuse...

I have a friend who is a mechanic at a golf course in New Hampshire, and he has to deal with the golf carts. He claims that the golfers abuse the carts by using two throttle positions: floored throttle and floored brakes. This is obviously abusive to the battery and [I assume] a regenerative braking system. Does anyone know of a circuit that will regulate the current flow out of the battery ...


Contact Enhancer, Battery Mfr

Started by BatteryUser in sci.electronics.design3 years ago 33 replies

QUESTION 1: I have several devices that have battery (alkaline AA or AAA) contacts that regularly get resistive. Opening the device and...

QUESTION 1: I have several devices that have battery (alkaline AA or AAA) contacts that regularly get resistive. Opening the device and spinning the batteries usually solves it but only for a day or so. What is available to coat the device contacts to prevent the constant opening and battery spinning ? These contacts are usually way down inside the device and are not all that easy ...


LT1185-based lead acid battery charger

Started by Piotr Wyderski in sci.electronics.design7 years ago 13 replies

I am designing a prototype charger of a lead-acid battery used as a backup power supply source. The input voltage is synchronously rectified...

I am designing a prototype charger of a lead-acid battery used as a backup power supply source. The input voltage is synchronously rectified 12VAC and the current is


Cordless corded tools?

Started by John Doe in sci.electronics.design9 years ago 21 replies

I just converted a Dremel 10.8 V rotary tool to use Bosch 10.8 V batteries. I always have the rotary tool immediately in front of me, so the...

I just converted a Dremel 10.8 V rotary tool to use Bosch 10.8 V batteries. I always have the rotary tool immediately in front of me, so the battery will either be worn on a neck strap or be set down near the work. The wires coming from the rotary tool plug into the battery, using a socket taken from another Bosch tool. That was done because the rotary tool battery charger sucks. App...


Coloumb counting

Started by bitrex in sci.electronics.design3 years ago 8 replies

Anyone implemented a coloumb counting algorithm on a uP before for estimating LiPo battery SOC? I'm powering an 8 bit AVR and a few external...

Anyone implemented a coloumb counting algorithm on a uP before for estimating LiPo battery SOC? I'm powering an 8 bit AVR and a few external widgets off a small 3.7 volt single-cell LiPo battery, about the size of a stick of gum, and would like to give it a rough estimate of the battery's SOC without using more hardware. I have at least one 10 bit ADC channel available for sensing. Fo...


Tesla Battery Fantasy Time...

Started by Jim Thompson in sci.electronics.design3 years ago 23 replies

Tesla Battery Fantasy Time... ...Jim Thompson -- | James E.Thompson ...

Tesla Battery Fantasy Time... ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Syst


Identify the connections on a cordless tool battery

Started by Anonymous in sci.electronics.design1 year ago 1 reply

Im trying to Identify the connections on a cordless tool battery. Not for any real reason, just curious why so many contacts are needed. Its a...

Im trying to Identify the connections on a cordless tool battery. Not for any real reason, just curious why so many contacts are needed. Its a 18v Hitachi battery from a cordless drill. Batt # BCL 1815 There are 7 contacts. One is not used. The 6 which are used are labeled as such. 1. + 2. - 3. T 4. LS 5. LE 6. L+ The + and - are obvious. But what are the others for?


Re: What's the short circuit current of a 9V battery?

Started by David Eather in sci.electronics.design3 years ago

On Mon, 19 Jun 2017 01:22:43 +1000, wrote: get hold of the highest resolution multimeter you can - it also helps if it is accurate but...

On Mon, 19 Jun 2017 01:22:43 +1000, wrote: get hold of the highest resolution multimeter you can - it also helps if it is accurate but resolution is more important in this case. measure the open circuit voltage of the battery call it V1 place a 330 ohm resistor across the battery. call it R There is nothing magical about 330 ohm - just that a 1/4 watt re