Car battery matching with alternator

Started by cameo in sci.electronics.design8 years ago 44 replies

I wonder what you think about the following problem: A car's battery needs to be replaced but the exact capacity battery is not available,...

I wonder what you think about the following problem: A car's battery needs to be replaced but the exact capacity battery is not available, though smaller or larger ones are. My feeling is that the battery capacity is matched by the manufacturer with the alternator's charging capacity, so the replacement battery should also closely match the OEM battery's capacity. Is my assumption corre...


Scope, RTC

Started by Anonymous in sci.electronics.design3 years ago 6 replies

Got this HP 54501, raster based CRT scope Indications are that the NVRAM chip, which is more of an assembly because it has an internal battery has...

Got this HP 54501, raster based CRT scope Indications are that the NVRAM chip, which is more of an assembly because it has an internal battery has died. That is most likely due to the battery. The battery has a connection to pins on it. ;the presumption at this time is the battery is in too poor state of charge to operate the chip. This has all the setup information in it so it i


impedance meter to test car battery

Started by Jamie M in sci.electronics.design3 years ago 56 replies

Hi, For a 12V lead acid car battery, at 12.6V and a measured internal impedance of 9mOhms, is that enough info to accurately estimate the CCA...

Hi, For a 12V lead acid car battery, at 12.6V and a measured internal impedance of 9mOhms, is that enough info to accurately estimate the CCA of the battery, or should a battery load tester be used? cheers, Jamie


Battery tester

Started by Carlos E. R. in sci.electronics.design11 months ago 19 replies

Hi, Many moons ago I bought an analog multimeter, and one of its functions was to test batteries. It loaded the battery with a resistor,...

Hi, Many moons ago I bought an analog multimeter, and one of its functions was to test batteries. It loaded the battery with a resistor, drawing some significant current (for three battery types) and then measuring I don't know if voltage or current (typical green-yellow-red zones). Right now it is on another city. So now comes a friend that says the battery for a DECT phone doesn't ...


Lead acid battery desulfination?

Started by Jan Panteltje in sci.electronics.design8 years ago 57 replies

Been trying to 'desulfinate' a 13Ah lead acid battery now for a few weeks. The method I used is to run 200 mA at 16V into a 12V battery. The...

Been trying to 'desulfinate' a 13Ah lead acid battery now for a few weeks. The method I used is to run 200 mA at 16V into a 12V battery. The battery had only 1/10 of capacity, now it has 1/8. Takes too long for my liking, would several month that way. So did some googling, and found this circuit diagram only: http://images.yuku.com.s3.amazonaws.com/image/pjpeg/f1116c552716baf0a54f0050308e...


9V Battery or 2 x AAA with 9V Converter

Started by Anonymous in sci.electronics.design8 years ago 34 replies

In terms of battery life, and assuming the same brand of Alkaline battery, is it more efficient to use a 9V battery or 2 AAA cells...

In terms of battery life, and assuming the same brand of Alkaline battery, is it more efficient to use a 9V battery or 2 AAA cells with something like the TL496 converter pictured here. http://www.electroschematics.com/6788/3v-to-9v-dc-converter/ If not, what is the approximate difference either way? The circuit involved is a test audio oscillator. Would be nice if they made mor...


Can car batteries work upside-down?

Started by Dave Vanden Bout in sci.electronics.design14 years ago 27 replies

I have a customer who needs a battery-powered system that will operate in any orientation. A car battery is the only thing that has the A-hrs...

I have a customer who needs a battery-powered system that will operate in any orientation. A car battery is the only thing that has the A-hrs he needs (I think). I assume a sealed car battery solves the obvious problem of leaking acid, but are there any other considerations that prevent a car battery from being used when it is upside-down? Are there other types of rechargeable batteri...


Charging time for 12 V battery

Started by Anonymous in sci.electronics.design10 years ago 18 replies

I have a 12 Volt battery, 9.5 Ah that uses a 12 volt charger 1.0 amp. Assuming the battery is completely discharged, is there a way to...

I have a 12 Volt battery, 9.5 Ah that uses a 12 volt charger 1.0 amp. Assuming the battery is completely discharged, is there a way to determine how long to charge ? Thanks, Andy


Can anyone explain how this battery charger works?

Started by Commander Kinsey in sci.electronics.design7 months ago 130 replies

https://imgur.com/a/b8l5qKQ Look at the circuit diagram. The positive of the battery is only connected through a capacitor. How can a...

https://imgur.com/a/b8l5qKQ Look at the circuit diagram. The positive of the battery is only connected through a capacitor. How can a capacitor possibly pass DC current to allow the battery to charge?


How to fight a lithium battery fire

Started by Flyguy in sci.electronics.design1 year ago 104 replies

So you own an electric car with a sizeable lithium-based battery, how do you fight a battery fire? Experience with fighting electric car fires is...

So you own an electric car with a sizeable lithium-based battery, how do you fight a battery fire? Experience with fighting electric car fires is not encouraging because you can't cut off the supply of oxygen to the fire like you can with a carbon fuel such as gasoline - the chemistry of all lithium battery variants supplies its own oxygen. There was a very large (mega) battery fire


Laptop battery charging?

Started by Dean Hoffman in sci.electronics.design2 years ago 2 replies

I recently bought a new MacBook Air. There are all sorts of tips about extending the duration of a single charge. Does it...

I recently bought a new MacBook Air. There are all sorts of tips about extending the duration of a single charge. Does it matter when I charge it if I want to get the battery's life to be the longest? Should I charge it when the battery is at 50%, 25%, or maybe let it run down to shutdown?


OT: Soldering large 18650/20700 lithium-ion batteries?

Started by John Doe in sci.electronics.design3 years ago 23 replies

I am neat, careful, and quick to avoid overheating when soldering. How possible is it to solder a large lithium-ion battery without damaging or...

I am neat, careful, and quick to avoid overheating when soldering. How possible is it to solder a large lithium-ion battery without damaging or degrading the battery? For connecting batteries together. I like doing things right, so I'm willing to buy a $100 Chinese battery connector welding box. But the foreseeable need is only about five two- cell battery packs. You do the math... Th...


vehicle battery supercapacitor kit ideas

Started by Jamie M in sci.electronics.design3 years ago 15 replies

Hi, I have installed and tested a supercap on a V8 engine as an experiment to avoid buying a new lead acid battery: Here is the supercap I...

Hi, I have installed and tested a supercap on a V8 engine as an experiment to avoid buying a new lead acid battery: Here is the supercap I used: https://www.ebay.com/itm/16V-83F-Farad-Capacitor-Super-Capacitor-2-7V-500F-With-Protection-Board -Module/223685920878 (16V-83F) I soldered ring terminals to it and bolted it directly to the 12V battery (in parallel with the battery). Be


another atomic battery

Started by John Larkin in sci.electronics.design10 years ago 16 replies

http://citylabs.net/ Looks like betas whacking solar cells. Makes no sense to me. A primary lithium battery will deliver power for over...

http://citylabs.net/ Looks like betas whacking solar cells. Makes no sense to me. A primary lithium battery will deliver power for over 20 years at a cost per joule probably a million times better than this. Not to mention getting a more sensible terminal voltage. How do they expect to charge a battery with 0.7 volts? That all goes for most of the "energy harvesting" things you read ...


75332P MOSFET drain connected to which battery terminal?

Started by John Doe in sci.electronics.design11 years ago 18 replies

I have a 75332P MOSFET on a cordless drill controller heatsink. I guess it's part of a pulse width modulator. The drain (flange) connects...

I have a 75332P MOSFET on a cordless drill controller heatsink. I guess it's part of a pulse width modulator. The drain (flange) connects directly to one of the battery terminals. Does the MOSFET drain go directly to the battery minus/ground terminal? Or does it go to the battery plus terminal? Thanks. -- My application... I'm desperately trying to develop a better inline ...


Need Op Amp for design

Started by Leslie Rhorer in sci.electronics.design5 years ago 73 replies

I have a little project am trying to design, and I am running into a little difficulty in the concept stage. I have a device that needs to...

I have a little project am trying to design, and I am running into a little difficulty in the concept stage. I have a device that needs to consume essentially zero power when shut off. A few nanoamps is fine. The device uses a 6S LiPo battery that must be monitored during operation to make sure the battery is not discharged beyond critical limits. To this end, the battery is conn


6V battery substitute

Started by David Lesher in sci.electronics.design2 years ago 4 replies

A friend inherited a small dirt bike. It has a quite deceased 6V battery. It's got a coil and points, not a magneto. So it needs a battery,...

A friend inherited a small dirt bike. It has a quite deceased 6V battery. It's got a coil and points, not a magneto. So it needs a battery, or substitute, to run. (He's happy to kickstart.) It gets stored for long periods. He asked if a super capacitor might work. He can charge it before starting. I'm debating in my head if it has a low enough impedance to keep things stable. ...


Battery replacement

Started by Ralph in sci.electronics.design1 year ago 12 replies

I have a remote control car that has a dedicated control and receiver at some unknown to me frequency. Not bluetooth or wifi. It was a...

I have a remote control car that has a dedicated control and receiver at some unknown to me frequency. Not bluetooth or wifi. It was a Christmas toy. It is a substantial car nearly 18" long. It uses a 8.4v nicad battery that I cannot find and really want to NOT use. I can get the battery specs if needed. The car is on vacation in the mountains right now. lol I want to replace with Li I...


OT: Smartphone always charging destroyed battery?

Started by John Doe in sci.electronics.design3 years ago 54 replies

https://www.flickr.com/photos/27532210@N04/ Another Chinese battery bit the dust here. Noticed my smartphone was bulging, the screen was...

https://www.flickr.com/photos/27532210@N04/ Another Chinese battery bit the dust here. Noticed my smartphone was bulging, the screen was warping. The cause was obvious so, not having a torx t1 screwdriver, I ripped it apart. Tried using a capacitor in place of the stock battery but that didn't work. An 18650 works, but it's charged to 4.36 V. The smartphone is used for Wi-Fi security...


Cooling an electric vehicle battery.

Started by Anthony William Sloman in sci.electronics.design1 year ago 52 replies

Electric vehicle batteries are about 85% efficient, but the 15% of the energy that you put in that you don't get out has to appear as heat,...

Electric vehicle batteries are about 85% efficient, but the 15% of the energy that you put in that you don't get out has to appear as heat, generated in the battery. The worst case would presumably be during fast charging. One has to wonder whether anybody has built a battery with heat-pipe down the middle, sticking into heat-sink extrusions projecting from either end. Nobody seems to do...