how to know whether my Digital MultiMeter is correct?

[BillC]

The problem is, my car is always outside, parked in the street. I cant trickle charge due to this setup.

 

It is a Fiat Panda 1.1 from 2002 (new in 2002) and it had the car-radio originally bypassed (so it can play even when the car is off), but I connected it different, so car off = radio off. The electronics in the car shut off around 30 seconds after the engine is stopped. After 30 seconds no current is used.

 

I drive very short trips (too short), AND this car lacks a battery-meter on the dashboard. So I have no idea what the state of the battery is. Almost every 2 years I have to replace the battery. So now I want to change my strategy, and check the voltage of the battery once a week.

 

As soon as the voltage is around 12.4V or so, Ill make a longer trip (let's say 45 minutes or so) so the battery will get a chance to recharge.

 

I understand this is still not the most ideal solution, but it is in my circumstance the only way of increasing my battery-lifespan.

 

Another solution would be a trickle-charger with a battery. I would first charge that device in my home, and then I could connect that device to my cigarette-lighter inside my car (there is an open connection from that to my battery). But I'm not aware of the existence of such a device.

 

Does exist a trickle charger that charges my car-battery, using a built-in-charged Battery (which can charged inside the house) so I can trickle-charge my car-battery without the need of a wire from my house-to-the-car?

 

This type of car btw.

panda.jpg

 

I have heard of Solar-Cell-charge devices for the Car Battery, but I have also heard those are pretty useless. Anyone with a positive experience with these?

I use a 1.8W solar battery maintainer(at that wattage it would take forever to charge the batteries) with a 2001 Ram pickup which I don't drive very often, it keeps the power door lock receiver and other electronics from discharging the batteries. Similar to the following.

eBay Auction -- Item Number: 331370843508

[Andromeda Stardust]

 

Haha… I am so fond of that car. It's my 2nd…. I have never owned another type/brand car. They are AMAZING. Check this ad from 1981… can't beat that right?

 

 

or check this… that is even cooler!

 

That car parking bit was funny.

 

As for multimeters, I bought a digital meter with manual selection knob. Like $17 at Walmart or Lowes or somewhere after my $50 Radio Shack auto-ranging went on the fritz. It seems safer than using an auto-ranging model for unknown source. If you know what you're measuringand use an appropriate setting, you won't f*** it up.

[HiassofT]

Haha I am so fond of that car. It's my 2nd. I have never owned another type/brand car. They are AMAZING. Check this ad from 1981 can't beat that right?

Ha, I never owned a car, but some 2 years ago I bought this multimeter - and I really like it!

 

 

BTW: pricing of Fluke stuff here in Europe is just insane, they cost some 50% more than in the states. For example digikey.com lists the 87-V at 400 USD but Farnell and RS want 500 EUR (without VAT) for the same thing - looks like they applied the EUR-USD exchange rate in the wrong direction...

 

so long,

 

Hias

[_The Doctor__]

http://www.avdweb.nl/tech-tips/multimeter-calibration-diy.html

 

http://www.instructables.com/id/Precision-multimeter-calibration-reference/

 

http://www.frankshospitalworkshop.com/electronics/diy-voltage_reference.html

 

http://www.kerrywong.com/2013/05/27/cheap-dmm-calibration-with-precision-voltage-reference/

 

http://www.eevblog.com/forum/chat/home-made-dmm-accuracy-check-calibration/

 

you can buy milspec parts for cheap to build some of your own calibration rigs....

Edited December 5, 2014 by _The Doctor__

[fujidude]

Anyone know of any vehicles using flash memory to store station presets or any other settings rather than requiring a constant current draw for dynamic RAM? Granted, the very light draw of most (don't know about those 2000 Caddys LOL) memory would take a fair amount of time to drain a big car battery too much...but... flash memory is everywhere and pretty damn cheap. Hasn't its time come for auto use?

[BillC]

Anyone know of any vehicles using flash memory to store station presets or any other settings rather than requiring a constant current draw for dynamic RAM? Granted, the very light draw of most (don't know about those 2000 Caddys LOL) memory would take a fair amount of time to drain a big car battery too much...but... flash memory is everywhere and pretty damn cheap. Hasn't its time come for auto use?

The power to keep the radio presets/clock setting is likely neglible. If a vehicle has electric door-locks with remote keyfobs(a lot of newer automobiles) the power draw from the RF receiver would be more and an alarm system increases the power draw even more, but even an interior light draws far more power. I once had the glove compartment light drain the battery on a 1989 pickup.

[fujidude]

The power to keep the radio presets/clock setting is likely neglible.

I know it's very little, but, it is not always trivial to reprogram a lot of settings in stereos and the like. A little bit of flash makes a lot of sense to me. Disconnecting the battery is a common troubleshooting technique for a lot of things.

[_The Doctor__]

Huh? I thought this was about meter accuracy and calibration...

Any vehicle that is old enough had mechanical am/fm presets, needs no flash, needs no memory, needs no current drawn.

Also ford had some pioneer produced units that stored stations even when removed... now was it capacitive memory or insternal battery back up, flash or prom? don't know...

Edited December 15, 2014 by _The Doctor__

[fujidude]

Huh? I thought this was about meter accuracy and calibration...

Any vehicle that is old enough had mechanical am/fm presets, needs no flash, needs no memory, needs no current drawn.

Also ford had some pioneer produced units that stored stations even when removed... now was it capacitive memory or insternal battery back up, flash or prom? don't know...

It started out about meters (and still is), but took a little curve into this area too. Such is the nature of free and dynamic communications. I am aware that (very) old car radios had mechanical preset positions you could set. I used to use them. But they are not relevant anymore since we have moved on to electronic memories; memories that are too often (my opinion) lost if battery power is interrupted. Capacitive would be an acceptable solution to this as long as it was able to outlive typical battery disconnect periods. Backup battery is less desireable because of aging/leaking unless it was easily accessible and replaceable.

[Van]

I have heard of Solar-Cell-charge devices for the Car Battery, but I have also heard those are pretty useless. Anyone with a positive experience with these?

Just reading thru the thread and this question caught my eye. I can say that back when I was in the Army, all our HumVees were retrofitted with solar cell trickle chargers. A small 4" x 6" panel mounted to the roof. Keep in mind that a lot of these vehicles were parked at the motor pool most the time and only run for an hour or two once a month.

Yogi

[fujidude]

Just reading thru the thread and this question caught my eye. I can say that back when I was in the Army, all our HumVees were retrofitted with solar cell trickle chargers. A small 4" x 6" panel mounted to the roof. Keep in mind that a lot of these vehicles were parked at the motor pool most the time and only run for an hour or two once a month.

Yogi

That's a good solution for that particular situation. I bought a brand new Harley Davidson Road King (2008 model in 2008), and am STILL on the original battery in it. I keep it on a smart charger all the time it is not being ridden. This includes during the whole winter when temps can get very cold here in WI. I just leave the battery in. Keeping the battery always just topped off and no more, keeps them tip top for a long time. It largely prevents the sulfating of the plates that can happen during self discharge.

 

I am a huge fan. The solar solution is great, so long as the battery side of the unit is a "smart" chanrger like I described. Now then, in my SUV I change out the battery every 5 years period. I will not risk getting stranded anywhere when it is 20 something below zero. And that's is exactly when marginal batteries love to fail you.

[Atari-Collector]

I have a couple DMV and one analog multimeter. That all pretty much agree with each other, one of the DVM's is a $5 cheapy from China. but works surprisingly well.. but i find my older Radio Shack DMV from the 90s a bit more responsive.

 

But I won't have as much faith in what sold be RS (aka "The Source" in Canada) today. I'd expect to to be no better then the cheap stuff from China. If you really want accurate today, go look for a Fluke brand and be prepared to spend a chunk of money on it.

[fujidude]

 

But I won't have as much faith in what sold be RS (aka "The Source" in Canada) today. I'd expect to to be no better then the cheap stuff from China.

 

It probably IS the cheap stuff from China. Back in the 90s it was probably the cheap stuff from Tiawon.