| | Good day by SDMickey - March 27th 2024 10:55 pm
| Lew Greger by MufflerMan Mike - March 27th 2024 5:15 pm
| | | Re: Starter Battery Stuff | Joined: Jun 2010 Posts: 1,080 Likes: 1 old hand | OP old hand Joined: Jun 2010 Posts: 1,080 Likes: 1 | Hey, 68.
We're getting ready to drive this morning so just a quick note ... we figured the 12 volt plug meter was just running through too much interference as it jumped around all over the place. Our new voltage display is similar to the one you showed only two wires not three. It will be wired directly to battery with small on/ off switch between. We've put one on the house battery already and it is reading just as well as our multimeter so pretty pleased with it.
More later. | | | Re: Starter Battery Stuff | Joined: Apr 2010 Posts: 2,847 Likes: 42 veteran | veteran Joined: Apr 2010 Posts: 2,847 Likes: 42 | Excellent. Did you fuse the wiring to the voltmeter? While small gauge wiring needed for such a light load is unlikely to start a fire if shorted, it is still wise to have it fused. If shorted it will become a parasitic draw and likely smell of burning plastic, but the non op voltmeter should be the red flag.
On such things I use the regular 1/4 inch insulated quick connect crimp terminals clasping the tangs of an ATC fuse. The fuse is 'supposed' to be within 7 inches of the battery terminals, which could then expose it to the corrosive mist when it is charging. So one should likely fill the quick connectors with dielectrc grease.
I've really been digging the 3 decimal place voltmeter. Right now it is on my dashboard 5v cluster sent to the gauges, as sometimes the temp gauge was reading abnormally high, and I have a solid state bucker in there feeding 5v instead of the stock contraption. The voltmeter does indicate that sometimes it is reading 0.297 high when the gauge is also reading high, indicating my voltage bucker is not perfectly keeping 5.000v.
What was weird is the stock vltag bucker contraption was able to be influenced by my old flip phone when it was pinging towers in 2g, my gauges would raise and fall dramatically the same time that weird interference noise would come through my speakers.
I have other temp sensors on my intake just below t-stat housing and on the radiator inlet which kept me from freaking out when the gauge would read high, but the reading would not always read high, and I wanted to know why, or more like confirm my suspicions thant my solid state voltage bucker was drifting. If it were just a single digit voltmeter it would never have drifted off of 5.0v and I would not have known, but 5.297v when the gauge is reading high is an 'AH HAAAA!"
I used a connector from a 3 wire computer fan to make this 3 decimal voltmeter more portable.
I once got a 2 decimal voltmeter that had 3 wires, but it was not able to be calibrated, and was 0.17v off, making it near useless for telling me what I wanted to know.
Safe driving. | | | Re: Starter Battery Stuff | Joined: Jun 2010 Posts: 1,080 Likes: 1 old hand | OP old hand Joined: Jun 2010 Posts: 1,080 Likes: 1 | Finally had a moment to respond....
"Did you fuse the wiring to the voltmeter?"
No. Didn't fuse. As you said, it is such a tiny wire gauge and completely visible to us at all times when on and off when we aren't in the van that figured it was not a big deal at this point. In the future, when I finalize installment instead of this temporary placement I may make it a better / fused set up but for now.... temporary.
"I've really been digging the 3 decimal place voltmeter."
I'm starting to get your 3 decimal place voltmeter appreciation. In the future I may go that route. For now we'll use the two we already purchased but I can see that it would be nice to see the extra digits.
Been playing with reading amp draw with my multimeter. Given that we never put a meter of any kind on our solar set-up, after five years, it has been neat to see that what we thought about various items and their draw was pretty accurate. Now we have more exact readings of what each items draws a various times though. So, that was fun.
Well, back down the road. Just finished climbing several 10 - 11,000 foot summits. Good times! | | | Re: Starter Battery Stuff | Joined: Apr 2019 Posts: 96 Likes: 1 journeyman | journeyman Joined: Apr 2019 Posts: 96 Likes: 1 | I ran my volt meter from the cigarette lighter and tapped off the wires behind it. That way its fused and I don't have to run wires or anything. Was simple and quick. The fuse for the cigarette lighter should be 10 or 15 amps and the volt meter i have uses less than 30 milliamps I think. | | | Re: Starter Battery Stuff | Joined: Jun 2010 Posts: 1,080 Likes: 1 old hand | OP old hand Joined: Jun 2010 Posts: 1,080 Likes: 1 | DontComeKnocken... Interesting. I wonder though if the wires to the cig lighter run through anything other than the fuse? I am looking for a full on direct connection to the battery since we already have a plug in 12 volt meter that goes into the lighter socket. | | | Re: Starter Battery Stuff | Joined: Apr 2010 Posts: 2,847 Likes: 42 veteran | veteran Joined: Apr 2010 Posts: 2,847 Likes: 42 | On my '89 B250,
Fuse #7 is for:
-Stop lamps(~ 5- 6 amps with 1157 incandescents).Brightness and Amp draw increase with higher voltage reaching light 1157 socket. -Cigar lighter( I have no data on actual cigar lighter amp draw) -Key and HeadLamp buzzer.(ripped this device out on day one of ownership, no data on amp draw) -Aux AC and Htr.( no data)
So anytime the brakes are depressed, ` 5-6amps of load is presented to the circuit that also powers the cigar lighter causing more voltage drop and a lower than actual battery terminal voltage. How much voltage drop depends on teh length of the circuit, the wire gauge, the total amp load, and the number and conditions of the connections between the plug and the path to ground terminal back to battery. Lots of variables.
These potantial shared loads on the circuit is enough to depress the voltage reading significantly ay cigar plug, from actual battery voltage. These shared circuits for above list are just from the fuse block, and do not represent shared loads of other electrics feeding from the circuits between battery and fuse block iin glove box.
So the ciggy plug voltage on a Dodge can be much lower than actual battery termial voltage, and likely reads lower than actual on most makes and models when the shareds loads are also on the cigar plug fuse circuit.
Step on the brakes and I guess voltage drops 0.1 to 0.2v at the cigar plug, and the 5-6 amp load of the 1157's brighter filament, is unlikely to be overloading the alternator. The battery voltage likely remains steady when brakes are depressed. Door buzzer still work? bet the open door lowers the voltage reading taken at the cigar plug too.
It can be proven with a multimeter, if one cares to take readings and record results.
Bypassing the spring loaded crappy connections of a cigar plug voltmeter is better, but true battery terminal vlotage will be higher when the brakes are depressed | | | Re: Starter Battery Stuff | Joined: Jun 2010 Posts: 1,080 Likes: 1 old hand | OP old hand Joined: Jun 2010 Posts: 1,080 Likes: 1 | 68. Thanks. Interesting about the brake pedals and voltage. We knew our cig plug was reading a tad lower but had already measured the difference at battery terminals and knew what to add back in. However, after years of that we are ready for a direct battery terminal reading on our volt meter. We'll head out to our summer position in a day or so and I look forward to getting this hooked up and seeing a more direct measure each time I turn it on. | | |
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