Electrical 12v low voltage cutoff

poor but proud

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Ill add in some weird caravan stereo shenanigans. The aircon and tv remote controls turn our caravan stereo on (never off) and also changes the channels. A problem, but not such a massive surprise you'd expect, having one remote impact another. But here's where the weird ramps up to a whole new level, our caravan stereo doesn't (read does NOT) have a remote control itself. You can imagine how many years it took to figure out what the hell was going on

The stereo also has outside speakers and we generally only use it outside so whenever we use the stereo we have to ensure the volume is zero before we turn it off because we learned the hard way lying in bed late at night changing a channel on the tv, or adjusting the aircon turns the bloody stereo on outside at the settings it was turned off at ... we cant have a giggle and then just turn the stereo off with its remote control because it doesn't bloody have one
this sort of suggests that any 12volt unit in a van that has a remote control probably has a standby feature that will suck power even if it shows off??????
 

Drover

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In the van I know whats using what, when and how much, well roughly, Big Mal doesn't have anything running unless its turned on by a proper switch, the diesel heater has a main power switch, the TV/STB's/Mobile broadband units all have a master switch for each of them along with other bits , if it didn't have a switch originally it has now, nothing on standby.... Dont forget to turn the AC off at the switch, it has a 12v circuit usually.....
Thats why I don't like all these techo things, screens, blutooth etc they chew power, the blutooth on your phone chews power not a drama when plugged into a power station but big waste when off grid, some even leave their chargers/Invertors and gear on, no wonder they need 800w on roof and 900ah in storage.

I hate outside stereos, mainly because the rest of us like to listen to our own music and some have a need to share ........... I find some good old C&W sorts them out.......... or a bit of Slade Alive............. sometimes even Blu Grass...oh yeah!!!!!!!
 

mikerezny

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Hi,

another power hungry device is the mobile phone.

This is my understanding:

Conserving power so the battery lasts longer is a distinct marketing advantage. Transmitting is a big power user so phones have adaptive transmitting power. When they are close to a tower they reduce the transmission power to conserve battery power.

However, if the phone is out of range of a tower they transmit regularly at FULL power trying to find a tower to connect to. Not ideal when you are out backpacking with no way to recharge. We would get a week before recharges in Melbourne, but the phone would be flat after a couple of days out backpacking.

A bit of a pain when off grid and out of range since they need charging more often.

The solutions when out of range are to go to flight mode or, as we do, turn it completely off.

Same goes for tablets with a sim card.

take care
Mike
 

Drover

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Too many folk leave location on and apps, not just on phones but all computers, allowing apps/programmes to check updates is another power/data user, things like faceache, messenger, mail apps canburn heaps of power. My stuff is shutdown tight even windows cant update, I dig surgery on it...... So cars eating power when shut down shouldnt be surprising.
 

Boots in Action

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While talking about unexplained power usage , when we first got our van it did not have a battery installed the set up only allowed power from 240 or car circuit. When we installed a battery we were still using power when nothing was turned on, after trial and error it was traced to the radio CD player which is a typical car unit which even when turned off stays in standby mode which uses the same power as if turned on. You can turn the unit totally off but any disruption to power feed put the unit back to standby mode we had to install an isolation switch to stop this happening , car radio/CD draw around 8 amp even when on standby this is not an issue in a car as the ignition switch isolated the unit ,by the way some tv units do the same thing , silent sneaky battery killers as if not known totally drains battery and causes battery failure in no time , not sure if this is common or my van was built Friday pm

Not so uncommon at all @poor but proud . My 2013 build Penguin with a Pioneer radio/cd player/memory stick player has a similar problem. Although turned off and display not on, it appears to need power to hold memory of settings. I too used to see slow voltage drop in battery voltage when arrived at home and even though all things were turned OFF, and van battery fully charged with "smart" charger, over a period of 3 or 4 weeks without further checks, battery voltage was down to 11.80v. Like you, traced it back to Pioneer equipment which was drawing 200ma all the time even when OFF!! Now fixed by removing 10A fuse for that equipment when ever at home not in use. Bit of a bugger really, as every time I go out, I have to retune in stations and fix all settings again!!! Still better than having battery go low, although having van on power at home to keep battery charged would prevent this happening. Now, I turn off the main power switch in van and only turn it on when pre-cooling fridge before travelling. This isolates ALL electrical loads from battery until needed, but still allows me to charge battery from my charger as I have dedicated fuzed line from external Anderson plug to battery terminals.
 
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poor but proud

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Not so uncommon at all @poor but proud . My 2013 build Penguin with a Pioneer radio/cd player/memory stick player has a similar problem. Although turned off and display not on, it appears to need power to hold memory of settings. I too used to see slow voltage drop in battery voltage when arrived at home and even though all things were turned OFF, and van battery fully charged with "smart" charger, over a period of 3 or 4 weeks without further checks, battery voltage was down to 11.80v. Like you, traced it back to Pioneer equipment which was drawing 200ma all the time even when OFF!! Now fixed by removing 10A fuse for that equipment when ever at home not in use. Bit of a bugger really, as every time I go out, I have to retune in stations and fix all settings again!!! Still better than having battery go low, although having van on power at home to keep battery charged would prevent this happening. Now, I turn off the main power switch in van and only turn it on when pre-cooling fridge before travelling. This isolates ALL electrical loads from battery until needed, but still allows me to charge battery from my charger as I have dedicated fuzed line from external Anderson plug to battery terminals.
Sounds like we ended up with a similar set up , we use portable panels which feed through an Anderson plug on the A frame direct to the battery via a circuit breaker, this allows me to charge the house battery without going through the van wiring, using solar, tug or battery charger, a friend of mine who is an auto electrician suggested the KISS factor so that there was very little technology to go wrong , just use heavy truck cable for battery feed lines to minimise voltage drop and put circut breaker in each section of cable for safety , my radio/CD was not as sneaky as yours it draws 8 amp so totally flattened the battery overnight start planning your next trip everyone because when they open the gates all the good spots will be gone in a flash , lucky that we will be 2000km ahead of the Mexicans this time bye
 
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Drover

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Big Mal didn't even have a 12v switch to turn the power off, I was amazed, I fitted a switch in with the pump switch, fuse box cupboard, it actually looks like it has always been there, so unlike my mods...... I have been going to fit LVC to van and tug but never seem to get around to it and I mean going back for years so now I just haven't bothered, one of those things that I seem to sense, last time something drained a vehicle battery would have been 1977 in Williamstown Vic....... @poor but proud your sparky operates on the same principle as I, KiSS certainly means he's on the ball I reckon, my portable can plug direct to battery or by just changing an anderson plug can plug direct into the vans reg to charge along with the roof top panels, (I can take the portable reg off line) I just use maxi fuses and have 8 B&S cables hanging off them...........The 2 solar sytems are seperate, the 240v supply is seperate and the 12v supply are as well so if one dies they don't drop the whole lot out, if one battery carks it I can disconnect, so I think redundancy is taken care of and with the old Ute I could even utilise its solar and aux battery if needed, not so the jeep (yet)..................
The hungriest power device in my van seems to be the stereo, positively chews thru it in fact the TV and a STB fired up nearly match it....... My current phone an LG is going to be a pain off grid as it just doesn't hold a charge for very long even with everything shut down, one phone call can give it a coronary.......
 

Boots in Action

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I get your figures but as for a ghost type current, the only occurance of significant discharge is contained within the LVC. As soon as that is disconnected all trace of evaporating power ceases. Ill connect the unit you have and see how that goes in comparison to the other 2 x boards.

Hi there @Crusty181, conducted further tests with a fully charged good 120ah AGM with LVD at 12.4v and LVR at 12.8v . No significant changes to original test results. Still 0.034A off load but still connected at 13.3v, and 0.082A at 12.4v off load (after load disconnected by unit). It is getting pretty hard to gauge when operating in hundredths of an amp!! Be interested to know your readings when you get set up.
 

Crusty181

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Hi there @Crusty181, conducted further tests with a fully charged good 120ah AGM with LVD at 12.4v and LVR at 12.8v . No significant changes to original test results. Still 0.034A off load but still connected at 13.3v, and 0.082A at 12.4v off load (after load disconnected by unit). It is getting pretty hard to gauge when operating in hundredths of an amp!! Be interested to know your readings when you get set up.
I tested the 3 x LVCs I bought, 1 x 10A board, 1x 20A board and 1 x "Boot box", same as yours. It was raining (its Vict) so I just used the vans outside 12v outlet which is over the very convenient fold down table, close to the equally convenient mains to turn the power to the van on and off. I set the cut off at 12.8 and cut in at 13.2 and just flicked the mains on and off to trigger the low voltage. I used an indicator light on an attached torch charger load (minus the torch) just to provide a visual on the cut in/out.

My first victim was the "Boots box"; connected 0.052A, then 0.095A. 10A board; connected 0.052A, then 0.076A. The surprise contestant was the 20A board which I tested, re tested, disconnected and retested, then packed up and went back again; connected 0.096, then 0.020. Ive also checked the photos I took 10 times whilst Im typing this. So the first 2 close enough to your figures, but the 3rd ones figures being reversed was interesting and unexpected result. I thought, without much actual thought, the 2 x boards kinda had a similar effect on the battery, but on these figures that wouldn't be right.
 
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Boots in Action

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I tested the 3 x LVCs I bought, 1 x 10A board, 1x 20A board and 1 x "Boot box", same as yours. It was raining (its Vict) so I just used the vans outside 12v outlet which is over the very convenient fold down table, close to the equally convenient mains to turn the power to the van on and off. I set the cut off at 12.8 and cut in at 13.2 and just flicked the mains on and off to trigger the low voltage. I used an indicator light on an attached torch charger load (minus the torch) just to provide a visual on the cut in/out.

My first victim was the "Boots box"; connected 0.052A, then 0.095A. 10A board; connected 0.052A, then 0.076A. The surprise contestant was the 20A board which I tested, re tested, disconnected and retested, then packed up and went back again; connected 0.096, then 0.020. Ive also checked the photos I took 10 times whilst Im typing this. So the first 2 close enough to your figures, but the 3rd ones figures being reversed was interesting and unexpected result. I thought, without much actual thought, the 2 x boards kinda had a similar effect on the battery, but on these figures that wouldn't be right.

@Crusty181 , what was the value of the load you placed on circuit. My test had 36w or 3A which is around what a compressor fridge might draw. An indicator lamp from a vehicle would only amount to 21w. Perhaps this has some bearing on figures??? The trouble when working in milliamps is that small things have a larger bearing on readings. Incidentally, the unit I have is rated at 20 amps.
 

Crusty181

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@Crusty181 , what was the value of the load you placed on circuit. My test had 36w or 3A which is around what a compressor fridge might draw. An indicator lamp from a vehicle would only amount to 21w. Perhaps this has some bearing on figures??? The trouble when working in milliamps is that small things have a larger bearing on readings. Incidentally, the unit I have is rated at 20 amps.
The load was only a tiny blue LED on a torch charger, so no load at all really. My issue was the drain on the battery with no load, ie just the board itself. I would have guess/assumed/BS'ed the load wouldn't have a lot of impact on the boards consumption, much like a relay just closing and opening the circuit independent of the whats on that circuit. I was going to BS that I know that from genuine knowledge, but I suspect that's pretty transparent. The Boots Box I got from your link, the other 2 are these

s-l1600 (3).jpg s-l1600 (4).jpg
 

Boots in Action

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The load was only a tiny blue LED on a torch charger, so no load at all really. My issue was the drain on the battery with no load, ie just the board itself. I would have guess/assumed/BS'ed the load wouldn't have a lot of impact on the boards consumption, much like a relay just closing and opening the circuit independent of the whats on that circuit. I was going to BS that I know that from genuine knowledge, but I suspect that's pretty transparent. The Boots Box I got from your link, the other 2 are these

View attachment 65052 View attachment 65053
@Crusty181 , no matter what the theory, nothing like a real field test to provide accurate results. Circuitry just uses up power!!
 

Crusty181

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New 12v ponderage experts. Is it possible to wire up a light with 2 switches, one front and one back ie turn on at front and off at back, and vice versa. Much like house hallway lights with a switch either end
 

mikerezny

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New 12v ponderage experts. Is it possible to wire up a light with 2 switches, one front and one back ie turn on at front and off at back, and vice versa. Much like house hallway lights with a switch either end
Hi,

Easy peasy as long as you have light switches with changeover contacts. Most 240V light switches are a changeover switch plus a spare looping terminal.

But you will probably have to run an extra wire between the switches as shown in the diagram below.

take care
Mike

diagram.png
 

Crusty181

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@Boots in Action and @mikerezny and maybe even more @chartrock might get some entertainment from this.

Some time back I won a a couple of $1000 worth of gear in some online competition. Among the gear was satellite tracker which I was torn between the car and the van. The tracker is limited to cell phone network, but at around $300 is a little better than the eBay stuff. It has geo-fencing which I think is mandatory, so thats a plus. Anyways what to do with it.

Like most folk we have a few old mobile phones so I got to thinking ..... I grabbed one of the old mobiles, used a couple of free Apps, then wrote some code to fill in the gaps and missing functionality .... and shazzam.

The phone is now a geo-fenced based satellite live tracker ready to be put to work. When device (hidden in the car or van) leaves the geo-fence, a gps tracker immediately starts live tracking and records continuously to the device. A txt msg is then sent to my own mobile phone, the msg is intercepted by a another simple App I wrote which lights up the phone like a Xmas tree, and screams the house down. The msg gives me the current location, direction of travel, speed and accuracy of the van or car. If the coppers get involved and take over monitoring the pings, the tracker/phone still secretly sends the same data to me (giving me the opportunity to get there first). I can also call the tracker/phone and silently listen in on the goings on in the car. Bonus is the tracker/phone is battery optimised, so if they kill the power it will still work long enough for me to ...... aSsisT tHe pOlicE

My home made tracker will go in the van at this point even though its performs better than the $300 package, because modifying the geo-fence is a little hands on at this stage of development and the van doesn't move as much as the car, nor really need geo-fencing away from the factory. It will still track despite not adjusting the geo-fence, and it will continue to track outside cell range. At some point the intention is to write some code to send adjusted geo-fence data to the device remotely .... but they day may never come

Isolation can be productive
 
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Drover

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So thats the same as my old phone linked to Telstra find my device.......