Thanks VolvoCarPC and Oldspark,
You have both been most helpful. I will start a thread detailing what I intend to do as I get close to the build. I have been read your comments and I'm confident I know what I require now.
I'm looking forward to hearing how testing is going with the camera. I have a rear facing camera but I'm thinking about introducing a forward facing one too.
Thanks very much,
Check the corrections I've made in my previous post ... reread it all over
Superb, 'a picture paints a thousand words'. Thank you - I understand what you have done and why :).
Originally Posted by VolvoCarPC
Many, many thanks :)
About the camera.
Well it's behaving very bad now... When I put on reverse the LCD auto-switches to AV2 - FINE. But as soon as I disengage the reverse it auto-switches to VGA and start auto-config which takes about 5-6sec. But what happens if I have to put on reverse again - nothing. It is still auto configuring the VGA and no camera view is shown until that process ends - BAD.
So my idea now is to make a timer or something, so that in parallel parking I'll be able to put on reverse - first - reverse - first as many times as I need without switching the AV2 and VGA.
So far I got a kit from the local radio-shack which is 555 based timer with trigger button and force stop button. The idea is to set it to 60 sec and to find a way to "push" the force-stop button by putting in 2-nd gear. This way when I first put on reverse I'll got 60 sec to park without the LCD's stupid VGA auto-config. If I'm exiting the parking lot and i need just 20 ses for example when i put on 2-nd gear this will stop the timer and VGA signal will be back.
I'll make a video tomorrow of the behave now, so that letter to be able to show you the difference.
The things that happen whilst I'm asleep! (I went to bed at sunrise. I'm now wondering if I should go go to the races (the Melbourne Cup) - it's a nice sunny 24C public holiday...)
Where do I start?
Great diagram! And probably my favored type - ie, if not a "circuit diagram", then a wiring diagram "pictorial" showing actual batteries & relays etc.
It has great info like "autoreset (if possible)" fuses and shows each fuse close to each battery.
One fault IMO is the PC fuse - that should come from the 2nd battery, NOT the interlink. Hence if te interlink fuse blows, the PC is still electrically connected to the battery.
Also though glass fuses are shown (because they look better than others), I suggest always avoiding glass fuses. Yes - glass was IMO superior to the old open ceramics in old Euro vehicles, but newer "blade" type ATS & ANL etc fuses are far more reliable. The blades ate one piece with a more secure connection to their holder, and have no "fuse wire to end cap" bonding which is notorious for letting go in poor quality and aged glass fuses.
One issue/warning - the 5A fusing from alternator (L/D+ charge light wire) to the isolator relay. I doubt many alternator charge light circuits can supply 5A; the old external electro-mag regulators can, and probably any regulator that uses a relay (SPDT) to control the charge light circuit. But newer alternators (regulators) may use solid-state (transistorised) switching.
I have recently written elsewhere about how a relay coil load can damage/ruin regulators/alternators and how they may not be designed to supply any current at +12V (since traditionally they only had to ground dash lights etc of maybe 1A -0 2A total).
Anyhow, I'd reduce it to 1A or maybe 500mA - enough to handle the isolation relay.
And only ONE fuse is needed (in theory as close as possible to the alt/regulator), however I do not have a fuse there, and I am not aware of any vehicle that has a fuse in that circuit.
A trivial note re earthing/grounding. I have a fig-8 cable between my batteries, hence +12V and GND cabling and that is mainly because the 2nd battery sits in the tub of a ute.
If it were a "normal" vehicle, I'd simply rely on the normal chassis GND - ie, GND the 2nd battery to nearby chassis. I might add a separate interconnecting GND cable as I have done for headlights, but that IMO is overkill unless chassis/body interconnectivity is suspect.
I'll leave that here and start a new reply re a VSR solution to the "charge light extinguished during cranking" issue. But first, a coffee. Maybe even breakfast.
But holy-poo guys, your replies are buddy terrific!
Ok guys - VSRs:
Davefocus informed me of a cheap VSR (voltage sensing relay) type battery isolator - namely eBay item 370837856033. (I thought it was ~AUD$12 but now see it's closer to $25. Still, that is much cheaper than the norm of >$80 for 80A etc units.)
I have since found that that is a Ring Smartcom RCT460 and its specs are 30A with cut-in at 13.5V and cut out at 13.2V.
No info on (yet) on its quiescent loading (its "constant" drain on the min battery) nor its delay times, though it did state "up to 45 seconds to turn off" which may mean a 45 second delay, or zero delay and based on battery surface charge decay, or anywhere in between. Nor does it say that <13.2V (or say <12.6V etc) means instant disconnect so that a second crank does NOT have the batteries interconnected. (That's a flaw in some battery isolator designs I have seen.)
The RCT460 is only rated for 30A, but as we all know that is no problem - if we need higher we simply buy a cheap "master" like the RCT460 and add a relay of our choosing since a 30A VSR will have no problem energising 60A or 600A relays. (It's the same for multi-battery installations - just one master/VSR plus one isolation relay for each battery or battery group.)
As we know, if you have a charge light type circuit, the plain UIBI or charge-light controlled relay is the best isolator. That does not have the voltage threshold problems of the VSRs nor their undesirable delays (noting that "priority charging" is not a feature - it is a mere delay and it is undesirable (except in some rare situations)!).
The UIBI however assumes that the charge light circuit can energise a relay. The problem I have is that I cannot find info on how much +12V current different alternator/regulator D+/L circuit can supply - it's a case of experience else trial & error, however the error may well mean a new alternator. (Not a big deal for me - I get alternators from car wreckers for $45 and always have a spare.) That loading problem can be overcome with a buffer - eg, a smaller relay or better still, a MOSFET or transistor to drive the relay coil(s).
Another issue with the UIBI is if the charge light extinguishes DURING cranking. This is a big no-no if you want clean power from the 2nd battery during cranking (eg, for PCs & audio).
Otherwise, as I wrote earlier, "parallel cranking" is actually desirable provided (1) the interlink can handle it (without blowing fuses) & (2) the 2nd battery is not overstressed by its contributing cranking current.
However, in my experience few alternator charge lights extinguish during cranking - most require greater than cranking RPM to extinguish. [Noting that the charge light itself is irrelevant - it is the alternator's D+/L circuit that drives the UIBI. However where UIBI type systems are used for fuel pumps etc (as several OEM vehicles do), then the charge light bulb else other bulbs are needed for limp-home mode - ie, disconnecting a faulty alternator's D+/L so that the bulbs will pull-up the UIBI relay's #86 aka coil+ to +12V to turn on fuel pumps or electric chokes or open fuel valves etc.]
But what if the charge light extinguishes during cranking and thereby interconnects the batteries which we DON'T want?
Get a different alternator. That'd be my solution since I do not use the 48-year old OEM generator and use $45 alternators instead.
But otherwise the simplest solution is to get a VSR since - if properly designed - battery cranking voltages will be far less than 12.5V and hence the VSR will (should!) NOT be closed - ie, batteries NOT interconnected.
Of course that assumes a VSR under-voltage cutout that overrides any VSR turn-off delay.
[ Note - a VSR is merely a Voltage Sensing Relay. A voltage sensing battery isolator for vehicle use (aka smart isolators etc) must also have various delays to prevent undesirable and potentially hazardous situations. This usually involves a turn-on delay (of say 15 - 45 seconds) which they "market" as a feature (namely "priority charging" rotflmfho!) but some also have turn-off delays to ride thru short transients (brake lights, flashers) or high loads at low RPM (wipers, lights, when idling).
However, be award that although I have started using "VSR" to refer to voltage sensing battery isolators, a VSR may not be a "battery isolator". ]
The UIBI "no parallel cranking" solution could include an initial turn-on delay (you can then add $50 to your UIBI sale price by calling that "priority charging" LOL!) or maybe a manual switch, though I'd suggest sucking it and see unless you are certain parallel cranking occurs.
Ideally with parallel cranking, the current from the 2nd battery during cranking should be checked to ensure it is not too high - after all it is difficult to calculate what that current will be (battery and interlink resistance etc). But I'd suggest that with (Yuasa NP) 12AH or larger with typical starters (~250A) and the main battery providing most current, it should not be a major problem.
But with commercial voltage sensing battery isolators being so cheap I am now more in favor of suggesting them - ie, $20-$30 versus >$80 - provided their behavior is acceptable.
Although the ~$20 MW728 "battery protector" was ok, being a cig-socket 10A device it was not as suited for this type of wired in application. And IMO its 10mA quiescent aka standby current was a bit high.
(I still recommend the adaptable $22 Oatley K227 "Dual Battery Controller" kit with its 80A capacity and negligible standby and operational current loading, but that's a DIY kit and requires an enclosure and connectors. But IMO it's great. It is easily reverse-polarity protect (I added a diode or 2); is suitable for 12V or 24V operation, and can be used as a battery protector aka under-voltage cutout. BTW - its standby current is 500uA (0.5mA) or 50uA without the indicator LED.)
Anyhow, no solutions, but maybe extra info and considerations, and suggestions (suck & see).
But a big thanks to Davefocus for putting me on to that RCT460! (Geez people, I don't have time to surf the net and stay up to date!)
Geez Volvo, you scared me with that! But then I realised you meant (interrupting) the D+/L alternator wire. Phew!
Originally Posted by VolvoCarPC
I know it's stupid to have thought of cutting the MAIN alternator B/B+ wire that goes to the battery, but that goes to show how stupid I can be, or am.
[ Did you read about similar discussions on a "hi-tech" EMS hacking site where an alternator charge-light controlled relay was mentioned as the method to control the fuel pump instead of oil pressure which (1) fails safety requirements, & (2) can cause severe engine damage. (Yes - I know it's ECU/EMS/EFI and the ECU should be controlling the fuel pump - after all, this was not a Bosch EMS!)
Anyhow the moronic retorts were capped by the last replier that referred to cutting the heavy wire from the alternator. (I thought the dude that said he'd prefer blowing his engine than preventing engine damage was a hoot. He could not get the UIBI working despite help from his electrician dad and despite so many others that had wired a UIBI successfully to the same alternator etc!) I still muse over that site and the amount of effort over non issues - not that I visit often. ]
Ok, so Fiorente won the Melbourne Cup. Yay - look how much money I saved by not betting.
PS - I gave Davefocus some brief connection and wiring info. Later I was so amused seeing your (VolvoCarPC's) reply #130 which was much the same. Geez men, what is this? Agreement? A common understanding?
The main difference was my scaling. A max of 50A capacity is desirable because 50A auto-resetting breakers are common and cheap and 60A relays are also common & cheap.
With the 30A rated Smartcom RCT460 in mind that could be reduced to 30A breakers (and hence ATS breakers instead of the 50A "stud blocks").
But VolvoCarPC's "Calculate (ask for assistance)..." cable and fuse and battery capacity ratings is the key here.
The link must carry the full/max current of the load (easy?) plus the max recharge current of the battery (not so easy!).
So for a 10A or maybe 20A load and a 12AH (and maybe 40AH AGM), 30A may suffice. (I have written elsewhere about how initial high charge currents that cause breaker tripping often reduce and the breakers eventually stop tripping.)
Gotta love battery design eh?
Sorry, English is NOT my mother language and probably I've changed the word order ....
Originally Posted by OldSpark
Well, earlier that day I've promised Davefocus I'll make the posted schematic. I saw that you have already answered him, but promise is promise, so I had to draw it and I did.
Originally Posted by OldSpark
No you can't blame YOUR English for that - that is the fault of English. Your English is very good.
Actually I see it as more my fault - I did not read it in context ie, it is obvious from previous threads (and logic etc) that you meant the charge-light wire. [I often read things "afresh" as if I'm old and forgetful, else had a career assessing "changes" (documents like tech or legal papers, designs, test & evaluation etc).]
And I feel as dumb as an Australian hacker - imagine being dumb enough to think you meant cutting the heavy +12V alternator wire! Ha!
But rest assured, your expression was not the problem. (That's why I wrote my reaction - I thought is was funny, and at my expense - the joke was on me, not on you!)
As to the schematic, a promise is a promise. And you had no way of knowing what I had done behind the scenes (hence why I rarely deal OFF the public forum thread).
Besides, as a wise writer in this thread cited.... "a picture paints a thousand words".
And that schematic conveys to many things not written - eg, ground paths & connections.
BTW - wrt alternator/regulator wiring, I'll usually only mention the battery-voltage "Sense" wire as "S" and the chargeLight wire as "L". (The GND and heavy +12V aka alternator (current/power) output aka B or B+ are implicit as "standard connections". And I used to refer to the IGN+12V wire as "I" but they tend to be rare these days, else implicit.)
I use S & L because they are common international labels. I also use to D+ because it is the common name for the charge-light wire in "single wire" alternators, hence D+/L (their S = Sense wire is internal to the regulator).
Be aware that S & L may not apply to actual alternators/regulators. For example (esp. Ford) - "A" is sense; "I" is charge light (or IGN), and "S" may be Stator.
Check the wiring of your alternator/regulator before any work is performed.
Haha, OK. I'll say it again - English is not my mother language. I didn't get the joke right.