Sterling DC DC battery chargers

[Davey]

Have had TJM Parramatta totally stuff my dual battery system up and won't take any responsibility for installing a projecta 100 isolator even though its charging the aux battery at 12.5V...

Most on here use either the ctek or redarc, I was surfing the web and noticed the sterling DC DC chargers, has anyone used one of these:
http://www.sterling-power-usa.com/library/ProCharge-B IP68 B2B owners manual.pdf

What is appealing is they say to fit as close to the starter battery as possible.

Do I stick with the ctek or go the sterling? Any thoughts?

Cheers
Dave

 

[Old.Tony]

Never heard of the Sterling, it's like placing a bet on Jack Wigginson to win the V8 Supercars next year (you never heard of him? Neither have I).

C-Tek not only has the runs on the board, they wrote the book on how everyone else does it. Redarc is an Australian company that doesn't do TOO badly.

Placing the isolator as close to the battery as possible is good sense, because it will see the battery voltage almost exactly. Use 8G cable to the rear to reduce voltage drop and make sure there's a fuse on both ends.

 

[Davey]

Thanks for the feedback old Tony, is it of concern that the system is activated at > 13.3V?

I believe the c-tek cuts in at 12.7V.

Am I reading to far into it?

 

[Old.Tony]

The higher it cuts in, the more juice your cranker is going to have. That feature is basically there to ensure the cranker gets recharged before doling out power to the auxiliary system. It's sort of a safeguard, but practically it's not vital.

In terms of the precise voltage, when a car is NOT running, its battery will sit "full" at around 12.7+ volts (12.7 for flooded, 12.85 for Gel, 12.8 for AGM). Any voltage chosen from 12.7 and higher means the starter battery is full. When you turn on your ignition, chances are your cranker is going to sit slightly lower than 12.7V (so even the C-Tek will be 'OFF'). You turn the key for (say) 5 seconds and 500A * 5/3600 = 0.7Ah of your battery capacity disappears. It will take the alternator (at idle, assuming no lights on and around 10A available) 4 minutes and 12 seconds to fill it back up.

It is true that a discharged battery, when placed directly in parallel with the cranker (ignore the alternator and the isolator for the moment) will drag the voltage of the cranker down while the amps flow into the discharged battery. The alternator (actually, the regulator) usually responds by ramping the voltage up a little more to keep it at the optimum level (usually 14.1 to 14.7V). Part of this is the reason why they trigger on at a higher voltage, but will allow a fair drop before turning off again - it prevents cycling. Nothing to do with men in black spandex on pedal-powered machines, either.

The C-Tek however is NOT just an isolator, it's a charger. The Projecta unit they installed is just an isolator that switches on when the alternator is able to bring the voltage up enough. The two units are quite different.

At best, an isolator will charge the battery at a rate consistent with the main battery voltage + available current + loss from the cable between the systems. It's ALWAYS going to be less than your alternator is capable of, so your auxiliary battery is ALWAYS going to have less charge than your cranker.

A DC-DC charger on the other hand will perform some magic with the power, boosting it where needed, to provide the best possible charge for your auxiliary battery.

Hope that's not too murky to follow!

 

[Tappet]

I was just about to post but Old Tony is all over it

 

[TigerST]

Only thing to add to Old tony is Smart alts as they sit around 11.9v when car isn't running. and about 12.5 when it is.

 

[Malicious]

I have found that some obd2 dongles report the wrong voltages , I have one that read correct, one that reads low and one that reads high. Currently developing more d40 things, so only reliable voltage monitor is a good stand alone meter

 

[Davey]

Thanks for the responses gents, out of curiosity, is there any official nissan documentation on the variable voltage alternators?

I'm starting to lean more towards c-tek due to the cut in voltage.

Having had an orbital in my previous patrol which would run an engel 40L for 3 days; now I've a much similar optima yellow top d34 in the navara which is unable to run a waeco CFX35 overnight is quite annoying, then to be told by the so called experts that you'd be lucky to get a night from the optima is downright ludicrous...

 

[Old.Tony]

I have found that some obd2 dongles report the wrong voltages , I have one that read correct, one that reads low and one that reads high. Currently developing more d40 things, so only reliable voltage monitor is a good stand alone meter

I thought there was a PID for the voltage from the ECU itself, not just the adapter. PID 42 should contain the answer in two bytes, multiply the first byte by 256 then add the second byte and divide the result by 1000.

 

[Old.Tony]

Thanks for the responses gents, out of curiosity, is there any official nissan documentation on the variable voltage alternators?

I'm starting to lean more towards c-tek due to the cut in voltage.

Having had an orbital in my previous patrol which would run an engel 40L for 3 days; now I've a much similar optima yellow top d34 in the navara which is unable to run a waeco CFX35 overnight is quite annoying, then to be told by the so called experts that you'd be lucky to get a night from the optima is downright ludicrous...

The D34 is a 55Ah battery. Fully charged, you stand to safely use 80% or 44Ah. The CFX35 claims to draw an average of 0.77V per hour (which is remarkable for the Danfoss compressor) and 54W on 240V (which is about 4.5A on 12V and much closer to what I'd expect). I suspect their claimed draw is for a fridge that isn't opened.

Let's assume though that the average draw during the night IS at the claimed figure ... 0.77A for (say) 10 hours is just under 8A, so your battery should manage a night without any drama at all. On a typical run - where it draws its full power for 50% of the time - that's 4.5A over 12H for each day - your battery lasts for 2*44/4.5 = about 20 hours.

In practice, it's a chest fridge so it will keep the cold rather than lose it every time you open the door, so cycle times are greatly reduced. Your D34 should be able to power the fridge for at least 2 days on average, perhaps less in summer, and more in winter.

I admit I'm not a big fan of the Danfoss compressor. I had one in the Waeco 140L fridge in the previous caravan and while its capacity was fantastic, and its ability to cool was great, it would suck the life out of the battery, forcing me to add a second solar panel to the roof and use BOTH panels exclusively for the fridge battery - and even then, on cloudy days, there were times when I'd have to start the genny.

 

[Malicious]

I thought there was a PID for the voltage from the ECU itself, not just the adapter. PID 42 should contain the answer in two bytes, multiply the first byte by 256 then add the second byte and divide the result by 1000.

That is correct but strange things happen with some of the software looks at the adapter voltage rather than the correct PID out of the box

 

[Old.Tony]

That is correct but strange things happen with some of the software looks at the adapter voltage rather than the correct PID out of the box

That's nuts. What happened to making things standard? Oh well, glad I have a multimeter!

 

[TigerST]

I have found that some obd2 dongles report the wrong voltages , I have one that read correct, one that reads low and one that reads high. Currently developing more d40 things, so only reliable voltage monitor is a good stand alone meter

Thanks for the responses gents, out of curiosity, is there any official nissan documentation on the variable voltage alternators?

I'm starting to lean more towards c-tek due to the cut in voltage.

Having had an orbital in my previous patrol which would run an engel 40L for 3 days; now I've a much similar optima yellow top d34 in the navara which is unable to run a waeco CFX35 overnight is quite annoying, then to be told by the so called experts that you'd be lucky to get a night from the optima is downright ludicrous...

stuff the c-trk needing a relay to work. Redark would be the way to go.

That's nuts. What happened to making things standard? Oh well, glad I have a multimeter!

Mine reads from the ECU and I've used a Multimenter it's the same as the reader.

 

[Malicious]

That's good , have found several software that gives the first option of adapter voltage, so for some not so technical people it isn't noticed and the voltages can vary , something to watch

 

[TigerST]

Yeah..... I try to double check everything. Biggest problem I think people will find is how low the volts drop when crusing..... with engine running I've seen mine drop as low as 12.4volts.

 

[Malicious]

Maybe still need the green wire mod or a diode to keep it up a little higher

 

[TigerST]

Diode over priced bit of junk. I aviod touching things on my engine like that. The Smart Alt works fine and I find most people do the green wire mod because everyone else is doing it. There are many other ways around it without upsetting nissan. Redark and c-trk have come up with ideas so you can charge your 2nd battery to full. And those not running a dc-dc charger are only trickle chargeing there battery anyway.

 

[Malicious]

Diodes are cheap as chips like 10c each but when enclosed into a fuse housing they tend to go through the roof, there will be one on the market soon with a PTC auto resetting fuse for around $20, still allows the smart alternator do it's thing but will up the voltage approx 0.6v which can be useful even with a DC to DC charger,

 

[TigerST]

.6 is still way below the normal 14v. The D40 are not the 1st truck to come out with Smart Alt. I think the biggest problem with new tec and lasy people not been stuffed to work out how to use their car.... Just after a quick fix. Sometime been costly. DPF is a great example of this. Buying delete pipes then tricking the system. When a High frow DPF and burn off now and then will do the job fine.. Befriend your truck and it will love you.

 

[Malicious]

Very true , but even .6v can increase the efficiency of a boost regulator, having seen some that cutout at 12.7v so 12.4v plus .6v will bring it up just enough to keep the charger working