What say thou about VSR's and "smart" alternators?

[TWIH]

An Australian website (https://hooshmand.net/dc-dc-charger-vs-vsr-isolator/) discusses dc to dc vs VSR's and says:

"The advantages of a VSR are that you get the potential full advantages of a dual battery system mentioned above, namely, that a) if the car is off and you're powering accessories, you won't drain your cranking battery, and b) if you need (in a pinch) to use your secondary battery to crank the car, you can override with the click of a switch.
The disadvantages of a VSR are that you'll never fully charge your accessories battery, and thus never get full use out of it.
Why is that? Well, it varies by car. But it's for the following reasons: (Begin copied portion of article):

[*][b]Cars don't try to optimise to keep the cranking battery at 100%; you'll only get about 80% out of it.[/b] They simply don't need to, so why should they? A cranking battery will last longer if it's not fully charged, and there's no way you need all the stored power to start the car. So they won't do the same for another battery, either. Firstly, a basic alternator + regulator/rectifier doesn't optimise for stages of charging of a battery (you have to charge them at a different rate as they get more full). Secondly, they don't even try. So you'll only get about 80% out of your secondary battery.

[*][b]Modern cars (~2015 onward) have "smart alternators".[/b] Smart alternators may detect that the cranking battery is at 100% and then turn off the charging system, even if the accessory battery is at less than 100%, and so may [i]never[/i] charge the secondary battery.

[*]If there is [b]voltage drop[/b] between the cranking battery and the second battery (if there is any distance between them, or a thinner gauge cable), then the [b]secondary battery won't be fully charged[/b]."

(End of copied portion of article.)

My Ford Edge has a BMS (battery management system) which apparently is is the dreaded "smart" alternator.  There are complaints on Ford vehicle (mostly F150) forums of batteries going dead due to not getting a full charge, that seems to echo what this article says.  So in that event, is the only real answer the dc to dc charger for these later era vehicles?  

[frater secessus]

If I had a smart alternator and no solar yeah I'd use a DC-DC charger that was designed to work with them. I hear there are add-ons that can trick the smart alt into delivering full voltage -- I don't know if that's bad for the alt. If non-trivial solar is present it will handle the Absorption/Float duties.

I have a VSR installed with a standard alternator. Doesn't get much use as I usually do the "14 days in one spot" thing.

[TWIH]

Couldn't edit the original post, waited too long...

From a 2016 F150 forum, this is what happens when the smart alternator gets lazy: "The alternator is de-clutched when charging is not needed. It will kick back in to recharging the battery when it senses voltage needs increased." Another response was: "As many of you know, the PCM controls the alternator. In fords newer trucks, the alternator actually shuts down to get better MPGs. If you drive short trips like I do, the alternator is NEVER doing it's job. These trucks need a lot of juice....and I am not sure why ford would do this."

If that helps peeps understand what the supposed "gas savings" is from. Several posters report that they just disabled the BMS monitor that's on the positive post of the starting battery. It throws a code but no CEL, and they don't have further low battery problems. Maybe that's all that is needed in order to use a VSR instead of a couple hundred dollar dc to dc charger.

Here's what one poster said about that fix/hack: "A way to bypass the battery saver mode without having to "tune" your truck, as long as your battery and generator are in good operating condition, is to unplug the inductive pickup at the negative battery cable right by the battery. This will allow the alternator to work like normal." (Though my BMS is wired to the positive but no matter...)

I think Ford's idea to implement this on-demand charging crap was to gain minute mpg gains during EPA testing cycle, however in the real world, we're better off with a proper voltage regulated charging system."

[sternwake]

many Automakers in the last 15 years have programmed their voltage regulators to basically reduce all load the alternator can place on the engine when crusiing at light throttle, all in an attempt to increase MPGs.

C.A.F.E laws in North America, basically reward manufacturers for a higher 'fleet average' mpg, so this strategy of sacrificing the battery to eek out a few 0.01% of MPG is all about increasing profit into the executives's pockets.

The goal of such laws is to increase fuel economy, but they backfire, as any tiny amount saved is eaten up by transporting and recycling prematurely failed batteries. But the Executives can buy more shiny stuff they don't need.

I don't like VSR's as surface charge will keep batteries connected, sometimes for long after the charging source has shut off. And with Solar, the voltage will stay above the separation trigger, sending what might be unneeded current to the starter battery when the house battery would be better off receiving all of it.

Also some VSR's choose 12.7v as a separation voltage. My Northstar AGM has a fully charged resting voltage of 13.07v Drag it to 12.7 and it is well less than fully charged.

Set it and forget it with automatic stage 8 owner fellate products, often has negative consequences,
but ignorance is obviously so incredibly blissful.

[TWIH]

So SW (or anyone) what's the best charging system if you are very limited on solar and don't drive a lot? Dc to DC?

[TWIH]

So SW, you said: 
"And with Solar, the voltage will stay above the separation trigger, sending what might be unneeded current to the starter battery when the house battery would be better off receiving all of it."

Therefore would you recommend a simple on-off switch or auto circuit breaker disconnecting the house battery from the vsr so that it's solar only at times?  

Does the surface charge (from having active solar and an isolator/vsr together) mean there's little chance of the vsr allowing the "bulk" charge to occur?  

What I thought was fairly simple is now getting more complex. Maybe vsr's with their cut in and cut off voltage setpoints are a waste? 

Grr, continued issues when all I am trying for is some bulk charging when driving to work and some solar to top the battery off, if conditions allow (and for the last 3 days and tomorrow, conditions suck for solar here in central NC). 

[sternwake]

I derail for ideal.

The VSR will allow bulk charging, no issue with that as it relates to vsr function.
The VSR just will keep batteries in parallel after engine shut down from either surface charge, or if the solar maintains higher voltage.

It can be argued that holding the engine battery at charging voltages after engine shutdown, is a good thing.

DC to Dc chargers exist, because the voltage regulators that the vehicle came with are not allowing higher voltages required to more quickly charge a well depleted additional battery.

A large well depleted battery can often accept much more than the 20 40 or 60 amps of a DC to DC unit is rated to pass, but only when the vehicles voltage regulator allows and holds voltages in the mid 14 range, which few do, and if the cabling between alternator and house battery is fat.

Because so many vehicles today basically sacrifice the battery, keeping it well undercharged for minute improvements in MPG's, then a Dual sense VSR, one whish senses charging voltages On either house or engine battery, is a good thing, when solar is involved. The house battery will charge slightly slower as it has to share the solar wattage with the engine battery. A single sense VSR only parallels the batteries when the engine battery receives charging voltages

My complaints with VSRs and solar presumes a nearly fully charged engine battery which does not need the solar keeping it at elevated voltages, but that is not the case on a vehicle with a MPG tuned voltage regulator.

A simple On/Off or 1/2/Off/Both switch makes Human error likely to occur, at some point.

My system is wired with manual control with manual switches, but I basically eliminated having a second battery closing in on 6 years, and those now switches rarely get moved. When I did have a dedicated house battery, having to remember to turn them accordingly became annoying, and often all batteries simply remained in parallel always, and the so called dedicated engine starting battery would get cycled along with the house. Never any consequence though, other than the engine battery not living as long as it conceivably could.

I think a 40 or higher amp DC to DC charger is a good solution on a lot of vehicles. My main complaint, easily dismissed, is a well depleted battery can accept more than 40 amps, and an alternator can certainly make more than 40 amps, so bulk charging is not as fast as it could perhaps be compared to a voltage regulator seeking allowing 14.7v and fat copper to the depleted house battery.

But it could be inconsequential to another vehicle in different usage, one with a longer drive to work and lots of time for solar to do its thing after getting there.

[TWIH]

So the thing to remember is get a dual-sensing DC to DC (as if there are single-sense ones, dunno').

Now then a simpler and cheaper continuous duty solenoid, that doesn't buck up the voltage, would therefore not be useful in a smart-alternator vehicle? Am I getting this right?

Regulator or engine computer "sees" the paralleled batteries but which voltage does it read, starting, house or a combined one?

Sigh, newbies...