Nightmare Reducing Battery Charging Voltage Corrector

theoldwizard1 wrote:

grizzzman wrote:
I tested my trucks charging system on a 20° F day and it ranged from 14.4 volts at start up and dropped to 14.00 volts later in the day.

I suspect that driving all day long the charging voltage at the vehicle battery will be lower than 14.0V, probably in the 13.4V-13.8V range.

Perhaps in your truck that may be true.

MrWizard wrote:
In a TT tow situation, i don't think a 200% boost is needed
And even if it was used, send voltage to a solar charger controller

THIS IS BY FAR THE BEST SOLUTION !

You should be able to find a PWM 12V solar charge controller for less than $100. Set the output of the boost converter to about 16V.

No worries mate !

As usual, the one thing missing is that the termination of the charger's voltage control loop is not right at the terminals of the battery(ies) being charged.

What I want is a battery charging setup in which whenever I dial in 14.4volts (or whatever volts) using knobs/buttons on the charger ... that's exactly what winds up on the battery(ies) terminals regardless of the size of the wire running between the charger and the battery(ies). Of course this requres a charger also with knobs/buttons to set maximum current so as to not burn up the wiring and not to exceed the current capability of the charger.

The reason for the above is that I'm pretty sure that when battery manufacturers specify charging voltages, the voltage they're referring to is voltage being maintained on the battery terminals - not voltage at the charger. It takes a separate wire feeding back from right on the battery terminals to the control circuits in the charger to do this.

Why didn't they stick the thermistor in the tailpipe? If a fact someone is using a fork lift driver to design a battery maintenance device. The correct place for a thermistor bias is right at the lead of a battery post. The battery by light-years is the most vulnerable and sensitive component of a 12-volt system.

The ONLY way 14.3 constant volts applied to a battery would be appropriate is a following example...

Calcium calcium flooded battery with a battery terminal temperature of @50F That assumption is not rational.

With the tri-paralleled boosters has a current sharing exercise been conducted? At what percentage of load (each)? At say 70%> load a hogging effect may become drama. Voltage adjustment balancing compensation must be stable and repeatable.

NOTE: Thermistor placement allows a connection to a battery lug instead of a battery post.

BOOST BUCK has an inherent liability of the sender remaining valid while back at the towed bank of having the bucker fail and latch.
a fuse rather a breaker must then be incorporated before entry into the booster. I would tend to add capacity redundancy at the bucker end.

14.4 volts for AGM?

14.6 volts for Flooded?

And high voltage transmission is always of great interest. Imagine 70% decrease in transmission current !!!

And muse a novel way to control ON/OFF. Or parallel switching for bi-directional

Abandoning ship --- have to go to work on the Meanwell RSP-1500-15

GordonThree wrote:

...
I've never seen the voltage below 14.1 volts. Typically it wobbles a little between 14.1 and 14.3, that's after driving for hours.
...

Same here, same truck basically. 220Ah alternator.
Never seen less than 14V.

Have been told it can reach 15V+ when temperatures drop. But apparently it uses the temperature probe located in the outside driver's side mirror? What if you have a battery warmer?

Interesting discussion
I have used several of the smaller Drock devices on projects
And have been happy with them

In a tt tow situation, i don't think a 200% boost is needed
And Even if it was used , to send voltage too a solar charger controller
Would a few seconds ramp up, or drop out, have any real effect on charging batteries ?, I really don't think so

Using these as the sole power source for some other device that needed a higher voltage to operate, might result in the device dropping out or turning off,
But that is not what is being discussed..,. Is it ?

theoldwizard1 wrote:

GordonThree wrote:
My new truck ecu seems to prefer operating at 14.3 volts, indicated by two dmms. I haven't measured the voltage at the Bargman however.

If it is truly charging the battery at 14.3V for a long period of time, you will be buying a new battery very soon ! Modern charging systems vary the charging voltage A LOT ! They will charge the starting battery ant a high rate (voltage) for a few minutes after starting and the taper back to a very conservative charging voltage of around 13.4V

13.4V at the battery is probably less than 13.0V at the trailer connector and even lower at the house battery !

I've never seen the voltage below 14.1 volts. Typically it wobbles a little between 14.1 and 14.3, that's after driving for hours.

Everything is in storage right now waiting for spring, I'm curious to test the voltage at the Bargman both just after starting and after hours of running.

I suspect there's some sort of electronic voodoo at work on this electical system. I will test the battery terminal voltage as well. My readings were from a 12v outlet in the cab.

Segue When you start shopping around for theses clever little DC-DC converters, you will stumble across some that have a digital display for setting the voltage and current. Obviously quite handy !



The controls and display are obviously done on the top add-on board that must contain an inexpensive microprocessor. Various testing on YouTube show while this does seem to work correctly under "most" operating conditions, but NOT ALL OPERATING CONDITIONS ! First for high boost voltage (more than 200%) above the input, it can take several seconds to get there ! Second, for output voltage that are lower than the input voltage, you may get a spike applied to the output.

If you have "sensitive" devices connected to one of these, test under multiple conditions !

grizzzman wrote:

MEXICOWANDERER wrote:
Question

They can be paralleled?

With isolated negatives, I assume a digital Delta T digital panel volt gauge is out of the question?

Answer yes.

Grizz, you are being very optimistic about parallel operation ! Like Mex, my gut says one or more of these is going to fail !

I am curious to know exactly what IC they are using.

landyacht318 wrote:
Ok, Say the voltage reaching this soon after engine starting, is 14.8v, and you have it set for 14.4v.

What happens. Magic smoke exit left?

IT does not say it is a buck/boost converter.

True, it does not say "buck/boost" but if you keep the voltage within the input range you should have a reasonable assumption the you should be able to obtain any voltage in the output range.

If you shop eBay, you will see the IDENTICAL board sold by many different vendors, typically with no brand name, at many different price points.

I also found out that is more expensive design, but it appears to be a slightly better design. At least they put a bigger fan and a vented case around it !