Alternator to Battery Charger....

[boywonder]

Originally Posted by E350

What is actually going on with the Sterling Power unit and why is it so special?

I'm curious about this as well.........

In a typical setup with a house battery and starting battery at different states of charge, I'm assuming that each battery will draw some percentage of the total alternator current based on their input resistance, with batteries that are discharged having a lower resistance than batteries that are at a higher charge state.

If it's truly charging the house batteries with more current than what the house batteries would see just connected to the alternater, that would imply that the unit is boosting voltage for the house batts, which would require additional current from the alternator since TINSTAAFL.

Edit: I just checked out the owners manual for the unit......it's basically is a smart multi-stage charger that additionally boosts the charging voltage to the house batts when alternator current is sufficient and the chassis battery is over 13VDC.....sort of an alternator "optimizer".

[haywoodphotomaccom]

Just took a drive around watching how the unit works after I drained down the house and chassis battery a bit overnight.

The system takes a few minutes to calculate charge curves after start up. About 3 minutes each time.

On start up I saw 120 amp max coming from the Alt for the first few minutes at idle. It quickly settled to about 60amps. 40 to the chassis and 20 to the house. When the Boost mode was hit at the three minute mark the house went up to 35-40 amps and the voltage up to 14.5 or so.

Once I started driving all the numbers went up at the Alt was putting out more Amps. Just off idle it comes up a good amount.

While driving I saw the amps go up from 30 or so up to 70 to the chassis battery after turning on the headlights and heater.

It is interesting watching all the values go up and down based on driving conditions and things turned on and off in the vehicle.

DOM is domestic battery on the readout.

[haywoodphotomaccom]

So far so good with this product. Took a week long trip to the mountains over New Years and watched how the unit worked under various conditions. I had very little solar contributing to the batteries this trip based on where I was parked most of the time. I took a few short trips around the mountain each day sight seeing and watched the values the Alt was putting out to the house and chassis battery. When the House battery was low I consistatly saw the charger putting out 2-3 times the amps to the house battery when in Boost Mode.

I have yet to see the 4-5 times charge rate the literature states is possible but I'll keep watching.

[Scalf77]

Brent,
I want to thank you for posting about this product, it is always nice to get some real feedback on some of these products. I do appreciate you taking time to do this. It is encouraging to see that you are getting better performance out of set up then before. I suspect that the 4 to 5 times the charge rate is a best case condition, and may never be met by your set up. First the charge rate will be predicated by your level of discharge and size of your battery bank. Second, you may and probably are still limited by your current alternator. In this case I am assuming you have the standard V10 115 or 135 amp alternator. The amount of current that this unit will provide will still be limited by the output of the original alternator. In fact the maximum that it provides will be somewhat less because of the conversion factors involved in the charge algorithm.
I will try to provide my interpretation of the unit (based off of reading the documentation, as I do not have one). First, this unit is really a couple of devices in one, and could possibly simplify some (especially new) installations. First, it does away with the need for a separator or isolator, as this has a split diode isolator built in. The second part of the unit a more like an advanced regulator for the alternator, this allows it to perform much like a real 3 stage battery charger Bulk, Absorption, and Float cycles. This is the real plus to the unit. So you may wonder how it actually get more charge out your alternator and provide all these wonderful features. In the simplest terms it make your alternator work harder, by pulling down the alternator output voltage, this makes the alternator work much harder, just like when you turn on your headlights, megawatt stereo, air-condition, etc. It also has some nice options like battery temperature feedback, remote sensing, and a remote control that lets you monitor the various currents and voltages.
Pros

• • Eliminates the need of a separator or isolator
  • Eliminates the concern of battery technology mismatches, it provides different voltages and current to the house (domestic) and the van starting batteries
  • Turns alternator into 3 stage battery charger with optional temperature compensation, and remote sensing.
  • Multiple battery type settings for house (domestic)
  • Does not affect PCM
  • Maximizes power provided by alternator

Cons

• • Makes your current alternator work harder, most likely producing higher temps and earlier life failure. They do provide an optional alternator temp sensor, and also have a built in software timer on their boost mode.
  • While this will improve the charging characteristics of any alternator it will not make up for a undersized alternator. If you are having issues when running high current devices.
  

I am sure there are other things that I missed.
E350, if you already have an option for a second alternator then you could just use their alternator regulators since you could isolate the starting system with the second alternator and get pretty much the same thing.


-greg