Steve queried: > Without knowing the people or the product I'm instinctively a little > cautious about any web page that says why such systems don't work, then > tries to sell me something to help overcome the problem. I've personally > had good experience with both Sterling and Adverc BMSs in split charge > diode systems, and haven't seen excessive voltage on the starter battery > circuit. Having said that I don't recall seeing any alternator that can > throw out 14.4V without a BMS fitted so even with a zero loss split > charge system (such as the one being sold here) it would be useful.
Bruce's summary from Chris's page of why you don't need an alternator controller with the latest technology engines/alternators was spot on. The only thing he didn't mention was that modern vehicle batteries are more tolerant of higher voltages these days also. So, the combination of higher output voltage alternators and voltage tolerant (gassing resistant) batteries means that you can punch more charge into those batteries more quickly. In my experience you cannot fault Chris's technical explanations explaining the background to the electrical scene and he's not doing it just to get you to buy his products either. I've used his Smartgauge, Smartbank and heavy duty split charge relay on my French boat (I only had the one alternator on that engine because it was also fitted with a TravelPower) and it worked brilliantly. Excellent indication of Domestic battery bank state of charge which never got out of sync with the batteries, super, intelligent control of the split charging. Chris doesn't claim, nor is it intended to be, that a SmartGauge/Smartbank system replaces an alternator controller IF YOU HAVE AN OLDER, LOWER VOLTAGE, ALTERNATOR. If you have such a beast then you should ideally fit a controller as well. What he is saying is that if you have a modern, high-output V alternator that you will be wasting your money buying an alternator regulator as the alternator and external regulator will regulate at about the same voltage anyway. > > My immediate interest is that I now have a 24V/260A Niehoff alternator > but rarely get more than 160A from it (no split charge diode or BMS) and > am contemplating putting in an Adverc in given past good experiences. It > does have adjustable output voltage (0.2V steps as I recall but not sure > that the upper limit is as high as 28.8V) so might take a look at that > first (one I have an engine in the boat again ;-) ) Exactly, your alternator is limiting its current output because it soon sees a rising voltage and its own regulator controls the output V and, hence, the current is controlled as a function of battery voltage and internal resistance. If you put an Adverc on the system it could improve the output and, of course, it will intelligently over-ride the internal regulator to give you a recurring boost charge every so often. >From memory alternators are not supposed to be run at full output for any >length of time. I seem to recall reading max 75% of current output as the max >continuous but can't confirm that. Roger
