Gday Les and ALL,
Thanks for the input and too bad you weren't on the Syncro Tour for an A-B comparison because some of us were in despair due to running out of battery power to keep our upright 12vdc compressor fridges cold. Being away from 240v power (for recharging purposes) for more than 7 days, many campers struggled due to inadequate daily recharging, mostly via the alternator. Hence this issue arising post Tour.
From what I've seen and read, adding a house battery means that some type of controller also has to be installed to manage the 2 battery system. Hence, as you say, your van has an electronic isolator by Piranha, mine has one by GSL. They both do pretty much the same job. I expect the other syncros had something similar too, but many of us still struggled. Seems to me though that adding an isolator is just one part of the solution.
John Figgis explained to me his experience, that before doing any other power generating mods, the foremost solution to securing an efficient, adequate and speedy source of energy back into the batteries is to fit a "power" or "smart" alternator regulator. This replaces the stock regulator in the 90 Amp Bosch alternator.
By design, I understand a typical standard charging system controlled by a standard regulator is limited to gradually recharging batteries to a maximum of around 60-70% capacity, priority given first to the starter battery. This contrasts with a "smart" regulator which achieves in excess of 90% and does so more speedily. So 20-30% plus is a huge gain when struggling for every bit of energy. And experts say that to maximise the life of batteries, generally speaking, keep them fully charged as much as possible and try to avoid discharging them below about 50%. So do your sums, with the standard regulator, that means if you want your batteries to last, then a maximum discharge down to 50% up to a maximum charge of 70% means you only have a working range of 20% of your battery capacity to run your electric equipment because of the charging limits set by that regulator. Whereas the smart regulator achieves 40% plus working range, which represents at least 100% better than the standard regulator. That's a big improvement.
John Figgis fitted a smart regulator a number of years ago to his syncro, together with a 250 AH battery. I understand he had no problems generating enough power into his batteries and hence, had a cold fridge for the duration of the Syncro Tour and beyond. On balance, I understand he chose this method of power generation, preferring its added simplicity and efficiency over solar and generator etc alternatives.
I'm presently looking into what smart regulators are presently available at the moment. I know they are not cheap, but then
what is? So far, the model "Next Step 2", made in Seattle, USA by "Ample Power", seems to be top of the tree. It's available for purchase in Australia, in Sydney and possibly Queensland. You may need a competent auto electrician to fit it.
In conclusion, can I recommend an excellent publication to anyone needing to gain a working knowledge of many things to do with Campervan electrics, by an Australian, for Australian conditions, as follows
Publication is titled "Motorhome Electrics & Caravans Too!" by Collyn Rivers.
Visit Collyn's website for more info at www.caravanandmotorhomebooks.com . Highly recommended, it's easy to read and very handy as a reference book for all manner of campervan electrics and equipment issues.
Hope this helps. Cheers.
Ken
--- In Syncro_T3_Australia@yahoogroups.com, "Les Harris" <leslieharris@...> wrote:
>
> I have used 3-way refrigeration in the past, with limited success. As has been noted, as the temperature goes up, the efficiency goes down. It was better than nothing, but not by a lot.
>
> About twenty years ago, I bit the bullet and bought an Engel. The difference was dramatic. Turn it up a tiddle too high, and everything freezes rock solid !! And that is almost regardless of the ambient. And that was the earlier Engel; the new ones are even more efficient in terms of power consumption for cooling obtained.
>
> I have always run sizeable auxiliary batteries and, even when stopped for several days in mid summer, have rarely had to run the engine to top them up. I carry a digital voltmeter so it is easy to get an accurate reading of the auxiliaries and charge accordingly.
>
> The most important piece of gear is a good quality battery isolator. I have used Sure in the past and now have the top Piranha solid state system. It is of the "intelligent" variety and manages the charge to the main and aux. battery or batteries. This signal wire which goes to the dash and is connected to the charge light is routed through the isolator. It reads the main battery and gives it full charge until it reaches about 13.5 volts, then begins to direct part of the charge to the aux bank. If the main falls to 12.5 during this operation, it stops supplying the aux bank and directs full charge to the main. When both aux and main are up to full charge (14+) the isolator drops the charge rate, as in a normal alternator system. It is also capable of distinguishing the number and capacity of batteries in the aux bank and charges accordingly.
>
> Now that solar panels have dropped in price by an unbelievable amount, it is no longer worth a king's ransom to add an array on the roof. Even on overcast days, it still puts a significant amount into the aux bank.
>
> Any compressor fridge will outperform any absorption unit, and the Engel is extremely efficient. And, on top of that and as Phill has pointed out, adding a 12V fan to blow through the condenser will improve it even further for very little extra current draw.
>
> Les
>
--- In Syncro_T3_Australia@yahoogroups.com, "Les Harris" <leslieharris@...> wrote:
>
> I have used 3-way refrigeration in the past, with limited success. As has been noted, as the temperature goes up, the efficiency goes down. It was better than nothing, but not by a lot.
>
> About twenty years ago, I bit the bullet and bought an Engel. The difference was dramatic. Turn it up a tiddle too high, and everything freezes rock solid !! And that is almost regardless of the ambient. And that was the earlier Engel; the new ones are even more efficient in terms of power consumption for cooling obtained.
>
> I have always run sizeable auxiliary batteries and, even when stopped for several days in mid summer, have rarely had to run the engine to top them up. I carry a digital voltmeter so it is easy to get an accurate reading of the auxiliaries and charge accordingly.
>
> The most important piece of gear is a good quality battery isolator. I have used Sure in the past and now have the top Piranha solid state system. It is of the "intelligent" variety and manages the charge to the main and aux. battery or batteries. This signal wire which goes to the dash and is connected to the charge light is routed through the isolator. It reads the main battery and gives it full charge until it reaches about 13.5 volts, then begins to direct part of the charge to the aux bank. If the main falls to 12.5 during this operation, it stops supplying the aux bank and directs full charge to the main. When both aux and main are up to full charge (14+) the isolator drops the charge rate, as in a normal alternator system. It is also capable of distinguishing the number and capacity of batteries in the aux bank and charges accordingly.
>
> Now that solar panels have dropped in price by an unbelievable amount, it is no longer worth a king's ransom to add an array on the roof. Even on overcast days, it still puts a significant amount into the aux bank.
>
> Any compressor fridge will outperform any absorption unit, and the Engel is extremely efficient. And, on top of that and as Phill has pointed out, adding a 12V fan to blow through the condenser will improve it even further for very little extra current draw.
>
> Les
>