Originally Posted by
drivesafe
Hi Greg and not sure what you mean but here is some info that may be of use to you
With more than 4,000 D3s and D4s equipped with my DBS. Both here and around the world, they are well and truely tested and here is a comparison with other types of DBS.
this is also for other D3 and D4 owners who are looking at fitting some form of dual battery system to their Discos, but do not fully understand how different systems actually work and which give the best all round performance.
For those still trying to sort out fact from advertising fiction, the following should help.
The first problem most people have when trying to determine what is the best system for their needs, is the amount of misinformation that is used to market many of the products used to set up a dual battery system.
A perfect example of deliberate misinformation is the advertising hype used to sell DC/DC devices. It is not just misinformation but also the lack of full disclosure that results in people ending up with an over priced but under performing dual battery system.
There are plenty of sellers claiming that an alternator will not fully charge a battery but then claim that a DC/DC device "CAN" fully charge a battery, and it is this type of claim, that makes it sound like you need a DC/DC device because it can do what an alternator "ALLEGEDLY" can not do.
While the claim that a DC/DC device "CAN" fully charge a battery, is correct, but unless the potential buyer is aware of what is actually required to fully charge a LOW 12v battery, they then are lead to believe that a DC/DC device will do a batter job than an alternator can.
Reality is that the only time alternators can not fully charge batteries, is when the vehicle is not driven long enough to allow the alternator to do what it is designed to do.
This is where the advertising misinformation comes in.
The same short driving that prevents an alternator from from fully charging a battery will have at least the same effect when charging with a DC/DC device and in many cases when charging a low battery with a DC/DC, the battery will actually ends up being in a lower state of charge at the end of a short drive than what it would have been had it been charge by the alternator.
Here is a real world example of what the misinformation can lead to.
If you have an Optima D34, a 55Ah auxiliary battery, in a low state of charge, a combination of the high operating voltage and the high current from the D3 and D4 alternator, you can charge the Optima from 0% SoC ( 10.5v ) to well over 95% in under an hours drive.
Using a 40 amp DC/DC device, it will take around 90 minutes to achieve that same level of charge and using a 20 amp DC/DC device will take close to 3 hours, to do what your alternator can do in under an hour.
Furthermore, with a DC/DC setup, you have 45Ah available to power your accessories, but with a Traxide DBS, you have 90Ah available. NOTE this extra usable battery capacity is available with out the need to add another battery, there is no additional weight or lose of space, as would be needed to get the same amount of usable battery capacity when using a DC/DC device or any other VSR type isolator.
So you need to do your homework before outlaying your hard earned cash.
Here are some other comparisons between Traxide DBS performance and that of other types of DBS setups, when used in a D3 or D4.
With a Traxide setup, you also have the advantage of Back-Discharging, which allows the Auxiliary Battery to help to keep your Cranking Battery in a higher state of charge. Something no other dual battery system does.
The Load Sharing operation of a Traxide Isolator means you halve the work load of your batteries. Both while charging and while discharging. And because of the lower currents required, there is an additional benefit of helping to extend the operating lifespan of both batteries.
The new generation SC80 and DT90 isolators also have Reverse-Charging, allowing you to charge and maintain both batteries with a battery charger or solar, no matter which battery you connect the charging source to, something you can't do with a DC/DC device.
The Sharing of both the load and the charging is also particularly useful if you are free camping with a camper trailer or caravan. Allowing for much longer stays between charges.