Most boats or specialised vehicles have multi-battery bank installations. This type of installation can cause problems if the battery chemistries in the installation are very different from each other (i.e. gel and open lead acid etc), or the battery voltages may be different i.e. you may have a 12V charger and require 24V for 1 battery bank (or vice versa). Maybe even one battery may be 20 ft away from the charger resulting in massive voltage drops. A good example of this is a GEL battery bank for your starter battery bank and an Open Lead Acid battery bank for a secondary / auxiliary battery system and a 24V lead acid sealed for the bow thruster. This causes a problem for most multiple standard output battery chargers as they can only be set to 1 battery chemistry type and 1 voltage. The usual thing is to set the charger to the lower voltage chemistry which, in turn, reduces the potential performance of the charge on the other battery bank with different chemistries plus damaging the battery bank. For example, you could have a GEL battery requiring 14.1V and 13.5V float but also an open lead acid bank requiring 14.8V charger and 13.5V float. Obviously, the 2 charge cycles cannot be achieved at the GEL setting, the open lead acid battery bank will not charge at a high enough voltage and would end up sulphating the battery bank. This would result in premature destruction of the bank and a warranty failure on that bank as it was not charged at it’s recommended charging curve. If the 14.8V range was used to keep the open lead acid batteries happy then the premature destruction of the AGM battery bank would be assured as they would dry up. The warranty for these batteries would then be forfeited for the same reason as explained before.
There are 2 key different technical ways to do this:
1) Switch each output on for a period of time and convert that output to a different chemistry setting and scan through the outputs. This method is simple but, in effect, is a poor solution because for example, if you have a 60A charger then you can only switch on 1 output during a time frame this supplies reduced power to full batteries but starves the empty batteries of the time they need to harvest the full charger power potential during that time span. The result is, for example, a large domestic battery bank and an engine start and bow thruster bank would result in the 60A only effectively being a 20A to the main domestic battery bank in that scanning time frame.
2) 3 individually adjustable outputs, this is, by far, the best and only totally effective way of achieving this, however, in effect, you have to add an expensive output stage controller to each output resulting in a massive price rise (over 2-3 times the cost of the standard unit). Its very unlikely that an OEM boat / vehicle builder would fit this type of product as standard due to the high initial purchase cost of such a unit.
The Sterling solution
The new Sterling module approaches this from the same angle as adding an output stage to each output. We effectively place in a box a voltage booster and the output stage from a digital charger. This means that the new device can be added to any of the output terminals of our Pro Charge Ultra (or most other competitor companies multiple output charger). This will allow the main 3 (or more) output charger to be set at the lower chemistry voltage for the likes of Gel, then, by adding the new Sterling Multi chemistry module to one of the outputs (must be connected to an output of a current limiting charger and cannot be connected direct to a battery (see fig 1 and fig 2). One can adjust that output to a totally different charging chemistry profile. The output voltage and charging curves are independent of the charger’s input voltage. This enables a totally different chemistry to be selected, this gives all the advantages of the multi chemistry charger without the huge extra cost, and can be simply retro fitted to any multi output battery charger (within the limitations of the product).