Jump to content

West Marine Battery Combiner


Recommended Posts

Hi,

 

I noticed today that my West Marine Battery Combiner (model 308280) was switching on and off about every 60 seconds.

 

The switching on and off was happening on 13.3v (combine) and strangely seemed to be disconnecting at 14.1v. Thats odd.

 

I confirmed this with my Victron Smart Solar monitor and the battery voltage graph.

 

The engine was not running and the only charging source at this point was solar.

 

I cant explain why this might be happen, even more explainable was that, at the time I had the ON/OFF switch in the photo set to OFF - so it shouldn't have been doing any combining.

 

I have yet to do a complete drawing. But anyone able to shed light on this?

 

20190901_114141.jpg

Screenshot_20190921-083852.jpg

Link to post
Share on other sites

Here is a very helpful reply from Ann-Marie at Yandina (who designed and made the combiners for West Marine). It may be helpful for others in future so reposting here:

 

1.  What is the point of the external ON/OFF switch between the two poles of the VSR?
The on/off override switch on Yandina and West Marine brand Combiners can be used to force the Combiner ON  which connects the batteries together for emergency starting if the starting battery is low.  It will act like jumper cable and after a few minutes allow the engine to be started.
The on/off override switch can also be used to force the Combiner to stay OFF.  This may be used if a trickle charger or small solar charger is not putting out enough current to support the 1/8 amp that the Combiner uses when ON.
Yandina Combiners draw no current when OFF.

2.  Why might the VSR be cycling through a process of switch on (13.3v) and off again at (14.1v) after an engine start
The Combiner makes sure that the alternator does not get overloaded.  When the increased charging load gets connected it can exceed the capacity for which an alternator was designed and cause excessive heating.  Under these conditions the Combiner will cycle off for a percentage of the time to allow the alternator to cool.  As the level of charge improves the current gets less so the heating is less until eventually the Combiner stops providing cooling cycles.

3.  Can multiple alternators with different profiles charge the same batteries?
The primary purpose of battery charging profiles is to protect the battery from damaging voltages and to force the charge in as fast as possible.  A generic alternator such as found in automobiles has a "safe" profile that will not harm any batteries.  But by limiting voltage it is also limiting the amount of current it can get into the battery so charging will take longer.  The voltage at which lead acid batteries start to form bubbles in the electrolyte is about 14.2 volts.  Although bubbles are advantageous in liquid electrolytes, they can displace electrolyte in a gel battery which may not get re-absorbed and reduce battery capacity.  During the bulk stage of battery charging, the alternator can safely put out a higher voltage than 14.2 and force more current into the battery because there is voltage drop in the battery circuits and the voltage across the electrolytes will be much less than the alternator voltage.  As that charge voltage increases the extra "forcing" voltage has to be reduced to protect the battery from over-voltage and this is what is happening in a multi stage regulator.  The profile can be tailored to match the individual characteristics for maximum charging rate. 

Using both your alternators is quite OK.  It will mean that the total output of both alternators will less than the total of their individual capacities because subsequent to the bulk stage the regulators will be reducing output due to the higher voltage being introduced by the other alternator.  Some references characterize this as the alternators "fighting" each other which is a misleading term.  In fact they are both charging in later stages but charge rates are reduced by the effect of the other alternator.  Depending on alternator sizes and batteries, adding a "generic" alternator to a "smart" alternator of equal size may not decrease charging time by 50% because the smart alternator will be able to put out a higher voltage which will make the dumb alternator think the battery is already charged and put out less current.  Only during the early "bulk" stage will both alternators be putting out maximum.

 

4. Why would it still click even after the engine and alternators were shutdown?

It is common to hear a Combiner cycling for quite some time after charging has finished since the artificially high voltage left over from charging will remain on the batteries especially if there is any other charging source.  Don't forget that the Combiners are bi-directional.  With no load at all on the batteries that residual high voltage can take many hours to dissipate.  It represents no additional battery capacity since it can't support any current.  If one of the batteries is low, the combiner will try to charge it since it still has more than 13 volts but the sudden load will immediately drop the voltage to 12.8 and the Combiner drops out in about 20 seconds.  With the load removed the voltage on the fully charged battery will float back up above 13 volts and the cycle will repeat.

 

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...