Battery Combiner

[Tomtom39]

Afternoon"
I have a battery combiner on my beneteau and it means my starter battery always receives first charge when the engine is switched on!
It went on the blink the other day so I have replaced with a like for like switch but this has worked for a period of 3 weeks and now the same problem of the switch never switching to the domestics and charging only the starting battery.
The batteries are all new and reach a good charge of 14.2 volts (gel batteries)
Can I presume that this switch is used to acid batteries and because my domestic does not drop below 13.1 it never switches across or is this not the problem,
Currently to overcome the problem I have removed the combiner and slaved the wires together!
Can someone assist. I have checked the small alternator relays which are also connected to the combiner and all seems fine
Regards
Nick

[Bash]

First thing to check is to see whether there's a voltage drop at the battery terminals. It could be that the combiner never senses the voltage it's looking for because of such a drop.

[Tomtom39]

Well I have a volt meter on my domestic side which read 12.8 which I thought would indicate that it should kick across

[goboatingnow]

what make of combiner is it.

Dave

[Tomtom39]

Well had one previously that came with the boat a beneteau from 2003 and it was silver and looked very automotive in it's appearance
I have now purchased one that is much smarter but probably the same product in a smarter case. Not sure of the brand but purchased from a marine store.

[goboatingnow]

Victron/Cyrix make a lot of common combiners, there good in my experience.

[CharlieJ]

The combiner is probably not seeing a high enough threshold voltage to combine. Blue Sea's Model 7610 Product Documents for SI-Series Automatic Charging Relay - Blue Sea Systems requires 13.6VDC for 30 seconds or 13.0VDC for 2 minutes before it will combine.

If you can provide the model number, I can get more specific.

Hope this helps.
Charlie

[Mark Johnson]

I ran the dockside charger, alternator, and solar array... (even wind at one point), directly to the "house bank" alone, and the combiner is between the house bank and engine cranking battery. This way my "spill over charge", which I have the least control over, goes to my much less expensive battery. (the engine battery). Since the engine battery is mostly full all of the time, and my self regulating alternator maintains over 14v when running, having the engine battery floated at 14.2 all day when motoring and the batteries therefore combined, seemed a bit excessive, so I put a switch on the blue Sea Combiner to disable the combine function when I choose to. (This is described in the unit's instruction book).

Now I crank the engine and after an hour of running, switch out the combiner, disconnecting the charge from the now, well charged engine battery.

In reality this extra precaution may not be an issue, as I have forgotten to switch them out before, leaving the combiner on, and my little $69 engine battery seams to last about 3 years, no matter what.

Having all charge sources go to the house bank only, and letting the combiner take care of the engine battery, is a very simple way to wire ones system, and has been successful for us for 15 years.

Mark

[Tomtom39]

Does the combiner need to be of a certain amps? I have 400 amp hours of 12 volt batteries, I am only asking as when I used to turn the ignition key I would hear the combiner click but now since not working this is not the case and wonder if it is not of the right rating!

[goboatingnow]

I actually now , that the best way with multiple charging sources, typical of cruising boats , the best way is to connect all the charge sources to teh domestic bank and size everything acordingly. Then use an Echo charge to maintain the starter battery.

Dave

[CharlieJ]

TomTom39-The combiner has to be rated to the charge sources. 100 amp alternator requires an auto charge regulator (combiner) rated for 100 A. Add 40 amps of solar power, the combiner must be rated for 140 A.

I agree with the other posters, tie all of your charging sources to the house bank and let the engine start battery ride on its coattails.

Charlie

[US1Fountain]

Originally Posted by Tomtom39

Does the combiner need to be of a certain amps? I have 400 amp hours of 12 volt batteries, I am only asking as when I used to turn the ignition key I would hear the combiner click but now since not working this is not the case and wonder if it is not of the right rating!

Curious as to why a combiner would instantly combine when the ignition key is turned on, unless the combiner is wired to always parallel the battery banks when key turned. Blue Seas M-L series are designed to parallel banks for additional power if needed.

Thinking that the combiners contact noise would be less noticeable when disengaging, vs when engaging.

Have read where under certain conditions where a combiner can cycle in/out and wear out prematurely.

Is the new replacement combiner actually a combiner, and not just a short duty relay used to parallel batteries for starting? Beings it is physically smaller in size.

[barnakiel]

Why should it combine to a battery that is fully charged in the first place?

Why should a battery at 13.1 ever need charging?

b.

[Tomtom39]

Well I think gel batteries can be charged harder hence the volts being up at 14.2

[barnakiel]

Originally Posted by Tomtom39

Well I think gel batteries can be charged harder hence the volts being up at 14.2

Much depends on what you mean by harder.

Acids can often be charged at 14.4. Charging gels this hard is not a good idea.

b.