Charging Multiple Battery Banks

[nmit5903]

Have yet to bite the bullet with a combiner and watching posts with interest.

I have 2 banks I am concerned with (happy to trickle charge 3rd gen set from a small portable solar charger), the starter and house, each have their own alternators.

House is charged via a Smartcharger/inverter and solar panel which can at present be manually switched between the starter and house banks.

My goal is to remove the manual switch of the solar and automate so that the starter remains in good shape when the boat is left on the mooring for weeks at a time.

Had a look at the Proisocharge which seems to be more of alternator charger distribution thing - which is not what I need

I am still inclined towards the combiner although the echocharger option is still hovering in the background.

[gspeak]

Originally Posted by nmit5903

Have yet to bite the bullet with a combiner and watching posts with interest.

I have 2 banks I am concerned with (happy to trickle charge 3rd gen set from a small portable solar charger), the starter and house, each have their own alternators.

House is charged via a Smartcharger/inverter and solar panel which can at present be manually switched between the starter and house banks.

My goal is to remove the manual switch of the solar and automate so that the starter remains in good shape when the boat is left on the mooring for weeks at a time.

Had a look at the Proisocharge which seems to be more of alternator charger distribution thing - which is not what I need

I am still inclined towards the combiner although the echocharger option is still hovering in the background.

This is the diagram of my proposed system that I sent to Andina for comment/approval before I bought the Combiners. It is how I now have my system hooked up & everything is working as hoped. No switching & all charging sources charge all batteries, & then isolate when there is no charging source available.

Maybe others would like to comment on the appropriateness of my setup.

HTH

Dave

[nmit5903]

Many thanks. Plan is very helpful. I have to work around a few legacy issues however back to thinking the combiner is the way to go. I don't have multi outlet smart charger. My single outlet 40A charger inverter works very well but only charges the house bank. Starter charged from a small alternator. The combiner will I think give me the flexibility to charge the house bank and starter from the solar panels when on the mooring.

[nmit5903]

Suggestion by two electricians at the Sydney Boat Show is why not fit a VSR? Simple, cheap and drown at need a combiner or duo charger?

[Andina Marie]

But a Combiner is a VSR, or actually the VSR is a copy of the Combiner.

[nmit5903]

Nothing other than a VSR in the combiner?. Why call it a combiner and not just a VSR for the non techo's. now I feel like a dill.

What is the remote on in the Yandina?

[Andina Marie]

Why call it a combiner and not just a VSR for the non techo's.

Why call it a VSR when it emulates a Combiner?

I invented the Combiner in 1992-3. I was working with West Marine to find a better solution to battery isolation than the diode isolators with their traditional problems.
Having created the product I needed a name so the Combiner name was selected to be the OPPOSITE of an Isolator.

We sold them under the West Marine brand name for about 10 years until West Marine ceased putting their brand name on "in house" products.

Yes it is more than a simple VSR. There are hysteresis and timing functions as well as an auto-reset thermal shut down. A bonus is it can limit the load on the alternator to a safe lever as opposed to an isolator that charges the lowest battery first and then adds the other batteries in parallel.
In particular our Combiner draws virtually zero current when not Combining.
It can also be used as a voltage regulator to limit the destination battery to 14.2 volts.

The remote connection can do three functions. It can be used to force the Combiner ON, it can be used to disable the Combiner and it can be configured to provide a remote display.

[nmit5903]

Many thanks. So some questions:

When starting the engine ( I have an old 109hp 6 cylinder Ford Bowman diesel) ehich i garher can deaw up to 650a on starting) draw - that obviously would not trigger the combiner?

In remote on position - does the combiner effectively give the engine access to the house bank for emergency start situations - this is needed for vessels on survey

[nmit5903]

Just put specs on - sorry about typos - but presume you get my drift

[sailinglegend]

Originally Posted by Andina Marie

.....It can also be used as a voltage regulator to limit the destination battery to 14.2 volts.....

Andina can you please clarify this statement as your product literature is not that clear. By "limit the destination battery to 14.2 volts" does that mean when the destination battery gets to 14.2v the combiner disconnects, or does it regulate the destination battery and hold it at 14.2 volts. If it disconnects then the destination battery will never get a proper charge if you use this feature.

[Andina Marie]

When starting the engine ( I have an old 109hp 6 cylinder Ford Bowman diesel) ehich i garher can deaw up to 650a on starting) draw - that obviously would not trigger the combiner?

Correct, in fact the Combiner monitors voltage so high current load is not detected.

In remote on position - does the combiner effectively give the engine access to the house bank for emergency start situations - this is needed for vessels on survey

No, the Combiner does not "effectively" supply enough current for emergency starting. In fact the Combiner has a low voltage drop-out that will typically be triggered during starting to protect the Combiner and loads on the "other" battery. The Combiner can be used to help starting to some extent. You would use it like you use jumper cables. Using the remote control you would turn it on and wait 5 minutes for it to transfer charge from the "good" house battery to the "discharged" starting battery but this is very iffy and there are better alternatives.

Andina can you please clarify this statement as your product literature is not that clear. By "limit the destination battery to 14.2 volts" does that mean when the destination battery gets to 14.2v the combiner disconnects, or does it regulate the destination battery and hold it at 14.2 volts. If it disconnects then the destination battery will never get a proper charge if you use this feature.

It does regulate, it does not just disconnect. It is what they used to call a "bang - bang" regulator, used on automobiles for over 70 years in the days before power transistors. When the destination battery gets to 14.21 volts the Combiner stops charging it, when it drops to 14.19 charging is resumed so the destination battery remains at 14.2 volts.
It is true that this will make charging the last few amp-hours a little slower but the battery will still get a full charge. Fully charged voltage is around 12.8 volts so at 14.2 on the terminals, significant current will be flowing to charge it. If it is severely discharged the bulk of the charging will have taken place BEFORE it gets to 14.2. At 14.2 it already has most of its charge, many charging sources go no higher than 14.2. We only recommend using this feature on older alternators or chargers that were intended for lead acid batteries and can get as high as 15.6 which can damage modern sealed batteries. It is also a protection from shore power charges with an automatic equalization schedule.

[nmit5903]

Andina - ok to put a combiner between a 6V bank in series giving 12v with two 12v starter bank in parallel? Sparky says no as they charge at different rates?

[Maine Sail]

Originally Posted by nmit5903

Andina - ok to put a combiner between a 6V bank in series giving 12v with two 12v starter bank in parallel? Sparky says no as they charge at different rates?

They are both 12V banks. You need a sparky that has a basic understanding of charging systems...

[Andina Marie]

Originally Posted by nmit5903

Andina - ok to put a combiner between a 6V bank in series giving 12v with two 12v starter bank in parallel? Sparky says no as they charge at different rates?

This is a joke right?
A 12 volt battery is actually 6 two volt batteries in series.
A 6 volt battery is actually 3 two volt batteries in series so two 6 volt batteries in series is a total of 6 two volt batteries in series.
There is no electrical difference, it is only a mechanical difference.
Of course the two 6 volt batteries must be matched as closely as possible. The cells in the 12 volt battery are automatically matched as closely as possible.

Perhaps Sparky was assuming that the amp-hour capacity of the 2x6 volt batteries is different than the amp-hour capacity of a 12 volt battery. In this case the charging rates will be different but the current will divide between them exactly in proportion to their capacity. Sparky and many others assume that if you charge two batteries in parallel that 50% of the current goes to each battery but nothing could be further from the facts.

You CANNOT increase the % of charge on one battery in parallel with another at a "faster" rate. If it was charging faster it would have to be at a higher voltage but this is impossible if they are connected together.

[nmit5903]

I wish it were a joke. Started out with something that I thought was quite simple and there seem to be at least two views on almost every aspect.

Digressing - found to my amazement today that my two 80W solar panels are actually drawing current (3.7A each) when in the shade and that neither is fitted with a diode to stop that - effect being the array is only ever working at or near half capacity as one panel or other is generally shaded. Regulator useless as well but that's another issue.

Considerations are summarised:

AGM v flooded cell in different banks - not a problem
One battery discharging to charge the other - untrue
6v bank in series/parallel on house bank v 2 12v on starter - think Ok?
Combiner may assist but won't allow enough current to start engine from house bank if starter bank flat - true

If I have understood and different config of 6v and 12v banks both giving 12v is ok - Combiner together with a switch to enable emergency start from the house bank should do the job.