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Connecting a solar charge controller to a battery bank


TimCr

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Hi. Please can you advise?  I am looking to install a couple of solar panels to charge my battery bank. I have 3 leisure batteries and 1 starter. I want to charge both the leisure batteries and the starter. Can I do this from one positive and one neutral output from the charge controller or do I need two; one output to the leisure and one to the starter?  

Edited by TimCr
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14 minutes ago, TimCr said:

Hi. Please can you advise?  I am looking to install a couple of solar panels to charge my battery bank. I have 3 leisure batteries and 1 starter. I want to charge both the leisure batteries and the starter. Can I do this from one positive and one neutral output from the charge controller or do I need two; one output to the leisure and one to the starter?  

Yes if you also fit a VSR but to be sure we need t know more about your charging sources.

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Thanks for the reply, Tony. What’s a VSR? Currently the batteries are charged by two alternators on the beta 38. Edit. I just googled VSR and found that it splits the charge. I don’t think I have this as I have 2 alternators. So I guess that some charge controllers can split the charge. Otherwise I could have 2 sets of panels with 2 charge controllers; one to charge the starter and one to charge the leisure 

Edited by TimCr
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35 minutes ago, TimCr said:

Hi. Please can you advise?  I am looking to install a couple of solar panels to charge my battery bank. I have 3 leisure batteries and 1 starter. I want to charge both the leisure batteries and the starter. Can I do this from one positive and one neutral output from the charge controller or do I need two; one output to the leisure and one to the starter?  

If you connect one charger output to both leisure and start batteries, then you are in fact connecting those batteries together making one bigger battery. Which is not what you want! You need to have some sort of charge splitter device such as a VSR. But then again, if the starter battery is in good condition it should last many months without any need to be recharged.

2 minutes ago, TimCr said:

What’s a VSR? Currently the batteries are charged by two alternators on the beta 38. 

Voltage Sensitive Relay. It is wired so as to connect the sets of batteries together when the system voltage is raised to a charging voltage, ie when some source of charging is active (solar, shore powered battery charger, alternator etc).

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14 minutes ago, nicknorman said:

If you connect one charger output to both leisure and start batteries, then you are in fact connecting those batteries together making one bigger battery. Which is not what you want! You need to have some sort of charge splitter device such as a VSR. But then again, if the starter battery is in good condition it should last many months without any need to be recharged.

Funny you should mention that. I replaced the starter battery 3 months ago but my automatic bilge pump was playing up and emptied it last week ?

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Just now, TimCr said:

Funny you should mention that. I replaced the starter battery 3 months ago but my automatic bilge pump was playing up and emptied it last week ?

Most people run their bilge pumps from the domestic batteries. Bigger capacity, and if the bilge pump runs excessively and flattens the battery then you can still start the engine.

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31 minutes ago, nicknorman said:
34 minutes ago, TimCr said:

 

Voltage Sensitive Relay. It is wired so as to connect the sets of batteries together when the system voltage is raised to a charging voltage, ie when some source of charging is active (solar, shore powered battery charger, alternator etc).

I have a charger for when I connect to shoreline power so I guess that must have a VSR. I wonder if it would be possible to feed the solar charge through that?

14 minutes ago, nicknorman said:

Most people run their bilge pumps from the domestic batteries. Bigger capacity, and if the bilge pump runs excessively and flattens the battery then you can still start the engine.

That makes more sense. Especially as starter batteries don’t like to be run flat and leisure batteries tolerate this better. I wondered why that wasn’t the case when I discovered what had rinsed my starter battery. But then I think Liverpool Boats did funny things when it was built in 2004 ?

Edited by TimCr
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So, upon further research, my options are to either have have one charge controller with a VSR in the line or 2 charge controllers from 2 separate solar arrays or a single dual battery solar charge controller from a single solar array. Am I over complicating this?

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5 minutes ago, TimCr said:

So, upon further research, my options are to either have have one charge controller with a VSR in the line or 2 charge controllers from 2 separate solar arrays or a single dual battery solar charge controller from a single solar array. Am I over complicating this?

I have a battery charger that has 3 outputs, so will charge 3 different battery banks. I could guess that there are solar charge controllers that can do the same.

 

Having said that, I have a 1 - 2 - Off switch that allows me to direct the charge from both my charger and solar controller to either my Lithium Battery Bank, (1), or to my Lead Acid Battery Bank, (2).

 

I think my alternator charges the Lead Acid Bank and Starter Battery via a Voltage Sensitive Relay.

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8 hours ago, TimCr said:

So, upon further research, my options are to either have have one charge controller with a VSR in the line or 2 charge controllers from 2 separate solar arrays or a single dual battery solar charge controller from a single solar array. Am I over complicating this?

Yes you are! ? If the engine battery is only used to start and run the engine, then it doesn't need to be continuously trickle charged and can be left for weeks if need be. My boats first engine start battery lasted nine years with its only charging being from the engine alternator when the engine was run. In winter it could be many weeks between starts and it always span fast and fired up first turn of the key. This was a Beta engine with twin alternators similar to yours. Just have the house batteries connected to your single solar controller. Don't bother with a VSR. VSR's are used mostly to charge both house and engine batteries from a single alternator to keep them electrically separate and ensure that the start battery always has enough charge to start the engine, even if the house batteries are flat. You have two alternators, so you already have a separation between engine and house circuits.  As has already been mentioned, have the bilge pump run off the house batts, not the engine batt.

Jen

Edited by Jen-in-Wellies
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Just fit the VSR and be done with it.

I have two alternators, a single outlet charger and solar.

The solar and charger are wired to the domestics. 

There is a VSR that is switched from the domestics.

This means that the solar and charger will charge the start battery as well.

The other positive is that when  charging from the alternators during the first phase of charging I get an extra 20amps going into the domestics from the starter alternator.

Its a simple system that has worked well for the last couple of years.

Edited by Loddon
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30 minutes ago, Loddon said:

Just fit the VSR and be done with it.

I have two alternators, a single outlet charger and solar.

The solar and charger are wired to the domestics. 

There is a VSR that is switched from the domestics.

This means that the solar and charger will charge the start battery as well.

The other positive is that when  charging from the alternators during the first phase of charging I get an extra 20amps going into the domestics from the starter alternator.

Its a simple system that has worked well for the last couple of years.

Agreed but under certain conditions you might (not will) get an apparent charging fault indication that worries some  people until they understand that there is no fault and why it happens - one charge warning light glowing/pulsing and the buzzer burbling/chirping with well charged batteries.

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24 minutes ago, Tony Brooks said:

the buzzer burbling/chirping with well charged batteries.

Once I hear a faint buzz I know the batteries are charged, it took a lot of double checking to realise there was no fault ;)

 

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2 hours ago, Loddon said:

Once I hear a faint buzz I know the batteries are charged, it took a lot of double checking to realise there was no fault ;)

 

I call that an advantage but I get questions from people who have solar charging and have left the boat for a week or so in high summer and then get very worried when they go back aboard and start the engine so for others on the forum its always worth mentioning it can happen. It would probably stop the moment a hefty electrical load was turned on.

Edited by Tony Brooks
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2 hours ago, Jen-in-Wellies said:

Yes you are! ? If the engine battery is only used to start and run the engine, then it doesn't need to be continuously trickle charged and can be left for weeks if need be. 

Unfortunately my automatic bilge pump is wired to the starter battery before the cutoff switches and my battery was rinsed by the pump when it developed a fault so for peace of mind I prefer the starter battery to be charged also

Edited by TimCr
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21 minutes ago, TimCr said:

 

Unfortunately my automatic bilge pump is wired to the starter battery before the cutoff switches and my battery was rinsed by the pump when it developed a fault so for peace of mind I prefer the starter battery to be charged also

Moving the bilge pump connections to the house batteries would be much cheaper, quicker and easier than installing a VSR, or any of the other ways of trickle charging the start batt. If the start battery were to suddenly die, a pair of jump leads mean you can start the engine from the house batteries till it can be replaced. I've had to do that once in thirteen years.

Jen

Edited by Jen-in-Wellies
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36 minutes ago, Jen-in-Wellies said:

Moving the bilge pump connections to the house batteries would be much cheaper, quicker and easier than installing a VSR, or any of the other ways of trickle charging the start batt. If the start battery were to suddenly die, a pair of jump leads mean you can start the engine from the house batteries till it can be replaced. I've had to do that once in thirteen years.

Jen

And also, since the domestic bank is a lot bigger than a single starter battery, your bilge pump will run for much longer. Which is comforting if you think your hull may spring a leak. (And if you don't think your hull might spring a leak, why are you leaving a bilge pump on anyway?)

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2 hours ago, David Mack said:

And if you don't think your hull might spring a leak, why are you leaving a bilge pump on anyway?

The bilge pump is connected to the battery before the isolator switch so the only way to turn it off is to disconnect the battery. Many boats have this arrangement apparently. Although being connected to the starter rather than the leisure battery appears to be uncommon 

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7 minutes ago, TimCr said:

The bilge pump is connected to the battery before the isolator switch so the only way to turn it off is to disconnect the battery. Many boats have this arrangement apparently. Although being connected to the starter rather than the leisure battery appears to be uncommon 

There should at least be a fuse in the wire to the bilge pump, which you could pull out without disconnecting the battery. But I'd be fitting a separate switch in the wire as well.

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47 minutes ago, TimCr said:

The bilge pump is connected to the battery before the isolator switch so the only way to turn it off is to disconnect the battery. Many boats have this arrangement apparently. Although being connected to the starter rather than the leisure battery appears to be uncommon 

I bet many boats do not. At least as @David Mack says the BSS requires a fuse or circuit breaker and normally there is a bilge pump switch as well. Often one that lets you control the pump manually or allows the float switch to do it. I would suggets a fairly minor rewire.

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2 hours ago, Tony Brooks said:

I bet many boats do not. At least as @David Mack says the BSS requires a fuse or circuit breaker and normally there is a bilge pump switch as well. Often one that lets you control the pump manually or allows the float switch to do it. I would suggets a fairly minor rewire.

Yep. I have a bilge pump switch which allows me to turn the pump on as required.  This also has a circuit breaker on the consumer board. But my bilge pump is wired from 2 sources, one of which appears to be directly from the starter battery and can be activated by a float. The float was being deceived by some stern gland grease that had gotten into the bilge causing the pump to run continuously and drain the battery. I have learned the lesson of keeping a tidy stern gland and bilge and the pump is now working as it should. Back to topic, I think I know what is required to connect my solar panels to the battery bank. I’m going to get a dual charge controller. Happy days. 

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A single MPPT controller like this one will charge both your domestic battery bank and your starting battery.  The main charge goes to the domestic batteries with a trickle charge going to the starter battery, which is all it needs.   I have one on my boat and it has breathed new life into the 9 year old batteries which came with the boat when I bought it 3 years ago.

 

(edited for typos)

Edited by malp
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43 minutes ago, malp said:

A single MPPT controller like this one will charge both your domestic battery bank and your starting battery.  The main charge goes to the domestic batteries with a trickle charge going to the starter battery, which is all it needs.   I have one on my boat and it has breathed new life into the 9 year old batteries which came with the boat when I bought it 3 years ago.

 

(edited for typos)

Yeah. I think that’s the sort of solution I’m going for. Thanks ? 

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2 hours ago, TimCr said:

The float was being deceived by some stern gland grease that had gotten into the bilge causing the pump to run continuously and drain the battery. I have learned the lesson of keeping a tidy stern gland and bilge and the pump is now working as it should. Back to topic, I think I know what is required to connect my solar panels to the battery bank. I’m going to get a dual charge controller. Happy days. 

A dual output charge controller will only keep a start battery alive while the sun is shining. A typical bilge pump may be taking 4A, which is 48Ahr over a 12 hour night, with no charge going in from the solar panels. Longer and more in winter. Enough to seriously deplete a single start battery, especially if it is older and has low charge capacity. Better to prevent the bilge pump coming on when not needed and have it connected to the house battery bank, where there is more charge available.

Jen

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