3 output Victron charger

[KenMcCulloch]

Shortly installing a Victron 12v charger to look after a starter battery and 250Ah domestic bank. The manual gives no guidance on what the three outputs might do so I wonder if it makes any difference which goes to what, and whether it matters that I’m only using 2 of the three. I have seen arrangements where a third charger output is connected in parallel to the main battery bank, others where a short cable bridges the unused output and the one connected to the main battery, and yet others where the third output is not connected to anything at all. Which is best, I wonder?

 

[pvb]

If the manual doesn't give specific advice to the contrary, you'll be fine just using 2 of the 3 outputs.

 

[Wilfred123]

I have recently installed a victron 3 output charger (30amp) to charge 2 banks and I had the same questions having moved from a sterling charger where a link to the unused terminal was required.
I sent the question to the victron technical support who confirmed that there it makes no difference which terminals are used and there is no need to link any unused terminal.
I assume that although the charger has 3 outputs, that are not independent and each bank will receive the same charge regardless of the condition of the bank.

 

[<152587>]

You cannot generalise on these devices. For instance you will probably find one of the outputs is 3-4 amp start battery maintenance out put. You need to specify the actual model for a definitive answer to this enquiry. Many different models with their own spec. Victron manuals are usually very comprehensive, surprising.

 

[pvb]

You need to specify the actual model for a definitive answer to this enquiry.

I gave the definitive answer in post 2.

 

[Wilfred123]

Ok, the model I was referring to was a Blue Power IP22 30amp

 

[PaulRainbow]

You cannot generalise on these devices. For instance you will probably find one of the outputs is 3-4 amp start battery maintenance out put. You need to specify the actual model for a definitive answer to this enquiry. Many different models with their own spec. Victron manuals are usually very comprehensive, surprising.

No he won't.

 

[RichardS]

Ok, the model I was referring to was a Blue Power IP22 30amp

The manual is available online https://www.victronenergy.com/uploa...ry-Charger-(1)-(3)-IP22-EN-NL-FR-DE-ES-SE.pdf so the answer, as PVB says, will definitely be in there.

Richard

 

[VicS]

You cannot generalise on these devices. For instance you will probably find one of the outputs is 3-4 amp start battery maintenance out put. You need to specify the actual model for a definitive answer to this enquiry. Many different models with their own spec. Victron manuals are usually very comprehensive, surprising.

I think this will be made clear in the manual. The Op says there is no guidance as to what the three output might do. Therefore it is reasonable to conclude that one is not a limited output for topping up a starter battery

 

[KenMcCulloch]

Thanks guys, that’s pretty much what I thought, just acknowledging the limits of my own knowledge and understanding, really. I have read the manual carefully and it is silent on the questions I asked. I assume then that the current to the starter battery should rapidly fall to zero, more or less, even when the domestic bank is being stuffed with energy at whatever current the charger delivers at a given stage. Is that correct? Needless to say I have recycled the old 1-2-both battery switch so the two banks are entirely isolated from one another on the +ve side.

 

[PaulRainbow]

Thanks guys, that’s pretty much what I thought, just acknowledging the limits of my own knowledge and understanding, really. I have read the manual carefully and it is silent on the questions I asked. I assume then that the current to the starter battery should rapidly fall to zero, more or less, even when the domestic bank is being stuffed with energy at whatever current the charger delivers at a given stage. Is that correct? Needless to say I have recycled the old 1-2-both battery switch so the two banks are entirely isolated from one another on the +ve side.

Very basic explanation....

The charger will make power available to all of the batteries, at the same voltage. The batteries will take what they need/can. It's all they can eat, self service, not force feeding. So the engine battery will quickly reduce its intake to a few amps or even less, whilst the domestic bank could still be chomping into 20 amps.

 

[BabaYaga]

I assume then that the current to the starter battery should rapidly fall to zero, more or less, even when the domestic bank is being stuffed with energy at whatever current the charger delivers at a given stage.

In my understanding, the risk of over charging the starter battery in this situation has to do with voltage level, not current (which the battery will regulate by itself).
The voltage level can be harmful in the short term by being too high for the battery type in question or in the long term by staying at the correct level for too long, that is by not dropping to a safer float level when the battery is fully charged.
In my view the latter problem could be at hand when someone is living on a boat connected to shore power for an extended period. Permanent or recurring loads (fridge) on the domestic bank could prevent the charger from dropping the voltage to float level, which will be especially harmful to the unloaded starter battery, as it could see absorption voltages for much too long.

 

[Plevier]

BabaYaga is correct.
If your regime is such that the charger frequently runs in its 14.4V mode to recharge your domestics, the starter battery will be overcharged and suffer water loss and increased corrosion if always connected to the charger. (Assuming it is just for starting and is not discharged by any other duties.) It will only want an occasional refresh charge to top up what it gets from engine recharge.

 

[PaulRainbow]

In my view the latter problem could be at hand when someone is living on a boat connected to shore power for an extended period. Permanent or recurring loads (fridge) on the domestic bank could prevent the charger from dropping the voltage to float level, which will be especially harmful to the unloaded starter battery, as it could see absorption voltages for much too long.

This is incorrect. If the boat is connected to shore power for a time all batteries will charge and go into float. A decent charger will then maintain the batteries whilst acting as a power supply for the varying loads.

For instance, my charger currently sits at 13.6v and 3.3a, the battery monitor reports that the batteries are at 13.6v and are taking a maintenance current of 0.2a. The 3.1a difference is the loads from my laptop/tv etc.

 

[GrahamM376]

BabaYaga is correct.
If your regime is such that the charger frequently runs in its 14.4V mode to recharge your domestics, the starter battery will be overcharged and suffer water loss and increased corrosion if always connected to the charger. (Assuming it is just for starting and is not discharged by any other duties.) It will only want an occasional refresh charge to top up what it gets from engine recharge.

For the reasons you state, my shore power charger only supplies the domestics but I can switch the engine battery in if I want for the occasional top-up. It's also excluded from the main solar as the Victron controller often outputs 14.8v for the Trojans. 2 x cheaper single output chargers each configured for battery type being charged is a better bet than most multi output chargers which just split the same charge regime through diodes.

 

[PaulRainbow]

BabaYaga is correct.

He is incorrect, because he talks about liveaboards in marinas, i previously explained why this is wrong.

If your regime is such that the charger frequently runs in its 14.4V mode to recharge your domestics, the starter battery will be overcharged and suffer water loss and increased corrosion if always connected to the charger. (Assuming it is just for starting and is not discharged by any other duties.) It will only want an occasional refresh charge to top up what it gets from engine recharge.

I agree with this, but still disagree that it applies to boats on long term shorepower, unless they have poor chargers. The charger should maintain the batteries at low charge regimes whilst acting as a power supply for the loads, so it won't keep charging at 14.x volts.

More likely would be boats with solar arrays. During the evening/night power will be used and the domestic bank depleted. In the morning the solar controller will be outputting 14.x volts to charge the domestic bank and the engine battery will be exposed to this voltage.

The same could be said to apply to boats that do a lot of motoring or motor sailing. With the engine running the alternator will be charging at 14.x volts to charge the domestics. Mobo engine batteries will generally be subjected to 14.4v for hours on end.

Whilst the theory that this will damage batteries appears sound, the conditions have existed for decades and we don't see lots of premature engine battery failures.

 

[BabaYaga]

A decent charger will then maintain the batteries whilst acting as a power supply for the varying loads.

I think far from all charger are 'decent' in this respect. Also, the size of domestic bank could influence the behaviour of the charger, as it reacts to voltage levels. A given load should cause a larger voltage level drop on a smaller bank.

 

[PaulRainbow]

I think far from all charger are 'decent' in this respect. Also, the size of domestic bank could influence the behaviour of the charger, as it reacts to voltage levels. A given load should cause a larger voltage level drop on a smaller bank.

Size of battery bank would be irrelevant, subject to the charger being a good one. Mine reacts instantly to varying loads, there is no voltage drop at the batteries, as the loads are being supplied by the charger.

Fair point that not all chargers are decent/good.

 

[BabaYaga]

So what is your estimate of the proportion good/decent chargers vs. poor in this respect in actual use today?

 

[GrahamM376]

The same could be said to apply to boats that do a lot of motoring or motor sailing. With the engine running the alternator will be charging at 14.x volts to charge the domestics. Mobo engine batteries will generally be subjected to 14.4v for hours on end.

Mobos, yachts and cars without any "add-on" boosters all charge the same, bog standard alternator peaking between 14.2 & 14.4v.

Multi stage shore power chargers are different in that many work to timed charge levels rather than being smart. Beats me why some weekend sailors spend vast sums on multi output chargers connected 24/7, when a small solar panel backed up with a cheap Halfords charger would do the job on the odd occasion it's needed.