3 output Victron charger

[PaulRainbow]

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

Noidea. Most production boats built in the last 20 years are fitted with reasonable chargers. The liveaboard sailors you refer to also tend to be more aware of the chargers they use.

So what is your estimate of the amount of engine start batteries that are failing prematurely because they are connected to dual output mains chargers, decent or otherwise ?

 

[PaulRainbow]

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.

Everyone is different, but a decent charger that will act as a power supply is usually a good idea, even if only weekending.

There are other options of course. A good charger with power pack capabilities just connected to the domestic bank gives plenty of power in the marina and the small solar panel could keep the engine battery topped up. Or even fit a second mains charger with a low output maintenance charge.

I big solar array connected to the domestics with a small panel for the engine might be a good solution.

It really depends on the boat and the pattern of power usage.

 

[pvb]

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.

And, of course, most boat starter batteries aren't significantly different from car batteries, which are subjected to highish voltage for hours on end. Many modern cars run at quite high voltages - around 14.8v isn't uncommon.

 

[Plevier]

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.

That is not true during bulk/absorption phases. If the engine battery starts off nearly fully charged as it commonly would, while the domestics need a full charge cycle, the engine battery is indeed being "force fed" at up to 14.4V and will take more current than is optimal at its state of charge. Damage will not be immediate but over a period if this happens repeatedly it will suffer increased corrosion and water loss.

 

[pvb]

That is not true during bulk/absorption phases. If the engine battery starts off nearly fully charged as it commonly would, while the domestics need a full charge cycle, the engine battery is indeed being "force fed" at up to 14.4V and will take more current than is optimal at its state of charge. Damage will not be immediate but over a period if this happens repeatedly it will suffer increased corrosion and water loss.

I was looking at the battery voltage readout on my car today. It was routinely registering 14.9-15.1v, so should I be worried about my car battery? I'd expect it to last 5-7 years.

 

[Plevier]

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



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.

You are assuming that the charger, once a cycle has been completed, is smart enough not to revert to charge mode if it sees an increase in load. I think some are prone to do that. (I am not pointing at Victron which is a top make and I would hope is smarter than that, but you appeared to be generalising.)

Re 14.4V in vehicles or mobos, I would suggest it's not that often that boats of "amateur" size (can't think of a better word, I'm sure you will know what I mean) run like this for more than a few hours. A while ago coming back from Holland I was stuck with engine for about 28 hours as there was absolutely nil wind and my batteries did get bloody hot and definitely deteriorated. That was at about 14.2V - standard alternator on a D1-30. I'm sure big boats that do run constantly do not stay up at that level all the time, they will have more sophisticated control.

 

[PaulRainbow]

You are assuming that the charger, once a cycle has been completed, is smart enough not to revert to charge mode if it sees an increase in load. I think some are prone to do that. (I am not pointing at Victron which is a top make and I would hope is smarter than that, but you appeared to be generalising.)

I make no such assumptions, i speak from observing chargers. Sterling don't do it, neither do Victron, not that i have seen anyway. I'm generalising a little, perhaps, but no more than anyone else and i have repeatedly referred to "decent" chargers. Cheap and nasty chargers may give different results.

Claims were made that live aboard boats connected to shore power would damage engine batteries, i believe this to be incorrect. I was onboard all last Winter and again this Winter, connected to shore power by a Sterling Pro Charge Ultra, i have never caught it force feeding my engine battery, i have never found the battery hot. It is a sealed calcium car battery of 700CCA and the "magic eye" is still full. It has also just spent the Summer connected to 260w of solar power, via the VSR, again no signs of any problems and i do have decent onboard monitoring.

Some of the bigger boats may well be fitted with smart alternators, at least the newer ones.

 

[RIBW]

Dear all,
I thought I'd ask the manufacturer a question. The interchange follows.
[I am only an observer in this exchange, so no flak please. Personally, I will be fitting each battery bank with a separate charger.]

Me: I have read the manual but I am confused about how to charge two separate banks of batteries using two of the 3 outputs. If the battery on one output (e.g. the engine starter battery) achieves full charge, what is applied to the battery (say, a 20% discharged 'house' battery) ?

Victron: It is like with Communicating Vessels, the battery with the lowest SOC will get the most current .

Me: So if I read your answer together with the 'ABS' paragraph in the manual, a fully charged battery could have the ABS voltage applied for up to 8 hours after it is fully charged. That is, all outputs have the same voltage and the fully charged battery will not be floated until the discharged batteries have been fully charged?

Victron: correct when one battery is fully charged the absorption voltage will* only go to float when both batteries has filled up, but this will be no problem , because the current is low .

Cheers
Bob

 

[matthewriches]

The 2 mainstream brands I deal with both Mastervolt and Victron will not cook a battery unless the battery goes into meltdown and actually asks for the power, in which case the charger will happily cook it.

 

[PaulRainbow]

The 2 mainstream brands I deal with both Mastervolt and Victron will not cook a battery unless the battery goes into meltdown and actually asks for the power, in which case the charger will happily cook it.

A few people on here seem to think they have discovered perpetual energy, whereby you can boil something by simply applying a voltage to it, with no current. 3rd World will be well pleased

 

[matthewriches]

Good o. I'll watch my kWh meter sit idle then.

A few people on here seem to think they have discovered perpetual energy, whereby you can boil something by simply applying a voltage to it, with no current. 3rd World will be well pleased

 

[BabaYaga]

Claims were made that live aboard boats connected to shore power would damage engine batteries, i believe this to be incorrect.

I think I made a fairly modest 'claim' in that direction, using words like 'there is a risk' and 'could be at hand'. Very far from saying that damage would happen in every case or even in a majority of cases.

Your approach

This is incorrect.

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

is a bit different.

Each to his own.

 

[Plevier]

A few people on here seem to think they have discovered perpetual energy, whereby you can boil something by simply applying a voltage to it, with no current. 3rd World will be well pleased

Who's said that? I certainly haven't. If you apply 14.4V to a fully charged battery you will get significant current, which results in electrolysis and heating. Basic fact.

 

[PaulRainbow]

I think I made a fairly modest 'claim' in that direction, using words like 'there is a risk' and 'could be at hand'. Very far from saying that damage would happen in every case or even in a majority of cases.

You said "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."

I said that was incorrect.

I still believe that to be the case. Victron agree with me. My Sterling charger agrees with me.

Whilst the theory you present may sound plausible, all evidence that i have seen is to the contrary. Consider all of the boats with dual output mains chargers, split charge engine charging and solar controllers charging both banks, where are all of the prematurely failed starter batteries ?

 

[PaulRainbow]

Who's said that? I certainly haven't. If you apply 14.4V to a fully charged battery you will get significant current, which results in electrolysis and heating. Basic fact.

My engine has not been started for weeks. It has been connected to the Sterling charger since late Sept, when the solar yield became to low to run the boat unaided. I have just lifted the cover on the engine battery, it is notably cold to the touch.

I'm perfectly happy to force the mains charger to restart in whatever mode you choose, for however long you think might be useful and to monitor current into the engine battery and measure its temperature. But it won't be the first time i've tested/monitored what's going on, last time i had several amps going into a partially depleted domestic bank, with a fraction of an amp at the engine battery, no excess heat.

 

[noelex]

If you are buying a new charger an option worth considering is a seperate small charger for the start bank. Companies such as Victron, Mastervolt and many others make small intelligent chargers. These are not expensive in the smaller sizes. The two battery banks will be regulated independently, which is slightly better. The whole output of the larger charger will be devoted to the house bank. It also allows for the use of different battery chemistry for the start and house bank. If the main charger fails, by swapping a couple of leads over, the start battery charger can be changed to charge the house bank so it adds some redundancy.

It also keeps the two battery banks completly seperate. So if one charger fails and damages the battery the engine can still be started on the other bank.

 

[Plevier]

My engine has not been started for weeks. It has been connected to the Sterling charger since late Sept, when the solar yield became to low to run the boat unaided. I have just lifted the cover on the engine battery, it is notably cold to the touch.

I'm perfectly happy to force the mains charger to restart in whatever mode you choose, for however long you think might be useful and to monitor current into the engine battery and measure its temperature. But it won't be the first time i've tested/monitored what's going on, last time i had several amps going into a partially depleted domestic bank, with a fraction of an amp at the engine battery, no excess heat.

But presumably your Sterling charger has not been putting out 14.4V constantly since September, only for the first few hours.
Try 14.4V continuously for 4 months and see what happens.

 

[lw395]

I was looking at the battery voltage readout on my car today. It was routinely registering 14.9-15.1v, so should I be worried about my car battery? I'd expect it to last 5-7 years.

5 to 7 years of say 12,000 miles a year. That's 300 or 400 hours per year on charge. Or about 4% duty cycle.
Of those hours, for many of them, it will actually need charging, so the hours over overcharge in its lifetime are much less than the 2000 hours of its life it might be at 15V.
The problem with yachts is with solar and shore power you can have a much higher duty cycle. If your system is putting in a couple of hours of overcharge twice a day, thousands of hours can rack up.

Also the criteria for a car battery being 'dead' often don't include serious loss of capacity. So long as it will crank the car for 10s in a temperate climate, we are happy.

 

[PaulRainbow]

Also the criteria for a car battery being 'dead' often don't include serious loss of capacity. So long as it will crank the car for 10s in a temperate climate, we are happy.

What more do you want your engine start battery to do ?

 

[PaulRainbow]

But presumably your Sterling charger has not been putting out 14.4V constantly since September, only for the first few hours.[/quote[

That's what i've been saying all along, see post #14

Try 14.4V continuously for 4 months and see what happens.

I don't have any equipment stupid enough to allow that.