Charging for 780AH @ 24V House Bank

[botanybay]

Originally Posted by Pelagic

I also found this new Victron Quattro 24/5000/120amp
combination Invertor/charger which seems to do it all.

http://www.victronenergy.com/upload/...rochure_EN.pdf

Any opinions?

I am running the Quattro 24/8000/200 amp unit and I am EXTREMELY pleased with the unit.

I normally run on dock power through a Skylla-I 100A charger so the boat is running 50hz 230V but I can easily run dock power through it also (currently testing that mode and it seems to be very happy).

I run dock power through their auto-selecting 3600 watt isolation transformer, on a 208v dock I am consuming about 3300 watts to produce 100a of charge.

These units can be paralleled without issue so two of the Skylla-I units (which weigh in at 17lbs each) would be another way to get the charging you want from the generator.

The Quattro solution has the nice feature of being able to program the power limit for the generator and if the house loads go above the generator limit then it pulls off the battery.

Great piece of gear!

[smac999]

200a at 24v is huge. You will need 2-3 chargers to do that. You wil not find a single one.

If you don't need a 5000w inverter (that is also huge).
The magnum ms 4024 or 2024 are probably cheaper. At 100a or 60a. Add a 2nd or 3rd charger only

[SVNeko]

If you don't mind, why such a huge bank if you only need an 1800 w inverter?

Sent from my SM-T210R using Cruisers Sailing Forum mobile app

[smac999]

Originally Posted by SVNeko

If you don't mind, why such a huge bank if you only need an 1800 w inverter?

Sent from my SM-T210R using Cruisers Sailing Forum mobile app

depends what he is running. you'd still kill that huge bank in 5 hours with an 1800w inverter constant draw...

larger inverters are really just for surging.

[botanybay]

The nice thing with the huge inverter / charger is that much of the electronics is common (transformers, etc) and the inverter / charger can know what is going on with regard to battery state, input current, output current, etc.

That said, if large charging is all that is needed, the Skylla-I chargers are amazingly lightweight and can put out 100A at 24V for extended periods of time. The only downside of these chargers is that they only accept 180V - 260V and are not capable of working in the 120V regime.

[SVNeko]

Originally Posted by smac999

depends what he is running. you'd still kill that huge bank in 5 hours with an 1800w inverter constant draw...

larger inverters are really just for surging.

- Maxing it out for that long is not a realistic way to look at it.
- He didn't describe any consumers that would require such a huge bank.
- Its not that big an inverter, particularly for such a big bank.
- The surge point is irrelevant and anyway contradicts your idea that he might be running it flat out for 5 hours straight.

[Stu Jackson]

AGMs, right?

You are aware, are you not, of the high acceptance of these types of batteries? 25%C is on the low side.

You might enjoy this:

AGM Battery Issues (from Maine Sail)
AGM Batteries - Making The Choice - SailboatOwners.com

[mitiempo]

Originally Posted by hellosailor

..... your charger should have a battery temperature sensor or the option to add one. This is normally a little tab that gets bolted directly to a positive battery post and tells the charger what the temperature of that post is.

Temp sensor goes on the negative post.

[mitiempo]

You do have one issue which has not been mentioned. Agm batteries are fussier than flooded batteries and will have a very short life if not fully charged often - once or twice a week. As you are on the hook this will be very hard to accomplish as the last 15% or so of charge current takes in the neighborhood of 8 hours. This is true if your charger is 100 amps or 500 amps as the batteries' resistance climbs and they accept less and less current.

You can use as many chargers as necessary to add up to the total amperage you want. Their current will be cumulative in bulk. As the batteries come up to absorption one or more chargers will reach their set point first but by then the battery bank will be accepting less and less current due to increased internal resistance.

If at a dock and plugged into shore power there is no problem but on the hook it means many many hours of generator time unless you have a large array of solar panels and/or a wind generator.

[sailinglegend]

Originally Posted by mitiempo

.....Agm batteries are fussier than flooded batteries and will have a very short life if not fully charged often - once or twice a week......

This is often quoted on here but where is the evidence to support this?

Lifeline are one of the few honest companies who have published data on Morganscloud.com about the lifecycle of their AGMs and this could have led to your conclusions. The site said:

Justin Godber at Lifeline, provided us with new batteries, defined what expected battery life should be, depending on charge regime, assuming daily discharge to 50% and full time voyaging:

1. Fully charged after each discharge (not feasible on a voyaging boat). Estimated life: 6-9 Years.
2. Fully recharged at least once a week and equalized once a month. Estimated life: 4-6 Years.
3. Only recharged to 85% and equalized once a month. Estimated life: 2-4 years.
4. Only charged to 85% and never equalized. Estimated life: 1 year.

My AGMs are ten years old and still going after 7 years as a permanent liveaboard mostly at anchor in the Med. My charging regime is I fully charge every 2-3 weeks and equalize twice a year.

On the same site Justin Godber also talks about Flooded Lead Acid and Gels and goes on to say:

ALL batteries need to be fully recharged to avoid sulfation build up on the plates. I am not sure if I can post links on here so before I do I am asking. I can send links for Trojan Battery, Deka Battery, Odyssey Batteries, etc…They all state the same thing. Batteries must be fully recharged to avoid damage and premature failure. This is why:
As I mentioned before these are all lead acid batteries. They all perform the same chemically when charging and discharging. These batteries are all made from lead and lead dioxide and electrolyte. When the battery is discharged the plates go under a chemical reaction called lead sulfate. When the batteries are recharged this reaction is reversed. This reversal changes the plates from lead sulfate back to lead and lead dioxide. When the batteries are left to sit in a discharged state the lead sulfate does not get reversed and starts to harden, or crystallize. When you look at it under a microscope it looks like crystals. The longer it sits like that the harder it gets and slowly starts to grow farther around the plates.

So does anyone have any hard proof or testimony that AGMs need to be charged more often than FLAs?