Charger, Solar, Etc.....

[Jennyq]

Hi All,

Looking for a little help from the community.
I am new here. Have been lurking for a while.
This is our first sailboat. We are making the switch from power boating.
We bought a 1999 beneteau 36cc
We love the boat and after almost 3 months of getting it ready to cruise,
( nothing worked on the boat, nothing ) the last thing is charger, inverter and solar.

We want to stay at as few marinas as possible.
We have 4 (6) volt batteries (275 amp) in 12 volt series together as house batteries.
I think we will use under 200 amps a day
The boat had a 20 amp charger and no inverter.
Maybe watch a little tv at night, laptop, phones, fridge etc...

Was thinking of putting 400 watt solar.
Bought an inverter charger of 2000w and 55 amp charger.
the battery says on it 50 amp minimum 85 amp maximum charge
They are Rolls AGM

Is my set up going to work?
Dont think I can fit any more solar, my davits are low and Im putting them on the bimini( flexible)

Thank you in advance,

jen

[Summitfun]

Jen,
First, make a usage budget to get a handle on your approximate power needs.
Then you can build your system.

Talk to eMarine in Lauderdale (no affiliation). They may be able to give you a "system" price & make some suggestions.

Search the forum for past postings to economize your usage: LED lamps & other ideas.

Mike

[dlymn]

Do you mean 275 amphour batteries or a total available of 275 amps. I always halve the amphour rating of lead acid batteries to stop damaging bthem by over discharging. Assuming 275 amphours each that calculate to 275 amphours in total available power (am I wrong again StuM?) If it's 275 total then you only have 135 available.
At our latitude, the house solar guys say that we have an average of 5 hours full solar charge per day. That's 0 in winter and too much in summer. In reality our house system averages 3.5 hours a day. However panels on a boat might be very different. panel angle, shading, boat movement will reduce the energy production levels. Given that you might only use theboat in summer, the extra hours of sun might compensate for this. If you are sailing, I would imagine that solar energy production would be much lower. Given all this, I would guess that in summer, moored, you should be able to generate 2000 w (12v x 167 amp) and so should be able to top up your system. So, if your daily consimption is under 135 amps, it should work.......in summer......moored.
BTW flexible panels won't perform as wellas fixed and if you attach them directly to the bimini material, this will reduce production a little. panels work best when they are kept cool

[Jennyq]

Thanks for the reply
we have 2 sets of 275.
I did the usage worksheet, already have all led lights.
The big usage would be cruising electronics.& fridge

We really didn't want to put the hard panels on the davits as they are low and would need a new frame.

I am really looking for battery charger info now. Will I have to run a generator 2 hrs a day?, not bad and is my 55 amp charger going to be enough?

[StuM]

Just to clarify:
You have 4 x 6 Volt (V) AGM batteries arranges in series/parallel as one 12V bank.
The batteries are rated at 275 Amps (A) at 6V

That means that you have 550 Amp hours (Ah) storage.

A good principle is to keep your battery bank above 50% State of Charge (SOC), so you have 275Ah available.

Your estimate is that you will use less than 200Ah per day (Note: that's Amp hours, not Amps!). So your battery bank is reasonable for your intended use.

The battery's recommended charge rate is 50-85A. Since you are running at 12V in series/parallel, each series bank will only see half of your charging Amps, so that means that ideally (for fastest charging), your system should be capable of delivering 100-165A.

Now to solar charging:
400W will deliver at peak sun about 30A (in theory - a lot depends on what sort of charge controller you have) and you can estimate about 150Ah per day from it.

I'd work on the basis that you will need about 50Ah more on a daily basis.

Unless you can fit in a bit more solar, you are going to have to run your engine+alternator or a generator for an hour or so every day to get that (Preferably early in the morning when you batteries are depleted from overnight use so that they can accept high charge, and before the solar is providing a lot of energy)

(I'm discounting other options such as a wind generator etc).

[StuM]

Originally Posted by Jennyq

Thanks for the reply
we have 2 sets of 275.
I did the usage worksheet, already have all led lights.
The big usage would be cruising electronics.& fridge

We really didn't want to put the hard panels on the davits as they are low and would need a new frame.

I am really looking for battery charger info now. Will I have to run a generator 2 hrs a day?, not bad and is my 55 amp charger going to be enough?

If you are using a 55A charger, you are not taking full advantage of the high acceptance rate of your AGM batteries but it will do the job.

From my previous post, if you run your generator early in the day, you should be able to get away with quite a bit less than 2 hours running.

[dlymn]

Originally Posted by Jennyq

Thanks for the reply
we have 2 sets of 275.
I did the usage worksheet, already have all led lights.
The big usage would be cruising electronics.& fridge

We really didn't want to put the hard panels on the davits as they are low and would need a new frame.

I am really looking for battery charger info now. Will I have to run a generator 2 hrs a day?, not bad and is my 55 amp charger going to be enough?

At 50 % discharge, you should have ample to run rour boat. We get 2 dayeys fulluse out of our 280 ah batteries (140 nett)
Don' forget recharging computers etc. A 50w sound system chews up plenty. TV @ 300 w, that's 25 ah @ 12v.
your charger is commonly used for shore power and can be hooked up for hours on end as long as it's a smart charger and goes into float mode. your alternator on the motor will do a fair but not full charge. We run 2 x 80ah alternators and just the motoring in and out of port helps a lot. Of course you will also motor on many days and this helps. At anchor, our system gives us a days usage with 45 minutes of engine operation A generator will help, but please, for the sake of those near you, don't run it all the time. Even though youm might have a 2 kva gennie, it will not charge at this rate. I'm not sure, but if it's running through your high voltage system then the charger sets the rate. Assuming daily discharge at 150 ah and no solar input, it will take 3+ hours to recharge at a charging rate of 55 amps. The fuller the batteries get the slower they charge

[StuM]

Originally Posted by dlymn

At 50 % discharge, you should have ample to run rour boat. We get 2 dayeys fulluse out of our 280 ah batteries (140 nett)
Don' forget recharging computers etc. A 50w sound system chews up plenty. TV @ 300 w, that's 25 ah @ 12v.
your charger is commonly used for shore power and can be hooked up for hours on end as long as it's a smart charger and goes into float mode. your alternator on the motor will do a fair but not full charge. We run 2 x 80ah alternators

Please! using incorrect units will just confuse the OP.

...
Assuming daily discharge at 150 ah and no solar input, it will take 3+ hours to recharge at a charging rate of 55 amps. The fuller the batteries get the slower they charge

A LOT more than 3 hours. More like 6-8 hours to reach full charge

[Jennyq]

Thanks for all the input.

To clarify, if I understand what I have correctly, it's 2 banks of 2 6 volt batteries all in series, parallel so yes, 550 amp hours.

If I put 400w solar and use less than 200 amp hours a day. It is best to start the generator for an hour in the morning then let the solar take over?

[StuM]

Originally Posted by Jennyq

Thanks for all the input.

To clarify, if I understand what I have correctly, it's 2 banks of 2 6 volt batteries all in series, parallel so yes, 550 amp hours.

If I put 400w solar and use less than 200 amp hours a day. It is best to start the generator for an hour in the morning then let the solar take over?

1. Correct.

2. Correct. In the morning when the batteries are depleted, they will be able to accept all the energy that generator + charger can put out. You can then let the solar handle the absorption charging as the acceptance rate declines through the rest of the day.

[Jennyq]

Ok great,
I noticed on the battery says on it minimum charge 50 amp
so if the banks are split in two they will only be getting 25 amp
will this ruin the batteries or should it be ok as long as I top them off the rest of the day with the solar.
The batteries are not new, at least a few years old, but I don't want to buy new ones either, $350 each I believe.

[Jennyq]

One more question. Pure sine wave or modified sine wave?
I have a small led tv and a MacBook on ac power.

[StuM]

You won't ruin the batteries with charging below 50A as long as you charge them long enough to bring them to full charge. The "minimum" for AGM seems to be mainly based on the time required to bring them to full charge.

Just a word of caution on the Rolls 6V 275Ah batteries. Rolls rate then at C/100 (i.e. the Ah you would get by discharging them over 100 hours). More frequently batteries as show at their C/20 rate, so when comparing Rolls to Trojan etc, the Rolls 275Ah is actually equivalent to what most manufacturers would call a 230Ah battery.

So I'd figure on having 460Ah with 230 available rather than 275Ah available.

From Rolls:
"The initial charge current is recommended to be set at I1= 0.25 X C20 (Imax= 0.35 X C20) in order to fully charge the batteries within a reasonable amount of time. It can be set lower, however please be aware that charge time will increase so make sure the batteries have enough time to fully charge before being put back into service. Rolls AGM batteries have a low internal resistance allowing them to be charged at a higher current, therefore faster, than conventional flooded/wet batteries."

For your battery bank, .25 * C20 = 115A !

[StuM]

Originally Posted by Jennyq

One more question. Pure sine wave or modified sine wave?
I have a small led tv and a MacBook on ac power.

I'd go with pure sine wave. You never know what else you are going to want to put on it in the future

Some LED TVs will be OK on modified sine wave, but a lot of newer ones aren't. Your Macbook power adapter should be fine on MSW

[DeepFrz]

You may want to read this article by Maine Sail (Compass Marine) to get a better understanding of the amount of time required to charge your battery bank.

How Fast Can an AGM Battery Be Charged..? Photo Gallery by Compass Marine How To at pbase.com