When to use Solar

[motion30]

, so I have my solar panel system setup with 825 watts of solar panels in and outback 60 amp controller. . Everything seems to be working well. Now my question. I am currently at the dock and have had the battery charger turned off ,so am i needlessly cycling my batteries therefore shortening their life? Would I be better off just leaving the charger on with a constant float charge?

[smac999]

I doubt the batteries are discharging much over night. 25-50ah?.. how big is your bank. do you have a battery monitor? you're probably only dropping a few %


the wear is directly related to how deep the cycling is. if you were droping to 50% every night then yes. but then would mean your bank is way too small.


personally the damage done to the batteries is probably a much smaller concern then damage done to the boat by corrosion with it pluged in. if you don't need ac for other things. leave it unplugged. if you are pluged in anyways. then yes turn it on.

[motion30]

My battery bank is 12 6volt golfcart batteries. Total over 1300 amps. Voltage in the morning is never less then 12.5. Often 12.6. No battery monitor. Usual running 3 small fans. 9 cubic ft fridge and 12 volt tv and kvh satellite system and led lights

[sparrowhawk1]

There was a similar thread where what was suggested is buy a cheap battery and have your battery charger and all house loads connected to it. Also lower your solar controller float voltage (I think it was to 13.2)since there will be no load on your big bank.

[newhaul]

If you don't need the shore power to run anything on the vessel an solar is carrying properly then don't even plug in the shore cable your zinks and wallet will thank you I don't have mine plugged in at all so I don't get any charge for power but plugged in I would have a minimum of 5 USD charge just to read my meter plus any power used.

[S/V Alchemy]

Originally Posted by motion30

My battery bank is 12 6volt golfcart batteries. Total over 1300 amps. Voltage in the morning is never less then 12.5. Often 12.6. No battery monitor. Usual running 3 small fans. 9 cubic ft fridge and 12 volt tv and kvh satellite system and led lights

I think you mean "1300amp hours (Ah)", and are you getting this from a multimeter if you don't have a battery monitor?

Why would you NOT have a battery monitor for such a large bank? Diagnosing loads/draws is a big part of calculating your reserve and "what gets turned off first if it's cloudy for five days".

[TacomaSailor]

We have six T-105 batteries and 500 watts of solar panels. We have lived aboard much of the last 15-years with the last five being in San Diego.

I can't remember the last time I turned on the battery charger, except to occasionally test it. We are plugged into shore power but the only thing that runs off the shore power is a 27" LCD TV and a small desktop computer. During the few day of cool weather in San Diego we also run a 1,200 watt space heater off the shore power.

Our first set of T-105 lead acid batteries lasted 7.5 years and our current bank is six years old and seems to be in perfect condition.

The comment about a minimum charge is important. Our marina has a $10/month minimum shorepower connection charge. But, that is trivial compared to the $1,020 dock charge for two liveaboards.

[motion30]

Originally Posted by S/V Alchemy

I think you mean "1300amp hours (Ah)", and are you getting this from a multimeter if you don't have a battery monitor?

Why would you NOT have a battery monitor for such a large bank? Diagnosing loads/draws is a big part of calculating your reserve and "what gets turned off first if it's cloudy for five days".

Yes 1300 amp hr. The 6v batteries are rated at 220ah each. I had a battery meter on my last boat and I liked it. The way this boat was set up from the factory. , the batteries are all over the Motor compartment with no one central ground. it will be fair job to get just a single ground cable. I would like to do that but am unable to right now

[newhaul]

Originally Posted by TacomaSailor

The comment about a minimum charge is important. Our marina has a $10/month minimum shorepower connection charge. But, that is trivial compared to the $1,020 dock charge for two liveaboards.

With that dock fee you really don't want to hear about my $140 per month. The $5 fee to read makes more difference to the annual total ($60 per year)
Verses a meer $120 for you.

[a64pilot]

I think you are needlessly cycling your batteries and shortening their life, although probably not that drastically as I assume a shallow discharge each night, except for when the days are excessively cloudy etc.
But without a good monitor, I doubt you'll know really.
I'd use the charger on a float charge, assuming it's a good charger of course, why cycle them at all except when your using the boat?

[a64pilot]

You have a dozen batteries?

[Crom]

Im a big fan of using the batteries and charging with solar, wind and prop generator when undersail. Do you have a pulse charger?

[motion30]

Originally Posted by a64pilot

You have a dozen batteries?

Yea. Even dozen

[a64pilot]

Originally Posted by motion30

Yea. Even dozen

Wow that's a lot of batteries,
the fact that you have several grounds should not matter as I assume they are all connected to a common ground, you should still be able to install a battery monitor.
My Balmar smart gauge has three wires, two positive for two banks, and one ground, that's all there is to it, no shunts or anything else, and it seems to work well.

[Utahsailor]

Your setup is similar to mine: 1100 AHr T105s at 12V, 840 W solar panels but on a mooring. With fridge, freezer, LED TV, KVH sat antenna we have never seen below 80% on the Balmar Smart Meter, and usually are at 90% in the mornings. They are always at 100% by 1 PM on a sunny day. This small draw should result in very long battery life, so I would just not hook up to shore power unless you have a string of cloudy days.