A way To Save Charging Time

[Kenomac]

Originally Posted by sailorboy1

Not really true. Only on forums do boat need to become solar aircraft carriers. 8 months of cruising and still using the same 290w I had before starting and the lowest I'm seen battery charge is 78% once, normally the lowest I see is 85%.

Does your battery bank recover back up to 100% by the end of the day?

[jibstay]

Originally Posted by robbievardon

Kenomac, I don't understand your reply. Where does your power come from at night/sunless days? What do you do with your surplus/why do you need surplus? What level of efficiency do your panels run at?Do they track the sun?

My guess is that the building is still connected to the local electric utility company, but the energy generated by solar is being sold to the utility company for an amount that equals or exceeds the monthly usage bill.

[a64pilot]

Originally Posted by sailorboy1

Not really true. Only on forums do boat need to become solar aircraft carriers. 8 months of cruising and still using the same 290w I had before starting and the lowest I'm seen battery charge is 78% once, normally the lowest I see is 85%.

You, nor I are 54' Oysters either. Likely he has more than one fridge, and other "things" that require electricity.
And we have generators too, all three of us, and run them I'm sure when its prudent to do so.
I concede to two generator runs a week, likely will be more, I won't be out to prove anything, however I do plan on being comfortable if possible.
Those generator runs will I hope put a real big dent into a slowly increasing deficit from Solar alone.

Pure Solar only really looks to be viable with a Lithium bank.
IF your obsessing and trying to make you bank last as long as possible, if you accept a shorter life, then it will work for a regular LA bank too.
I concede that there is a lot of logic in using inexpensive, widely available batteries and changing them every few years as opposed to exotic, expensive ones that you need to make last a long time to break even

[sailorboy1]

Originally Posted by Kenomac

Does yours go back up to 100% by the end of the day?

Not each day. If I think it has been too many days I run the generator in the morning to get some bulk charging done.

[conachair]

Originally Posted by sailorboy1

Not really true. Only on forums do boat need to become solar aircraft carriers. 8 months of cruising and still using the same 290w I had before starting and the lowest I'm seen battery charge is 78% once, normally the lowest I see is 85%.

Same here full time livaboard, 300w and 2 x trojan 105, rare to go much under 80% overnight. Fridge and laptop worst drains. Sunny days will get to full again (from watching voltage & amps in with occasional hydrometer to check. Still takes a good chunk of the day to get all the way to full again, no way to speed up things up after 80% no matter how many hundreds of amps you have available.

[Kenomac]

If I run the generator in the morning to get back up to 90%, will 375w-450w of solar be able to top off the batteries daily? The only things running during the day at anchorages are two refrigeration units, a deep freezer and the fridge and occasionally the Spectra watermakers. Usually, we run the watermakers while the generator is running.

[weavis]

HI Ken
Ask your dealer if he has the ability to calibrate your equipment.

[barnakiel]

Ours does. It is just the question of having heaps of solar area per any given batt bank size.

When it does not, simply push thru the bulk before the sun is up, with your genset or alternator.

b.

[a64pilot]

I'd say that in my opinion that 400W of Solar will be taxed running a fridge and a freezer.
Before people jump in and object, I doubt these are little 4 cu ft boxes.
This is a big, nice boat, and I'd expect big nice fridge and freezer too.
What do you guys see amps wise on average out of 400w ? say 12 or so?
Not Max on a perfect day, an average number? Refrigeration and freezer when the compressors are on will pull I'g guess 5 or 6 amps each, mine does anyway.

[a64pilot]

I go through I think about 100 AH a night.
So in the morning a 20 amp average Solar output for five hours should get me back to charged right? Well no, of course you have to put back more in than came out, nothing is 100% efficient, but lets not forget that 100 AH load that is being used during the day too.
So to get fully back to 100%, I'd guess i have to generate 225 AH?
How big an array do you have to have to generate 225 AH a day, on average?

[sailorboy1]

Originally Posted by Kenomac

If I run the generator in the morning to get back up to 90%, will 375w-450w of solar be able to top off the batteries daily? The only things running during the day at anchorages are two refrigeration units, a deep freezer and the fridge and occasionally the Spectra watermakers. Usually, we run the watermakers while the generator is running.

It depends on the amp hours and how well the sun it going to hit the panels. I figure my panel on a good day will do 90 ah. If I start the day at -90 ah I will end the day at around -20-30 ah on my 290w bank. So that in the mid 90s state of charge. If I run the generator in the morning till I'm -60 ah out I will end day less than -20 ah normally and get to about 97% charged. If I run the generator in morning till I'm at -30ah the solar will get the batteries to 99-100%

Otoh if the boat is going to point north all day and the sun is out the batteries will fully charge from -90ah without the generator.

So if I don't plan to fully charge I probably run the generator 40 minutes in the morning and also run the hot water heater, use the toaster at breakfast, defrost the freezer, etc and whatever I need sv power for. If I plan to get fully charged I have to run the generator around 1-1.5 hours. Because at 85-92% state of charge I can put 50-60 amps into the battery, but st 92+% I can only put in around 30 amps acceptance. This also means that if run the generator in the afternoon and the solar has already gotten the batteries back into the 90s that I don't really get any charging it beyound what solar would have,

[Kenomac]

All very helpfull responses.

If I occasionally, say once per week turn off the fridge and freezer for a few hours, will I then be able to get the batteries up to a full charge using just solar assuming I'm at 90% or better to start with?

[Kenomac]

Originally Posted by a64pilot

I go through I think about 100 AH a night.
So in the morning a 20 amp average Solar output for five hours should get me back to charged right? Well no, of course you have to put back more in than came out, nothing is 100% efficient, but lets not forget that 100 AH load that is being used during the day too.
So to get fully back to 100%, I'd guess i have to generate 225 AH?
How big an array do you have to have to generate 225 AH a day, on average?

The plan has always been to run the generator for at least an hour per day to bulk charge and use the heavy hitter appliances during that time. And also to have the added redundancy of another power source.

Last season for a week while anchored off Kotor, Montenegro, I found myself stuck with an out of service generator awaiting parts from America... then the engine quit on me for two days until I figured out the problem.

That stunk. But I still had a working dinghy with a 15hp motor for backup.

Redunancy is key if one plans on doing this cruising thing full time and actually getting someplace.

[sailorboy1]

Turning the freeze and frog for a few hours wouldn't save any power, it just delays it. But if f you needed the owner just to get amps into battery just because you wanted to get charged it would help. But normally by the time you are close to being fully charged solar it not being fully used because the batteries are acceptance limited

[Kenomac]

Doesn't the battery bank want to see 100% float status every few days? Otherwise, it seems like the max charge goes down, down , down until I plug into shore power to get back up to 100%

Will solar improve this situation, or will I not see much of a difference?