A way To Save Charging Time

[Paul L]

Originally Posted by Kenomac

High quality small flexible panels cost more.

That was my point. You can purchase flex panels for a fifth of the Solbian cost. While the Solbian have better connectors it is hard to justify their costs. If you replaced the cheap panels every 3 years they would still be less expensive.

[StuM]

Originally Posted by Kenomac

Some of these mysteries now have numbers.

During the day with only the stereo turned on the drain is 1.5Ah, when the freezer compressors turn on with the associated water pump, the drain increases to a total of 11Ah on the meter for 10 minutes, then drops back to 7Ah. The fridge draws 3Ah on start up, then drops back to 2Ah. When both units are running at the same time, the total draw is 9Ah continuous after they settle in when combined with the stereo.

The fridge runs 5-6 hours per day (24hrs) and the freezer 4-5 hours per day. Each runs at least 3-4 hours during the daylight hours, less at night.

Of course, all those "Ah"s are really "A"s

It's hard to give advice to someone who doesn't know the difference between Amps and Amp hours .

[StuM]

Originally Posted by Kenomac

Today's amp burn was 70 amps over a nine hour period. Fridge, freezer, iPad and stereo.

Now I'm going to run the generator for an hour while I cook dinner and see where I'm at.

Presumably, that's 70 Amp hours?

[mitiempo]

Originally Posted by Kenomac

Today's amp burn was 70 amps over a nine hour period. Fridge, freezer, iPad and stereo.

Now I'm going to run the generator for an hour while I cook dinner and see where I'm at.

70 amps x 9 hours is 630 AH, isn't it?

[StuM]

Originally Posted by mitiempo

70 amps x 9 hours is 630 AH, isn't it?

And people wonder why I keep on ranting about using the correct units.

[sstuller]

If the Rolls Battery Manual calculation is to be believed Mr. Conachair could reduce his absorption time in half by replacing his two T-105's with one 12 volt 100 AH battery. This would still provide the capacity he needs at 50% DOD. The assumption is that the charging current (300 watts) would remain the same. Thanks.

[Kenomac]

The overnight 10hr discharge amount was 50Ah bringing the total 24 hr usage to approximately 120Ah when the genset isn't running. Add in an additional 20Ah for cooking when the genset is running and you have my 24 hr total being somewhere close to 140Ah. Or whatever units I'm suppose to use.

Looks to me like the 450w array is the way to go, which should then require just running the genset for 30 minutes in the morning and again around supper for 30 minutes to warm water and take care of the electric cooking load along with water production with the Spectra units.

[mrm]

Originally Posted by Kenomac

The overnight 10hr discharge amount was 50Ah bringing the total 24 hr usage to approximately 120Ah when the genset isn't running. Add in an additional 20Ah for cooking when the genset is running and you have my 24 hr total being somewhere close to 140Ah. Or whatever units I'm suppose to use.

Looks to me like the 450w array is the way to go, which should then require just running the genset for 30 minutes in the morning and again around supper for 30 minutes to warm water and take care of the electric cooking load along with water production with the Spectra units.

My calcs suggest that you will be better off extending morning generator run one hour into the acceptance phase (perhaps run watermaker in the morning?), then 450W of solar should be able to top off your bank nicely. Other than that, looks like you are all set.

[Sailmonkey]

Originally Posted by Kenomac

The overnight 10hr discharge amount was 50Ah bringing the total 24 hr usage to approximately 120Ah when the genset isn't running. Add in an additional 20Ah for cooking when the genset is running and you have my 24 hr total being somewhere close to 140Ah. Or whatever units I'm suppose to use.



Looks to me like the 450w array is the way to go, which should then require just running the genset for 30 minutes in the morning and again around supper for 30 minutes to warm water and take care of the electric cooking load along with water production with the Spectra units.

How do you use 20ah for cooking when the generator is running?

That part confuses me, but the rest is pointing towards happiness with the 450 watts.

[Kenomac]

Originally Posted by Sailmonkey

How do you use 20ah for cooking when the generator is running?

That part confuses me, but the rest is pointing towards happiness with the 450 watts.

I'm estimating how much would be used if I didn't run the generator.

[a64pilot]

Originally Posted by Kenomac

Unlike before, now with the electric cooking going on, the charger is still able to put in 60-80 Ah. Before the additional charger, it would read zero or a negative number while cooking.

This is the key to the puzzle we were missing, why he in fact has shortened his charge times considerably with a larger charger, where conventional wisdom is you don't.
He has a monster house load that was using all the capacity of his older smaller charger.
Usually there is no monster house load, and its assumed close to 100% of the chargers capacity is going to the batteries

[Kenomac]

Originally Posted by a64pilot

This is the key to the puzzle we were missing, why he in fact has shortened his charge times considerably with a larger charger, where conventional wisdom is you don't.
He has a monster house load that was using all the capacity of his older smaller charger.
Usually there is no monster house load, and its assumed close to 100% of the chargers capacity is going to the batteries

You got that right. I was thinking the same thing when I made the discovery. 80amps going in while I was cooking, instead of zero.

BIG difference. You get an "A"

This alone saves over 1 hour of generator charging time per day! With or without the solar.

Microwave, induction cooktop and infrared oven plus watermakers consumed most if not all of the 50 amps the smaller Mastervolt 24/50 charger was able to put into the battery bank. Now with the additional Mastervolt 24/75 charger, an additional 75amps goes in on top of what's being consumed.

[Sailmonkey]

Ah, I hadn't realized you were running the cooktop, etc through an inverter instead of directly off of the generator.

[StuM]

Originally Posted by Sailmonkey

Ah, I hadn't realized you were running the cooktop, etc through an inverter instead of directly off of the generator.

Yep, all we were told was that he used the high load items when the generator was running. If he'd said at the start that those high load devices were going through the inverter/charger this thread would have been a LOT shorter.

[Kenomac]

Because we're an American market 110v boat in the EU, everything must go though the inverter except the waterheater which is 230v and I believe the cruise air/heat is also 230 but we never use it.