Have to Upgrade My Battery Bank - Acid or Lithium ?

[RaySea Lady]

Looking for technical help on batteries.

My battery bank is made up of 5 - 8D batteries giving me a total of 1200 Amp Hours. However, with 50% available, this gives me 600 amp hours which is enough to run for about 4 hours before I have to turn the genny on. My draw with refrigeration etc.. is approximately 150 amp hours and I would like to achieve 8 to 10 hours of running time before having to recharge.

So...

Mastervolts slimline battery, two slimlines fit in the space of 1 - 8D and provide 400 amp hours which times 5 is 2000 which at 50% is 1000 or 6.5 hours of running which is still shy of the goal.

The other alternative which would fit in the space and provide what I need is Lithium which I know very little about other that the process seems very complicated with BMS systems and special charging etc...

I have a Freedom 30, 3000 watt Xantrex inverter/charger on board which provides power for the 120V refrigeration of 14 amps per hour at 120V. I would like to avoid having to replace this unit since it was replaced new n 2009.

I will be making these changes over the winter storage season.

Can anyone offer any other alternatives?? I am not the most technical guy so I am looking for something that will fit the space I currently have, if I have to buy an additional charger then so be it, and not be overly complex to manage and will fulfill the goal.

[ViribusUnitis]

It would seem that there are basicly two minds about using batteries.

One is that you should never use more than 50% of your battery capasity, because it will destory the battery's life.

The other is why not use it. Batteries are built to be replaced at somepoint anyway. The amount the life of the battery shortens is not as fast as the capasity is used. It might be more cost effective to just use the batteries down to the fullness of their capasity, and then replace them with more flooded cell batteries as required.

Flooded cell batteries are cheap, and readly avalible just about everywhere.

[motion30]

my thoughts are how are you going to recharge all that battery in a acceptable time frame If I understand you are running the air cond from the gen set That is already a large battery bank and its only good for hrs? Possibly the lithium batteries and a large charger is the only answer for you I believe most large yachts run the gen sets full time

[Kapena]

Your problem is the refrigeration unit....but I think (hope) you have miscalculated. A modern regrig will draw 20 to 30 amps at 12vdc. You are running 14 amps at 120vac (about 150 amps at 12vdc)...nearly 10 times too much. Did you misquote the source?

You have plenty of battery power...plenty compared to most boats. You are also using the battery capacity properly (ignore Virus post). Hate to say it but you already know the issue (you posted reference to it)...it's the refrig unit. See if you can sell this one off and maybe a few people can post recommendations for a better unit. Adding more batteries is just delaying the inevitable.

[RaySea Lady]

Originally Posted by ViribusUnitis

It would seem that there are basicly two minds about using batteries.

One is that you should never use more than 50% of your battery capasity, because it will destory the battery's life.

The other is why not use it. Batteries are built to be replaced at somepoint anyway. The amount the life of the battery shortens is not as fast as the capasity is used. It might be more cost effective to just use the batteries down to the fullness of their capasity, and then replace them with more flooded cell batteries as required.

Flooded cell batteries are cheap, and readly avalible just about everywhere.

You have a point but I don't like the idea of having them give out on me at any time...

[RaySea Lady]

Originally Posted by Kapena

Your problem is the refrigeration unit....but I think (hope) you have miscalculated. A modern regrig will draw 20 to 30 amps at 12vdc. You are running 14 amps at 120vac (about 150 amps at 12vdc)...nearly 10 times too much. Did you misquote the source?

You have plenty of battery power...plenty compared to most boats. You are also using the battery capacity properly (ignore Virus post). Hate to say it but you already know the issue (you posted reference to it)...it's the refrig unit. See if you can sell this one off and maybe a few people can post recommendations for a better unit. Adding more batteries is just delaying the inevitable.

Nope, not misquoted, one unit is an 18 cf half freezer, half fridge side by side unit which draws 8 amps and the other is an 11 cf all refrigerator which draws 6 amps. Only other items on that bank are my navionics, 3 garmin multi functions, and a computer. all other 120v items are off while running.

This refrigeration was just installed last year and is what is needed to keep the admiral happy, so now I would like to find an alternative to running the generator all the time, other than 4 hours of battery life, while cruising.

We have been spending 4 to 6 weeks cruising each summer for the last few years.

Lithium may be the only cure for this but I was hoping to hear of other alternatives or of options within the Lithium field.

[btrayfors]

If you are truly drawing a total of 14 amps @ 120 VAC, then you've really got a problem.

That's WAY WAY WAY too much for refrigeration....like about 10 times too much.

You should be able to get adequate freezer and frig space with a total draw of less than 14 amps @ 12 volts DC, provided you are running modern 12VDC refrigeration.

If you're not, I'd think seriously about replacing the refrigeration -- even if it is "new" -- since that would probably be less expensive in the long run than trying to beef up your already more-than-adequate house battery and charging capacity.

JMO,

Bill

[Adelie]

If you are running AC then I understand how you could be drawing that much current. If not then you need to figure out what all the demand is and see if you can't trim it some. Adding insulation to the fridge would help. Consider LED or flourecent lighting.

If you can't get demand down then you need to make a decision about cost.

The cost of the Inverter/charger you got is going to be nothing compared to the cost of LIPoFe batteries. Mastervolt lithium batteries are selling at about $6700 currently. 6 of those should about fit in the space of 2 standard 8d's and give you 1920ah, of which 80% is usable instead of 50%, so about 1536ah. That will give you a run time of about 10hr between charges. Also you should be able to able to recharge in about 1/2 the normal time. From Mastervolt's literature there isn't a special charger they want you to use, it just needs to conform to certain specifications so you may be able to keep your charger/inverter. All for about $40k.

[skipmac]

Hi RaySea Lady,

How are you guys?

Looked at your figures and the power usage seems to be high. A standard home style, upright, refrigerator/freeze unit should draw about half what you give. You say your unit is pulling 14 amps at 120V AC? That is 1680 Watts. A full sized, 12-14 cu ft home unit is rated 600-800 Watts or 6-7 amps.

The 14 amp rate would account for the 150 amps/hour you report pulling from your battery bank but unless you are using some giant, commerical refrigerator freezer you need to look at that usage.

Can you tell us more about the refrigeration system like brand, cubic feet, wattage, etc?

[RaySea Lady]

Wow ! I am trying to avoid running the generator all the time. At 40K of costs to do this with batteries, ( I was expecting 5 to 7K) I am better off to just run the genny all the time and when it goes replace it for 20k.

The refrigeration is an 18 cu/ft commercial side by side refrigerator freezer, 9cu/ft each. Has a corian countertop with 2 inches of R10 insulation under the counter top since this unit is on the covered flybridge. This unit draws 8 amps at 120V. The other galley unit is an 11 cu/ft all fridge unit that draws 6 amps at 120V.

They can be seen in my album. Link below.

[btrayfors]

My god!

It just might be cheaper to replace the Admiral and install 12V marine refrigeration :-)

Bill

[RaySea Lady]

Too much invested in the admiral after 43 years... Be cheaper to get another boat...

Originally Posted by btrayfors

My god!

It just might be cheaper to replace the Admiral and install 12V marine refrigeration :-)

Bill

[hellosailor]

"It would seem that there are basicly two minds about using batteries."
Yes and no. When you cycle wet lead batteries below 50%, you radically cut down the lifetime total number of amp-hours that the battery will supply. it isn't just a matter of how quickly you will use up the batteries, but if you cycle a battery to only 30% discharge, you may be able to store and use, say, 50,000 amp-hours of power through it. Cycle it to 50%, that may go doen to 25,000AH. Cycle it to 100% and it may go down to 12,000 AH.
So by cycling them below 50% you are not just using them up faster--but you are going to get only half the total power storage/use out of them.
That's why there really is only one criteria here, do you want to get the most economical use out of the battery? Or have a smaller cheaper battery bank, that will cost more in the long run because it has to be replaced 2x-4x more often?

RaySea, it sounds like you have no choice except to explore lithium batteries. Some of the makers SWEAR you need an expensive power management system that will double the already pricey cost of the batteries. Others say no, it isn't necessary at all. Believe 'em all, but none of them warranty the batteries for anywhere near what they say the lifetime will be. Whatever the lifetime and cost really may be, the bottom line is that lithium WILL allow you to store more amp-hours in less space and since you can't decrease your power needs...ante up, shop lithium.
And get any claims in writing, along with the best warranty you can.

Although in your case? It might pay to have blocks of dry ice delivered to the boat. Keeps the box nice and frigid, cheap compared to lithium with a charge management system.<G>

[RaySea Lady]

Originally Posted by hellosailor

"It would seem that there are basicly two minds about using batteries."
Yes and no. When you cycle wet lead batteries below 50%, you radically cut down the lifetime total number of amp-hours that the battery will supply. it isn't just a matter of how quickly you will use up the batteries, but if you cycle a battery to only 30% discharge, you may be able to store and use, say, 50,000 amp-hours of power through it. Cycle it to 50%, that may go doen to 25,000AH. Cycle it to 100% and it may go down to 12,000 AH.
So by cycling them below 50% you are not just using them up faster--but you are going to get only half the total power storage/use out of them.
That's why there really is only one criteria here, do you want to get the most economical use out of the battery? Or have a smaller cheaper battery bank, that will cost more in the long run because it has to be replaced 2x-4x more often?

RaySea, it sounds like you have no choice except to explore lithium batteries. Some of the makers SWEAR you need an expensive power management system that will double the already pricey cost of the batteries. Others say no, it isn't necessary at all. Believe 'em all, but none of them warranty the batteries for anywhere near what they say the lifetime will be. Whatever the lifetime and cost really may be, the bottom line is that lithium WILL allow you to store more amp-hours in less space and since you can't decrease your power needs...ante up, shop lithium.
And get any claims in writing, along with the best warranty you can.

Although in your case? It might pay to have blocks of dry ice delivered to the boat. Keeps the box nice and frigid, cheap compared to lithium with a charge management system.<G>

Thanks for the reply.

Since my intent was to try to save hours on my Westerbeke 12.5kwh generator, by having enough battery power to run what I need, and, assuming Adelie is correct with pricing in the 40,000 range for lithium batteries, it does not seem to make sense when the whole generator could be replaced for about half that price and it only consumes 1 gallon per hour of diesel.

So, the pricing seems to have answered my question and I will run my generator whenever I am cruising and replace the generator if I ever have to.

Westerbeke tells me these can run 10000 hours if they are maitained properly.

Thanks everyone for the help.

[Adamante]

Originally Posted by RaySea Lady

assuming Adelie is correct with pricing in the 40,000 range for lithium batteries,

You certainly can pay $40K for the batteries, depending on where you buy them, but there are much cheaper sources. Whenever I am pricing a lithium battery system, I budget $400 per KWhr. So with your prospective 20 KWhr system, I would expect to pay under $10K for the whole bank, including an optional BMS.

But I am curious where you are getting the current draw data for the fridges. Is it from a spec sheet, name plate, or actually measured with a clamp-on ammeter?