Need Battery Advice

[jcrlaw]

I have my new Outback 3232 inverter and mate installed and think it is great; however, it is now time for new (improved) batteries. Thought I knew what I was doing until three phone calls today. First one recommended the Rolls 8HHG25 with 275 amp hours at 475.00 each. Next company did the calculations and said the HHG's would not service the boat appropriately (in other words, I would go below the 50% level) and recommended the Rolls 8CS25PM with 820 amp hours at 1,650.00 each. Third company steered me to 8 volt golf cart batteries and is faxing me information. I'm lost. I want to run the refrigerator, TV and a few lights through the night. I'm open for recommendations. Thanks.

 

[johngalt]

Jcrlaw, I have a Freedom 20 inverter on my boat{41c} that is powered by two standard 8D batteries [approx 200.00 each] and we stay on the hook many weekends and I have not had a problem getting through the night. I turn off the hot water heater but power the fridge,lights,Tv's DVD players, house battery charger etc. all night long. I usually fire up the generator and run it for the typical business day[9 to 5] and I can keep going indefinitely. If I need to use the range I use the genny, but short jaunts of the microwave also work nicely on the inverter. Bruce

 

[Diver Down]

I'm not a battery expert but I'm working on this same issue and have benefitted from some pretty good advice from others on this forum. I've gone back and forth on the Rolls vs golf cart options and have decided to go with the GCs for my house bank. I just finished an energy audit of sorts and have concluded that I need about 145 amp hours of juice (including inverter loss) to run the following fixtures/appliances from the battery bank for one 24-hr period:

- Microwave: 0.5 hr
- Five spiral fluourescent lights: 4 hrs.
- Refrig/freezer: full 24 hours
- DVD player: 4 hrs.
- LCD TV: 4 hrs
- CD player: 5 hrs.
- Coffee pot: 0.5 hrs.

I believe I can get 340 amp hours of capacity by tying together GCs and still get the 32V I need. I really don't think I'll ever use as much energy as I considered in my calculations, so I think I'll be able to get by on the hook for a full day w/o running the generator. I know others on this forum have already found that to be the case.

 

[SKYCHENEY]

jcrlaw,
I also have an Outback 3232. I have it hooked up to four 5 year old Interstate 8V195's. I don't know the amp/hour capacity of those batts, but I can run everything overnight without any problem. This would include the galley side by side refrigerator, a bar refrigerator, lights, microwave, tv, etc.

I think the only way to know for sure is to take an energy audit as stated before. You need to know how many amp/hours you plan to use in 24hrs before you can decide which batteries to get. I have not done this since I planned to just use the batts that were there until they died. I really expected to have to replace them soon after installing the inverter. This, fortunately, has not been the case.

 

[MikeP]

Ditto what Sky said almost word for word! The 32 volt bank in the boat with what look to be rather low cost batts installed by PO more than 5 years ago have been fine for overnight (and longer) inverter use.

 

[ThirdHatt]

Sky, I am sorry to say that I have some bad news for you: Interstate has DROPPED our beloved 8V195! Now you can only get 8V batteries by size, and the one larger than the 8V195 (same as the 8v deka, etc) weighs more and has LESS reserve capacity and cranking power!

I bought 8 last February but a bum alternator on my port engine fried my port bank. I called the Interstate distributor for 4 more and he informed me of this new development. Luckily, he found me 4 new old stock in Texas and sent them to me.

Just thought you'd want to know!

 

[TedZ]

Best/cheapest i've found.

http://raebattery.com/

Ted

 

[jcrlaw]

Thanks all.

Sky and Mike P: Those are the batteries I currently have and they are only 4years old. I can't get through the night with just the frig. The calculations I was given say the frig takes 318 amp hours in a 24 hour period. (I don't know if this right or wrong, just what 2 battery dealers told me.) Add the ice maker, TV and a few lights and I last about 4 hours at best. I have equalized, but still not any better. I believe the PO's maintainence history of the batteries for the 18 months he had them was not up to par and may have caused some damage. So, time to make the plunge. Any further advice is appreciated.

P.S. Carl Guzman's Reel Estate was sold and left our island today. New owner is taking her to New Bern for a total makeover!

P.P.S. Sky: Let me know when you will be on Marco and we'll have you aboard for a cocktail cruise!

 

[MikeP]

318AH sounds like a huge amount for a fridge since they really only run a relatively short time unless they are opened a lot. That rating might be based on a 12v inverter system. If so, it would be just a bit more than 1/3 of that with a 32V system.

It could be that, as you said, the batts may be in poor condition. Once they get to that point there isn't much you can do except replace them. My plan is to replace the current batts with Rolls/Surettes when the current ones give out. They were the original batts (1980) and according to the PO, they lasted until he replaced them just before we bought the boat in 2004! Pretty impressive!!! As Sky said, I assumed I would be replacing them long before now.

The Outback 3232 seems to be extremely efficient and I can't imagine a better inverter for these 32V boats.

 

[Brian Degulis]

Your frig and ice maker will cycle on and off the temp and how often you open the door will vary. So it's hard to say just what the consumption will be over a 12 hour period. I would guess at about 3A @120V so that's 360W That will require 11.25A @32v. There are losses so lets say 12A over 12 hours that will require 144 Amp hour. You don't want to discharge over 50% so you need 300Amp hours of battery capacity. So if you use 8V batteries @ 167 Amp hour (Deka 819) you would need 2 banks of 32V.

When I put my inverter in (3200W outback) I wanted that kind of battery capacity so I tied both banks port and stbt together by jumping the parallel relay. Then I disconnected my Gen starting batteries from the main system and built a 32V bank with the golf cart batteries dedicated to the Gen sets. This way if I ever took the main bank down to far to start the engines I would always be able to start the gensets and re charge.

Brian

 

[Pascal]

the fridge is big draw... for our full size freezer on top unit plus a few lights, expresso maker and gridle in the morning, TV, etc... we need about 300 to 400 AH in 20 hours at 12v (no ice maker, water heater off) so that shoudl be around 150 at 32v... if you dont' want to get below 50% discharge you need 300 AH or more

at 12v, we have 8 GC batteries for 880AH, I woudln't mind having an extra pair. sometimes if we dont' watch it we barely make it 20 hours (I like running the genset in the evening)

 

[bobk]

We run a side by side in the galley and have an under cabinet wine cooler on the aft deck. Lights, digital TV etc. All this is handled by 6 Workaholic golf cart batteries. I haven't tried to figure out how long they will hold up, but overnight is no issue. We cook with the generator, so the batteries get topped up in the AM as well as from the alternator when running and again in the evening when preparing dinner. 4500 miles under our belt this way.

Bob

 

[Nonchalant1]

Sounds like your okd batteries need to be replaced, or are not getting fully charged. We have a 53MY with a regular household 19.0 cu ft. refrigerator and run it all night all the time on an old, inefficient inverter with just the house bank, which is 4 Rolls HHG25PMs. The refer. draws 6 amps with average temps and use, no icemaker and the cabinet dampness control set to off.

You can check your batteries with a simple turkey baster style hydrometer. Measure the specific gravity (i.e. 1250 when charged) in every cell and if one cell is bad in one battery (more than 10% off the others) it's dead. When this happens, the charger will sense that the whole bank is fully charged and shut off early, then the bank runs out of charge very quickly.

Regular batteries usually only last 4 to 5 years. The higher the heat where the batterise are, the shorter their lifespan. Engine rooms are bad for batteries. You can run 'em longer than 4 or 5 years sometimes, but you risk having the bank go bad on you when you really need it. Rolls batteries last 10 years or more on average.

Remember, when you hook four 300 AH 8V batteries together in series to get 32V you still only have a 300 AH bank. Hooked in parallel, battery amp hours are cumulative, but hoked in series, the bank has the same AH as one battery.

Doug Shuman

 

[GJH]

..."when you hook four 300 AH 8V batteries together in series to get 32V you still only have a 300 AH bank. Hooked in parallel, battery amp hours are cumulative, but hoked in series, the bank has the same AH as one battery."

This is where a lot of people get confused. The answer to the above is that it is irrelevant. Energy is consumed in watts. The 4 300AH 8 volts in series provide 4 times as many watts as one does. This is the critical number. Your AC appliance is consuming watts, that is amps times the 110 or 120 volts your inverter is putting out. A bank has to be viewed really in terms of kilowatt hours to properly compute loads and discharge rates.

My personal preference is to have purpose built battery banks, so the short burst, high amp thruster and washdown pump are on one bank of two 8ds in series (24 volt), the genset has its own Group 31 12v starter, the inverter has 4 Group 31 deep cycles, series/parallel 24v, the usual 32v start bank for the stbd engine and start/"house" 32v on port. I didn't like the idea of the genset being a single point of failure if I drew everything else down, especially a main engine start bank.

I still gotta get a 24v alternator attached to one of the mains to charge those 24v banks. Anybody here done this off the front pulleys of 8v92s?
Boat is a 56my.

George