How many batteries?

bshillam

Member
With the addition of, "Together Again" I am back to evaluating our needs for electricity. Our current set up has one dedicated start battery, one house. I'll be adding a Wallas, Espar or Wabasto forced air system to the boat. While away from 110 we will be on a dock without electricity or hanging on the hook. Typically we don't hang out for more than two to three days at a time without moving on. I plan on running the installed frig and when it gets under 60 the forced air heater, we don't run inverters or use a lot of lights after dark. I can add one or two more batteries for a total of three. How many house batteries do you have? How long can you hang out w/o electric? Thanks.
 
Byrick, think of adding solar panels or a Honda generator to recharge your batteries if you are hanging without shore power for up to three days! Also a Victron battery monitor so you actually know the state of your batteries! How many batteries? How big is the house battery? We have two but they are not big or expensive (NAPA Premium Marine batteries).
 
Pat Anderson":1tdj03d4 said:
Byrick, think of adding solar panels or a Honda generator to recharge your batteries if you are hanging without shore power for up to three days! Also a Victron battery monitor so you actually know the state of your batteries! How many batteries? How big is the house battery? We have two but they are not big or expensive (NAPA Premium Marine batteries).

CONCUR!

Get the second house battery and add either solar or a generator,

I have a

1) Honda 1000i generator (quiet as they get),

2) a Vectron 40 amp smart charger (automotive style, keep it dry). The 1000i's full output is in 120 VAC, so you need the charger to convert the current into 12VDC), and

3) a paralleled 4 battery group 27 battery pile that boasts 460 amp-hours of reserve (really 230 a-h, since only 50% should be drawn down.)

The combination ='s endless electricity and "hang time".

Solar would also be good, depending on how much sun you get at your latitude/climate/ect.

Hope this helps!

Charge! :lol:

Joe. :teeth :thup
 
It doesn't look like you have much of a load to me - except for maybe the fridge. While I know it is not the exact same thing, I can boondock in my motorhome for easily a week on two 6V commercial golf cart batteries without even putting a dent in them while fishing or hunting in the fall. What's running? Water pump, lights, propane furnace, TV, DVD, computers, fans, and probably other stuff. The 6V golf cart batteries are of similar size to the group 24 12V boat batteries, except they are taller.

As for my CD22, I have one battery for each engine (twin 45s) and one for the house. It works well for 3 day stints (or even longer) and I have a Wallas, pumps, and the typical load of lights. I do not have fridge and I know they draw a lot on 12V.

I would say having a charger would help a lot. If you can do it 2 6V golf cart batteries are the way to go if you don't mind lead acid.
 
First, the best size battery is the group 31 (I don't know about what space you have in the new Rosie 246). If possible it is best to keep batteries, the same size (capacity), age, and type. One has to separate the reserve capacity and amp hours. Generally the Reserve capacity is about 2x the amp hours. (This depends on how the current is withdrawn and the end point voltage). I prefer to look at amp hours, since that is closest to what I actually use. The Group 31 will usually have anywhere from 10% to 25% more power available than a group 27, for just a little longer case.

Because you have the refrigerator, and may have to run the heater all night, I would have a minimum of 3 group 31's. You can either configure the house for the heater, and the second house for refrigerator. The 3rd is engine start.

You will want VSR to combine the batteries, when you are running the engine.

I agree with Pat and Joe--we carry a 1000 watt Honda generator, and it runs a 30 amp battery charger, plus we have a 3 bank 30 amp MasterVolt charger built in. I can put in 30 amps in an hour when in bulk stage. When in hot weather, we run the generator to regard the drain on the refer/frezer battery (about 60 amps in 24 hours). AGMs do allow for a somewhat faster charge rate--and that is one of the several reasons to get AGM batteries.

Solar panels work great in the sun--consider angle to the sun, any shade, and % of sun in your boating area.
 
We use 2 Group 29 deep cycles for 1 bank (house and start) and have a Honda 2000 (will charge battery bank in case of emergency) and a smart charger and have a digital volt meter at the helm to keep track of the charge level. I have a special cord to plug into the generator and run under the motor well to the port side aft cabin 30amp receptacle. We run the gen when we need to but if anchored for days in one spot it runs about and hour in the morning and an hour at supper time. Volts never go lower than 12.1 and fridge is always in use.
 
Honda twin BF90s: I wanted 3 batteries - one engine start battery and two house
batteries in parallel. Honda Rep said "No" to both engines on the same battery
with 'no' explanation.

Anyone here know why?

Rest of the story: I got 3 batteries - one for each engine and one house. All wet
cell Interstate Group 27s the dealer said will last me about 4 years, just like the
high priced batteries. You'd think by now I'd know when I was getting snookered.

Aye.
 
Agree with the above and can tell you how it went for us. We used two grp31 AGMs plus a 30watt solar panel to power the house in the 25 running the standard refer plus Wallace for heat and other normal loads. That bought us 3hot-5cool days of power at anchor before we needed to fire up something gas powered. It was enough for us and the small solar panel really added 1-2 days compared to not having it, even though is was not very large. We eventually sold the generator because we never sat still long enough to need it. Now we still run two grp31 AGMs, but no refer so it is overkill even though we do run an electric trolling motor while fishing.

Solar is great and if you do it right and battery up... you can likely avoid the need for a generator.

On your boat, I would go with 3- 31 sized units like Bob said so you have an extra margin and room for inverter use if you ever want it.

Greg
 
I am going to add at least one more house, either a 27 or 31 depending on whats there already. This will make up a total of three batteries, two for house and one for start with a combiner switch.
 
BrentB":lumzle29 said:
Two OBs on one battery could cause problems with the regualtor (confusing them) and could over heat them

Bingo! Nice job, Brent!

Each motor is trying to charge the same battery, which it does by applying higher voltage to the battery than the battery already has, thus pushing current through it backwards until it reaches a higher state of charge.

To sense how charged the battery is, the regulators sense the battery's voltage by measuring the resistance it has to charging.

However, when trying to do so, each regulator senses not only the battery's voltage/resistance to charge, but also the voltage applied by the other charging system, which is relatively high, in order to charge the battery.

Thus each regulator cannot sense the battery's real voltage/state of charge, but is being confused by the other charging system trying to do it's job.

Confused yet? The regulators are! :lol:

Hope this helps. :idea

Joe. :teeth :thup
 
Sea Wolf":2pkw8sey said:
BrentB":2pkw8sey said:
Two OBs on one battery could cause problems with the regualtor (confusing them) and could over heat them

Bingo! Nice job, Brent!

Each motor is trying to charge the same battery, which it does by applying higher voltage to the battery than the battery already has, thus pushing current through it backwards until it reaches a higher state of charge.

To sense how charged the battery is, the regulators sense the battery's voltage by measuring the resistance it has to charging.

However, when trying to do so, each regulator senses not only the battery's voltage/resistance to charge, but also the voltage applied by the other charging system, which is relatively high, in order to charge the battery.

Thus each regulator cannot sense the battery's real voltage/state of charge, but is being confused by the other charging system trying to do it's job.

Confused yet? The regulators are! :lol:

Hope this helps. :idea

Joe. :teeth :thup

Thanks but that's clear as mud.

How does the above dovetail into a 3 battery system with a triple battery main
distribution panel having 2 dual circuits and battery switches plus 2 ACRs
(automatic charging relays; all 3 Blue Sea Systems) which supposedly automatically
combines batteries during charging, isolate them when discharging and starting
engines?

Aye.

Grandpa used to say, "If you can't understand it, can't fix it
with a hammer and screw driver, you shouldn't have it."
 
For all the caution I take, I only have one battery on my boat, but usually have a backup (all charged up) on board as well.

One issue on my boat is that it came wired very poorly. Everything worked, but there are lots of splices, very little organization, and lots of rats nests. Nothing is labeled and far too many wires lead straight to the battery.

I need to install more busses and/or maybe swap my original fuse panel for a nice breaker panel and not have to carry so many fuses with me, although the original panel would be fine with a little more bus capacity.

I'm grateful for this thread. It is good info and good motivation to do something I probably should have done awhile ago: Rewire and add figure out my battery bank.
 
you have a sophisticated system

ACR combines batteries during charging (regulator sees one battery), and isolates them when charging has stopped and after battery voltage has fallen. It is intended to keep a load from discharging both of the batteries. I assume it is setup as a 3 battery banks. Diagram would be useful
nice setup
 
Hi Foggy, FWIW on my former twin engined trawler we ran the charging wire from 1 engine to the starting bank and the other one to the house bank. It worked fine as long as you don't have them combined. I don't know why that wouldn't work on your outboards.
 
The 'system' was installed by C-Dory at the factory when I told them I wanted 3
batteries, instead of 2, which I thought in my head was going to be one starting
battery and two parallel batteries for the house bank. What I got was one switch
for "House'' (1 battery) and one switch for "Engines" (2 batteries). Apparently for a
3 battery system, two ACRs are required which acts like the brain to flow electrons
the right way without anything frying or exploding (my read).

It's all diagramed on the Blue Sea Systems website somewhere. And, to date, it
works, seemingly, despite the 'black box' concept to me.

So, I'm not sniveling, just reporting.

Aye.
 
A lot of good input here. I went through this a while back and this is what I ended up doing because I was strict on keeping the batteries in the Starboard Lazarette. I have 2 group 29's (very tight fit) with the blue sea systems add a battery system. The running lights and cabin lights are all LED. I know the running lights don't matter since the engine is charging but figured I'd change them all and sealed them well so hopefully I will never have to worry about changing them again.

I have all the electronics you speak of except of the big one-the fridge. Have you considered a Yeti or similar styled cooler? They are an expensive inital investment (cheaper than the fridge) but in my experience worth it. I"ve done a test at home in an average temp of 65F and got over 10 days with good ice. Of course all of this depends on location (direct sunlight), how often your opening it etc...... For my needs it works well and is one less electronic device to break too.

I always keep an eye on battery voltage while anchored but the add a battery system really puts your mind at ease because you know you will always be able to start the engines.

I'm also a paranoid indivudal so I always carry either a jumper pack or the honda 2000 with me when on longer trips.

Good luck with your decision.
 
I started looking at Blue Sea's Add-A-Battery but it is good for 2 -
not 3 - batteries. So, I had to ratchet things up ACR wise, as above,
for my 3 battery system.

There are small hi voltage chargers out there that make great claims about
starting car engines. Maybe, but no reports I've seen yet. Plus, I'd never
carry one of these in my pants pocket...

Aye.
 
Just an aside: Don't discount the idea of 6 volt golf cart batteries. I once traded out a bad 2D or 4D (I forget), for two golf cart batteries, that I had read about in "Consumer Affairs" magazine. They had better ratings than the much bigger battery they replaced.
 
The best battery hasn't been mentioned: 2 golf cart batteries in series. They have a capacity of 225 ah-hr @ a 20 hr rate. This will give you 112 ah-hr for a 50% discharge cycle. They're much sturdier than a RV battery and can recover from charging misteakes. Trojan T-105's are the best, but Costco has some cheaper ones; as with all Costco stuff not as good, lower amp-hrs.

Journey On also has a group 31 as a backup battery. We use a Honda 1000i, which will charge at 30 Adc. No need for a voltage sensitive combiner, because we always run off the golf carts. Unless I screw up, as I did at Catalina, when we used the grp 31. That one has a capacity of 150 a-h, giving a usable capacity of 75 a-h. Compare this number with the golf cart numbers.

Boris
 
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