Battery choice

[ruiz488]

Hi Guys and Gals!

I need to replace my batteries and like all of us, I have space and weight constrains.
I'm projecting using in between 100 and 150 A/day and also planning to set up a 200 A alternator with AR 5 regulator..... what is the forum's suggestion?

1) 4- 6 V tall flooded at total of 740 A
2) 4 group 31 12V flooded total 620 A
3) 4/5 group 31 12V AGM at 420-525 A.

I'm partial to the AGM but wih the 6 V a get far more amps...but as usable as with the AGMs?


thank you

[k1vsk]

All good choices and personal preference certainly plays a part in what you finally decide. Given the AH needs to stated, check out the Torjan L16Ts which might give you the longest life presuming your okay with monitoring fluid levels frequently. Everybody has their favorite theory on whether or not AGMs are worth it.

[camaraderie]

Ruiz..First, I might rethink that 200A alternator. That will bequite a strain on most engines and 100-125 should be plenty for your needs. You don't want to be using the engine for charging your bateries unless underway anyhow.

I don't know why 4 AGM's should give you less amp hours than 4 flooded. The mfr. specs may vary between brands and they may rate agressively or conservatively. As a class, Group 31's should deliver the same amps sso you may just need to look at a different brand or determine the "rating" system but I would use 110AH as your average. I don't know HOW any flooded group 31 can deliver the 155A/H's you claim. That is a 4D rating!!
You don't spec out the 6V battery so I can look at it but I am thinking that you may be looking at a VERY different rating spec since each would have 155AH rating at 12V for what you say to be true. Those would have to be VERY big 6V batteries.
Do you have links to any of these products?

[erps]

Ruiz,
When two 6 volts batteries are combined in series, you double the voltage but not the amperage.

Ray

[btrayfors]

I suspect Ruiz knows that, and he's done his homework.

Four Trojan L16H's (420AH each) would give him 840AH at 12V. Four Trojan J305H's (335AH each) would give him 670AH at 12v. These are both "tall" 6V batteries. Lots of choices of these from other manufacturers as well.

Ruiz...

My preference would be to go with choice #1. I agree with the comment about rethinking the 200A alternator, because:

a) you don't need that much to charge a 700AH battery bank....100-120A would be sufficient; and

b) the problems of adequately belting at 200A alternator are magnified significantly over, e.g., a 120A alternator.

Bill

[camaraderie]

Ahhh...thanks Bill...they are big! Guess he has the depth to handle that but no more "floor" space. I agree with your advice...840 is better than 440!

[ruiz488]

Thank you al of you for the support, I'm glad I joined this forum.

Few comments
1) the 6 V ad 12 V flooded are all fom Crown batteries which seem to have an excellent reputation.
2) Th 6 v are 16" high instead of the standard 9" average so there is the difference in capacity and also weight about 123 lb.
3) The capacity of 155 and 185 A is for their model CR 155 and CR 185 wich as the same dimensions as the type 31 so therefore I called them 31 to simplify the mail. ( look in the Crown battery site )

4) The AGM batteries mentioned are Lifeline which are suposed to be top notch West Coast made and standard equipment on upscale new boats. I do not know why their rated capacity is somewhat lower that the equivalent flooded, I assumed that is part of the technology etc.

5) The reason why I choosed or planning to, a 200 A alternator is based on Nigel Calder's reccomendation, his book and personal boat and he is considered the "guru" of electrics/electronics.

He has on board his 40 cruiser
-675 A agm's total in house plus 100 a starting AGM
-2 alternators ..1 for the starting battery (plus additional support) of 80 A and Balmar of 200 A. the first one with internal regulator and the 200 A with a AR 5 also from Balmar.
He supplements its power genration with a wind vane and 2 Siemens ( wattage unknwon presumabbly 75 W)

Let us remember that AGM do not have charging limit ( theoretically) while with flooded you do not want to go over 25/35 % of total capacity maximum.

Calder has all standard equipment on board a long range cruise, windlass, 12 V freezer and cooler, SSB, electronics, audio etc etc.

I hope it helps alo lke many of you, I am somewaht concerned about such a large alternator but it seems to be the way to gfo theses days, more eficient, less time running the engine a fairly medium charge ( good) etc.
althogh the power penalty is considerable azt close to 8 HP for the 200 A alone.

[ruiz488]

Thank you al of you for the support, I'm glad I joined this forum.

Few comments
1) the 6 V ad 12 V flooded are all fom Crown batteries which seem to have an excellent reputation.
2) Th 6 v are 16" high instead of the standard 9" average so there is the difference in capacity and also weight about 123 lb.
3) The capacity of 155 and 185 A is for their model CR 155 and CR 185 wich as the same dimensions as the type 31 so therefore I called them 31 to simplify the mail. ( look in the Crown battery site )

4) The AGM batteries mentioned are Lifeline which are suposed to be top notch West Coast made and standard equipment on upscale new boats. I do not know why their rated capacity is somewhat lower that the equivalent flooded, I assumed that is part of the technology etc.

5) The reason why I choosed or planning to, a 200 A alternator is based on Nigel Calder's reccomendation, his book and personal boat and he is considered the "guru" of electrics/electronics.

He has on board his 40 cruiser
-675 A agm's total in house plus 100 a starting AGM
-2 alternators ..1 for the starting battery (plus additional support) of 80 A and Balmar of 200 A. the first one with internal regulator and the 200 A with a AR 5 also from Balmar.
He supplements its power genration with a wind vane and 2 Siemens ( wattage unknwon presumabbly 75 W)

Let us remember that AGM do not have charging limit ( theoretically) while with flooded you do not want to go over 25/35 % of total capacity maximum.

Calder has all standard equipment on board a long range cruise, windlass, 12 V freezer and cooler, SSB, electronics, audio etc etc.

I hope it helps alo lke many of you, I am somewaht concerned about such a large alternator but it seems to be the way to gfo theses days, more eficient, less time running the engine a fairly medium charge ( good) etc.
althogh the power penalty is considerable azt close to 8 HP for the 200 A alone.

[Cruisingdad]

Well, I would give the lifelines a positive reccomendation. They are pros and have great customer service. They know their stuff and believe in their product(s).

As far as the alternator, I have to say that I agree that 200amps is pretty darned high. What if you are going to weather or into a strong current. If that thing is pulling 200, is your engine strong enough to still maintain the power you need? I don't know what you have, displacement of your boat, etc... (so telling us what your engine is will probably not do a lot of good, since there are many other varying factors). I would probably just drop a 100-120 in with a MS Charge controller, and plan on running it longer. If you have a generator, I would DEFINITELY not go with a 200 because the generator will be more efficient (fuel).

Instead, consider a wind gen and solar panels to help you balance out your load needs.

Just my thoughts.

- CD

[camaraderie]

Ruiz...understand your reasoning. I have over 1000AH of batteries on my boat and still would not put a 200AH alternator on my engine...despite Calder!! He is indeed a guru and I follow his advice myself on many things but the stress on the engine bearings is considerable. May I suggest you contact your engine manufacturer and ask them is attaching a 200AH alternator would have any effect on your warranty.
I understand now why your battery A/H atings are a bit higher than standard wet group 31's. One thing I guess you are considering is that with a larger wet cell bank you should probably be able to deliver the same bulk charge amps in a relatively short time as you could with the AGM's if you are close to 800AMP capacity with wet cells and a 200Amp alternator. Plus...you'll have extra usable capacity. Offsetting this is the additional maintenance you will face and the longer projected life. Tough decision...but cost differential should probably sway you to the flooded unless the space is really difficult to get at for maintenance.