Size of Battery Charger

[Saltyhog]

Originally Posted by zboss

Yes, planning on putting them under the pilot berth. There are currently 3 x Group 27 plus hardware mounted in there but there is a good 4-5 inches available above the top of the existing batteries. Just enough to squeeze in the lifeline batts I think. The electric guy is checking it out this week.

I believe I have room for six 6V lifeline GPL-6CT batteries. The existing 3 DC27s sit side by side... I can squeeze four lifelines into the same space. Then there is room for one more in that location. I would put the sixth into the starting battery area.

A four winds II came with the boat but I am not sure its working. We plan on adding Solbian panels to the dodger (2 x 50 watt) and probably (4 x 50 watt) to the bimini top. That would give us 300 watts of solar and maybe a working wind generator. We currently have a 90 AMP balmar alternator. I'm not sure if its externally regulated or not... have not gotten that far in my analysis of the vessels electrical system yet.

Nice! I'm glad to hear you're planning on using the Solbian panels. I'm planning on doing the exact same installation on our CR-38. I really like that I can add all that solar with out adding a bunch of junk on the stern. Will need to deal with a bit of boom shading, but I think that is a good trade-off for not cluttering up the stern with an arch etc. Plus, they'll be easy to stow if I want or need to take down the bimini.

Do you have a wood battery box under the pilot berth? Our's has this plywood box with lid that holds all the current batteries: 2x GRP31 for house, and 1xGRP27 for start. Sounds like you have a separate area for the start battery. Where is that?

BTW, Our boat is just across the bay from you. We're in Rock Hall. Next time I'm over there we should get together as I'd like to compare notes and plans for the boat.

-Tom

[Stu Jackson]

Before you spend your hard earned $$ on AGMs, consider this:

AGM Battery Issues (from Maine Sail)
AGM Batteries - Making The Choice - SailboatOwners.com

AGM Battery Issues and the Blue Seas Dual Circuit Switch (from Maine Sail) "DARN AGM Batteries"
Darn AGM Batteries - SailboatOwners.com

[zboss]

Originally Posted by Saltyhog

Nice! I'm glad to hear you're planning on using the Solbian panels. I'm planning on doing the exact same installation on our CR-38. I really like that I can add all that solar with out adding a bunch of junk on the stern. Will need to deal with a bit of boom shading, but I think that is a good trade-off for not cluttering up the stern with an arch etc. Plus, they'll be easy to stow if I want or need to take down the bimini.

Do you have a wood battery box under the pilot berth? Our's has this plywood box with lid that holds all the current batteries: 2x GRP31 for house, and 1xGRP27 for start. Sounds like you have a separate area for the start battery. Where is that?

BTW, Our boat is just across the bay from you. We're in Rock Hall. Next time I'm over there we should get together as I'd like to compare notes and plans for the boat.

-Tom

Yes, we also have a battery box. The starter battery is located further aft in another compartment. I have attached a pic.

We would LOVE to get together and trade notes and see your boat. Our boat is on the hard for a refit until (we hope) early October. Maybe we can drive on by some weekend when you are around, we will be working on the boat pretty much every weekend between now and october except this weekend to attend the JB concert here in Virginia.

[Saltyhog]

Originally Posted by zboss

Yes, we also have a battery box. The starter battery is located further aft in another compartment. I have attached a pic.

We would LOVE to get together and trade notes and see your boat. Our boat is on the hard for a refit until (we hope) early October. Maybe we can drive on by some weekend when you are around, we will be working on the boat pretty much every weekend between now and october except this weekend to attend the JB concert here in Virginia.

PM sent. -Tom

[hellosailor]

zboss-
As long as you are in for a major refit (batteries and charger) this really is a time to look into battery differences. I love AGMs because I hate battery acid, it always finds a way to eat something. BUT. Wet acid batteries are 1/3-1/2 cheaper no matter how you look at it. And for some odd reason the world dismissed gel batteries, when the companies that make all types are now quietly saying "Oh, right, well, gel is superior to AGM we make them all and know that." The big caveat with gel is that if you overcharge them--you destroy them. And they need a specific lower charging voltage, from the alternator as well. But they may be your best bet, if you match the chargers to their voltage.

And regardless of battery type, I'd suggest caution with the Honda. They're fine units but any genset can be a carbon monoxide problem when it is used on a boat. If you plan to have dockside power available most of the time, maybe split off a piece of your budget for solar panels instead. They can do a remarkable job at gently but fully topping off your batteries and keeping them that way, whether you are on or off the boat. No monoxide, no noise, no fueling.

[Forever Freedom]

Originally Posted by zboss

No problemo... where did you get that sizing info. I now understand why he is recommending what he has... I have room for the lifeline AGM's due to the height of space available, and per the manufacturer directives for these batts I need a charger which is 20% of the capacity.

I think I need to redirect him to the Trojans or similar, which was my first thought. What size charger is recommended for Trojans on a % basis?

Also, I am having trouble grasping what 1/C, 2/C, etc. mean. I understand that C means "overall capacity" but don't get the '1' or '2' designation.

- z

The info came from the Mastervolt site. If you are going to get Lifeline Batteries, then pages 19,20 and 21 of this are essential reading: http://www.lifelinebatteries.com/manual.pdf

[mbullock]

My only comment would be that if you aren't going to upgrade your charging capacity then don't spend money on the Lifeline batteries. I spent a long while thinking over a similar problem. At the end of the day the Lifelines are very expensive BUT very good. However, in order to get the 'very good' bits you must charge them well. As someone else has said Lifeline require at LEAST 20% the capacity of the bank, and their song and dance is charging to something like 250% of the bank (I don't have the manual right now so that's a guess!) - either way they will take a give a lot of current. The flip side is that AGM's seem to want to be 100% charged at least every month, and as stated Lifeline want their batteries to be given a thump. If you want to stay static re charging capacity why don't you go with cheap sealed lead acids, they cant take probably more than ~15% and probably wont ever get past 90% charged and will probably fail after a few year - but they will be around 25% the cost of the LifeLine's so in the end you can have 4 failures!

In the end I got a great deal on Mastervolt AGM's and fitted those. For a ~500ah / 24V bank I fitted 120ah of charging capacity from shore or genset power. I still need to sort out alternator and solar/wind...

the other option is to use no power and have tiny batteries

[Forever Freedom]

Originally Posted by mbullock

My only comment would be that if you aren't going to upgrade your charging capacity then don't spend money on the Lifeline batteries. I spent a long while thinking over a similar problem. At the end of the day the Lifelines are very expensive BUT very good. However, in order to get the 'very good' bits you must charge them well. As someone else has said Lifeline require at LEAST 20% the capacity of the bank, and their song and dance is charging to something like 250% of the bank (I don't have the manual right now so that's a guess!) - either way they will take a give a lot of current. The flip side is that AGM's seem to want to be 100% charged at least every month, and as stated Lifeline want their batteries to be given a thump. If you want to stay static re charging capacity why don't you go with cheap sealed lead acids, they cant take probably more than ~15% and probably wont ever get past 90% charged and will probably fail after a few year - but they will be around 25% the cost of the LifeLine's so in the end you can have 4 failures!

In the end I got a great deal on Mastervolt AGM's and fitted those. For a ~500ah / 24V bank I fitted 120ah of charging capacity from shore or genset power. I still need to sort out alternator and solar/wind...

the other option is to use no power and have tiny batteries

I second this. It's pointless getting expensive batteries and then not fitting a commensurate charging package. We have spent a lot of money on Balmar alternators and external charge controllers; a Victron Phoenix Multi Inverter/Charger 12/120/2500; solar panels and controllers; a Fischer Panda 4000i generator - all connected with large diameter multi strand tinned cable to reduce voltage drop. After 10 years we have just installed our 3rd set of 4 X 105 Ah sealed leisure batteries as the domestic bank - not bad considering we live aboard for 10 months of the year and we are an "all-electric" boat, including cooking, microwave, washing machine, electric hookah compressor, water maker, electric windlass, 3 X Macs etc., etc. I think we all tend to consider the batteries first but, if you can't charge a cheap bank properly, what is the point of getting an expensive one . . .

[Stu Jackson]

Originally Posted by Forever Freedom

I think we all tend to consider the batteries first but, if you can't charge a cheap bank properly, what is the point of getting an expensive one . . .

That is a very enlightened quote. Thanks.

I think a LOT of folks "struggle" with boat electrical systems, I certainly have helped dozens of them, as have many folks on this and other forums.

This and the post before have discussed the requirements for keeping AGMs healthy. One that is included in the links I provided in my last post (written by Maine Sail) include this important proviso: they fail catastrophically with little warning, while wet cells will deteriorate over time and should be quite evident to anyone who's watching the store.

Good luck, regardless of your choice.

[ranger58sb]

Originally Posted by Maine Sail

IIRC correctly Lifeline recommends, in their technical manual, a charger capable of a min of 20% of Ah capacity for the longest life. This is the min recommendation. Just be glad you don't have Odyssey batteries as they want to see a min of 40% of Ah capacity...

Hmmm.... I have two banks of 300Ah Odyssey Group 31s (plus a smaller gen starter... on a 3-bank 40-amp charger.

You're saying I'm under-amped (so to speak)? It happens I've been planning a charger charger upgrade, but haven't been in a big hurry...

-Chris

[Capt Alfex]

ranger42c:

Yes. You have a 2 x 300 Ah = 600 Ah + 50 Ah (gen start) = 700

Therefore you should have 70 Amp charger minimum using 10% sizing.

A 3 bank charger is "normally" designed to charge Start Battery Banks (50-200 Ah) using 5-40 amps to charge each individual battery.

Once you get a House Bank, it is "usually" a deep cycle type and has over 200 Ah capacity. Then you would probably have an inverter/charger which have 100 Amp chargers built in.

So in your boat: A single bank charger for the gen start battery and also an inverter/charger for the two Group 31 banks.

PS: Some inverter/chargers have an additional built-in smaller 10 amp charger called an "echo charger" for just charging start and gen start batteries.

[ranger58sb]

Originally Posted by Capt Alfex

ranger42c:

Yes. You have a 2 x 300 Ah = 600 Ah + 50 Ah (gen start) = 700

Therefore you should have 70 Amp charger minimum using 10% sizing.

A 3 bank charger is "normally" designed to charge Start Battery Banks (50-200 Ah) using 5-40 amps to charge each individual battery.

Once you get a House Bank, it is "usually" a deep cycle type and has over 200 Ah capacity. Then you would probably have an inverter/charger which have 100 Amp chargers built in.

So in your boat: A single bank charger for the gen start battery and also an inverter/charger for the two Group 31 banks.

PS: Some inverter/chargers have an additional built-in smaller 10 amp charger called an "echo charger" for just charging start and gen start batteries.

Thanks. Yes, I knew about the 10% sizing rule of thumb, and in fact that's why I've been planning an upgrade anyway.

But I'm not sure how to understand Maine Sail's note about 40%...

-Chris

[Capt Alfex]

Maine Sail is talking about absorbed glass mat (AGM) batteries made by Odyssey® which require a battery charger with 40% of Amp Hour (Ah) capacity to charge with. They even have a special list of chargers that they recommend for their batteries.

So, unless you are using these type batteries, don't worry about it. Use the 10-20% of Ah capacity and you will be fine.

[ranger58sb]

Originally Posted by Capt Alfex

Maine Sail is talking about absorbed glass mat (AGM) batteries made by Odyssey® which require a battery charger with 40% of Amp Hour (Ah) capacity to charge with. They even have a special list of chargers that they recommend for their batteries.

So, unless you are using these type batteries, don't worry about it. Use the 10-20% of Ah capacity and you will be fine.

Yep, those are the batteries I have.

Before I installed the first bank (early 2006) the Odyssey guy reviewed my current set-up, and pronounced it acceptable. I don't remember seeing the 40% number anywhere before, but of course I'm looking now...

-Chris

[Maine Sail]

Originally Posted by ranger42c

Thanks. Yes, I knew about the 10% sizing rule of thumb, and in fact that's why I've been planning an upgrade anyway.

But I'm not sure how to understand Maine Sail's note about 40%...

-Chris

For the best longevity of your expensive TPPL batteries Odyssey suggests at least 40% of "C"... It is in their technical manual... These batteries like to be hit hard and Odyssey has determined that 40% of capacity is what is minimally needed. Hitting these minimums with Odyssey can get very hard when banks get large so you often just suck it up and take the cycle life hit..