Battery management

The current situation:

I Close tomorrow on my (new to me) 2003 Ocean Alexander 456. I need new batteries. All of them are bad. It has 2 8d gel cell batteries for the house bank, one each 8D lead acid battery for each engine, a 4D battery for the 12 KW generator and a Group 31 for the 6KW generator. All batteries but the house bank are normal lead acid and the house bank is gel. The engines each have a 115 amp alternator. The alternator, I believe, is regulated for a lead acid batteries.

I am having batteries delivered to the boat on Tuesday and need to tell the shop on Monday what type of batteries to bring. I hope to take the boat from Pompano Beach Florida on Friday to Norfolk Virginia.

My thought is to continue with the current configuration of the gels for the house bank and lead acid batteries for everything else. The house bank has his own charger which is programmable for jail cells. The 12 KW generator and two engine batteries are all tied to A 30 amp charger. The 6KW generator is tied to a trickle charger.



My thought is that I can parallel the engine batteries in the house bank while the engines are running, which will provide a total of 230 A of power to the 4HD batteries. Gels take a higher voltage the lead acid and should not be harmed by the lower charge voltage put out by the engine alternators. I will top the batteries off periodically wall I sure power or while running the generators. I understand that when running the charger I will have to open, that is to say, shut off the parallel connection between the house bank and the engine batteries.

Does this configuration and my plan for battery power management makes sense to those of you who were experience with trawlers?

Gordon

Personally I would rather have AGMs than gels, or plain old deep cycle lead acid flood batteries for house use and simplicity.
Who are you using for a supplier down there? I've done most of my heavy battery buying in So. FL.

George, I am having the batteries delivered by Fort Lauderdale battery. They are charging 500 for gels and $550 for AGM. That is for 8Ds. I would use all lead acid, but the house bank is in a very difficult spot and it is difficult to monitor the electrolyte. I would essentially have to take the cushion off a Settee, open the floor and crawl into the into the ER to check the electrolytes. That is a lot of work to go through and no maintenance batteries would be so much easier. I was thinking of jel cells for the house bank, because their charge voltages more closely resemble normal lead acid batteries. When using the two engines to charge all the 8D batteries I thought that the greater similarity between gels and lead acid Would result in a happier charging system.

Girdon

"I would essentially have to take the cushion off a Settee, open the floor and crawl into the into the ER to check the electrolytes."

Perhaps not needing to check weekly would be a help?

Hydrocap | Information

www.[B]hydrocap[/B]corp.com/info.htm


HYDROCAPS are a must for lead-acid battery users. Just look at the increased safety, reduced maintenance, increased battery longevity and reliability as well ...

Gordon J said:

Gels take a higher voltage the lead acid and should not be harmed by the lower charge voltage put out by the engine alternators.

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I'm almost positive I've seen battery specs where gel charging voltages are LESS than FLAs. You might double-check, using manufacturer's specs for all your specific target batteries.

I could be wrong, of course. Memory would perhaps be a wonderful thing... if I had one.

I think I'd investigate 6V golf cart batteries for the house instead of the 8Ds. Two 8Ds is about 490 Ah. Six GCs is about 660 Ah, and might fit in approx. the same physical space. Lifeline (and maybe others) makes AGM 6Vs, so no maintenance. And each individual batteries weighs less than an 8D, so you might survive the schlepping a bit better.


Whatever... you'll want your charger(s) to be right for the optimum regime each bank as suggested by the battery manufacturer, no matter what chemistry or configuration.

-Chris

I appreciate the comment about golf cart batteries. Perhaps next time that I change out batteries. I really don't want to go through the work now love making cables and reconfiguring a boat. My cast now is to take the new boat 1000 miles of the ICW and park it in my backyard.

I think my question might be boiled down to the following: Will running both engines and keeping the engines 8D batteries parallel with the two HD house batteries charge all four batteries with 230 amp hours, but can find out put a boat engine alternators? Will each of the alternators see the other and monitor their output accordingly?

Thanks and advance for your thoughtful answers.

No.
Why spend a lot of money becuase you are in a hurry?
If you take the time to have along term plan, there is no reason why whatever batteries you choose can not last 5 to 8 years, maybe more.

However, by having a variety of batteries, with all different chemistry, you are cruising for a bruising.

Your current plan leaves you no secondary charging backups with changing or screwing up something.

Personally, I would go with all AGM's or Golf Cart, with the only exceptions being the start batteries for Engines and Gen.

Also, in my research, I have seen NO advantage of GEL over AGM and some disadvantages, which I frankly don't remember because at that point, I'd made up my mind.

Also, chronic under charging a battery will lead you being in the same situation a year or two from now.

Please Gordon. Take a deep breath and slow down, if only ONE day.

Gel Cell batteries were first developed for aircraft and other applications where venting, tipping and inversion were problems. AGMs then came along and are superior in all respects to Gel Cells. So if you have to use 8Ds and don't want to have to check and add water, then use AGMs and not Gel Cells. Flooded cell batteries would be cheaper, but unless you go with very expensive batteries, true deep cycle batteries are generally not available in 8D sizes. Any battery charger with a Gel Cell setting probably also has an AGM setting, so make that switch. The AGMs should work fine if paralleled with your alternator output as they have a similar charging profile to flooded cell batteries.


But I absolutely hate 8D batteries. All it takes is a single jumper wire to make two GC batteries work in place of an 8D, so it is not a big deal to switch.


But what kind of boat are these in? The Beneteau 423 listed in your profile doesn't have two engines and would not need an 8D to start it if it did, so it must be something else. What engines do you have? 8D starting batteries are almost certainly overkill unless they are DD 6-71s or similar "big iron".


And finally, you have 115 amp alternators on these engines. Are they externally regulated with a three stage charger. If not, you will not see anywhere near a 230 amp charging rate.


DC battery management is one of the most complex things to think about, configure properly and operate properly on a long term cruising boat. It is almost impossible to understand your system and your DC needs and offer a comprehensive solution over the internet. You probably need to spend some time with a qualified marine electrician.


David

I am no fan of gels. Mixing AGMs and normal lead acid CAN be detrimental to AGMs, but not necessarily so. And I will probably go with AGMs. My question had more to do with using both engine alternators simultaneously to charge start batteries and house bank.

My sail boat had only one engine and. House bank of 4 rad AGMs batteries. The start battery was also AGM. I never used the start battery but instead used the house bank exclusively. So, I was charging the house bank when motoring.

Now, is the logic the same when running two trawlers? If both engines are running in parallel with house bank, do I have a potential charging output to house bank of 200 plus amps? OR, will the two alternators see each other and reduce their output?

This boat also has two gensets that have separate start batteries, so theoretically, I should never be in a bind electrically, if I forgot to open the parallel switches and ran the engine starts two low. (And of course I know that is not good for the batteries).

So let's assume that I have thoroughly researched batter chemistry, understand the potential improvemen of golf cart over 12 volt.

Thanks again for your answers and input.

David,

Answers to some of your questions I original post. Engines are Cummins 6BTA5.9

The problem of golf carts is two fold at my current location: battery box configuration and making battery cables.

Understand that I may not get the total of both alternators; my question had to do with two alternators charging house bank and start batteries...what issues might I face. With charging voltages of 13.8 - 14.2, the AGMs will never be topped off until I turn on generators or connect to shore power.

So my question has more to do with using engine alternators to charge house AGM bank.

Gordon

Gordon J said:

Mixing AGMs and normal lead acid CAN be detrimental to AGMs, but not necessarily so. And I will probably go with AGMs.

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Can't speak to the alternator question...

When we started our switch-over from FLA to AGMs, I asked the Odyssey guys about mixing... 'cause I had one dying bank of 3x Group 31s, one good banks of 3x G31x, and one good genset starter battery (G27, I think)... all on the same charger. And there's that pesky expense thing; didn't want to buy it all at once, if I could help it.)

The charging profiles for the FLAs and the AGMs were similar, but not identical. The charger has a switch only for FLAs or Gels. The charger guys (and their manual) said use the FLA setting for AGMs.

The Odyssey guy told me the charging profiles were close enough so we could replace the bad bank, keep using the good bank and the good genset battery, and all on the same charger.

(Then we eventually replaced the other banks, about 3-1/2 years later.)

That first bank of AGMs has been through 10 seasons, now, still holds voltage somewhere up near full. (And the others still act like new.)

As I said before, Lifeline makes 6V AGMs, so you can (if you want) get the best of both golf cart and maintenance-free in the same product. Maybe others make that combo too. I haven't priced, maybe cost and arm and a leg, but it'd probably last a decent while.

I also haven't checked charging profiles to see whether such a bank could co-exist on my current charger when I have to replace the older 3xG31 bank. I'm thinking of putting an inverter-charger all alone on that bank anyway, though, if I replace 3xG31s with 4xGCs.


I think 6x GCs fit in approx. the same space as 2x 8Ds.

-Chris

Gordon

You started this thread by saying your batteries are bad. Do you know why? Until you know and can properly monitor things (BMKs, hydrometer) all advice is just guessing.

To keep it simple and get on the road, AGMs for under couch and coin flip the rest. Just don't try anchoring out though, you may be stranded.

Gordon, I have no experience as you asked for in your initial post, but if the alternators are internally regulated I would be fearful that you won't get anywhere near the amount of charging you need and it is just a guess as to how each will respond to the presence of the other in the charging circuit.

I understand the problems of location and time that you are facing. I also recognize that you are wanting to get your question answered.

For this coming trip, a quick and dirty solution would be to keep the engines charging their own batteries and simply run your large generator to keep your house batteries charged as needed. If I understand the situation, your larger generator should be capable of your house. It is hard for us sailors to reconcile running a generator a lot, but it is what it is. When you get home, you will then have the time to come up with a final plan.

A group 31 will be fine for the 12KW genny.

I think my question might be boiled down to the following: Will running both engines and keeping the engines 8D batteries parallel with the two HD house batteries charge all four batteries with 230 amp hours, but can find out put a boat engine alternators? Will each of the alternators see the other and monitor their output accordingly?

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Alternators only put out max current for a brief period until battery voltage increases a little. They would probably overheat if otherwise.


I sure would try to resurrect those old batts for the trip. You have enough gennu power to charge the start batteries for a start unless they are dead short. Use the genny for house lights if you are not at a dock. Get home then figure it out.

bayview said:

Alternators only put out max current for a brief period until battery voltage increases a little. They would probably overheat if otherwise.


I sure would try to resurrect those old batts for the trip. You have enough gennu power to charge the start batteries for a start unless they are dead short. Use the genny for house lights if you are not at a dock. Get home then figure it out.

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That was kinda my thinking. You have a ton of electrical power. Get home and then do it right. I wouldn't rush to replenish a potentially flawed system...or one that is less than optimum. Get home....sort it out...and then do it right!!!

I appreciate everybody's comments. The batteries are totally toast. I can only start the engines when I parallel all batteries and keep the battery charger on.

I believe dad to the previous owners maintenance personnel kept the batteries on parallel and charged the gels and FLA's at 14.6 V. They have been cooked. There is no question that I will be getting new batteries tomorrow. I am going down to the ER now to measure the battery boxes to see if they will accommodate golf carts.

Thanks for all the advice. I will figure out how well the alternator batteries keep the house bank afloat. I wish this boat had a status of charge meter, unfortunately it does not. That is now on my to do list.

If you have a voltmeter, you can determine your battery charging. Select the start battery and check resting voltage. Select house batt and Check resting house V. Reselect start batt and start one engine and check V. Start second engine and check V, then stop first engine. Check V.

Select house batt and check V with second engine running. Start first engine and check V. Stop second engine and check V.

If your batt V changes each time you change charging sources, you have an indication of what's connected. If no change in V, there's no connection.

All boats can be different. Mine has been modified to always provide the charge to the respective battery regardless of switch position. The switch only selects load, not charges. The alternator charges are wired directly to their respective bank.

bayview said:

Alternators only put out max current for a brief period until battery voltage increases a little. They would probably overheat if otherwise.


I sure would try to resurrect those old batts for the trip. You have enough gennu power to charge the start batteries for a start unless they are dead short. Use the genny for house lights if you are not at a dock. Get home then figure it out.

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Not true. A car alternator yes; but not a true marine alternator.

How do you think I charge my 880 amp/hrs every day.

An 8D battery box will accommodate two GC batteries, but they will slide around a bit. Better to get a box that fits or put a space inside to secure them, but for short term, ok.


Two internally regulated (or three stage externally regulated for that matter) alternators will coexist fine in parallel. They will just share the load. An externally regulated alternator will recharge several times faster because the fixed voltage of the internally regulated alternator isn't enough for rapid charging past about 75% charged. A three stage regulator will push the voltage to 14.5 or so at that point, whereas the internal regulator is fixed at about 13.5 v.


8D starting batteries is overkill for everything. A good Group 31 with decent sized cables and good connections will easily start a Cummins B. Look for a Group 31 with a 950+ CCA rating. They weigh about half of what an 8D weighs. Again one will fit in an 8D battery box, but better to get one specifically made for it.


David

My 8D battery boxes each hold 3 GC LA batts. I personally removed the 8D batts and inserted the 3 GCs. They fit fine.

Wxx3 said:

Not true. A car alternator yes; but not a true marine alternator.

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Not true. At least of all "marine" alternators.

If you are talking about Ft Lauderdale Battery and Alternator, they are a good shop and straight shooters. My advice, beyond going with AGMs instead of gels for most of the reasons given by others, primarily the similar charging profile to FLA, would be to discuss your issues with FLBA. If it is relatively easy for some husky fellows to take out and install 8Ds I'd stay with them.. manhandling and cabling a couple of golf carts in a rough space is no dream either.. and the 8Ds could well be simpler.

Make sure you check and chargers or regulators involved have not been set to charge gels, and not all of them are easy to switch back. Another excellent source of info is Ward's.

I confronted this issue with my (2) 8D 24v thruster (and miscellaneous other stuff) bank tucked in the generator room. They took a little doing to extract and replace, but the guys I had muscle them around felt it was easier than screwing around with multiple smaller alternatives… none of which I was in any shape or disposition to do myself.

Properly charged gel batteries, and I am suggesting quality GEL's like the East Penn or Sonnenschein Prevailer, can be some of the longest lasting deep cycle batteries I've seen in the marine environment. The key here is "properly charged"...

I have numerous GEL banks on cruising boats in excess of 12 years and one bank in year 16. It's not just me who has noted long GEL life, Sandia National Labs has conducted numerous PV studies showing the long cycle life of GEL's.

I can only offer my experience across many hundreds of cruising vessels. You certainly can maximize the cycle life of any AGM or GEL battery but it can get expensive to do it correctly for optimal cycle life. If the batteries are not going to be treated properly; temp compensated charging, not in an engine space, correct charging voltages, regularly cycled back to 100% SOC, etc. etc. then good old flooded deep cycles can make a bit more sense in a sub optimal installation.

I install a lot of AGM batteries but they are always installed and addressed as a compete system not just a drop in replacement for flooded batteries. These day's I am doing more Firefly AGM than the others, but case sizes are limited to G-31. They are tremendously robust batteries that are designed to be PSOC cycled (partial state of charge cycling). The fact that Lifeline AGM's can be equalized makes them a standout for a PSOC environment but Odyssey & Northstar, with the ability to absorption charge at 14.7V, limits the need for EQ.. In the Practical Sailor PSOC testing they out performed the Lifeline's most likely due to the 14.7V absorption limit vs. 14.4V...

John Harries has written extensively about AGM's and it's a must read for anyone considering AGM:

Morgan's Cloud AGM's

Perhaps the best way to see how a battery could perform, against its siblings in a line up, is to look at a manufacturer who makes all types. For the Deka/East Penn brand this is how they rate their own batteries.

Important: Only ratings within a brand/manufacturer are useful. Cross brand cycle life data is often pretty useless because there is no industry standard for testing and each manufacturer may choose a different BCI test..

Most of the cycle life data from manufacturers is Disney fairy tale stuff if you try to apply it to marine market use.. Only in-house manufacturer testing across their own batteries can be compared for guidelines of "lab" data.

East Penn:
-GEL Cycles to 50% = *1000 Cycles
-6V Flooded Golf Cart - Cycles to 50% = *700-1000 Cycles
-12V Flooded 4D, 8D, 24, 27, 31 - Cycled to 50% = *350 Cycles
-AGM Cycled to 50% = *300 Cycles

*NOTE: These are usually not what you will see in the "real world" because this is white coat white glove lab data.

That is not my data but Deka's own data across their own batteries taken right out of their literature.....

As can be seen;

*They rate their 12V DC wets at 50 more cycles than AGM. (not a true deep cycle)

*They rate their 6V DC wets at 400 - 700 more cycles than AGM

*They rate GEL at 700 more cycles than AGM...

Course this is only East Penn..

The problem with GEL batteries was the folks who initially marketed them not really the batteries themselves. GEL was having a hard time gaining foot hold due to the lower voltages (14.1V) so they began telling everyone it was okay to charge them with flooded profiles. This was a mistake.. It gave GEL's a black eye and allowed the AGM makers to gain a stronger foot hold.

AGM makers then began a misguided marketing campaign about depth of discharge, initially recommending 80% DOD to justify cost. Today most recommend 50% max cycling DOD. Initially some even suggested a lack of sulfation etc., etc... They too gave themselves a black eye and had to adjust much of the early marketing.

If I was choosing a cruising bank of valve regulated lead acid batteries for my own vessel, and Firefly was not an option, it would be a bank of Sonnenschein Prevailer GEL's.

If you can charge the GEL's properly don't discount them. If you can charge quality AGM's properly don't discount them either. Lauderdale Battery knows GEL's better than anyone I know of.

FWIW I have no real dog in this fight, I don't use lead acid batteries....

For a $50 difference for an 8D AGM vs Gel I would certainly go AGM.

Sounds to me that if your boat is equipped with gels and it's also properly configured to charge the gels and you're considering replacing gels....then....gels just might be the best answer. I've learned a lot from this thread! Great post, CMS!

Put me in the golf cart column. Just swapped out 3 8D POS batts with 11 battery bank (8-GC2 for house+3-Group 24 to start). If you want to anchor out or cruise at all golf cart bats are the only true deep cycle (wet cells) and give you FAR more amps per dollar ratio. There are almost no deep cycle 4D, 8D, Group 27, 24, 31 batts out there. It doesn't matter what the sticker says... It just ain't so.

HOWEVER... If your situation calls for low-access, maybe you DO have to fork out the buck for maintenance-free batteries. Only you can decide that.

Just to bring everybody up to speed, I have opted to go with 8D normal lead acid batteries. After doing research on the boat yesterday I found that the original inverter charger – A trace – has only two settings: one for gel and one for normal flooded batteries. The gel setting charges the batteries at 14.5 to 14.6 volts. This is more in the AGM resume and probably not suitable for gels. I am guessing this is why the current gels are no longer good.

So with the current inverter charger, I am limited to AGM's charging as gels or flooded acid batteries.

I appreciate the answer on two engines charging the house bank. That is what I suspected and that is what makes sense. I just wanted to make sure that there was nothing going on that I did not understand about charging from two engine simultaneously.

Gordon

Capt.Bill11 said:

Not true. At least of all "marine" alternators.

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Capt Bill,

Since you seem to know what I meant by "marine" and how it's different than a car battery, why don't you explain the difference to the rest of us boys and girls?

Gordon J said:

Just to bring everybody up to speed, I have opted to go with 8D normal lead acid batteries. After doing research on the boat yesterday I found that the original inverter charger – A trace – has only two settings: one for gel and one for normal flooded batteries. The gel setting charges the batteries at 14.5 to 14.6 volts. This is more in the AGM resume and probably not suitable for gels. I am guessing this is why the current gels are no longer good.


So with the current inverter charger, I am limited to AGM's charging as gels or flooded acid batteries.

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Reasonable hypothesis.

I know you said servicing those house batteries would be difficult; maybe investigate battery watering solutions to mitigate.

FWIW, somebody mentioned (within the last 2-3 days or so) a brand I'd not heard of, either here or on Cruisers Forum... said it was the boss. Google "Battery Watering Technologies".

Another FWIW, our AGMs say they need a minimum 40-amps and bulk/absorption charges between 14.1 and 14.7V... quite a wide range of "acceptable." Happens our 40-amp charger does 14.7V on the FLA setting (it's old-ish and has no AGM setting or profile), and then floats at up to 13.5V... so serendipity worked.

-Chris