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Batteries again

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Dave5041
Former Mainsheet Editor

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USA
3758 Posts

Initially Posted - 03/04/2015 : 19:08:26

Dang it, my 8 year old Walmart battery died. I did the homework and and am torn between replacing it with another maintenance free (almost) flooded cell or replacing both batteries with gels. AGM lost out due to their reduced capacity for a given size even though I would only need to buy one since it would be compatible in charging. Their greater capacity per pound is of less concern to me than total capacity in the volume I have available. Independent tests also support gels being much more tolerant of deep discharge in regards to service life. Buying batteries isn't nearly as much fun as buying other boat parts.

Dave B. aboard Pearl
1982 TR/SK/Trad. #3399
Lake Erie/Florida Panhandle

Voyager
Master Marine Consultant

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5434 Posts

Response Posted - 03/04/2015 : 20:58:04

If you replace one and they're wired in parallel, you gotta replace both. That gets really pricey.
If, however, you have two separate batteries (A-B-Both-Off) then it's not so critical unless you frequently use "both" in parallel.
But if you use the A battery for house and the B battery for backup, you should be fine. I bought a flooded group 27 for my main battery.

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

redeye
Master Marine Consultant

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3478 Posts

Response Posted - 03/05/2015 : 07:43:45

Buy one agm maybe. I feel I need less battery with a solar charger putting in power all the time.

If you have a solar charger..

IMHO

Ray in Atlanta, Ga.
"Lee Key" '84 Catalina 25
Standard Rig / Fin Keel

Edited by - redeye on 03/05/2015 07:48:54

Stinkpotter
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Djibouti
9089 Posts

Response Posted - 03/05/2015 : 08:40:18

With a gel-cell, just be sure your charging system is properly regulated specifically for gels. Ordinary chargers or voltage regulators on motors can damage a gel-cell. AGMs are less persnickety.

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage before going over to the Dark Side (2007-2025); now boatless for the first time since 1970 (on a Sunfish).

Edited by - Stinkpotter on 03/05/2015 08:41:26

OLarryR
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3480 Posts

Response Posted - 03/05/2015 : 09:56:27

Agree with Dave B's assessment of being careful with the charging on Gel batteries. This can be a concern if your onboard charger is old or does not have a specific setting for Gel batteries.

It would be that flooded batteries, while they need the periodic water filling, are actually the most forgiving of all the batteries regarding charging method/parameters and they cost the least of the 3 main battery types.. Then comes AGMs. Gel batteries have a more narrow ideal/required charging range (ie. voltsage/amps).

When I was considering replacing my flooded batteries, the first thing I did was check to see if my solar controller had a setting for all 3 (flooded, AGM & Gel) and it did. However, my onboard Guest battery charger and instructions did not mention anything about AGMs or Gels, though, I believe I had also at the time reviewed the new Guest charges in West Marine and the newer Guest Chargers do mention settings and/or versatility of their smart chargers for use with non-flooded batteries. I then called up the mfr to talk to technical support and ...well it's hard to now recall what was said but apparently my older charger would be okay for AGMs buit they were not so sure about Gels.

So, understand you have other considerations to factor in before making your decision but recommend check out any chargers or controllers you presently utilize to see if they will be compatible with your selected battery type.

Larry
'89 Robin's Nest#5820, Potomac River/Quantico, Va
http://catalina25.homestead.com/olarryr.html

Dave5041
Former Mainsheet Editor

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3758 Posts

Response Posted - 03/05/2015 : 13:07:34

Arrhhg! My #2 battery was at 11.5V after an all night charge, good enough for one engine start. I guess I'm going flooded cell. My single bank charger is compatible with all types and goes through the battery switch to allow independent charging. I read a good, archived, decade old article comparing the three types. My favorite part was the recommendation for Trojan Group 27's for $65-$85. Wish I could sign up for those retroactively.

Update: The Walmart batteries that I have endorsed for so long changed in 2011, a year after I bought my last one. The amp hour rating is now based on a 1 amp draw instead of 5 and didn't go up. Reserve capacity is down, and that is the only standard test published. I'm going with Deka Group 27s, a solid, middle of the pack flooded battery for $118. Its rated at 90 AH on a 20 hour draw down, a better test than a 5amp draw. That is the largest battery that will fit 2 in the available space with a separator. Trojan Battery has a great comparison chart of major brand batteries. Batteries get reengineered, so it isn't necessarily completely current, but it is helpful. Yes, Trojan makes superb group 27 - for $225.
http://www.trojanbattery.com/pdf/TrailerBoats_batteryguide_201105.pdf

Dave B. aboard Pearl
1982 TR/SK/Trad. #3399
Lake Erie/Florida Panhandle

Edited by - Dave5041 on 03/05/2015 21:19:27

islander
Master Marine Consultant

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4032 Posts

Response Posted - 03/06/2015 : 06:42:39

Good choice on the Deka, Deka is the maker for WM batterys just re-branded and is IMO one of the best. I really don't see much of any advantages in GEL OR AGM batterys.Not for the added cost. Its not like they last any longer. 2- 6 volt batterys would give you more bang for the buck in the added charge/discharge cycles that they give you. Maintanance free batterys can get you in trouble. People tend to ignore them untill they have an electrical problem. If you have to add a little water to the flooded batterys once in a while, Big deal, Looking over your batterys and connections should be part of your anual inspection anyway.

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Voyager
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5434 Posts

Response Posted - 03/08/2015 : 19:15:40

Scott (Islander) - I think I am going to be very satisfied with my flooded Group 27 battery this season, next season, the season after that, and so on... If I get 7 good years out of my new battery, I'll be delighted. My 30W solar charger and 7A regulator will hopefully take care of my boat out on the hook without shore power.

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

Dave5041
Former Mainsheet Editor

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3758 Posts

Response Posted - 03/08/2015 : 21:21:11

You should be in great shape. Check the water (distilled), discharge them at least 10% once a month and never more than 50% and keep them charged. Sitting discharged is what kills most batteries.

Dave B. aboard Pearl
1982 TR/SK/Trad. #3399
Lake Erie/Florida Panhandle

OLarryR
Master Marine Consultant

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3480 Posts

Response Posted - 03/09/2015 : 03:24:44

My 2 flooded batteries lasted for about 7+ years. The last 6+ years were with me when I purchased the boat back in SEPT '05 and I only used a 20 watt solar panel to keep them fully charged - I only used light loads weekly and so that helped. They still had life in them but circumstances or fate just had me wind up replacing them perhaps a year earlier than necessary. We had a hurricane set to hit us and I decided to buy a battery as a backup along with a bilge pump to rig inside my house sump pump tank in case the electricity went out. I decided to buy an AGM as I described up above in my other posting. As it turns out, when the hurricane passed and the electricity to the house never had a hiccup, I was left deciding what to do with the brand new AGM battery. I was looking into using it along with a solar panel to hook up LED landscape lights but that decided against it - That's a story in itself. So...then decided to bite the bullet and buy a second one to replace my boat batteries which were still good but standing voltage was starting to fall off during the last year or two and so that's how I wound up replacing my batteries.

My flooded batteries, I checked the water levels periodically and wound up adding water perhaps 3 times a year, not more....and probably added more water that went into the compartment versus the cells. A small funnel probably would have helped...but that would have been the easy way to do it.

Larry
'89 Robin's Nest#5820, Potomac River/Quantico, Va
http://catalina25.homestead.com/olarryr.html

islander
Master Marine Consultant

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USA
4032 Posts

Response Posted - 03/09/2015 : 05:18:19

quote:
If I get 7 good years out of my new battery, I'll be delighted.

Im happy with 6-7yrs, Properly cared for batteries will get that far. They say that batteries don't die an early death, But instead are murdered by their owners.

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Voyager
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5434 Posts

Response Posted - 03/14/2015 : 12:46:08

OK, so I installed the new Group 27 battery in Passage and its connected to the solar panel and regulator. The voltage was 12.80 VDC when I installed it and I stopped in yesterday, ran the lights and the radio for a while and measured the voltage again and it was 12.78 VDC. When I left, the regulator was in charge mode. I'm going to keep an eye on it to make sure the new battery is indeed a good one. I assume that if I find any problem in the first few months, I can return it for a full return with the receipt. I put the receipt in a baggie attached to the battery so I don't have to look far to find it!

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

TakeFive
Master Marine Consultant

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2272 Posts

Response Posted - 03/14/2015 : 12:49:50

quote:
Originally posted by Voyager

...I put the receipt in a baggie attached to the battery so I don't have to look far to find it!

If the receipt is printed on thermal paper, you might want to make a copy of it. The thermal paper could fade to white at room temperature, or turn all-black at high temperature. Don't ask how I know about this.

Rick S., Swarthmore, PA
PO of Take Five, 1998 Catalina 250WK #348 (relocated to Baltimore's Inner Harbor)
New owner of 2001 Catalina 34MkII #1535 Breakin' Away (at Rock Hall Landing Marina)

Voyager
Master Marine Consultant

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5434 Posts

Response Posted - 03/14/2015 : 13:16:05

good advice! thanks

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

Voyager
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5434 Posts

Response Posted - 03/18/2015 : 08:25:59

Just got an email from Practical Sailor about their long term testing of AGM batteries. The full report will appear in their May issue, here are some interim points on their blog.
(Pls let me know if its a good link or not)

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

Edited by - Voyager on 03/18/2015 08:26:54

islander
Master Marine Consultant

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4032 Posts

Response Posted - 03/18/2015 : 09:17:56

Just re-enforces my opinion that AGM's aren't worth the added cost. Just way too finicky. Wet cell's are more forgiving and cost effective. Also I've read that (and points out in the article)They are very sensitive as to how they are charged. If you happen to overcharge them by improper charging you might as well throw it out.

quote:
Size your most powerful charge source, usually an alternator or inverter-charger, for a minimum of 20 percent of bank capacity. Odyssey TPPL AGM�s prefer 40 percent of amp-hour capacity as minimum charge current.

So with a 90amp battery you would need a minimum 18amp charger. Does your solar panel or engine put out that? This will only happen if your plugged into shore power with a smart charger.

quote:
Charge to full as often as possible, this point cannot be over emphasized.
Get back to at least 80-85 percent state of charge (full capacity) with each charge cycle and get to 100 percent state of charge as soon as you can thereafter.

How many of us do that. Do you not go sailing because the battery isn't 100% charged?
I'll stay with my wet cell..

Scott-"IMPULSE"87'C25/SR/WK/Din.#5688
Sailing out of Glen Cove,L.I Sound

Edited by - islander on 03/18/2015 10:36:14

Voyager
Master Marine Consultant

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5434 Posts

Response Posted - 03/18/2015 : 10:45:29

Scott - Agreed
My two charging systems are:
1. the Honda 8HP outboard with a 12A regulator. The bulk charging voltage seems high: ~ 14.4-14.6VDC range and the top end float is in the low 13VDC range.
2. A 30W solar panel that puts out about 0.5-1.2A at 18VDC open circuit and somewhere around the mid 14s VDC when charging. Its regulator is a PWM type.

I don't use shore power or a home-based battery charger.
I keep the battery topped off following most trips or day sails.

I think the outboard alternator would be too hot for an AGM, and I'd be tempted on a long motorsail to disconnect it once the battery was fully charged (e.g.: stop the engine, disconnect the fuse, restart the engine).

Seems like an AGM would require too much messing around IMHO.

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

redeye
Master Marine Consultant

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3478 Posts

Response Posted - 03/19/2015 : 06:43:40

Mine ( AGM ) is 5 years old as of June and stays topped off from the 12 watt ( .78 amp and something like 14.7 volts in full sun ) with the solar regulator holding it to 14.7 I think..

I looked at the volt meter in full sun last weekend and it read 14.

It seems like now adays the regular wet cell would do the same for a lot less money... it will be interesting to see how long this battery will last.

I don't ever seem to draw this battery down using using LEDs mostly.

Ray in Atlanta, Ga.
"Lee Key" '84 Catalina 25
Standard Rig / Fin Keel

Voyager
Master Marine Consultant

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5434 Posts

Response Posted - 03/19/2015 : 17:46:25

Ray,
That's good news. I've got LED except for my bow light and one cabin light, but I use a CPAP machine for sleeping overnights.
It takes a 12VDC input (nice) at 1-2A so I can run it all night using the battery.
In the past I also had an incandescent anchor light, but now I've got a LED there too.
Aside from the stereo, the CPAP and any remaining incandescents, I'd be surprised to run the new Group 27 flooded battery down too far.
But you can only know that by making a weeklong passage.
I'll be delighted to give it a try - hurry up May!

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

britinusa
Web Editor

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5404 Posts

Response Posted - 03/20/2015 : 06:27:11

I just bit the bullet.

Our 2 WM 75AH Group 24 batteries died from dehydration and old age.

We received a WM add in the mailbox and they were selling Group 24 batteries for $99

Turns out they are not 75AH!

Searching the net, I found that one of our customers has them.

BatteriesPlus

And they came with a $10 mail in rebate!

Paul

Joint Decision. (Sold)
PO C250WB 2005 Sail # 841.

Moved up to C34 Eximius

Updated August 2015

OLarryR
Master Marine Consultant

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3480 Posts

Response Posted - 03/20/2015 : 18:53:36

Interesting reading the addl comments since I last responded to this posting thread. Agree that flooded batteries are very forgiving with how they are charged compared to AGMs and even more so compared to Gels. In regards to the AGMs, they seem fine, I have now had my 2 AGMs for 2+ years and seem to charge with no problem utilizing my 20 watt solar panel. First of all, I have light loads and never discharge the batteries that much - fish finder on while sailing, occasional use of the VHF and nav lights now and then for perhaps a couple of hours. I electric start my Honda 9.9hp and while it has a 12amp charger, I usually use it for only getting out and back in to the marina (10 minutes or more each way) and sometimes for an hour if no wind and heading back. I think the key to success with the AGMs, especially if you have a small solar panel as your main charger, is that you very rarely ever get close to discharging the batteries to any significant degree. My flooded batteries lasted 7+ years and hopefully these AGMs will last about the same. The are quite expensive compared to flooded batteries with main benefits being only that you do not need to add water and the specs indicate the loss per day just standing around doing nothing is less compared to flooded batteries. Depending on any controllers you have onboard, if they do not have settings for AGMs and/or the controller specs do not specifically mention that they work with AGMs, then rather than change controllers, best to go with the flooded batteries. if your controllers work with AGMs, then you have the option of either type. Flooded is okay, just add water periodically. AGMs are okay but not necessarily a good choice if you frequently discharge them significantly.

Larry
'89 Robin's Nest#5820, Potomac River/Quantico, Va
http://catalina25.homestead.com/olarryr.html

Edited by - OLarryR on 03/20/2015 19:01:19

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