Batteries

[FF]

>I thought this could have related to the new batteries I just bought that had been on the shelf for a year.>

Put them in the trunk of your car and go to a place that repairs golf carts.

They will have a capacitance style battery checker (expen$ive) that will tell you the state of your year old batts.

Should take 5 min for 1/2 dozen batts and will give a realistic report of their condition.

Batts will loose 1% to 3% internally per month , so a year of sitting could be there sulphated to scrap already , only having 10%-or 20% of their rated capacity after a full charge.

 

[Baker]

Well, the DieHard Group 31 Platinum Marine AGMs are bought and installed. I will let y'all know how it goes....

 

[CPseudonym]

Hey John, what's the warranty on those? Am looking to upgrade next year and like what I've seen of these.

 

[Baker]

Hey John, what's the warranty on those? Am looking to upgrade next year and like what I've seen of these.

Damn dude...sorry. I just saw this. The warranty is 3 years full replacement. That is not the only thing that sold me. It is also the fact that you can take the battery out and go to your nearest Sears and look somebody in the eye while having them replace it on warranty.

Another thing is...I guess I put a lot of weight in Internet ratings. They rated VERY highly(4.8 stars). I had a friend that said he could get me some Energizers from Sam's for $180. I looked at the internet reviews on that thing and it was 1 star with multiple reviews....most of them one word replies for every word that is synonymous with "junk". Anyway.....

Lastly, and completely of no consequence....they are this cool ass ice blue with a grey top. With all 5 tucked away in their respective spots...they look pretty badass....kinda livens up the engine space!!!

 

[CPseudonym]

Sells me. Most important thing you pointed out aside from 3 year full replacement is being able to go straight to Sears and make eye contact with the person honoring the warranty IMO.

 

[johnma]

Deka is East Penn and they are the second largest battery manufacturer. most of what they make is private labeled. My company is an East Penn dealer and we're in the truck parts business. earlier in this thread i suggested calling your local truck parts dealer or call East Penn directly and ask them. Don't mention marine as they will refer you to a boat dealer and we all know what that anchor decal does to prices. Tell the truck parts guy you want an AGM in the 8D size. It will take him a day to get it but the price will be a lot less. You might be able to buy one cheaper on the internet, but then you will have to pay the freight for a 150 lb battery. if anyone in the Philadelphia, South Jersey area needs a battery, send me a pm (for that matter, we have locations from Maine to South Carolina)

John
MS390

 

[Bay Pelican]

Faster charging for AGMs. In practice what does this mean.

AGMs are touted as permitting faster charging then lead acid. In the real world, Bay Pelican, does this have any practical effect?

Bay Pelican has 12 Trojan 105 six volt batteries. Two chargers, one Magnum, one Victron, are used with the bank split in half, thus each charger charges six batteries for a total of 675AH. In the bulk charge stage each charger will output about 100 amps then quickly drop down. The 100 amp is within the limits for charging of a 675 AH lead acid bank.

If I switch to AGMs and use the AGM setting on both chargers will the bulk charging state run longer than with the lead acids. If not I have no faster charging.

Can anyone explain how this would work?

 

[ranger58sb]

Faster charging for AGMs. In practice what does this mean.

AGMs are touted as permitting faster charging then lead acid. In the real world, Bay Pelican, does this have any practical effect?

Bay Pelican has 12 Trojan 105 six volt batteries. Two chargers, one Magnum, one Victron, are used with the bank split in half, thus each charger charges six batteries for a total of 675AH. In the bulk charge stage each charger will output about 100 amps then quickly drop down. The 100 amp is within the limits for charging of a 675 AH lead acid bank.

If I switch to AGMs and use the AGM setting on both chargers will the bulk charging state run longer than with the lead acids. If not I have no faster charging.

Can anyone explain how this would work?

My first guess would be that you're maybe not using enough DC ("100 amps quickly drop down") to warrant a huge need for faster charging.

If you were using more of your capacity on a daily basis, the 100-amp charge could last for several hours. For example, our charger could hold its max absorption rate for up to 4 hours, if batteries required that, and before that they'd only begin drop off as batteries begin to accept less current. I'd suspect yours would probably hold that rate longer if you needed it. If you had AGMs, the "several hours" could be shorter than with FLAs... maybe.

-Chris

 

[O C Diver]

If you know which battery manufacturer you want to use for the AGMs, go to their website and see if they have a document on changing parameters for there batteries. For the money you will spend on the batteries, it's crazy not to atleast know the manufacturer's guidelines before buying them.

Ted

 

[CMS]

Faster charging for AGMs. In practice what does this mean.

AGMs are touted as permitting faster charging then lead acid. In the real world, Bay Pelican, does this have any practical effect?

Bay Pelican has 12 Trojan 105 six volt batteries. Two chargers, one Magnum, one Victron, are used with the bank split in half, thus each charger charges six batteries for a total of 675AH. In the bulk charge stage each charger will output about 100 amps then quickly drop down. The 100 amp is within the limits for charging of a 675 AH lead acid bank.

If I switch to AGMs and use the AGM setting on both chargers will the bulk charging state run longer than with the lead acids. If not I have no faster charging.

Can anyone explain how this would work?

You're charging at approx 0.15C or just 15% of Ah capacity. This is light for your bank size. Also, if you are not maximizing your Trojan charging, by setting absorption to 14.8V (temp compensated), then you could be getting more into the batteries in a shorter time frame and treating them in a considerably more healthy fashion. Most boats I set foot on are grossly under charging flooded Trojans and also grossly under absorbing them time wise.

Sure the Coulombic efficiency of an AGM is better than flooded (AGM, GEL and Flooded are all lead acid chemistry) so it converts more incoming energy at high states of charge, to stored energy but, unless you can maximize the charge rate to 25% to 40% + of Ah capacity, you're not really doing AGM's any favors nor maximizing the potential benefits.

Lifeline for example wants to see a minimum charge rate of 20% and Odyssey, the inventors of TPPL AGM's, want to see a minimum charge rate of 40% of Ah capacity for optimal cycle life. This is a 40A charge rate for a 100Ah battery or 270A charge rate on a 675 Ah bank.

There is also a rather wide quality spread among AGM's and how they handle PSOC use (partial state of charge). For info and comparisons between brands see the May 2015 and August 2015 issues of Practical Sailor. In this PSOC testing the Deka/East Penn AGM, Lifeline AGM, Northstar TPPL AGM, Odyssey TPPL AGM and Firefly Carbon Foam AGM were compared in a head to head 30 day PSOC test.

Not to be a spoiler but one AGM lost nearly 30% of its Ah capacity, in 30 PSOC cycles, and one battery lost no Ah capacity at all.. Not all AGM batteries are created equal.

 

[sunchaser]

CMS

Marty raises an interesting point regarding AGMs..

Using a 270 amp charger is ideal, but who has one for such a small battery bank? Not to mention the cost of buying and installing one. All to optimize a double the cost AGM setup vs a group of stodgy old Trojans.

As with Marty, we have a bunch of Trojan 105s with a Magnum inverter charger. We do use a couple of AGMs for indoor use - thruster.

All said, I bow to your much better understanding of battery science than I possess. Intuitively all we care about is safely getting us through the time on the hook and making up lost watts via cruising or genset run time. Works for us.

The only battery problems we've had are with the thruster AGMs. They petered out after 6 years. This set I'll throw away after 5.

 

[ranger58sb]

Lifeline for example wants to see a minimum charge rate of 20% and Odyssey, the inventors of TPPL AGM's, want to see a minimum charge rate of 40% of Ah capacity for optimal cycle life. This is a 40A charge rate for a 100Ah battery or 270A charge rate on a 675 Ah bank.

Useful reminder, thanks for posting. Not so easy to do. We've had decent success with Odysseys, even with an under-powered charging system -- a 40-amp charger for two main 300Ah banks -- until just recently. I'm guessing that's just luck, since (as you said once before) our usage is most often like a battery-backup UPS.

-Chris

 

[Bay Pelican]

CMS, super comment. Thanks

 

[Baker]

Not to be a spoiler but one AGM lost nearly 30% of its Ah capacity, in 30 PSOC cycles, and one battery lost no Ah capacity at all.. Not all AGM batteries are created equal.

Oh come on?????!!!!! You can tell us!!!! My bet it was the Dekka that did not fair well...

When I was shopping for batteries I did do some research. I talked to the Odyssey people and they echoed what you said. In fact, the lady on the line wanted to see 50%. She was not thrilled when I told her I had an 80 amp charger for a 400 amp bank. I have since added a Magnum 100 amp charger(and another 100 amp hour battery) and I it charges in tandem with the Charles if needed. I have only needed that much juice once when I accidently discharged the bank down to about 35%(inverter cutoff point). It was pretty interesting to see all 180 amps of charging on the battery monitor...