Battery Check

Sensing my batteries are needing more charging, I`ve done a check. All were on the boat at purchase in 2020 and tested ok.The main batteries are 2 SLA x 8Ds, 1200cca, 200Ah capacity. The (replacement newer) Pro Mariner 40A 2 channel charger is set to SLA.
I think the whole install (excl actual batteries) is factory. But now it gets messier.

Port 8D also feeds to the bowthruster battery,an Optima 34M, 800cca and 50Ah capacity, it`s AGM, and a good and pricey brand here.

Stbd 8D, as well as charge from alt and charger, gets regulated charge from 160w of solar. It also feeds the Genset battery, an SLA, 1000cca, capacity 150Ah.

The 2 8Ds both test well, above specified cca.

The bowthruster and genset batts test poorly and need replacing. I`m thinking, in their poor state they make excessive demands on the 2 8Ds, and what charges them,and that needs fixing. Genset batt served well, installed 2016. Can`t see an install date for the bowthruster batt so far. Even so, genset still starts fine, bowthruster works, not as strong as I`d like, hoping new batt helps.

I expect there are combiners somewhere for the 2 peripheral batteries. I`m going to get an electrician onboard to help with some other things, he can chase that down.
The 8Ds seem ok, I don`t need to change them. Going to be a difficult job due to location. But, I`ve been charging an AGM using SLA charging profile, via an SLA. Not optimal I suppose, but is it a no no? Do I get an SLA,if I can find one to fit,or another AGM? Or doesn`t it matter?

BruceK said:

Port 8D also feeds to the bowthruster battery,an Optima 34M, 800cca and 50Ah capacity, it`s AGM, and a good and pricey brand here.

Stbd 8D, as well as charge from alt and charger, gets regulated charge from 160w of solar. It also feeds the Genset battery, an SLA, 1000cca, capacity 150Ah.

I expect there are combiners somewhere for the 2 peripheral batteries. I`m going to get an electrician onboard to help with some other things, he can chase that down.

...But, I`ve been charging an AGM using SLA charging profile, via an SLA. Not optimal I suppose, but is it a no no? Do I get an SLA,if I can find one to fit,or another AGM? Or doesn`t it matter?

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Pinning down that "8D feeds another battery" thing would be good. I don't see any need for those connections to exist... but maybe it's just a battery-to-battery charger in between or something.

Optima started out with a good rep, and reading suggests they ain't great, these days. Don't know what else AGM might be available in your market. Full River? They seem to have a decent rep. We use Odyssey when we want to emphasize cranking amps, and Lifeline when we want to emphasize capacity... but I dunno if you have those, or if they're affordable. (They're an arm and a leg, here.)

Instead of using a "profile" it'd be best to specify exact voltages for any given battery... if you're charger situation will let you do that. In any case, look up the exact voltages you get from various "profiles" and compare that to the exact voltages each battery maker recommends. I think lower than recommended is usually somewhat better than higher, if you have to choose that way, so you don't overcharge anything.

FWIW, were it me, I'd go to all AGM... mostly because lithium still isn't in my price and "ease of installation" range... since I've got better thing to do with my time than contort myself into where our batteries are located. It's sometimes not impossible to change over from FLA/SLA to AGM a bank at a time.

-Chris

It sound like to need to make a wiring diagram of the batteries and how the are charged and the load they take care of. Than you can go from there on the best way to charge and use them to their fullest.

Thanks.
The marine electrician/boat mover who delivered my boat in 2020 texted me a basic diagram but it doesn`t specify the connection to the 2 peripheral batteries. He did say the diagram meant don`t run on "ALL", without saying why,same as the Boat "Manual". I`ll explore that when I get an electrician onboard.
I want to go AGM so 2 peripheral AGMs is preferable,but it`s premature to replace the 8Ds, they can be AGM when due.
Online I got conflicting information about having SLA and AGM on the one charger, from "they`re both LA just do it' to "it will cause under/over charging of one or the other". Thus this thread.

BruceK said:

Online I got conflicting information about having SLA and AGM on the one charger, from "they`re both LA just do it' to "it will cause under/over charging of one or the other". Thus this thread.

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Well... they are both LA, so that's not incorrect...

But I've found flooded and AGM "profiles" may or may not be useful when compared to specific batteries. I've found it better to translate charger profiles into actual voltages... then compare those available actual voltages to battery maker recommendations. Then decide.

In one case, we only had two profiles: flooded, and gel. Fine print in the charger manual said to use flooded for AGM. Finer print actually told me the real flooded voltages, and I could compare those to prospective battery brands. I know the flooded setting was great for the Odysseys we installed -- one bank at a time. Looking back, I think the gel setting would have been more appropriate for the Lifelines we installed later.

These days, chargers often offer more options. A more recent charger we installed gave us something like 16 profile options, 15 pre-sets and then one was "you pick your own voltages." Easy to work with...

-Chris

Appreciate your help.
Our esteemed late member FF (Fast Fred) could reel off charging profiles for most batt types, alas no longer.
After "online shopping", I was at the boat today measuring the existing batts. Another Optima Oddessy is about all that fits the bowthruster location, about $300 AUD.
The Genset 150Ah batt(? 6D in US parlance), was alarmingly hot. Constant unsuccessful charging, electrolyte diminished, > high heat, is bad. A neighbour`s SLA exploded last week. I disconnected it pending replacement, charger and 8D can relax now.
The aim is to go all AGM so I`ll replace these 2 with AGMs. The 8Ds are at least 3 years old, test well, but in time will give way to AGM. I`ll try checking individual battery profiles to see how close Flooded/SLA/AGM are. Failing that, the most important batts are the 8Ds. I wonder how charging the 2 peripheral batteries via an 8D SLA affects things, the peripherals are not talking direct to the charger. Not sure but I think combiners are just voltage actuated.
We are making headway. Unfortunately both electricians I wanted to try are away interstate for several months. Marine service people are thin on the ground here.

BruceK said:

After "online shopping", I was at the boat today measuring the existing batts. Another Optima Oddessy is about all that fits the bowthruster location, about $300 AUD.

The Genset 150Ah batt(? 6D in US parlance), was alarmingly hot.

I wonder how charging the 2 peripheral batteries via an 8D SLA affects things, the peripherals are not talking direct to the charger. Not sure but I think combiners are just voltage actuated.

We are making headway. Unfortunately both electricians I wanted to try are away interstate for several months. Marine service people are thin on the ground here.

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Optima and Odyssey in the same sentence sounds odd. Here, those are two different brands. Reading suggests Optima started out with a good rep, and has gone downhill from there... apparently after being sold off to a different manufacturer from original.

An Odyssey G31 sounds very viable for a thruster, if that's what will fit. Somebody on the forum recently confirmed one of the thruster installer companies over here usually fits two Odyssey G31s near their thrusters...

Sounds like a huge battery for genset starting. Our current is a flooded G24, and whenever it craps out I'll probably switch to a relatively tiny Odyssey Extreme ODX-AGM34 (was PC-1500) with 850 CCA.

BTW, we ran for several years with no charger on our genset battery other then the generator's alternator. The AGM didn't self-discharge much, so no problem. We happen to have a dedicated charger for the genset battery on this boat, and our other banks are 24V, so I'll keep it I guess... but don't really think it's all that necessary in an all-12V boat. Especially if it's easy to use jumper cables from some other 12V source in an emergency.

Pinning down those connection between batteries will probably move you further ahead...

-Chris

In today's world I would never get an AGM battery! They have no advantage other than not spilling/watering and on a boat with a 40A charger aren't even going to get the "faster charging" (they don't really).

Instead get Lithium Iron Phosphate (LFP).

Don L said:

In today's world I would never get an AGM battery! They have no advantage other than not spilling/watering and on a boat with a 40A charger aren't even going to get the "faster charging" (they don't really).

Instead get Lithium Iron Phosphate (LFP).

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I see there are use cases for LFPs, but we've not yet had a boat that would make it easily or affordably possible.

Our boats have all been built with dual-purpose battery architecture, each bank acting as a mains starter that also services about half of the DC house/electronics loads. Quite common in US-built production powerboats. (Not sure, but Bruce's boat might be similar.) Making an architectural change to isolate a house bank is daunting, potentially there can be real estate issues. and then there's all that cost and complexity thing associated with LFP.

(Recent thread examining LFP for a thruster bank... ditto.)

For us, that whole service spilling/watering thing (and potential off-gassing) is a big deal, and AGMs scratch that itch... at a decent (enough) price point. And having a dedicated 70A charger is different from a split-use (multi-bank) 40A charger.

IOW, in today's world, and for our use, I would always (at least) consider an AGM battery... and I think there's still a viable place for wet batteries, too, where service is easy and off-gassing isn't an issue.

I think I did see info about a high-cranking amp LFP recently. Big buck$ and not much capacity for dual-purpose work, IIRC. Can't remember where I saw that...

-Chris

ranger58sb said:

I see there are use cases for LFPs, but we've not yet had a boat that would make it easily or affordably possible.

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You have to check with the manufacturer if going to use as a start battery.

But I got 4 - 100ah LFP off Amazon a few months ago for $1319 including shipping and tax. Installation was easy and all I did was change charging programs.

ranger58sb said:

Optima and Odyssey in the same sentence sounds odd. Here, those are two different brands. Reading suggests Optima started out with a good rep, and has gone downhill from there... apparently after being sold off to a different manufacturer from original.

An Odyssey G31 sounds very viable for a thruster, if that's what will fit. Somebody on the forum recently confirmed one of the thruster installer companies over here usually fits two Odyssey G31s near their thrusters...

Sounds like a huge battery for genset starting. Our current is a flooded G24, and whenever it craps out I'll probably switch to a relatively tiny Odyssey Extreme ODX-AGM34 (was PC-1500) with 850 CCA.

BTW, we ran for several years with no charger on our genset battery other then the generator's alternator. The AGM didn't self-discharge much, so no problem. We happen to have a dedicated charger for the genset battery on this boat, and our other banks are 24V, so I'll keep it I guess... but don't really think it's all that necessary in an all-12V boat. Especially if it's easy to use jumper cables from some other 12V source in an emergency.

Pinning down those connection between batteries will probably move you further ahead...

-Chris

Click to expand...

Yes, I conflated Optima and Odyssey and Optima. I`ve ordered an Optima, cca 815,should keep the thruster turning the few times I use it.
Onan recommend a 135Ah battery for starting, it does seems huge. The genset of my previous boat had only its alternator for charge, I fitted a modest solar panel and simple regulator. I`ve ordered a 130Ah/1000cca AGM for it.

The thread took a lithium vs.everything else turn. I think I`m set, hope to discover the "combiner" method Integrity used. In a year or so I`ll likely be all AGM, solving how to set the charger.

BruceK said:

Onan recommend a 135Ah battery for starting, it does seems huge.

I think I`m set, hope to discover the "combiner" method Integrity used. In a year or so I`ll likely be all AGM, solving how to set the charger.

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Seems odd. Our Onan 21.5 kW genset only needs 625 CCA minimum... and I didn't see any capacity requirement.

Sounds like you're getting good to go...

-Chris

Most manufacturers frown on paralleling different chemistries for a host of reasons. Charge profiles are probably different enough to warrant isolation and the use of different charging profiles. I’m always suspicious of those quick test battery testers. The only way to really determine capacity produces a graph over time like you see in the manufacturers manuals.

Don L said:

You have to check with the manufacturer if going to use as a start battery.

But I got 4 - 100ah LFP off Amazon a few months ago for $1319 including shipping and tax. Installation was easy and all I did was change charging programs.

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Indeed. Darned if I can find that link I saw to an LFP battery usable for high cranking amps. Thought it was here, somewhere...

I did some match at the time, don't remember numbers either, but seems like they would have been way more than a pair of Lifeline 8Ds... which was ~$1700-ish, I think...

-Chris

Build your own wiring diagram, assume nothing and verify everything independently. It will likely save you time long run.

Before starting any of the following, give yourself at least 30 minutes of reserve time to ensure your bilge pumps are all powered/reconnected at the end of this process.

I would start by identifying every wire that connects to each positive battery terminal, When in doubt, disconnect and tape up the end of every wire connected wire/cable to a positive terminal or positive buss bar until you can follow up on it later. Sort out the cable runs and operation of any and all battery disconnects, selector switches or combiners. Sever the connections between all batteries using the switches or manually remove the cables if need be and charge all to float status with a portable charger, let the batteries rest for 6 hours without any loads and then load test each, independently.

Now you are finally have enough information to start making decisions about what batteries need to be replaced and what changes you may want to implement along the way. If you choose to keep batteries with different chemistries and/or significantly different ages, use a DC to DC charger to accomplish this and leave all large cable connections off, unless have a complete battery failure and need to jump power from bank to another.

Prior owners, marine installers and even some builders get lazy and connect DC loads to the most convenient battery bank unbeknownst to owner or next owner, these can create nightmares when trying to diagnose DC battery systems but unfortunately it is pretty common.

Finally, be sure that all bilge pumps are powered before leaving the boat when done or whenever you need to leave the boat. Hopefully you allowed yourself plenty of time to do this.

ranger58sb said:

Seems odd. Our Onan 21.5 kW genset only needs 625 CCA minimum... and I didn't see any capacity requirement.

Sounds like you're getting good to go...

-Chris

Click to expand...

That Onan battery spec was for the 6.5kw MDKD in my previous boat. I don`t have a manual for current 7kw Onan QD. Yes, 1000cca to start a little 3cyl diesel seems overkill. If the new bowthruster Optima arrives before the genset replacement I might try the old 800cca Optima on the genset.

If you are mixed batteries, then you need mixed chargers too. Get a separate charger for the AGMs and disconnect them from the SLAs.

Thanks. As our late Prime Minister Malcolm Fraser(who once "lost his trousers" in New York) said: "Life wasn`t meant to be easy".

Don L said:

You have to check with the manufacturer if going to use as a start battery.

But I got 4 - 100ah LFP off Amazon a few months ago for $1319 including shipping and tax. Installation was easy and all I did was change charging programs.

Click to expand...

Any change to the alternator?

I've not read the entire thread but your use of SLA, to me at least, is not clear.

Both AGM and GEL are SLA batteries but are of somewhat different construction with different charging needs. Similar but different enough to pay attention to.

The FLA, flooded lead acid, usually has the screw top filler caps for adding water as needed but not always.
There are also some WET cell types, flooded that, although not hard sealed they can benefit from water addition from time to time they too I have seen called SLA.

The SLA are not meant to be opened at all and if you do you have damaged the battery and will shorten its life regardless if it is AGM or GEL.


An AGM and a GEL battery are BOTH SLA. So when you say SLA which type specifically are you referring to, the AGM, the GEL, or the semi sealed FLA.

To me at least it can make a difference in the advice given.

C lectric said:

I've not read the entire thread but your use of SLA, to me at least, is not clear.

Both AGM and GEL are SLA batteries but are of somewhat different construction with different charging needs. Similar but different enough to pay attention to.

The FLA, flooded lead acid, usually has the screw top filler caps for adding water as needed but not always.
There are also some WET cell types, flooded that, although not hard sealed they can benefit from water addition from time to time they too I have seen called SLA.

The SLA are not meant to be opened at all and if you do you have damaged the battery and will shorten its life regardless if it is AGM or GEL.


An AGM and a GEL battery are BOTH SLA. So when you say SLA which type specifically are you referring to, the AGM, the GEL, or the semi sealed FLA.

To me at least it can make a difference in the advice given.

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My posts 1,4,6, should help but to summarize, I`m keeping the 2 approx 3yo 8D sealed non AGM non GELs which test fine,until one is unserviceable. And replacing with AGMs, the AGM bowthruster batt, and the 7yo 135Ah/1000cca Genset non AGM non GEL SLA.
Each 8D feeds, presumably via a combiner,one of the peripheral batteries, which both will be AGM.

The Pro Mariner charger is/has,for at least my 3yrs ownership, been set to SLA, not AGM not GEL. My present intention is to leave it that way until one of the non AGM non GEL 8Ds needs replacing, replace them with AGMs, and then set charger to AGM. I know that`s not perfect,it`s highly criticized by some, but it would make more practical/economic sense to dump the 2 "good" 8Ds right now than follow some of the suggestions. Assuming the 8Ds really are "good" because it seems my testing without a graph was deficient. And of course the 2 testing bad I`m replacing could actually be good, despite the 2016 genset simple SLA being so hot I feared possible explosion.
I have not,and have no intention, of opening a sealed battery

BruceK said:

The marine electrician/boat mover who delivered my boat in 2020 texted me a basic diagram but it doesn`t specify the connection to the 2 peripheral batteries. He did say the diagram meant don`t run on "ALL", without saying why,same as the Boat "Manual". I`ll explore that when I get an electrician onboard.

Click to expand...

My guess is the following. When you leave the DC load switch on the All position, it means the output of both batteries are linked together, to feed the DC loads. Consequently, when you're underway, the alternators of both engines are connected to each others, and the current regulator of one alternator will get fried because it's seeing the high voltage coming from the other alternator, instead of a lower voltage from a battery. At least, this is what happened on my boat, one of the alternator wasn't working, and the previous owner always kept the switch on All.
I have since changed the alternator, and leave the switch on 1 on odd days, and on 2 on even days, as recommended by the manual. I will remember the "All" position for the day when an alternator dies and I purposefully want to use the other to charge both engine batteries while underway.

Thanks Guilhem, it`s good to have an explanation and the GB Manual advice is worth taking. My boat is based on Island Gypsy design,IG was largely copied from GB, so it should be applicable. I just have to remember to switch between 1 & 2!

Guilhem said:

My guess is the following. When you leave the DC load switch on the All position, it means the output of both batteries are linked together, to feed the DC loads. Consequently, when you're underway, the alternators of both engines are connected to each others, and the current regulator of one alternator will get fried because it's seeing the high voltage coming from the other alternator, instead of a lower voltage from a battery. At least, this is what happened on my boat, one of the alternator wasn't working, and the previous owner always kept the switch on All.
I have since changed the alternator, and leave the switch on 1 on odd days, and on 2 on even days, as recommended by the manual. I will remember the "All" position for the day when an alternator dies and I purposefully want to use the other to charge both engine batteries while underway.

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I have run on 'ALL' often and not fried my regulator. Fast charge for house bank. An ACR actually automatically places two banks on the 'ALL' position using voltage sensing. What does happen is initial charge amps are double (each ALT output added) until voltage reaches ~13.6 at which point the regulator that is looking for this voltage at a lower amount than the other shuts down and only one alternator continues to charge ALL until full charge is done.
ALT while running/charging cannot have switching or ignition turned off, that can fry the reg. IMO and welcome any corrections.

For simplicity of effort and $$$ saving sake:

I'm am an "Ol' Stick In The Mud! - > When it comes to batts. Utilizing an age old, damn easy to deal with and inexpensive way to keep DC power readily available.

Rigs combined, we have 16 WLA Batts. 10 - starter batts / 6 - deep cycle batts

Starter batts last 10 +/- years before they poop out. Deep cycle about the same. 10 years ago... Cost per batt used to be $100 minus... now it's $100 ++

Current [pun intended] 4 deep cycle batts on boat were put in 2018 [5 years ago]. This winter they hold 90% charge after a month sitting idle with no use outflow and no charge input. After 3 to 4 weeks I usually give them an 8 hr. boost to 100% with 60 amp "Professional Mariner" charger [same charger our 1977 Tolly originally came with]. The exact same type deep cycle 4 batts I replaced in 2018 were 10 yrs old.

I get our batts at "Battery Plus Bulbs". East Penn is the batt manufacturer. https://www.batteriesplus.com/productdetails/battery/marine-and-boat/deep-cycle/sli31mdc SLI31MDC Duracell Ultra BCI Group 31M 12V 105AH 650CCA Flooded Deep Cycle Marine & RV Battery - $149.99 - 10% discount X 4 = $539.97 [plus tax] -: 10 yrs = $54.00 per yr. = $4.50 per mo. = 1.04 per wk. = $0.15 per da.

Well... you get the $$$ savings, reduced effort picture! Right??? LOL

PS: I also drive... with all of em cherry: 1967 Buick Wildcat / 1985, std. cab, 1-Ton, 4WD, 4 spd. standard shift, Chevy Cheyenne truck / 1992, std. cab, 1-Ton, 4WD, 5 spd. standard shift, Ford XLT truck / 1998 Ford Explorer XLT SUV.

Wife has a low mileage, beautiful, classy, fast, comfortable, sexy, great sound system, jet black, multi passenger, dash board touch screen with its original self cooling-cooler between the two rear seats! 2014 Lincoln MKT SUV - With - All kinds of computer crap running all its features.

Within last couple years the Lincoln cost over $4K computer chip repairs. During same couple years my 4 old cherry rigs cost less that $1000.

I really enjoy being: "Ol' Stick In The Mud"!

SteveK said:

I have run on 'ALL' often and not fried my regulator. Fast charge for house bank. An ACR actually automatically places two banks on the 'ALL' position using voltage sensing. What does happen is initial charge amps are double (each ALT output added) until voltage reaches ~13.6 at which point the regulator that is looking for this voltage at a lower amount than the other shuts down and only one alternator continues to charge ALL until full charge is done.
ALT while running/charging cannot have switching or ignition turned off, that can fry the reg. IMO and welcome any corrections.

Click to expand...

Is this a feature of your current boat, and/or the GB, and/or all twin engine boats?
I`ve also run on "ALL" without alternator damage, on 2 boats. But I also take notice of material appearing in a GB Manual. And the(sketchy) Manual for my Integrity, and the advice of my boat delivery marine electrician, both saying not to run on ALL.

BruceK said:

Is this a feature of your current boat, and/or the GB, and/or all twin engine boats?
I`ve also run on "ALL" without alternator damage, on 2 boats. But I also take notice of material appearing in a GB Manual. And the(sketchy) Manual for my Integrity, and the advice of my boat delivery marine electrician, both saying not to run on ALL.

Click to expand...

All boats with a 1-2-all switch will have this in all position. That is bat 1 or bat 2 or both.
On the current boat it has an on/off switch labelled combine.
Yes I have had it on all boats with two separate banks.

SteveK said:

All boats with a 1-2-all switch will have this in all position. That is bat 1 or bat 2 or both.
On the current boat it has an on/off switch labelled combine.
Yes I have had it on all boats with two separate banks.

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Is this response the experience of others?
On the peripheral battery replacement, the new Optima 34M now powers the bowthruster to a lusty growl. The genset battery is disconnected, its 1000cca AGM replacement charged at home pending install. The battery charger is relaxed, relieved of trying to maintain the two unmaintainable batteries.

Check Your Sealed LA Batts

Yesterday we removed the old 135ah/1000cca sealed VLRA genset battery. IG/Integrity batteries sit in a fibreglass box with cover lid. Battery out, a lot of white powder was evident, presumably sulfur from dried leaked sulfuric acid. The box kept the material contained and was undamaged.
It`s not long since, on 2 occasions, I checked the battery. First time it tested ok, 2nd time it was hot and tested bad,query catastrophic failure in between. I`ve heard of several explosions of these batteries on my marina,with messy results, we were lucky to catch it.
They might be "maintenance free" but they should not be inspection free.

Sealed LA and AGM on One Charger Setting

I searched for a Manual for my ProNautic1240P charger. At some point I`ll change the setting from Sealed LA to AGM. I need to know how, and it`s good to have the Manual.
I found the charge parameters:
Conditioning Voltage: same for SLA/AGM, 14.4V
Auto Maintain Voltage: SLA 12.8-13.6: AGM 13-0-13.4V.
It`s the latter which differs. AGM sits within the SLA parameters but not as low or as high. My 2 AGMs are charging off the SLAs so they get what the SLA`s have or if the charger operates, what the SLAs are getting.
It`s neither perfect nor, to my mind, dramatically bad. My Battery Gauge reads 13.4V usually, and when charging around 14.5V. I`ll replace the SLAs with AGMs at the first sign of tiredness, so far they continue to test "Good".