Fully charging your batteries after each discharge on a live-aboard cruising sailboat is simply not practical. Instead, most of us will cycle our batteries between 50 and 80% of their capacity. The bad news is that this will ruin your lead-acid batteries (regardless of type) in a distressingly short time due to sulphation.
The Solution
But there is an answer to this problem: regular equalization, a process where you deliberately overcharge your batteries for a specified time and voltage to remove the sulphation.
John
I’m truly dumb when it comes to electricity, but I’m going to ask this – What about solar panels & windvanes? Won’t these top up the batteries? Solar panels & windvanes can be used at a marina – no need for shore power. My windvane is connected to a regulator to prevent overcharging of the batteries. My hard solar panel is small & is put out on deck when I’m away.
What am I missing here ? (!!!)
Thanks,
Nick
PS – The solar panel & the windvane terminate in clips (as in alligator clips, or jumper cables) which I can move from one bank of batteries to the other as needed. A brilliant idea suggested by an electrician friend.
Hi Nick,
You are not missing anything at all. Solar and wind certainly have their place. And for a boat with light electricity use they can, properly installed, solve most of the problems we are discussing here.
However, for a situation like ours, where we typically use 200-250 amp hours a day, mainly due to computer usage to support this site and photography, as well as refrigeration, they would only make a real difference if we had a huge array of solar, or a really big wind generator(s). We don’t really have room for either, at least if they were installed in a seaman like way.
Also, neither will effectively equalize a battery since this requires a constant voltage without the variation that solar and wind are subject to.
Colin, AAC European Correspondent, uses solar and wind generation installed on the arch of his Ovni. Any comments Colin?
Isn’t equalizing the batteries a completely separate issue from the regular charge/discharge cycle that we all put the batteries through regardless of the number and kinds of charging capabilities we may have?
Now I feel like I’m missing something in this ‘conversation’.
On the topic of equalization; what happens when the batteries have to be left aboard for the winter while the boat is laid up? We have a couple of solar panels that will keep them topped up but there is no way to equalize them every month. Will we just suffer the loss of life at some point?
Hi Jay,
You only need to equalize monthly if you are discharging and then not fully charging daily. In fact if you have AGM batteries there is no need to keep the solar panels charging them since if they are not being used, they won’t self discharge over a winter.
All this should be clear, I hope, if you read the full Online Book. I know it is a lot of mind numbing detail but I have struggled mightily to cover a complex subject as completely as possible. Let me know if anything is fuzzy in my writing anywhere in the book.
Hi;
I have built one 24v 40ah LIFEpo4 lithium battery, and just bought a pre-made (DIY CLASS) 200ah 12v battery, which arrived today. I think these will be the standard batteries for many cruisers not too many years from now. Some highlights:
-little to no Pekert effect. 1c+ charging and 3c discharging allowed.
-1/2 of the weight
-5x the cycling ability
-no gassing, and no equalization
-works with most charging sources. Since they are designed to be charged up higher than most marine charging sources, current stops flowing before they reach full charge, but the % lost not charging fully is minuscule.
-Bulk charging extends up to 90%, and you can safely discharge 80% without grossly effecting the # of cycles. The cells I have in the Torqueedo pack are rated to 2000 cycles at 80% discharge, the Hipower brand cells in the 200ah 12v pack are rated to 1000 cycles at 100% discharge, I have not found their rating at 80% online yet. Thundersky brand cells are rated even higher.
Cost? You can put together what I bought, a 200ah 12v pack with a Battery management system to protect both the cells and your alternator, for about $1200 cell cost and $450 BMS cost. This one weighs about 80lbs in a 4d battery box, and is set to replace 4, t-105 wet cells at 445ah capacity.
Chris
Re. equalizing on solar/wind: With typical setups, I’d agree that equalizing from solar or wind power wouldn’t work. But I can’t think of any reason why a good buck/boost MPPT controller couldn’t be programmed to provide an equalization voltage from a solar or wind source. It should be just a matter of programming the unit’s microcontroller to allow a few different operating modes.
Re. LiFePO4: It’s interesting to see those costs, Chris- they seem to be coming down dramatically. The current interest in electric cars is causing a lot of money to be poured into battery development, and I would consider it quite reasonable to expect the option of choosing between a wide range of traction batteries using half a dozen different chemistries within six or eight years’ time.
Hi Matt,
Thanks for the comment. I would really like the idea of equalizing with solar or wind. My worry was that the voltage would drop repeatedly below optimal as clouds or lulls in winds came though. Could you explain a bit more about these buck/boost controllers? Also, could you link to a brand that you like?
I assume that they attempt to provide a constant voltage, although I would have still thought that the volts will drop if the total watts drop below that required to supply say 3 amps at 15.5 volts or 46.5 watts? Am I missing something?
Perhaps solar would be better than wind in that I have often seen wind power go to zero multiple times in an hour as lulls come through?
To make this work, I think you would need to split the battery bank in two and switch the charging feed back and forth so you could equalize one while using the other. But then we need to do that with our method, so nothing is lost there.
I’m also thinking you would need to have a bank that was equal to four times your daily use to make this work. That is if you wanted to be able to live as normal during the equalization cycle.
Justin again from Lifeline Batteries. Interesting posts. John, your article is right on about equalizing.
Re: Equalizing using solar and Wind. This can be done but it just needs to remain constant for the full 6-8 hours. This is usually the down fall to equalizing this way. If you can find a way to have it remain constant and still push good amperage then by all means use that source.
Re: LIFEpo4 or and Lithium Batteries for that matter. We have built and have been testing Lithium batteries for quite some time.
In summary here is the limitations to the technology that we have found.
•Requires protection circuit to maintain voltage and current within safe limits. Protection circuitry involves both additional hardware and software.
•On aircraft battery monitoring and alarms will be required for safe operation.
•Subject to aging, even if not in use – storage in a cool place at 40% charge reduces the aging effect.
•Transportation restrictions – shipment of larger batteries may be subject to regulatory control.
•Expensive to manufacture – about 40 percent higher in cost than nickel-cadmium.
•Not a fully mature chemistry – metals and chemicals are changing on a continuing basis.
•Extremely flammable electrolyte.
Although we are working very hard to provide top quality products we are also very concerned about safety. Right now the lithium cells are very dangerous and very volitale. If they get the wrong scenario you don’t want to be anywhere around that battery. Lithium Ion cells if ignited can and will burn at 1,100 degrees F. Not only do they burn at that temperature they also create their own oxygen at the battery plates, which means you cannot put out the fire. The cargo plane that just crashed in Dubai caught on fire because of the Lithium batteries aboard. Lithium batteries can spontaneously ignite if the air gets hot enough. That’s what they think happened. They think when it was sitting on the runway the cargo hold got up to 135 – 140 degrees and they self ignited.
We have come up with a non oxygen producing Lithium Ion but the electrolyte is still very, very flammable.
There are new shipping regulations going into effect January 2011 for Lithium Batteries and they are expected to cost the Lithium industry 1 billion dollars more annually. This means the price of Lithium is going up next year, not down. Not to mention they are now considered Hazardous Cargo even when shipping ground.
That still gives AGM batteries the best advantage.
Justin,
The info on the current issues around Lithium batteries is very helpful. I wonder if you have also been testing the new TPPL (Thin Plate Pure Lead) chemistry/constructions, like the Odyssey batteries. In their own product literature they are described as AGMs, but they are actually quite different. TPPL batteries are said to have very high charge acceptance rates and handle very deep discharges. The chemistry is still lead acid, so it would seem like equalization would still be required, but maybe less frequently? Please comment if you’ve been exposed to those.
John,
Were TPPL batteries an option you considered, and if so what put you off of them?
Thanks for this very helpful series of posts.
Justin;
You use the term Lithium batteries multiple times in your post. Knowing that there are multiple chemistries of Lithium cells, and they can be very different in their performance and safety characteristics, which ones are you specifically writing about?
Chris
So if I do not have access to shore power once a month, I should not go with AGMs, but with gel. I expect to have no shore power for montrhs at a time.
Hi Gert,
Unfortunately, going with Gells won’t solve this problem either. Any lead acid battery, whether it be Gell, AGM, or liquid filled, will sulfate and fail very quickly if not regularly fully charged.
In some ways Gells would be the worst choice since most Gells, perhaps all, cannot be safely equalized, so when they do sulfate there will be no way to get them back.
The bottom line is that if you want long life from lead acid batteries you have to come up with a way to fully charge them regularly. If you can’t do that, as most liveaboards can’t, then regular equalization is the next best thing.
Gert, it might be good for you to read through the comments on the posts in this series since some of our readers have come up with innovative ways to solve this basic problem, including using wind and/or solar to finish the charge or splitting the house bank in two so each gets two full charge cycles between discharges. Perhaps one of these ideas will work for you.
Hi John,
I believe a previous commentor tried to make this suggestion, but didn’t communicate it clearly. Let me try. If you have 2 house banks, could you use one bank to fully charge and equalize the other one (kind of like lifting yourself up by your shoelaces)? If each bank is 300 amps, to fully charge the offline bank from 85% to 100% would draw down the bank in use about 45 amps, plus some for inverter/charger inefficiency. To equalize add 3 amps per hour for 8 hours= 24 amps, plus inefficiencies. Say 80 or 90 amps out of the house bank in use. That is one hour of generator time with a 90 amp Iota charger ($400?) or a half hour if you stack 2 chargers. I hope there is a solution this simple…why won’t this work?
Hi Steve,
I guess it’s possible, but it seems complex and inefficient. I would also worry about wiring complexity. Bottom line, the system detailed in this series of posts, while fairly simple, is working very well after 18 months.
I also think that the efficiency loss would be far higher than you estimate.
I think that you might want to look at solar or wind to do the final finish off charging or equalization.
Hi John,
I am very interested in your research on this topic as I have a similar situation with a 47′ aluminum Van de Stadt based at a wilderness cabin in Alaska, nearest shore power 12 hours away.
AGM batteries are my first choice as I have an 8 kw generator that should be able to run at least 3 60amp chargers to take advantage of the high absorption rate of AGMs for bulk charging. Per my understanding of Justin’s post solar and wind are not consistent enough for a proper equalizing charge, but could charge the house bank in use.
After both battery banks were charged to 85% the generator could be shut down, and the house bank in use would be used to power an inverter and small charger that would complete the charge of the offline bank to 100% (@15A for 6 hours=90A) followed by the equalizing charge of 6 amps at 15.5 v for 6 or 8 hours (48A) Total 138A into the battery being equalized, plus inverter use & inefficiency. Maybe a 50% discharge (200A) of the in use L-16 house bank at most, assuming no extra generator run time for projects, or solar, wind, or alternator charge off the main engine (160A) which gets used a lot in Alaska. So lots of surplus power available at certain times. Worst case of 52 discharges a year if done weekly. According to the tables it seems like it would extend the life of the batteries, even with the extra discharge cycles factored in. At least in theory. A selector switch would be needed to choose the house bank in use to power the inverter, which would run the small charger. Another switch would be needed to direct the charger output to the offline bank being equalized. A small dedicated charger for each bank may be even simpler. I will sketch it out and hopefully see what I have overlooked. Seems like it could be kept very simple. (I have lots of ideas, and am happy if only 1 in 10 is good and worth pursuing. And the only dumb question is the one you didn’t ask.) Any suggestions are appreciated.
Steve
John, a number of years have passed since you worked with Lifeline to equalize your AGMs amd modify your charging methods. What was the result? Are still using the same AGMs? Also, if you are still in contact with Justin (and he is watching this site) I would love to hear his opinion about equalizing East Penn (Deka) AGMs. The factory says no, but it sounds like the ‘conventional guidance’ that Justin referred to.
BTW, we are on our second set of AGMs since 2002 but unlike you have been able to take advantage of ground charging resources. Our experience suggests that on-board generators are not necessarily the answer.
Thanks
jtc
Hi Joe,
I really can’t comment on equalizing Deka batteries and I don’t think it is really fair to ask Justin to do so either. As I understand it, East Penn specifically say that their AGM batteries should not be equalized. Anyone going against that would be taking on a huge liability if anything went wrong, such as a fire or explosion.
The bottom line for us, based on our testing, is that any battery that can’t be equalized does not belong on a voyaging sailboat.
Great info! The equalization makes sense and it looks like a real battery saver. My question pertains to a 48VDC (or 24 VDC) system which is comprised of multiple batteries in series. Do you need to equalize each battery individually? Or does this happen “naturally” based on all batteries are in series together.
Thanks, great website.
Chris
Hi Chris,
Seems no-one wants to answer your question so here goes;
It would not be necessary to equalise separately, the voltages applicable to the 12v system can just be multiplied for series connected batteries eg;
12v > 15.5
24v > 31.0
48v > 62.0
Mark
Hi Mark,
Oops, I missed that one, thanks for fielding it.
John,
Thank you for a very useful article.
I was wondering if there is any instance or reason you are aware of where a continuous battery maintainer/desulfater would be bad for AGM batteries? Unfortunately we live on shore power a lot right now, and I wanted to buy a maintainer for our AGM starting batteries to live on, such as this one: https://www.amazon.com/BatteryMINDer-Charger-Desulfator-Batteries-Model-2012-AGM/dp/B005EKY20K
The distributor said I did not need it, and actually said to not get it. Do you know of any reason why a maintainer/desulfater for AGM batteries, hooked up full time to AGMs, would be harmful? (Full River AGM batteries)
Thanks in Advance!
Conor
Hi Conor,
This has come up a bunch of times, so I think I will answer it with a post. Look for it soon.
Hi John.
We are in the process of designing the electrical system in our new boat. This obviously includes the choice of battery type. While discussing the possible choice of AGM’s, the following question came up. Why is it that different companies have opposing guidelines with regard to equalizing, although it is the same technology (or at least that is what you would assume). Lifeline (the brand you use) says you need to equalize. Trojan specifically indicates in their maintenance tips never to equalize AGM’s (https://www.youtube.com/watch?v=jCl5klSF4tE&frags=pl%2Cwn). At the boat show I got different answers from different dealers. Nothing conclusive.
This issue is important notably regarding the need for shore power. We would have relatively low usage (+/- 120 Ah), the possibility for a fairly large bank (500 Ah), a good dose of solar on the hard top (400 W, and more when at anchor) and a large alternator on the engine (175 Amps). Therefore it looks that we might get around with these charging sources for our daily usage. However, if we need to equalize, we now need to add shore power. Quiet a substantial investment (cable, plug, 2 chargers, a galvanic isolator, …).
Maybe the people from Lifeline can shed some light on this?
Many thanks
Philippe
Hi Philippe,
I see how this could be confusing. To make it clear, we need to turn it around:
All lead acid batteries that are not fully charged after every discharge, which is near impossible on a cruising boat, will sulphate and die prematurely if not equalized regularly.
Therefore we should simply never install a battery on a cruising boat that can’t be equalized.
This is particularly true for AGM batteries, as I’m pretty sure that while all lead acids sulphate, AGMs do so more quickly than liquid filled or gells.
Or to turn that around, AGMs that are not built strong enough to take regular equalization have no place on a cruising boat.
As to equalizing, it is possible with solar, but that requires some understanding and the right solar regulator.
As to not getting a straight answer at the boat show, that does not surprise me. Very few battery sales people understand their own product properly, much less how it will react to a typical cruiser use scenario.
As to Lifeline shedding more light, been there, done that: the above came from Justin, principle at LifeLine. See the above post.
Hope that helps to clarify a tricky subject.
Hi John.
Your statement ‘we should simply never install a battery on a cruising boat that can’t be equalized.’, helps clarifying things.
In summary. Equalization is a must. Choose only those products from a given company for which equalization is permitted or a must. While the charge source for equalizing does not need to be shore power, can be more tricky if using solar. I will look into this last aspect.
Thanks
Phiilippe
Hi Philippe,
That’s it exactly. The key to equalizing from solar is going to be having a regulator you can program to provide the necessary voltage and keep that up for 8 hours. And of course you need reliable sunshine. I think if it were me I would still be seriously thinking about shore power.
Phillipe,
I have talked to Lifeline about equalizing from solar specifically and they did not recommend it. Basically it was an issue of enough light for long enough. They recommend at least 6-8 hours continuous for equalizing and that is starting off at a battery at 100%! Not, 4 hrs today, 4hrs tomorrow.
Given that you have a relatively small power demand, and a pretty diverse and capable charing mix, it sounds like equalizing may be every 2nd or 3rd month, as you may re-charge your batteries pretty often.
Have you considered not hard-wiring a shore power connection for your relatively seldom equalization needs? I wrote previously about using a power max battery charger, with manual voltage adjustment, for equalizing and I was thinking, if you just put some alligator clips on the DC output, and keep the supplied cord with plug for AC input, you have a simple, equalizing solution for under 200 bucks and no installation requirements.
(http://powermaxconverters.com/product/pm3-12v-series/)
Cheers
Conor
Hi Conor,
I think that equalizing by solar is probably possible, given that it only takes 2-3 amps, but I agree that that there are a lot of variables here that could screw things up. A big black cloud comes to mind!
One thought on using these very inexpensive chargers. That is I wonder what the quality of the rectification is. The point being that any AC ripple in the output is very bad for batteries. Not saying that this is, in fact, a problem with these particular chargers, but it’s something to be aware of.
I guess, if it were me, I would still be going with a full on shore power system.
John, Conor.
Thank you for the further clarifications. I will look into this a bit further.
Shore power moves back to the top of the list. All things considered, tested and proven solutions often turn out to be less expensive than experimenting with ‘big black clouds’.
Thanks
Philippe
John, in a comment back in 2010 you wrote:
“The bottom line is that if you want long life from lead acid batteries you have to come up with a way to fully charge them regularly. If you can’t do that, as most liveaboards can’t, then regular equalization is the next best thing.”
So, what constitutes “regularly?” If through solar or a long day of motoring, batteries are fully charged once a week, is that “regular”?
Regarding using solar to equalize, the concern seems to be that it is too unreliable because a constant current is needed over a relatively long period of time for a battery bank of any real size. I would think that “partial equalizations” on successive days would still be beneficial, but maybe I don’t understand how the equalization actually works.
Hi Robert,
We have suggested full charge and equalization schedules from Justin and Lifeline here: https://www.morganscloud.com/2010/08/02/agm-battery-test-part-1/
And yes, equalizing, or even fully charging, batteries with solar is complex and will usually require reprogramming and monitoring the solar regulator. That said, I think both are possible, but the details are beyond what I can do in a comment. That said, I have been thinking a lot about just that and will probably tackle the issue some time in the future, although I’m guessing it will be a year or so…and to think I used to worry about running out of stuff to write about!
As to partial equalizations, Justin at Lifeline has advised against that.
Seems like the link is not good, I get the below response.
Page Not Found
Hi Jack,
Sorry about that, fixed now. Our automated link checker is down at the moment, but should be back up and running in a month.
Hi John! Love your website … tons of useful info! I have a question. Given that a battery bank should ideally be charged to 100% and given that the last 20% takes a long time what would you think of the following suggestion: have two battery banks (let’s say A and B). One (A) for use, the other (B) for being charged (and disconnected from my grid). The latter (B) would be charged with the engine or a genny and then fully charged with solar panels over a day or so. Should get them up to 100%. The other bank (A) is being used. When the charging bank (B) is full I would switch banks (and charging genny/engine & solar). The discharged bank (A) will now be charged with genny/engine and solar panels and the full bank (B) will be used. I would only need 300-400 AH per 24 hrs so having two banks of three 100AH batteries should do the job. What do you think of that idea? Cheap enough (I can get a 105AH battery for $120 or so) and easy to make a switch or even MacGyver one to switch automatically.
Hi Bob,
That should work fine, although it will take a bit of clever wiring to make it work. That said, I think on a practical basis if you are going to get 300-400 amps a day you will need a bigger bank than 600 Ah. Probably at least 800 Ah (two banks of 400 Ah).
By the way, if I were ever to add solar to our boat, this would be exactly the inducement.
John, This is a simple one but when you actually go through the process of equalizing your lifelines should you turn the breaker at the main panel off if you are in a position to do so. Will this help prevent any sensitive electronics (i.e. lights, refrigerator, etc..) from being damaged by the high voltage? Just curious on the details as it was recommended by my battery supplier that I equalize my Lifelines after returning from a 6 month trip cruising the Bahamas. I started seeing my voltage drop to around 12.6 -12.7 after fully charging the batteries. They would never get back up to 12.8V
Thanks for your help.
Hi Chris,
It really does not matter if the main breaker is off or not (may or may not be feasible, depend on how your charger is wired), the key point is that everything be turned off.
John, I want to start by saying that you provide a huge amount of value in your posts as the are the perfect balance of theory and practical application. For people who have never equalized batteries or reprogrammed a battery monitor you really put the mind at ease. I wanted to let you know that i equalized my Lifelines and all went well. While my batteries were not in bad shape i will start this good practice. I just wanted to tell you what i saw in case someone else like me reads this post.
I used my Truecharge 40+ equalization mode and also had to “trick” it to thinking batteries were flooded. The Charge put out 15.73V with about 1.83amp of current. I equalized for three hours. The batteries never felt hot to the touch nor did they discharge any gas. I was nervous at first but then quickly realized that I had made all the necessary precautions by taking the kids off the boat, turning off the main DC panel, and opening up the boat.
Thanks again for all you do. Hopefully someone else reading your blog will find this comment useful when trying to equalize for the first time.
Hi Chris,
Thanks very much for the kind words and the news that equalization worked well for you.
Hi John and all,
After decades of using high quality gel cells and been generally quite pleased, I am seeing the end of my present set which 6-7 years old and saw a fair amount of neglect and some abuse (down to 10+v for undetermined periods for ex) when Alchemy was abandoned in Newfoundland for 1 ½ years because of covid. One of the things I have appreciated about gels was their forgived-ness: as shown by the fact that we have been using the above mentioned set so far this season.
For replacement, I have been thinking of AGMs: in part because they seem to be dominating the recreational market and, now, in casual inquiry, seem to find that East Penn gel cells are hard to come by (my last set, this present set, are Sonnenschein bought in the UK).
In preparation, I have read your reports on AGMs and have some questions.
Before doing so, I would suggest that your statement that batteries that can’t be equalized have no place on a cruising boat be temporized: my gel cell banks last ~~6 years or so and, during some years, rarely see shore power. In contrast to AGMs, they seem not to need to be fully charged with regularity. And I have been pleased that they have bounced back, seemingly unaffected, from the occasional abuses I have inflicted on them.
One of my concerns about AGMs is that they like (perhaps need) to be fully charged with some regularity. My house bank is 6 group 31 gels (~~570ah). Your regimen for equalizing is intimidating both in equipment needed (new battery charger for one), the need to find shore power for periods of time, possibly re-wiring my 6-battery system into separate banks as I live aboard, etc.
Casual research seems to indicate that many AGM battery makers do not suggest equalizing.
My questions are: How much of a longevity hit would one experience with say, Lifeline AGM batteries, if they were fully charged (not equalized) once per month on shore power on occasional marina visits? Would you suspect there to be a hit on overall battery capacity (in other words, would there be a “set” that would decrease the quantity of amps available)? And lastly, are there AGMs that do not suggest equalizing worth looking at.
Thanks very much for your thoughts, My best, Dick Stevenson, s/v Alchemy
Hi Dick,
Not a lot I can add to what I have already written about the care required for AGM’s and bear in mind that was based on killing three sets and then working with Justin, principle at LifeLine. This chapter will tell you what will happen if you don’t follow the regime Justing and I recommend. For example the regime you mention will probably kill the batteries in two years:https://www.morganscloud.com/2010/08/02/agm-battery-test-part-1/
Bottom line, If you are not willing to follow the regime we suggest, and I understand why you are not, don’t buy AGM batteries.
Maybe stick with what you know, given that it worked well for you. I too had good service from gells, back in the day. I still like batteries that can be equalized, but clearly gells worked well for you without, so that’s what matters.
Another good alternative is liquid filled. Easy to get, and least expensive, can be equalized when required, and I think generally not as prone to sulphating as AGM.
Carbon foam would, I think, be the best option, but will require reconfiguration of your bank (a royal PITA) since they (I hear), don’t want to see more than 4 in parallel. That said, might be worth the work in that 6 is a lot of batteries to have in parallel.
More here on the options: https://www.morganscloud.com/2018/05/11/battery-options-part-2-lead-acid/
Hi John,
As always, I appreciate your thoughts and agree with your appraisals. I will likely stick with gels as they have been a workable compromise: fairly good life, forgiving and no maintenance. As I get older, the no-maintenance aspects of life on board gets increasingly appealing.
BTW, further calls around for East Penn/Deka gels discovers that NAPA batteries are East Penn re-branded. East Penn can’t deliver for months while NAPA can deliver in days. Weird world. I neglected to ask about their AGMs.
My best, Dick
Hi Dick,
Don’t even look at East Pen AGMs. I killed a pair in 12 months. Selling ADMs, that can’t be conditioned, to cruisers that who can’t fully recharge after each charge should be a crime.
Hi John,
Good to know.
From what you have written, I suspect any of the AGMs that are unable to be equalized would suffer a similar fate. I further suspect that this issue with AGMs is masked by how few live off their batteries and who are in marinas regularly with its shore power and so fully charge their AGMs.
When last in the US (15 years ago) I had good luck with East Penn gels. I hope they have maintained that quality.
My best, Dick
Hi Dick,
Just to clarify, sulphating is an intrinsic problem with all lead acid batteries, not just AGM. It’s fundamental to the way the battery works. In fact, it’s the modality that causes all lead acid batteries to eventually die. That’s why I prefer batteries that can be equalized. That said, I think AGM are prone to faster sulphating if not charged properly.
John – I am wondering how carbon foam batteries (Firefly) might affect one’s equalization strategy. From the Firefly manual:
“Restoration Charge
As stated, Firefly Batteries can operate in a partial state of charge for long periods of time without sustaining any permanent damage. The usable capacity will decrease, however, with each cycle within a partial state of charge, up to a point. In order to regain the full original capacity and in some cases more, it is necessary to perform a restoration charge. To perform the restoration charge: charge the G31 to 14.4V or the 4V/450AH to 4.8V and continue to charge until the current drops to 0.5 A on the G31 or 2A on a 4V/450AH and apply a float charge of 13.5V(4.5V for 4V model) for 24 hours. Fully discharge the battery to 10.5V (G31) or 3.5V (4V/450AH), and then repeat the same charge cycle.”
So a much longer equalization cycle (4x) but at a lower (float) voltage. And you have to do it 2 days in a row. Knowing that you have very positive comments on carbon foam elsewhere in this e-book, does this requirement affect your thoughts on Firefly vs standard AGM.
I am wondering if my existing Heart Interface Freedom 10 (circa 1994) charger/inverter is all I need and how I might do a restoration charge once a month in practice. Seems like shore power with my existing equipment would cover both load and restoration (float) charge needs without need to separate the batteries while not sleeping or leaving the boat, but it would take at least 3 days at the dock to do the cycle. (Not cheap and not want I want to do, but could get lots of chores done)
5-8 hours to recharge depleted battery back to 100%
24 hours at float voltage
5-10 hours to draw back down to 50%
5-8 hours to charge back to 100%
24 hours at float voltage
Anyone have real world experience with restoration charging of Firefly carbon foam?
Thx- Steve (btw, this site is an absolute gem).
Hi Stephen,
I was reading that just the other day since I’m considering Firefly for our new to us J/109.
My thinking is that all lead acid batteries require some kind of equalization cycle so the good news is that the Firefly can withstand this, unlike gells and all AGM except those from Lifeline. At least now Firefly are admitting that these batteries do require care, rather than the extravagant claims that were being made when they first came out. More here:https://www.morganscloud.com/2020/12/04/firefly-carbon-foam-batteries-are-great-but-read-the-fine-print/
Bottom line, the capacity of all lead acid batteries walks back over time due to sulphation and that process gets a lot worse if the batteries are not fully charged after every cycle, as is typical in boat use.
Still, the key to all this is will the Firefly batteries restore to a better state than other types after being partially charged for many cycles? Everything I’m hearing says yes, so I’m pretty sure I will give them a try.
Practical Sailor testing concluded-yes, a while back. See https://www.practical-sailor.com/systems-propulsion/fighting-sulfation-in-agms
Hi Stephen,
Yes, that was one of my sources. The study also confirms what I have long said: only AGM batteries that can be equalized should be considered for a cruising boat: Firefly or Lifeline.
Hi John,
Just followed the link over from your latest charging article and noticed that your conclusions on equalization may not apply to everyone depending on the specific battery manufacturer’s recommendation. In our case, our Trojan T105’s only recommend a 2 hour equalization but at a whopping 16.2 volts. This is a short enough period for us that we just shut everything down when fully charged and not underway at some point and do it, no multiple days or having to split the bank in 2 (I still do like what you do with 2 separate house banks but generally paralleled for other reasons). And we find that our 140W solar panel has no problem completing this task if it is sunny and towards the middle of the day on 4X GC2’s assuming we started fully charged so no need for shore power either. The limited sample size of equalization recommendations I have read seem to suggest that FLA allow for higher voltage shorter duration equalization than AGM but this is too small of a sample size to say definitively.
Eric
Hi Eric,
Good point that different batteries need different equalization. Also that solar changes everything. I definitely need to update this article in light of that.
Eric, I have a similar battery and solar set up. What is the rest of your charging system? How do you accomplish the equalization exactly? Bob Andrew
Hi Robert,
Our boat has 2 charge sources, an externally regulated alternator and a solar panel. To equalize, we get to full charge at anchor, typically due to having had good sun for a day or two but sometimes due to motoring then switch our main battery switch off and turn on the equalization on our solar controller and it takes care of the rest. Our 9 year old charge controller died a few weeks ago (solder melted out of a thru connector on a PCB) and I replaced it with a Victron SmartSolar. I have generally been quite happy with the unit but I can’t seem to get it to equalize the way I want so I will reread the manual this week and make sure it isn’t operator error and if I can’t fix it next weekend, it will be time for a call to customer service. It certainly is capable of doing what I want from a hardware standpoint, it just seems like the settings I program for equalization are not getting saved. If something were to happen like a squall line were to move in, I would just turn off the equalization and turn the battery switch back on and complete it another time.
Both charge sources go to the house bank and then the start battery is charged by a charging relay. All batteries are FLA so when the house bank gets equalized, so does the start battery.
Eric