Battery Charging While on Shore Power

[Paul Elliott]

My BlueSky controllers had no enclosure behind the panel, just the bare circuit board. I had it mounted in a spot that I thought would be well-protected, but somehow a few drops found their way to the circuit board. Technically it was my fault. I later bought the painted steel electrical box from them, but it wouldn't fit in the spot I had for it, so I just replaced the dead controller with a new one. The same thing happened -- I should have learned the first time.

I highly suggest that you protect the controller from any chance of being hit by drips or splashes.

[Celestialsailor]

It's in a SS box now but since reading your post Paul, I will silicon the holes where the wires enter and exit. They have to know about this problem.

[noelex 77]

Solar controllers do generate a bit of heat. They have large heatsinks and or fans to dissipate this. Be careful when mounting them in a waterproof enclosure that you are not reducing the cooling too much.

[Celestialsailor]

Thanx Noelex. The Blue Sky is cooled via it's face plate, being aluminum. So I took care as not to enclose the face...just the exposed electronics behind it.

[Cheechako]

Originally Posted by geoffh

Yes good advice Paul, it surprises me how many get that wrong !

Geoff

Interesting, never thought of that angle....

[Andina Marie]

I have a suggestion based on 20 years of marine battery experience.

If you spend lengthy time at a dock (6 months or more) without any stress on your batteries, you can kill them with short cycling. This is the situation where for months on end the only load is an occasional 12 volt water pressure pump, an electric toilet flush, nightly house loads etc. A good quality shore power charger will have no problem maintaining full charge and switching modes as needed to achieve it.

The problem is you are using perhaps less than 0.1% each time of capacity off the top surface of the plates and you can end up with a sulfation layer sitting at the top of the plates. The next time you really use them, the area under these patches of sulfation fail to get used and your battery capacity is reduced.

After killing a just about brand new bank of batteries this way I adopted a new technique.

When tying up at a dock for an extend time I disconnect the bank completely. I go to WalMart and get a cheap starting battery, any $30 to $40 battery will do. Connect this in place of the expensive battery bank. Even though small it will have amps available for pumps and sudden loads and doesn't need depth of cycle because the shore power supply will support all longer term needs.

Now you are using/destroying a $40 battery that is under warranty and saving your expensive batteries until they are needed. Once a month put them in parallel with the small one to top up any natural discharge. A monthly "short cycle" is a lot better than 10 to 20 short cycles per day.

[Celestialsailor]

Perhaps this is true of shore power charger but I doubt it. I have both a 3 step battery charger which is suppose to prevent sulfation and a MPPT solar regulator which is also suppose to prevent this.

[btrayfors]

Andina's right about one thing: batteries on float charge....even with a "smart charger" or a "smart regulator" will still sulfate over time. Best way to prevent this is to use them -- "exercise them" -- then give them a really full charge. In addition, a repeat absorption cycle of at least 14.8VDC every few days for an hour or so will do wonders (I have the data to prove it). Finally, if you have flooded batteries or Concorde Lifeline AGMs, they will likely benefit from an occasional equalization cycle....maybe once or twice a year, depending on your usage, their age, and other factors.

I do not agree with Andina's solution, though, for three reasons:

1. Putting a $40 automobile charger on your boat is dangerous...to the boat and to the batteries. They are not marine rated and if the worst should happen the insurance companies will have a good reason not to cover the loss.

2. A smart charger left on will accommodate any modest transient loads, including frig/freezer, bilge pump, water pump, etc. without any noticeable cycling at all. The charger will simply supply the needed current, while the batteries hardly notice.

3. I do not agree that it's a good idea to leave flooded batteries without charge for a month on a regular basis. They will continue to sulfate even when "fully charged" and their self-discharge rate is sufficient to speed up that sulfation process.

This is particularly true in hot/tropic areas. I can't tell you how many sets of Trojan T-105's I managed to kill on my boat in the Virgin Islands over an 11-year period because I'd fully charge them, then leave for a couple of months with instructions to the caretaker to "turn the charger on every week or two"...which he obviously didn't do....and return to find a very badly depleted/sulfated battery bank. An expensive lesson indeed! One brand new set was destroyed in only 6 months.

Bottom line: keep your batteries fully charged as often as you can and, in addition, exercise them, get them into a "repeat absorption cycle" frequently, and equalize them occasionally.

Bill

[Celestialsailor]

I appreciate your response. It's difficult to believe anything though since when you buy these so called "latest technology" chargers and regulators and they tell you in black and white that they prevent sulphation.

[btrayfors]

Originally Posted by Celestialsailor

I appreciate your response. It's difficult to believe anything though since when you buy these so called "latest technology" chargers and regulators and they tell you in black and white that they prevent sulphation.

Yes, you're absolutely right!

A better description for what most "smart chargers" do is to "help slow the pace of sulfation". Some of the newest ones, like the Sterling and ProMariner Ultra series, likely do somewhat better than others. And, even better, they have a true equalization cycle capability.

My Victron MultiPlus is fully programmable and, if you set up the parameters correctly, it can do a pretty good job of slowing sulfation and even recovering some lost capacity. Tests on 6 T-105's on my own boat have proven this.

The two-year battery study I've referred to a couple of times was designed to test the claims of some pulsing devices re: sulfation prevention. We tested 10 different devices from several manufacturers and were unable to prove any of those claims. A nationally recognized scientific testing lab was also unable to confirm the claims. Bottom line for us at least: they're mostly if not entirely snake oil, despite the elaborate claims by manufacturers and some users.

Example: after 18 months of cycling and pulsing/charging, one set of T-105's recovered significantly more capacity during a single 8-hour equalization cycle @ 16VDC than it had with the pulsers during the previous 18 months.

Bill

[Celestialsailor]

I am currently using 3, Group 31s for house and 1, Group 24 for starting. This has been my combination based on my "low tech" set ups I have done on all my past vessels. It's worked pretty well. With this set up, I have only had to replace one battery after 5 years. However, I'm sure the others were ready. I just did not have that particular vessel more than 6 years. The only thing which has changed for me is the better quality battery chargers...from the old heavy ferrite transformer type to the 3 stage I currently have and the on/off regulating solar charger to the MPPT unit. I'm sure we will see more advances in technology as well as more unfounded claims to that they give,.

[Andina Marie]

Originally Posted by btrayfors

Yes, you're absolutely right!
<SNIP>
The two-year battery study I've referred to a couple of times was designed to test the claims of some pulsing devices re: sulfation prevention. We tested 10 different devices from several manufacturers and were unable to prove any of those claims. A nationally recognized scientific testing lab was also unable to confirm the claims. Bottom line for us at least: they're mostly if not entirely snake oil, despite the elaborate claims by manufacturers and some users.
Bill

Thank you, I have to agree.

When they first came out many years ago I purchased a copy of the patent to see how they worked and if it was a product I should be manufacturing.

The theory behind the operation was that the sulfate crystals had a natural resonant frequence of mechanical vibration of 3 Megahertz. By sending high energy pules at that frequency the crystal would vibrate and break loose or self destruct like the wine glass in the old Memorex commercials. Based on that I've maintained that they were useless despite vigorus endorsements from satisfied customers. It is comforting to see a study based on facts that supports my gut feeling.

[btrayfors]

Yep, sometimes the gut feeling is right :-)

First clue we got was early on in the study we did a bunch of measurements on the 10 devices to be tested, using some pretty sophisticated lab gear including a very good spectrometer.

Guess what? They were all different! Different in pulse characteristics....amplitude, duration, frequency, rise/fall rates, periodicity, etc., etc. Hmmm...jeez, how can they all work?

Best anecdote I heard had to do with the home-built pulsers developed by a whole legion of fanciers and followers, many based on circuitry available on the web. One fellow built a "super pulser" which was so powerful that whenever he turned it on it knocked out his TV :-))

Note that I'm not disparaging pulse-charging; that has several very beneficial characteristics. Rather, I'm talking about the little pulsers which usually work on the battery's voltage itself and which -- as Andina said -- claim to be tuned to the "resonant frequency of lead crystals", i.e., PBSO4 deposits on and, eventually, into the battery plates.

Bill

[Stu Jackson]

Bill, Andina suggested getting a cheap battery, not a cheap battery charger.

[Jbaffoh]

I hope this is not a hijack of the thread, but it has me thinking about my battery health, and whether I should equalize.

I have 2 Trojan T-145's in series (260 ah @ 12v). They're 18 months old.

Trojan recommends bulk and absorption at 14.8v and float at 13.2v. My ancient alternator puts out slightly more than 14.5 volts, but I rarely use it. My PWM solar controller charges at 14.5 and floats at 13.6. The sun always shines in So. Cal. My batts have never seen 14.8 volts.

We sail two weekends every month, with 1-week trips every 3-4 months. According to my battery meter history, the max discharge has been only 18%.

Should I find a charger that reaches 14.8, and floats at only 13.2? Should I equalize?

My last 24-hour open circuit results (Monday) seemed pretty good--am I being fooled? Temperature compensated specific gravity readings were 1.280 for 4 cells, and 1.277 in one cell on each battery. Uncorrected voltage was 6.41 and 6.42. The electrolyte was 67°F, so adding .028 per cell, the corrected voltage is even higher.

I was thinking my system was working well despite not being fed per Trojan's recommendations. But reading these threads has me wondering.