Solar directly to batteries to equalize them

[S/V Alchemy]

Originally Posted by svmariane

Just my 2 pence worth, but...

500 W seems enough solar to do the job so I'm suspicious of your solar regulator. Is it an MPPT type?

If not..... Maybe check into the likes of this: TS-MPPT-60
TriStar MPPT » Morningstar Corporation

I've about 350 W solar and have no problems using our TS-MPPT-60 to equalize our 600 A/H house bank.

Better results if the (free) software is utilized from a laptop (or similar).

Note: We run our boat with solar & wind power - no genset, no shore power, and not using motor except to maneuver.

{Our TS-60 allows for future solar expansion vice being limited by a TS-30.
No affiliation with the company except as happy customer. }

This. Something isn't right if you can't get enough juice out of those panels. You don't mention whether they are shadowed or angled to make the most of non-noon light. My arch is curved to present (assuming I am hanging on the hook with bow due north for the sake of illustration) panels perpendicular to full sun approximately half an hour before dead flat panels do; the MPPT's function, of course, is to take the lower voltages from the flatter laying panels to be "blended" to the chosen set point. 20 V to a battery will cook it. The MPPT steps it down and amps it up (with an efficiency penalty) to a preset appropriate for your needs. Equalization voltages should be possible to achieve. So should be nights on seawalls with shore power and your charger (I assume you still have on) set to "equalize", which is faster than doing it via solar, depending on your need to equalize, size of bank, etc.

[S/V Alchemy]

Originally Posted by btrayfors

Mark,

Yes, that's what I've done since Feb 2012. The Victron is set to kick up to absorption voltage 14.8VDC every other day for 30 minutes.

Look at the yellow to green bars. That's the six-month period after I started using the every-other-day re-absorption voltage thing. A clear increase in measured capacity is seen in all batteries.

However, these batteries were already seven years old, and about 13 months later they all began to lose capacity (blue bars).

Battery #3 had clearly reached the end of it's lifetime. I removed it from the bank and went with the remaining house batteries for a few months until I replaced them all.

Attachment 116066

Bill

Seven years in a stock-issue FLA battery in a boat not hooked to shorepower is an excellent result and I have no doubt your service regime bought you a couple of years most won't get.

[Chuck Hawley]

Just a quick story about the value of equalization:

I sailed solo to Hawaii when I was 25 on a very simple sloop (2,000#) and a simpler electrical system. I had one Group 27 Trojan battery, one 50W solar panel, a VHF, an interior light, and a masthead tricolor. And an Autohelm 2000.

I got stuck in the Pacific High for a few days. On the second day, I went below and could hear my battery gassing vigorously. I mean really hissing and bubbling. It was calm enough in the High that it caught my attention. I looked at the battery voltage and it was about 16V. I was devastated. I ran to the transom and pointed the panel to the horizon, and turned on the VHF and tricolor and interior light to bring down the voltage. After the battery settled down, I topped it off with some distilled water.

I was in despair, thinking that I had fried my only battery, and I would have to hand steer the next 1,200 miles.

Of course, you can guess the result: better than ever battery performance, no negative effects, and smooth sailing the rest of the way to the Islands. I had inadvertently equalized my battery, using pure DC, although the rate was probably higher than optimum (about 4%C).

Cheers,

Chuck Hawley
(Formerly Moore 24 "Slim")

[zboss]

Originally Posted by btrayfors

I don't think it's required very often. And, I'd be leery about "automatic equalization", AKA uncontrolled equalization. With battery charging voltages that high, I'd wanna be right there to monitor/control what's going on.

Bill

I had extensive discussions with Trojan while in the process of determining things like what they define as a "cycle" and proper charge voltages being that I was going to buy solar controllers with automatic equalization.

The "unbalanced" guideline is just that, a guideline for those that want a distinct flag as to when they need to equalize - not a general position on how often equalization should take place. Based on that conversation with their engineering they don't have any guidelines as to what constitutes "too much equalization" but I was told "off the cuff" that every 30 days was probably not harmful but less than that is "probably too much".

I also asked about being hooked up to shore power for long periods and it does not make a difference according to them.

[svlamorocha]

Originally Posted by zboss

I had extensive discussions with Trojan while in the process of determining things like what they define as a "cycle" and proper charge voltages being that I was going to buy solar controllers with automatic equalization.

Do not confuse the (true) need to periodically equalize FLA batteries that are used under certain conditions or set a reminder to do do once a month with the (false) advantage of "automatically" equalizing.

Proper equalization requires a) starting with a full charge b) disconnecting loads that are not designed for 15.5V, and c) looking at specific gravity every hour(to decide whether to go for another hour). This means you cannot do it "automatically".

I have seen plenty of damage from unattended equalization on boat whose owners chose to believe in gimmicks from gadget manufacturers rather than engineering-based common sense from Maine Sail and the like. Iuf you choose to go for "automatic" equalization just make sure that you disconnect essential safety equipment you could not live without. Certain Iridium power supplies are particularly vulnerable to equalization voltage.

Fair winds

C

[donradcliffe]

The OP didn't mention the size of his battery bank. Five hundred watts of solar is enough to equalize at least 500 amp hours of FLA in one day if you have the batteries full in the morning. Bypassing the regulator is fine for equalizing with solar panels, as long as you don't turn on anything else and regulate the voltage yourself. If its starts getting too high throw a towel r part of the panels. If you don't have enough solar, isolate half the bank and do it, then do the other half the next sunny day.

[Sternwake]

The question as to whether a flooded battery needs to be equalized or not is easily answered, by using a hydrometer.

How often an EQ charge is required depends on many factors such as the average depth of discharge, how often since the last true 100% recharge, how many partial recharges, temperature, battery age and health.


An EQ charge should only be attempted after the battery has sat at ~14.8v until amps taper to about 2 to 3 per 100Ah of capacity, and then the voltage cranked up to 15.5 to 16v, with voltage sensitive appliances/devices removed

I found my one flooded group31 battery took 4 hours at 15.5v to max out SG on all cells but took only 45 minutes at 16v.

This 130 AH battery required 6.2 amps to achieve 16v after a few hours at 14.9v. I could do it on 200 watts of solar alone, if the battery was nearly fully charged in the morning, and the sunlight was uninterrupted. Usually amps had tapered to 4.2 to 4.4 at 16v when SG had maxed out at ~1.280, and later on I used my ammeter rather than the hydrometer to determine when to stop the EQ charge.

When one does not have the absorption voltage set high enough, and for too short a duration, then sulfation will form much quicker, Specific gravity will tank, and voltage under load will drop more drastically than a healthy battery.

The heavily cycled battery requires a different time at absorption voltage than the lightly cycled battery. There is no One size fits all formula as to how high, how long Absorption voltage is to be reached and held and no formula as to how often an EQ cycle needs to be performed.

The Hydrometer is the tool to allow an intelligent decision for these variables. Other people's 'Just Fine' stories as to what they believes works for them mean very little to somebody in a different climate, with different batteries, in different usage patterns.

Trojan lists a 14.8v Absorption voltage at 77f. Hold this voltage after each significant discharge until specific gravity returns to the 1.275+ level, compensated for battery temperature, and an EQ charge might never be required.
Allow only 14.4v and not enough time at 14.4 after a significant discharge, then the EQ charge will be required much more often, and be required to be held much longer before Specific gravity on all cells approaches their maximum baseline.

So as to how long or how often or how high a voltage is required in any specific usage, can only be definitively determined by the battery owner, armed with a hydrometer and the ability to achieve 15.5+ volts at the battery terminals and hold it as long as necessary until specific gravity no longer rises, or battery temperature starts rising rapidly, or is close to 120F already, or the amps required to maintain these EQ voltages begin to increase instead of tapering as usual.

My previous USbattery, group31, required, on a solar only recharge regimen, when depleted to 55% to 70% state of charge nightly, a 14.9 absorption voltage held for 2.5 hours, then a 15.3v finishing voltage held as long as the sun could hold it. By the 14th deep cycle, even with these rather absurd voltages and durations held after each discharge cycle, the Specific gravity had walked down to the 1.255 range, and I'm move all loads to the other battery, crank it upto 16v and 45 minutes to 2 hours at 16v would be required at 16v before 1.280 was attained again and performance restored to the maximum remaining capacity.

I got nearly 500 cycles from this battery, which is all that can really be expected in such usage of such a dual purpose 12v battery.

If I did not perform the 16v EQ cycle every 14 cycles or so, voltage under load performance dropped to hideous levels. If i waited to do an EQ charge every 30 cycles, the time required at 16v was doubled or tripled before SG maxed out and performance was restored.

Toward cycle 500, one cell, closest to the (-) refused to rise above 1.255 and it would heat up at the bottom of the cell about 20 degrees more than the rest of the battery. The Amps required to reach 16v were higher, and would barely taper as the SG on the cells approached 1.280. And of course water usage increased significantly at the end of its useful lifespan.

The final hail mary EQ charge on it, the amps required to attain 16v was over 7 amps, and never tapered at all, and after about 25 minutes just started increasing. I took it out of service that day.

I am not saying all flooded batteries require this same regimen, just that i spent a fair amount of effort experimenting to find the happy medium which allowed me to get my moneys worth out of this battery, and learned a heck of a lot in the process.

Flooded Battery care need not be mystifying, An Ammeter and a hydrometer are wonderful tools, as is an adjustable voltage charging source.

As far as bypassing the solar controller to achieve EQ voltages, I'd recommend waiting to do so only after amps at 14.8 have tapered to 2 to 3 per 100AH of battery capacity. Only then, allow higher voltages by directly connecting the 12v nominal panels directly to the battery, and of course disconnecting all loads which might be damaged by 15.5+ voltages, or loads big enough to not allow battery voltage to climb to 15.5v.

Dip the hydrometer every 15 to 30 minutes and stop the EQ charge when SG, compensated for rising electrolyte temperatures, attains 1.275+ on all cells, or amps required to maintain eq voltage begin to rise instead of taper or battery temperature begins to rapidly rise or approaches 120F.

If One cell's SG decides to stop rising when all the others are at 1.275 or higher, it might never respond no matter how long EQ voltages are held. If so then the clock just started ticking faster. I'd say to Expect no more than 50 to 75 more deep cycles from the battery before the capacity loss is so profound that even the most casual observer of voltage under load would know something is seriously amiss.

[zboss]

Originally Posted by svlamorocha

Do not confuse the (true) need to periodically equalize FLA batteries that are used under certain conditions or set a reminder to do do once a month with the (false) advantage of "automatically" equalizing.

Proper equalization requires a) starting with a full charge b) disconnecting loads that are not designed for 15.5V, and c) looking at specific gravity every hour(to decide whether to go for another hour). This means you cannot do it "automatically".

We have never had a problem with anything working or frying at 15.5 volts. Most electronics now work on a wide range of voltages.

With less frequent equalization there is no way there is enough solar time in a day to equalize your batteries properly UNLESS you do it on a regular schedule.

There is no need to wait 6 (or whatever) months between equalizations. All this does is result in the need to run a longer charging period when you DO equalize. It's my understanding that shorter equalization period (r.e. every 30 days) allows you to achieve the same result using a much shorter charging time, which is the basis of "automatic equalization".

Based on our experience I have no reason to doubt its effectiveness.

[svlamorocha]

Originally Posted by zboss

We have never had a problem with anything working or frying at 15.5 volts. Most electronics now work on a wide range of voltages.

With less frequent equalization there is no way there is enough solar time in a day to equalize your batteries properly UNLESS you do it on a regular schedule.

There is no need to wait 6 (or whatever) months between equalizations. All this does is result in the need to run a longer charging period when you DO equalize. It's my understanding that shorter equalization period (r.e. every 30 days) allows you to achieve the same result using a much shorter charging time, which is the basis of "automatic equalization".

Based on our experience I have no reason to doubt its effectiveness.

Good luck mate. You can do whatever you want but you are not following Trojan's recommendation, which requires a person to do various things.

Sent from my GT-I9192 using Cruisers Sailing Forum mobile app

[Maine Sail]

Please understand that none of Trojans suggestions, on when to EQ, are written with PSOC operation in mind. I have had long discussions with the folks at Trojan and had them tell me that in heavy PSOC use bi-weekly to monthly EQ's may be necessary.

As an example I have seen as little as 4 weeks of PSOC use result in a major measurable capacity loss due to sulfation yet each cell was still in perfect balance. EQing the battery at the end of four weeks brought most of that capacity back. If you went by Trojan's guidance, of only EQing when the cells become out of balance, you would have permanent sulfation damage where if caught in time it can still be reversible. Knowing and watching your voltage behavior, especially in a PSOC environment, can tell you a lot that SG readings won't or can't..

Setting charge voltage to 14.7V - 14.8V will only work if you can hold it there long enough to reconvert the sulfate.... This is certainly much better than 14.4V but you still really need to hold it there long enough to get to 98-100% SOC for it to not be a PSOC cycle.

Almost every dead battery I remove from boats has died due to sulfation, not due to grid erosion due to EQ. The rare overcharged batteries I find are most often due to a charger failure, wiring mistake, auto-EQ, or extended unattended controllerless solar charging. I even found a cheap ebay Chinese controller that was letting the customers batteries hit 16V about every 4th day. Of course there was no documentation what so ever with the controller yet every 4 days or so the batts would climb to 16V +/- even when set to AGM.. D'oh........

EQing a battery should really be done as an attended event and should not be an automated event if over about 14.8V. There is too much potential for a bad event when EQing a battery to let this be automated.. Be aware that some controller makers call 14.6V - 14.8V an "equalization cycle" but it really is not...

[roland stockham]

The problem here may but incorrect bulk charging. At EVERY charge cycle charging should run up to 14.8v min and stay there until the battery is charged before dropping to float voltage. (14.4v is for sealed cells but does not effectively recharge the cell). If the controller drops to float before the charge cycle is complete sulphation can occur. This is hard to achieve away from the dock. I have found that I can 'desulphate' batteries by hooking to shore power for a few day but switching the charger off for half an hour a couple of times a day so that it goes back to 14.8v. Each time I do this the s.g. at the end of the cycle goes up and when it stops going up batteries are properly charged. These voltages ONLY apply to vented flooded lead acids that can be topped up. If you use sealed lead acids just keep replacing them regularly when they die. Under typical cruising conditions sealed cells cannot be properly charged and have a life span of 4-5years. Vented cells should be good for 10-15 years. Whether sealed cells are AGM, Gel or simple sealed cell makes no difference if you can't top it up you can't charge it fully on the short heavy cycle typical in cruising.
I am going to be installing solar this year and will be looking at how to get the batteries up to full, I suspect it will only be possible if I turn most things off as I will only have a single panel

[Kerry1]

Originally Posted by Salty Mike

There is a discussion on here about battery orientation IIRC the plates should run side to side n)ot front to back. if one side is allowed to stay dry too long as in when you are running heeled over on a long tack it is bad on them.

Sent from my RCT6077W22 using Tapatalk

You raise an interesting point, but would it not be better to run the batteries athwartship? If you align them fore'n aft every single plate is equally exposed at heeling angle. When aligned across the boat one plate is exposed maybe twice as much as the next one, and the other virtually not at all as my diagram seems to illustrate. Am I missing something here? I have a 4 x 6v 232Ah Batteries all aligned athwartship.

[Sail IC]

Thanks for all replies.


As I have been expanding my solar, I have three controllers. 200W is connected to a Victron 75/15 MPPT controller. The remaining 300W to simpler (I think they are PWM or something like that) controllers. I currently have four Trojan T105 225Ah, so total 450 Ah at 12V. I might buy two more.


But neither of my controllers (or engines, Volvo standard alternators) can generate higher than 14.4V. The Victron have something called "battery saver mode", but its limited to 14.4V.


If connecting some solar panels directly to the battery bank, I could turn all main switches off including engine, so by that all electronics should not be saved.


My shorepower (mastervolt) can be set at 16V, but again, I'm hardly ever in a marina.


So question remains, would it be OK to connect part of the solar directly to the battery bank, monitor closely, but not breaking things.


Thanks for all the replies, but some of it is unfortunately a bit over my head (or knowledge) so to say

[mitiempo]

Originally Posted by Kerry1

You raise an interesting point, but would it not be better to run the batteries athwartship? If you align them fore'n aft every single plate is equally exposed at heeling angle. When aligned across the boat one plate is exposed maybe twice as much as the next one, and the other virtually not at all as my diagram seems to illustrate. Am I missing something here? I have a 4 x 6v 232Ah Batteries all aligned athwartship.

Here is the answer: Installation & Orientation of Flooded Batteries Photo Gallery by Compass Marine How To at pbase.com

[mitiempo]

Originally Posted by Sail IC

Thanks for all replies.


As I have been expanding my solar, I have three controllers. 200W is connected to a Victron 75/15 MPPT controller. The remaining 300W to simpler (I think they are PWM or something like that) controllers. I currently have four Trojan T105 225Ah, so total 450 Ah at 12V. I might buy two more.


But neither of my controllers (or engines, Volvo standard alternators) can generate higher than 14.4V. The Victron have something called "battery saver mode", but its limited to 14.4V.


If connecting some solar panels directly to the battery bank, I could turn all main switches off including engine, so by that all electronics should not be saved.


My shorepower (mastervolt) can be set at 16V, but again, I'm hardly ever in a marina.


So question remains, would it be OK to connect part of the solar directly to the battery bank, monitor closely, but not breaking things.


Thanks for all the replies, but some of it is unfortunately a bit over my head (or knowledge) so to say

Virtually all the voltage settings on your Victron 75/15 controller can be adjusted using their VE Direct software. A cable is needed from a Victron dealer - VE Direct to usb - and the software is free from Victron's site.

Here is the link showing what can be changed and how:
https://www.victronenergy.com/live/ve.direct:mpptprefs