Specific Gravity varied widely after topping up.

[landyacht318]

The other day I checked my 9 month old Crown batteries and found the plates exposed slightly on a few cells and cursed mightily. I hadn't checked them in about 3 months. I covered the cells with distilled water and charged them.

The next day I got more distilled water and filled the cells to proper level and charged them again.

The day before I added water, they were holding 12.6+ volts overnight using 20 amp hours out of a 230 hour bank.

The day after topping up the cells they dropped quickly to 12.2 using the same amount. An Hour ago I pulled out the hydrometer.
I found:
1 cell at 1.290
2 cells at 1.250
4 cells at 1.275
2 cells at 1.265
1 cell at 1.270
2 cells at 1.255

The thermometer on my hydrometer said -2 for temperature compensation.

So, I disconnected the batteries from the RV, managed to force my Schumacher charger to go into it's EQ mode and adjusted my solar setpoints upto 16 volts and tilted my panel at the sun.

Right now they are taking 17.3 amps at 15.5 volts, bubbling away aggressively. I am monitoring temperature and they are at 75f. The ambient temp is 75f.

Obviously I am hoping for the best, yet expecting the worst, and wishing I had the money to go with AGM 9 months ago. It is not really easy to check my batteries and I went too long and let a couple cells drop too low.

Hopefully this EQ cycle restores the performance.

My questions are: Can I get the SG back upto what I recorded when they were new(1.295 to 1.285)? Is that what I should hoping/ aiming for?

Does the max SG level determine how sulfated each cell it, never to return even after an aggressive eq cycle?

I've been plugging into the grid much more with these batteries, which is no doubt why water consumption increased, but the cycles on these batteries have been very shallow and not very many of them. No cycle went below 55% SOC and most were above 85% SOC. So if i killed another set of batteries by letting them get too low I will really be cursing up a storm.

I don't know how long the Schumacher is going to allow the eq cycle to continue, and the sun is dropping. It was not easy to get the schumacher to go into EQ mode. Since I started typing voltage has dropped by .1 and the amps by 1 but the temp has increased by 1.5. I had to try 3 times by turning on 40+ amps of load and waiting until the voltage dropped below 12.3.

I'll check the SG again after it shuts off and report back.

[landyacht318]

I am in Coastal San Diego. Rarely drops below 40f.

Cold temperatures thickening oil are not a factor in my engine starting, and even with weak batteries the engine has no issues cranking in the morning. I usually just use only the 7.5 year old wally world 27 to start it, and after 20 seconds or so, bring in the depleted Crowns to the alternator circuit. My Ammeter goes from ~7.5 amps, to ~58 when I turn my battery switch to both in the morning and more rpms will send the amps up into the 90's

[NinerBikes]

Cold weather thickens the oil in your crankcase and oil pump on your motor. It's normal for it to crank a bit slower in colder temperatures. When is the last time you changed out your motor oil?

[landyacht318]

Yes, access to my house batteries is a bit complicated, and uncomfortable on my neck and knee's.

I have been plugging in only rarely. I probably will tonight as I have some 18650's to refill as well. Sometimes My schumacher brings them into the 15's with 9 to 11 amps for a few hours and goes way over my amp hour counter 0 from full, other times it decides 14.7 for much less time is plenty and illuminates the green light, kind of agreeing with the Battery monitor within a few A/h. I'd say I plug in 3 times a month and every 4th time plugged in, it does an EQ cycle.

Still need to acquire an Iota or PD to replace Schumacher.

These past two sets of Crowns have used lots of water, much more than previous batteries. The rate of loss is increasing as they age.

My house battery box kind of stuffed to the gills with 2 27's, the limiting factor being length of 2 batteries side by side. I need 26&1/2" and perhaps more for 2 group 31's, I have 25&5/8". I've had to modify the battery handles so that the 27's fit.

MOdifying the battery box is not going to happen, it is a mistake I will live with, and honestly I've never needed the full capacity I've carried around for the last 5 years.

I'm seriously thinking of 3 agm's in parallel always via my Guest manual switch. The Engine battery is ~20 feet away, from house battery, total circuit length over 2awg wire. So it will not be a perfectly balanced battery bank. Perhaps I can rotate them yearly.

The crown DC27s are 115A/H when new and 62 lbs each, 230 AH total. I pretty much never take more than 70A/h overnight.

If I get 3 marine DHP group 34's for a total of 204 A/H I'm still not taking these Figurative 3 batts below 50% in normal usage Even just 2 in parallel is only ~50% DOD

lets Say my Crowns are rated at 600 CCA each, and my WW 27 is 650. All three together, 1850 CCA 345 A/H for 176 lbs

Thr 3 DHP' group 34 will have 2640 CCA 204 A/H total and 159 lbs.

My engine always starts easy, Only requires a single 650 CCA starting battery and my 7 tear old 650 cca battery has no issues.
I don't think even reducing my overall capacity is going to affect me being able to start the engine. 204 a/h of agms with 100 a/h removed from them probably still have more CCA then 345 A/H of flooded deep cycles with 100 a/h removed.


I occasionally forget to isolate my engine battery now, and cycle it with the house, and the engine still cranks fast and with authority first thing in the morning, but certainly not as fast as later in the day when engine is warmer and solar has all 3 batteries up in the 13 to 14 range.

I'm more worried about The 3 hungry AGM's together overwhelming my poor alternator, as I have fatter cables direct from alternator to battery switch, in parallel with original circuit path

[MEXICOWANDERER]

Agreed about your need for AGM, if access is a nightmare.

They are no longer teetering on the edge of a cliff - the ground is rushing up. fast.

[BFL13]

AGMs are what you need with that access problem in that RV. Big PITA having Wets in there now

IMO you did well keeping those damaged batteries going. Yes, replace them now before winter. ISTR reading that batteries fade quickly at the end.

[pianotuna]

Hi,

I would replace them--but not with lower capacity. I'd get three identical batteries. I'd add a trik-l-start for the chassis battery.

When did you last equalize/desulphate the bank?

[mena661]

landyacht318 wrote:

Thinking bout replacing all 3, at once, with smaller/ lower capacity AGM's, cause I've had a lot of work lately, and watering( lack of) has been my primary battery killer over the last 5 years.

That sounds like a good plan to me.

[landyacht318]

Update:

With the somewhat colder weather kicking in, and now with the time change, my usage has gone up, and the voltage under load is dropping into the 11's well before I goto bed, and I am waking upto ~11.7 with 11.5 minimums recorded with ~60 A/h removed from the batteries.( 2 group 27's, 115A/h each)

Nothing is not working properly at these voltages. They are still accepting 60 to 90 amps when I start the engine and bring them into the alternator circuit, but their voltage does climb higher quicker under such current than before.

I can tell that when they are fully charged and I have all 3 batteries cranking the starter, it cranks much slower than just a few months ago.

I'm just wondering how long I am going to push these. I think they are perhaps teetering on the edge of a cliff. As I type they are at 12.1 under a 7.8 amp load @ 30a/h from full, and the alternator was just feeding them 90 minutes ago.

My Wally world dc-27 engine battery is due for replacement too at 7.5 years old.

Thinking bout replacing all 3, at once, with smaller/ lower capacity AGM's, cause I've had a lot of work lately, and watering( lack of) has been my primary battery killer over the last 5 years.

Considering just leaving a future 3 in parallel always with the option to disconnect the engine battery if/when I start drawing them into the starter "click" realm, which honestly, has not ever been an issue, not since I've gotten solar.

[MNtundraRet]

Deleted.

[pianotuna]

Hi Landyacht,

It is not the temperature that causes the issue. H2S04 has a greater volume as the state of charge increases than water.

[landyacht318]

With my Mild temperature swings and the fact that they were close enough to fully charged, I was not worried about the expansion.

They just were not close enough to full, according to my amp hour counter, to take SG measurements where the readings would be comparable to my previous readings of which I have a long list throughout these battery's lives.

My batteries are not the easiest to access. Checking SG is a huge PITA whereas just filling them to near full is just a regular PITA.

[pianotuna]

Hi landyacht,

Watch out! When you charge them the volume of liquid will increase. It is best to add water to a fully charged battery--so long as the plates are not exposed. Then add enough water to cover the plates and fully charge.

[landyacht318]

Since voltages kept remaining higher for the same A/h removed, I decided it was past time to add more water. The batteries were not fully charged so I did not take any SG readings. The plates had no more than 1/8 inch of water covering them and 2 group 27's took over a half gallon to be filled to proper level a few mm under the arms hanging into the cells.

Now they are back to the voltages I've come to expect to seeing for a certain amount removed from them.

[MEXICOWANDERER]

"When Plates Go Bad"

Many times they load with sulfate, shed and end up in the sediment chamber. With the sulfate goes one component of the H2SO4 therefore it is no longer sulfuric acid and the electrolyte becomes more diluted, less dense, lower hydrometer reading. The excess H and O is dispersed into the air.