Trojan SCS 200 Equilazation Follow Up

[dclark1946]

I posted this a while back:

"What power supply current capacity would be required to equalize a single Trojan SCS 200 (Gr 27) 12V battery @ recommended 16.1 VDC?"

Since that post our trailer was at the dealer on two occasions For a total of three months for various warranty issues. In spite of my best effort to protect (pulled fuses to reduce current drain and leaving battery disconnect off) my two year old battery from discharge while at the dealer it was so discharged when we picked it one the first time it would not power the tongue jack. The dealer had replaced the fuses I had pulled.

In my search for an equilization power supply I finally ended up ordering a BK Precision 1688B (1-18V, 20A) lab type switching power supply with optical encoder voltage and current knobs that provide 0.1 V and A settings. It functions in either CV or CC mode depending on the load conditions.

In preparation for a two week dry camping trip I have been checking out this suspect battery (which is normally maintained with two 55W solar panels and a Morninstar controller) I isolated the battery using the cutoff switch and attempted to charge it with a Schumacher Ship and Shore auto charger set for 10A. The battery charged to indicated 95% with current dropping to 5.6A but just stayed there for several hours with the voltage at 15.2 and steady bubbling seen in all cells. I discontinued charging and let the battery sit for 24 hours and checked the open circuit voltage and it was 12.71 V. The SG at that time ranged from 1.280 with two cells reading 1.265.

At this point I attempted to equalize the battery with the BK power supply but the supply stays in CC mode (5.2A) and the voltage will not go past 15.3V even though it is allowed to rise to 16.1V. I even for a short duration set the CC for 10A but the voltage only went up to 15.4V. Last night after this I loaded the battery for about 10 minutes with the two ceiling vent fans and a few LED lights and then reconnected the Schumacher charger up for an overnight 2A charge. The charger indicated it was starting at 80% battery charge. This morning the charger indicated "100% charge " but seemed to be cycling between maintenance and charge about every few seconds.

I tried to equalize again this morning at 5.5A with the CV set to 16.1 but again the voltage will not go rise above 15.3V and the cells are still gently bubbling. At this point I am not sure I trust this battery.

Thoughts???

[MEXICOWANDERER]

jclark1946

Smart decision. A ruined vacation isn't worth it.

Definition of a ruined vacation.

A DW on the warpath.

[BFL13]

New off the shelf batteries need an initial goosing charge before you put them to use. That would be with the portable charger to get the required higher voltage for doing that.

[dclark1946]

I decided to go ahead and get another SCS200 before we left town rather than worry about the abused one. Turned the old in for core.

[BFL13]

If you like that routine, no need to change it really.

If you are not used to staying that long with that set-up, you might easily run into where the battery loses so much capacity doing successive incomplete recharges, at some point in the second week it can't get you through till the next day's recharge. Starting with the battery already not good as new, that will happen sooner. So a second battery would be a good idea just for that IMO.

You could choose to run the gen for half that time each day at twice the amps or run the gen for the same time every second day, by having that second battery, plus use your other charger instead of the converter to do the recharge.

The converter is only at 13.6 volts, no good for a faster recharge, but the other charger probably is more like 14.3 or whatever it does, so it can do higher amps. The 1000w gen can handle about 40 amps at 14.6v for charger output, depending on how high above sea level that is. You are not using the gen fully right now, and are using more gas than you need to. But that isn't much gas anyway, so not a factor perhaps.

You might be running the gen anyway for other chores. Whatever works to make a good camping trip is what counts. Having a routine you are comfortable with is a big part of that.

[dclark1946]

Yes we are close to civilization when we camp in Elkmont CG in the Smoky Mtn NP. Pigeon Forge is about 20 miles away down the mountain. That is where I buy gas for my truck and generator and could no doubt get a generic RV/Marine battery. A two gal tank lasts about a week running the EU 1000 to power the Wifco converter. Peak charge current for the single Trojan 12V battery is typically 12-16A. The generator runs about 4-5 hours every morning. At least once a week I connect an automatic charger that will charge at a higher rate. We run a ceiling vent fan all night and water pump/ lights. Works for us for many years.

[Cydog15]

Dick, I hope that works out but if not and you get another Trojan, look into Progressive Dynamics charger that outputs 14.8 during bulk which I believe is what Trojans recommends. It's not that new but not many sell it. One of my brothers swears by it and has never had to equalize.

[BFL13]

So the plan with one good 27 was to go off grid for two or three weeks and use the little gen to recharge the battery via the Rv's converter (whatever it is) ?

So you must be near enough to civilization to buy gasoline for that generator. That means maybe near enough to get a new battery if that one fails utterly. (Not likely--it just will have fewer AHs than when new. You might not even notice the difference.)

I would still take two 12v batts to save on gen gas. You could be running the gen to make 20 amps the one battery can take at its SOC instead of 40 amps the two could take for about the same gas use? (I have not done an exact comparison)

I edited that to account for a 1000W gen being only able to run a little more than 40 amps worth of charger.

[dclark1946]

BFL13 wrote:
https://www.trojanbattery.com/pdf/datasheets/SCS200_Trojan_Data_Sheets.pdf

I would take it along, but also take along a second 12v 27, like the Interstate half price ECONO POWER ones you can get , that are decent enough for this kind of work. ( I have two as "spares" and have no issues with them, other than that they are flooded 27s, but I put up with that for occasional use)

The only risk factor is how far from a battery store that sells marine/RV 27s will you be when off-grid?

Actually, if it were me, I would parallel that beat-up Trojan with the ECONO 27 and go with that as my bank. One 27 and 110w of solar is not much to be going out there with.

Interesting advice. The solar panels are just to maintain the battery at home since we camp in heavy shade in the Smokies and use an EU 1000for daily charging.

[BFL13]

https://www.trojanbattery.com/pdf/datasheets/SCS200_Trojan_Data_Sheets.pdf

I would take it along, but also take along a second 12v 27, like the Interstate half price ECONO POWER ones you can get , that are decent enough for this kind of work. ( I have two as "spares" and have no issues with them, other than that they are flooded 27s, but I put up with that for occasional use)

The only risk factor is how far from a battery store that sells marine/RV 27s will you be when off-grid?

Actually, if it were me, I would parallel that beat-up Trojan with the ECONO 27 and go with that as my bank. One 27 and 110w of solar is not much to be going out there with.

[landyacht318]

Trojan EQ voltage specs 2.7 volts per cell equalling 16.2v on a 12v battery.

That spec was bumped up from 15.5v a year or 3 ago.

Its my opinion that trying and trying to get a suspect battery to max specific gravity and resting voltage, withouut a deeper discharge then followed by a full charge might be an exercise in futility.

levelling off at 5 amps on a group 27 is not a good sign, if the ammeter can be trusted

[MEXICOWANDERER]

Being current throttled, the voltage will start out wherever it may then rise slowly. This is why it is so important to start out with a 14.7 volt initial charge until amperage flattens. Immediately disconnect then let the battery cool to ambient temp. Dip the cells, record readings, then start the 5% constant amperage charge. Stop the charge if voltage reaches 16.0 regardless of amperage. Let sit overnight then dip again.

If the battery fails to regain full electrolyte density then it is a goner.

I've seen electrolyte gain, .015 overnight although that isn't the best sign of good battery health.

[dclark1946]

MEXICOWANDERER wrote:
I have had to maintain GC batteries on equalization for 16 hours

Mex, Were you able to hold the target equalize voltage (16.1V for 12V) while holding the current to a nominal 5A per 100AH or did the voltage stay lower than target while holding the current at the target? I assume you started with a charged battery (as much as it could be charged). Or does the voltage not matter as long as you hold the current at 5A per 100AH until the SG stabilizes?

[MEXICOWANDERER]

I have had to maintain GC batteries on equalization for 16 hours