Is a Mean Well RSP-320-15 a good choice for Top Charging?

[racer4]

Hi all,

I am thinking of buying a Mean Well RSP-320-15 (they won't allow a direct link) power supply to use primarily for "Top Charging" the batteries. Is this a good choice for Top Charging?

I have a Cedar Creek 36CKTS with a battery compartment that holds four GC2 batteries. I bought four Trojan T-125 batteries with a combined capacity of 480 AH (20-Hr Rate). There is a 200W solar panel on the roof, factory installed with a Go Power GP-PWM-30 solar controller. The converter is a WFCO 9855 😞 and the Distribution Panel is a WFCO WF-8930/50. The trailer has a residential refrigerator powered by an inverter and batteries when not plugged into utility electric. I figure the refrigerator will use about 140 AH DC daily when powered by the inverter and batteries.

When we are camping without utility electric hookup, I plan to do daily battery recharges, 50%-80% SOC, with a Mean Well RPB-1600-12 (rated for 100A) powered by two Honda EU2000i generators (paralleled).

When we get to a campground with electric hookup, I will fully charge the batteries and then do a "Top Charge" with the Mean Well RSP-320-15. It is rated at 321W (21.4A at 15.0V) with adjustable voltage 13.5 - 18V. I plan to adjust the voltage output to 15.0V, and charge the batteries until they get to 15.0V. The 21A is 4.4% of the battery banks 480AH capacity.

I originally planned to buy and install these two power supplies / chargers in September, but I want to buy the smaller one now to work around a recent problem.

Problem: I bought the trailer in May. The 120VAC electric worked properly on a 4 week trip and for 3 days at home. The outlet at home is a standard 15A outlet that I have used for years to power RVs (light usage, converter and refrigerator) when parked in the driveway. I turned off the two main 50A 120VAC electric circuit breakers, turned them back on and then every circuit on the right side of the breaker box was dead. All the circuits on the left side work. I checked the GFCI outlet in the bathroom. The two buttons on it do nothing, no click, the reset button will not stay in when pushed. I cannot find another GFCI outlet in the trailer. I tried to open the circuit breaker box to check the right side 50A main breaker, but one of the four cover screws will not loosen. It turns roughly, like the nut flange is broken, but does not loosen. The refrigerator/ inverter circuit and the converter circuit are among the dead circuits. I can plug the refrigerator/inverter into the working vacuum cleaner circuit. I can't reach the converter plug to plug it in somewhere else.

RV repair shops are booked up here now for many weeks. I have a trip planned in a few weeks (paid in advance, no refunds). Until the AC electric is fixed, I want to work around the problem. The 200W solar panel should keep the batteries mostly charged, if we conserve DC electric use and stay in campgrounds with electric hookups to power the residential refrigerator. While traveling the trucks DC electric wire in the 7-way connector to the trailer should should supply most of the power needed for the inverter/refrigerator. If the batteries need additional charging I plan to use the smaller Mean Well RSP-320-15, adjusted to 14.8V. Thus the reason to buy it now, instead of in September.

I think the 120VAC electric problem is a bad main 50A circuit breaker. There are two 50A breakers, one for each side of the box. Does anyone have another idea as to why the right side circuits only would be dead? Anything else I can check?

Do you think my work around plan for the electric problem will work for about 15 days travel?

Is the Mean Well RSP-320-15 a good choice for top charging? Is my top charging plan right?

Thanks,

Chris

[MEXICOWANDERER]

I am going to try and make this simple...

An X factor of Delta T temperature/time gain at a high amperage rate
Is POSITIVELY not the same as allowing the same c/min gain
With much lower charging amperage. The temperature gain per amp/amp hour factor is rather LINEAR, And no this is not a charging regimen. It is a TEST factorial.

Say a battery gains 2c/hour at a 40 ampere charge rate. That is OK
Temperature gain of 2c/hour at a 5 ampere charge rate is absolutely not OK.

Yes electrolyte to ambient temperature Delta T plays a role in this. There is a complex formula written for this that would be absurd to post even if the posting would allow symbology. The very idea of implied braggadocio infuriates me and E=MC2 technobabble would help no one.

Impress the implied correct E (charge absorbsion voltage limit) across the battery. Using a digital thermocouple and clock, arrive at a temperature gain for one hour of charging time. Of course this exercise must be performed on a discharged battery. Keep measuring if your charge source is more than 20% of amp hour capacity but maximum E cannot be reached because of insufficient I (charging amperage). The best record keeping is done in 15-minute increments.

The temperature gain you see now should be the maximum GAIN permitted. If a battery sees a higher amperage going through it and temperature GAIN starts to suddenly ramp upward, STOP! You are over-amping the AGM. Still with me?

You are establishing an amperage/temperature gain profile. Use excel or draw a graph. A dying AGM going over to the Dark Side, will suffer inappropriate amperage temperature relationship.

I love to use the CAKE / OVEN analogy. The don't bake for 5 minutes at 2,000F one.

Similarly with an AGM do not bake the cake for three days at 150F

Chemistry is like math - utterly unforgiving.

And Landyacht, your insufficient charge rate hits the nail right on the head. You understand the need to reduce bulk voltage limit dramatically. This is one of the pitfalls of "only-solar" versus AGM. The 20% minimum is another.

I guess if this was easy for the average person to understand I would have had to find a different career.

[landyacht318]

Today I saw my battery was 98F, about 12F hotter than ambient and still climbing at 14.4v.

Took forever to lower absorption voltage on the solar controller. Wish it had a 10 turn potentiometer to twist instead of pressing a series of buttons about 3 dozen times, Just don't hit the back button.

Really wish I bought the more expensive solar controller which had input for a BTS. Worst 35$ I ever saved.

[pianotuna]

Hi Mex,

My Magnum inverter/charger includes an "on the post" thermocouple to adjust the charging profile. I'd assumed that was done by adjusting the voltage.

I'm in another campground with (lousy) wiring on a 15 amp site. Thank goodness for the load support feature or my Air conditioner would not be running.

110% of 27 x 4 would be about 119 amps. The Magnum can do 125 on a (good) 15 amp supply. I may just try the 119 figure on for "size", the next time I am in a generator recharging situation, if the batteries are hungry enough.

[MEXICOWANDERER]

Don for crying out loud, get your hands on an infrared thermometer (thermocouple) then charge your batteries at the same rate as everyone else with the same type of battery. Monitor for thermal buildup. Not just the top of the case, but the lead terminals. Improperly high charging rates WILL raise cell temperature and will raise terminal temperature. If it doesn't increase disproportionately with applied amperage, then common sense should tell you the battery is not undergoing damaging superamperage.

"Sir, why did you wait at this red light for forty-eight minutes?"

"Uhhh, it didn't change. Ya telling me I should run a red light?"

Good batteries, that use H2SO4 will gain temperature when a lot of amperage is put through them. If there is little or no temperature gain (using a RATIONAL value of amperage) then that charging rate is not inappropriate.

This doesn't mean 2,000 amps for ten seconds. Please no word games. The manufacturers of these items are after one thing, and one thing only - absolute positive maximum battery life despite "The Cost". Try 110% "recommended charge maximum to start off with. Your thermocouple will not lie to you.

[pianotuna]

Nice Jars John,

But charging amperage for yours is limited to 50 amps, almost double what is recommended for mine. That is why for our aardvark batteries it is best to research how to charge them.

[full_mosey]

I have 2 x 135AH Powerware telco pulls. specs PDF file

I read the specs before buying and I failed to see anything special.

The batteries are in service 100% and are used to run 2 x Dometic 12V compressor fridge/freezers.

They are being charged with 170W solar and a MS TS-45 PWM controller. A Magnum 1012 100W/50A inverter/charger is used with a Yammi 2k inverter genny or shore power. Both chargers are set to a profile quite like the Lifeline Voltage specs. Both chargers use temp comp cables. As I write this, it is 110F in the van and both chargers are showing float. The neg charge/load battery post with both temp sensors is 92F. A Turnigy Voltmeter is showing 13.16V.

The Powerware specs do tend to be slanted towards UPS. It is easy to calculate a bank size, for inverter use, due to the Constant-Wattage table; something rarely seen. Usually all you get is a useless constant-current table/specs. A designer should be able to meet any Service Level Agreement.

I was told these batteries were 5yo when I got them last Fall. I paid $95ea. I load tested them then, which I explained in detail previously, and they have performed very well since.

HTH;
John

[MEXICOWANDERER]

Specialty Telecomm and other weird design/use batteries do indeed have construction variances that necessitate weird recharging profiles. And I second Don's, opinion that UPS type AGM batteries need to be researched. Their quirkiness lies in the construction of negative plates.

As for flooded batteries...

The absolute OPTIMUM recharging rate is that which can fully recharge the accumulator in a 24-30 hour period of time. It'll gain perhaps 4% additional battery life. This means a 50% depleted group 27 can be successfully recharged at 3 amperes aiming for optimum lifespan despite inconvenience. However at the end of the charge cycle the low ampere recharge must revert all cell electrolyte readings to OEM new density.

Don, check your recommendations again. 27 amps seems like the minimum amperage for recharging as well. In bulk mode.

[pianotuna]

Hi Almot,

My surplus acid AGM's which are 139 amp-hours recommend charging rate be limited to no more than 27 amps. That is a bit over c/5.

I believe it is important to source what the particular maker recommends if long cycle life is a goal.

Almot wrote:
Just curious - mine are AGM anyway - is it charging current 5% of rated capacity, or 2.66 amperes?

[MEXICOWANDERER]

AGM is a different aminal...

Download the Lifeline PDF service manual and follow its guidelines. Too low a BULK charge rate raises hell with AGM chemistry. A good rule for BULK is >20% A/H capacity BULK charge rate.

[Almot]

MEXICOWANDERER wrote:

Charge each cell at FIVE PERCENT OF RATED AMPERE HOUR CAPACITY (constant current) 2.66 amperes to a maximum limit of 15.96 volts, or until such time as the electrolyte solution in all cells reverts to original new density

Just curious - mine are AGM anyway - is it charging current 5% of rated capacity, or 2.66 amperes?

[landyacht318]

racer4 wrote:
landyacht318,

Did you mean 'should not" or 'should' be able to accept 23A?

That amount of capacity, if still healthy, Should not be able to accept more than 21 amps if 95%+ charged.

I would not fear getting a power supply rated at higher amperage.

I can do the 5% constant current thing by fiddling with the voltmeter, but generally I would just bump voltage to 16v and if it required more than 5% of capacity to reach 16v, then I'd give it more time in the high 14's then try again, but I have done the voltage twiddling thing to keep it at around 5 amps.

[racer4]

landyacht318,

Did you mean 'should not" or 'should' be able to accept 23A?

[MEXICOWANDERER]

Ibuprofen and Tylenol Later...

The combination should work fine. While things are being charged, measure each three cell battery and note their voltage. This says a lot. If you find one battery voltage .3 lower than the others, designate it as the "Weak Sister battery". Time to get out the hydrometer and find out why. One cell weak? two cells? All three? If necessary take images with your camera, remove that particular three cell battery, take it to a battery shop and have them fast charge it. If it continues to be weak, it is a bad battery and will rotten apple in the barrel screw up the others. A strong load tester like the one an Interstate Battery DISTRIBUTOR has (Auto Meter load tester) can successfully test a suspected bad 3-cell battery. Similarly cell gravities that are unequal or flaky* is cause to replace a battery.

*Will equalize with other cells but falls back much too soon. The classic sign of an inferior brand of golf car battery.

[landyacht318]

Much depends on the batteries and their state of health.

If they are full charged they ' should' not be able to accept more than 21 amps.

One needs to know if there are loads on the batteries at this time too, or if they are disconnected from all possible loads.

I have run an 25 amp schumacher and my meanwell rsp-500-15 in parallel for ~65 amps. You can likely do the same with the Iota.

after the 15 minutes at 14.8v the iota will likely just drop out and do nothing while the meanwell takes over