Will this work and do I need a fuse? Mean Well power supply

[racer4]

Hi all,

I am planning to install a Mean Well RSP-1500-15 100A power supply about 3 feet from the batteries.

Will this work to fast charge the batteries from 50% SOC to 80% SOC?

Should I install a fuse on the POS+ wire between the Mean Well power supply and the batteries?

More information:
The Mean Well will be used to fast charge the batteries when off grid, with AC power from two Honda EU2000i generators.

Mean Well RSP-1500-15 Specs

I plan to use 1 AWG wire to connect the power supply directly to the batteries. The wires will pass through a sheet metal wall (battery compartment). I will drill holes and install grommets.

The batteries are four Trojan T-125, total 480AH capacity.

A spring wound 2 hour timer switch will connect the power supply to a 20A AC circuit. The trailers power cord will plug into the generator.

The trailer also has a 200W solar panel installed by Cedar Creek.

When plug-in AC power is available, an IOTA 55A converter will be used. The Mean Well is only for when off grid.

The biggest power user is a residential refrigerator, I estimate 150AH use per day through a WFCO 1000W inverter.

Am I on the right track? Will this work?
Is a fuse needed between the power supply and the batteries?

Thanks
Chris

[BFL13]

IMO there should be fuses in that collection of wires outside the battery box.

Here is a basic blurb on how you do "branch wire" fuses, to a buss bar, and then on, showing how the ampacity of the wires and fuses is cumulative. Ignore that this is related to car--it applies to RVs too.

IMO this is absolutely required where wires disappear into walls where you might not see them starting to melt.

http://www.bcae1.com/fuses.htm

---If the existing solar controller only goes to 14.4 as noted, then you might want the controller that goes with the Trimetric 2030 you are getting, so you can perhaps set the Vabs to 14.8.

There is no reason you could not use the Iota, MeanWell, and solar all at the same time so they add their amps. The Iota will drop out of play 15 min after the batts get to 14.6, but then the MeanWell and solar will keep going if they are at the same voltage.

[Fubeca]

You could easily put the shunt behind the battery box with just the addition of one fat cable from the negative post to the shunt, then attaching the other negative cables to the other bolt on the shunt.

You may have a perfectly clean and acid free battery compartment, but it doesn't take much to have gassing that can corrode your connections and any exposed metals. I wouldn't put my shunt in a battery compartment unless there were no other reasonable option.

[BFL13]

ISTR Mex recently mentioned that the shunt should be kept from battery gasses, but I don't know the risks. The example earlier in the other thread shown was on AGMs, while you have Wets. Mex will clarify I hope.

EDIT. Here is Mex in the other thread, "Keep shunts, buss bars, fuses and breakers as far away from a flooded battery as possible. A proper hookup will have one single solitary cable connecting the positive post and one single solitary cable connecting the negative post. Of course battery paralleling bridge wires are not counted."

You are right about successive 50-80s. Progressive capacity loss happens and then you have quite a job getting the batts back to 100%.

I had a post a few years ago about that with some graphs, if I can ever find it to link here. Go below the graphs for some numbers.

http://forums.trailerlife.com/index.cfm/fuseaction/thread/tid/24849190.cfm

My recovery method has been to fully recharge the batts at 14.8, then do an equalization style overcharge as the only way I could get their SG back to "baseline" (as new) SG value.

Recently, I forgot and left the bank at 14.8 overnight long after they had reached 14.8. In the morning, (no battery box, the batts are in the front cargo bay of the 5er with some ventilation) the LP alarm was going off and there was a strong smell of battery fumes. But--the SG was right up to baseline.

That suggests you can do a full recovery at voltages below what would harm the 12v systems, but be sure to have lots of ventilation, turn off the LP alarm ahead of time, and be ready to add water afterwards if needed. 🙂

[racer4]

OP here.

Thank you all for the responses.

To re-emphasize, the Mean Well 100A is for fast charging the batteries 50-80% when off grid and using the generators. The Iota 55A three stage converter will be used all other times.

Another reason I am using a power supply with adjustable voltage output is I thought the 200W solar panel putting out up to 11A at 14.4V might make a smart 3 stage converter think the batteries are more charged than they are, when it sees 14.4V on the circuit. Maybe not, but another consideration.

I am thinking of also getting a 23A Mean Well to use as a portable unit for "Top Charging" to 15V at 23A (about 5% of C20) once every ten or so fast 50-80% charges. I hope that will clean the sulfate off the plates. I would do that when I am back on grid. I want to keep the battery cables on (too tight to work in the battery compartment), so I want to keep the system voltage at about 15V or less.

I included some pictures to better show what I am working with.

The Mean Well will be mounted on the left side of the inverter.

Click For Full-Size Image.


This is the battery compartment. Tight fit. I plan to leave them hooked up year round. The 200W solar panel will keep them charged in winter time storage.

Click For Full-Size Image.


I am hoping to connect the shunt to the NEG post with a 4" 2 AWG wire. There is an auxiliary battery post there now that will probably be removed. I will use a longer bolt on the shunt if needed to hold four negative cables. The shunt will sit on top of the battery.

Click For Full-Size Image.


Backside of the battery compartment. The only visible fuse is on the inverter POS wire.

Click For Full-Size Image.


The 12V system POS wire goes to a terminal strip on the left. I do not see a fuse for that wire. The top outlet on the left is an extension of the vacuum cleaner 20A circuit, using 10 AWG wire to reduce voltage drop. The Mean Well specs say it draws 17A. I will run a 10 or 12 AWG wire from the outlet to the spring wound timer switch (20A rated).

Click For Full-Size Image.

BFL13 wrote:
...You really ought to have a Trimetric monitor in the mix. That would mean changing your wiring plan so that the shunt is just outside the battery compartment. The neg wires from both the Iota (if not using the frame) and MeanWell would go to the 500a shunt and then a fat wire goes from the shunt to the battery neg post...

I am ordering a Bogart Trimetric 2030RV to track the batteries state of charge (I didn't say that earlier).

I plan to install the 500A shunt directly next to the battery NEG terminal, sitting on top of the battery.

When you said "so that the shunt is just outside the battery compartment" , is it important that the shunt be outside the battery compartment? I plan to install the shunt inside the battery compartment with a 4" 2 AWG cable. Of course the shunt connects to the battery NEG terminal and all the negative wires connect to the other end of the shunt, so locating it outside of the battery compartment would be more work. Are the battery charging gases a problem for the shunt?


MEXICOWANDERER,
Thank you for your thorough response. I was hoping for a response from you. I have learned a lot from you. Thank you for all the education you provide.

At this point, I am leaning toward not using a fuse. I don't see one on the 12V system positive wire between the batteries and the terminal strip. I do want to be safe. I am still thinking about whether or not a fuse should be used.

Thanks to all,
Chris

[MEXICOWANDERER]

With the power supply ridiculously underpowered to imperil 2 gauge cable and with an intrinsic fuse within a run of 36" of cable can be routed so as to eliminate possibility of corrupting integrity. This is sort of micro hypothesizing failure scenarios is it not? Using common sense is -your- battery to starter motor cable fused? The power supply is utterly protected. The more krap added the more there is to deteriorate and fail. For utter protection of the prposed 2 AWG positive cable, nylon spiral wrap anchored with rubber lined Adel clamps would reduce chance of faults to near zero. Unless of course Freddy Kreuger was to be stuffed into the compartment.

[BFL13]

kiwiRVer wrote:
I would suggest you would be better off using a proper intelligent charger rather than a straight power supply.

What are the factors at play with that?

AFAIK a power supply works the same as a "smart charger" as long as you treat it as a manual charger and shut it off when it is "done."

The OP will use his to do a 50-80 and then shut it off. What's wrong with that?

A different thing, but it is true that you can use your converter as a "power supply" instead of as a "battery charger."

In that case it will do better when acting as a power supply. EG, I can use my 7355 converter ( single voltage at 13.8v ) to back- stop my battery bank while at the same time the inverter has a load on it that draws 90 amps from the battery bank. The 55 amper will do 56 constant amps, so the "net" draw (it is not net, but it looks like that) is 34 amps.

But the same converter, acting as a battery charger will only do about 35 amps on the wiring it has, and tapers from there. The thing being that a battery is not a normal sort of "load" but one that gets higher in voltage the more you charge it, so the difference between its voltage and the charger's fixed voltage shrinks, tapering the amps. That does not happen when acting as a power supply on a constant load.

On the fuse location, the power supply is to power the battery, so who gets the fuse? 🙂 One at each end of the same wire? Beats me.

[westend]

A fuse is typically used to protect the circuit that is powered. That would mean, in the situation of a power supply connected to a battery, the fuse would be toward the power supply, protecting the wire that goes to the battery. Of course, a fuse or circuit breaker should be installed on the battery's (+) phase cable within a couple of feet to protect that cable.

[MEXICOWANDERER]

Trojan will never argue with verifiable hydrometer readings. Resolutions of .02 volts are for unexpected control variance notation only. in real life, such resolution is completely questionable.

No one on the face of the earth can argue intelligently against an informed user bearing an accurate hydrometer. I would be absent from the line of questioners.

[MEXICOWANDERER]

I forgot to add the 2AWG cable as suggested by the author may offer superior mechanical strength of both conductor and cable lugs. Such circular mil x length would offer near zero advantage over 4AWG and only minor advantage over 6AWG. Cable lengths are too short to enter into the equation. But mechanical strength is in it's own world as far as relevance.

I notice with my Meanwells, Megawatts and Cheapos, a slight variance with positively stable reference resistance. i.e. .05 to .08 drift*. By guesswork I attribute this to the cheap circuit board potentiometer. Tap it with the blunt end of a screwdriver and watch voltage reaction. I would have hoped the high end power RSP units will have a multi-turn pot on the circuit board.

*From day-to-day

[theoldwizard1]

Trojan recommends different charging voltages

Boost Charge Time in Hours = (Depth of Discharge @20 hr rate X Capacity at 20Hr Rate / Maximum Charge Current) + 5 Hours

T-1275 specs

Charge time = (0.5 X 280 / 100A Charge current) + 5 = 6.4 hours

Trojan recommends a "bulk" charging voltage for their flooded 12V batteries (like T-1275) of 14.82V .

[landyacht318]

I've been using the Meanwell rsp-500-15 for 2 years now as my exclusive plug in charging source, and my scorn for automatic charging sources has only grown in intensity since.

While it is rated for 500 watts, it regularly surpasses 600 watts when the battery is depleted enough.

I employ 45 amp anderson powerpoles to disconnect it from DC when not in use.
When I unplug the 120vdc but it is still connected to DC, there is a click as the overvoltage protection kicks in.

Or if I lower voltage faster than surface charge depletes I will hear the same click.

The rsp-750-15 and -1000-15 have features that the rsp-500-15 does not. The desire for 1000 or 1500 watts suggests to me this will be used not just for top charging but for bulk charging and the OP asked about 50 to 80% charging.

When Maxed out, my rsp-500-15 makes a lot of heat. The very high rpm 40mm fan is very loud. I added more fans and heatsinking to keep this fan from coming on at lower amperage outputs, and to extend its life. I would recommend additional airflow aimed over meanwell casing, for use when maxed out charging depleted batteries.

Perhaps add some of these to meanwell casing for additional heat dissipation:
https://www.amazon.com/ENZOTECH-Memory-Ramsink-BMR-C1-Heatsink/dp/B002BWXW6E/ref=pd_sim_sbs_147_1?_e...

My voltage range on the rsp-500-15, with a 10 turn 1000 ohm bourns potentiometer, is 13.12v to 19.23v.

While I intended to use a wind up timer, I have never bothered installing one. But if I did, I'd want a 6 hour timer, as 4 hours would have the unit shut off early as my AGM battery takes no less than 3.5 hours for amps to taper to 0.5% of capacity once absorption voltage has been reached( usually 25 to 35 minutes at 40 amps), and with many partial state of charge cycles accumulated, can take much longer for amps to taper to 0.5% of capacity at absorption voltage.

[MEXICOWANDERER]

I read the OP's post thoroughly.
Because of the layout out his text, the inclusion in plan of a 4 hour windup (infinite resolution) timer and other intrinsic factors particular to his post...

I feel the poster knows exactly what he is doing and why he is doing it 🙂

This is all too obviously a charge augmentation in support of meaning auxiliary to an existing onboard charger.

Now to answering his questions:

350 watt power supplies have a circuit board ten ampere fuse. I have not dissected the 1500 model but there must be a circuit board fuse or the power supply cannot meet either UL or CSA safety specifications. This is a Taiwan unit from one of the largest power supply manufacturers in the world. The inclusion of a circuit board 20 - 30 amp soldered cartridge fuse therefore must be considered a "given" not a guess.

If that soldered fuse should go open circuit, there is a problem with the circuit inside the cabinet. Replacement of the fuse is minor compared to repairing the cause of fuse failure. OK? These fuses are vastly over capacity of the unit in question.

Therefore it must be concluded that any safety device used in the circuit would be from the batteries to the unit -because- of failure or fault in battery to power supply input compromising. A short - a connection pulled loose.

Aside from this perspective must be maintained. Are there circuit breakers protecting the circuit from the battery to the onboard converter and distribution DC fuse panel? Arguing for the power supply circuit to be fused must automatically include argument that the OEM battery to converter supply be similarly protected -both circuits- at the battery end. It would be irrational to argue for one and not the other.

I measured a spurious .001 ampere draw between battery and unpowered power supply. This may or may not have an origin of bleed in the unit's capacitors. The effect if not worth chasing down IMO. The 100 volt PIV rating of the schottky rectifiers precludes current reversal.

Racer 4, presents a clear indication he knows what he wants and he is pursuing a path in which he feels comfortable.

The timer proves he acknowledges the minutes or hours to be assigned is to be considered. it is obvious he realizes voltage values as presented by the manufacturer. If he chooses 14.8 volts then by trial he can discover the time parameter versus starting battery voltage how much to wind the Intermatic. I fail to acknowledge that someone with the intent of assembling such a system cannot comprehend time calculations versus observed starting battery voltage. For a vast majority of RV'ers time spent at Vmax becomes almost laughably easy intuitive.

Check when the battery cells start to bubble then terminate the charge. Note the time spent charging versus the starting voltage. Is this overwhelmingly complex? if yes, then the use of a 3-stage converter is mandated. Some folks are crippled in some areas of mechanical aptitude.

It is the crucial time spent at IDEAL Vmax that conventional converters have no way to deal with. They compensate by demanding inappropriately long term charging spent at lower voltages. Inappropriate because it is similar to watching a draft horse pack a lunch box. Generators and generator run time are both expensive and for many including me - I don't want to endure unneeded and excessive noise and fumes. Then there is the matter of the grinning cashier at the gasoline station.

Occasional top charging can be increased in amounts per kWh drawn by letting the electrolyte bubble slightly longer every tenth charge. If two hours seems to be ideal for regular charging starting at a certain voltage then top charge by adding 15 minutes to the two hours.

Proponents of totally automatic charging are fully entitled to have the right to charge the way they wish. But they do not have the right to declare operator controlled sophisticated"custom" charging as being deleterious, hazardous, or invalid. The louder they yell the more they discredit themselves.

I have spent far too much time with batteries to have the wool pulled over my eyes.

BUT BUT CAVEAT BUT BUT READ THIS...

Batteries can not be equalized by cranking up voltage to 16.0 volts. AMPERAGE LIMITATION and THROTTLING is an absolute must or batteries will be damaged. Use paralleled 12 volt 50 or 100 watt light bulbs to throttle amperage to 5% of rated ampere hour capacity. This does mean the direct disconnection of the main charge lead line from power supply to batteries during the equalization event. And the disconnection of batteries to hotel loads for overvoltage protection.

I feel I must address the situation where a bi-directional charge relay will allow inappropriate flow of high voltage to the chassis battery. I am familiar with the Blue Seas and the Sure Power charge dividers. Both units, have a terminal to chassis negative that must be in-circuit for the device to work. The chassis negative circuit employs an 80 milliamp flow to enable the device. A small switch can be used to interrupt the charge divider operation during equalization.

And finally, a fully recharged battery is a longest lived device. undercharging a flooded battery is electro-chemical arteriosclerosis. People who total 5% of the kWh transactions of a serious off grid boondocker are poor choices to hear opinions about battery lifespan versus charge protocols. Hydrometer and total kWh transaction accumulations are the sole valid points to consider.

I wish Racer4 good fortune and will dispose myself to his questions.

Charger augmentation is not for everyone. It may or may not be appropriate for even 7% of RV users. But if it is warranted, then nothing else but charge augmentation on the face of the earth can do it's job and the penalties at least to me are unbearable. Forcing myself to be stupid is not one of my strong points.

[azrving]

.

[kiwiRVer]

I would suggest you would be better off using a proper intelligent charger rather than a straight power supply.