The batteries don't have to be perfect to still do the job. No panic to rush out and replace just yet.
A newbie guy with a used trailer, I was helping had two old 6s (Interstate/USB U-2200s) and was running his microwave etc with a 3000w inverter from those two batts no problem.
I checked his SGs and one of the 6s had SG in the red on one cell and two in the green, while the other 6 had two cells in the red and one in the green, best they could get to on a proper recharge. Still worked! I was amazed to say the least.
I sold him my spare 130w panel and got that set up for him, and he went for two more months like that till end of that summer camping season, and got away with it.
I told him to wait till Spring before buying new batts. He then got four new 6s for the new season and is now starting his third year on the new batts.
So there you go.
Meanwhile, I hope you found whatever was the problem with the 75 not charging after you re-installed it.
I remember in school in the 1950s they told us how in Japan in the 1930s they were getting going, but cheated by having a factory in "Usa" , Japan, so they could print on the product, "Made in Usa."
Of course, after a slight interruption in the 1940s, :( , they got going again and didn't need to cheat anymore.
LY that is the new PowerMax with a hole in the side so you can get at the little pot inside with a small screwdriver like for eyeglass frames. (Second hole is for a switch that changes it from 3 or 1 stage, which is adjustable voltage for that one stage)
Idea is you can use it as a regular 3 stage or as an ADJ as required--very nifty concept, but a little awkward to operate without being right up to it. It only comes with the external knob and voltmeter if you special order that, or just buy the older model with those.
I can't tell from the photo what is what for checking things. Seems he used two red wires from the terminals (ran out of white?) but hard to match the photo to the earlier schematic.
Anyway, OP- with solar and WFCO turned off -just turn on the PM-75 (see the green light is on!) and use the meter to check for voltages starting right on the unit's two terminals, and then at each junction along the way to the batteries looking for the break in the path either on the neg or pos path or both.
Be too easy if it is just no 120v input--no green light--to fix that.
It is a puzzle why the 75 did nothing after being reinstalled. It did have DC output in its bench test before that. No doubt the OP is chasing that down with a multimeter.
Once this all gets sorted out, I would like to see (photo please) how the PM-75 is installed so you can get at it to operate the voltage adjustment pot and see the voltage changes as you do that.
Just getting at the hole to put in the small size screw driver is one challenge. Running back and forth to see the Trimetric display is another. A voltmeter co-located with the adjustable converter solves that. If you can easily see the voltmeter while twiddling the pot!
It is easy to arrange for all that in some RVs and not so easy in others, depending on physical layouts. The OP could demonstrate how he does it, which would help others. With adjustable voltage converters becoming the new thing, we are all going to have to solve that somehow.
Good news that you were able to recover the batteries according to SG. Of course you still have to prove them by loading them and seeing if they stand up to that, but fingers crossed.
For the battery gurus-- I am unclear how you can use equalize level voltages on the batts when they are not fully charged. In this case they were near dead flat. So what is that all about that you can only equalize a full battery?
It appears the near dead batts needed the high voltage to kick start them into recovering their SG, and a "gentle" approach did not work.
I don't see this as a case where a "smart charger" needs the batts to have at least some voltage before it will even operate. The converters did operate, but at a lower voltage level where nothing happened.
There are "unknowns" why the two converters did not operate but the portable charger did. We know nothing about the rig's set-up wiring etc and whether it is valid. We don't know if the installed (how?) PM 75 set to 14.8 was no use in getting the near dead batts going, or even if that was tried out-- only that the WFCO at 13.6 was unable to get them going. Last we heard the PM was removed from its installation, so when did it get to try this?
Anyway, back to one thing, which is testing the PM for 75 amps now there is enough battery to power the 1500w inverter with an 80 DC amp draw, eg, a kettle. That would also be a battery test before applying the PM 75, to see if they are ok now.
The poor OP is going through a lot of difficulties here, but good for him keeping his cool and us up to date--we are learning useful things here. :)
I didn't see where the OP stated whether his inverter was with or without built-in transfer switch. If it's without, the GFCI outlet is the only AC output and it has a hardwired bonded conductor.
............ I purchased this Kisae on sale at the Buffalo NY WestMarine for US$343 and wasn't really sure about it's reputation.
These local guys sell them and I know they are very fussy about what they sell, since it comes back to them if it is no good, so they have to be careful.
I had one of those CanTire PSW 1000w inverters that was wired internally like that. I also had a battery disconnect switch on the neg side.
With that switch open and no shore power cable plugged into the inverter, I had no 12v in the rig. BUT as soon as I plugged the shore power cable into the inverter the 12v things (lights etc) worked!
I decided it must be the way the inverter is on the battery for input, and that the rig's 120v and 12v share the frame as a ground and somehow the way the inverter chassis ground went to the frame plus the weird way the inverter's receptacles were wired up for GFCI and its chassis, Not quite sure how it all connected but it did.
Nothing bad happened, but it did negate my neg side disconnect switch between battery and frame. "They" do warn you about neg side disconnects, where the pos side is left live and "anything" can make a neg path you were not expecting.
Maybe try tipping them on their sides for ten minutes and then go upright again. That worked with my old 27s to get the SG up more.
Any voltage you have now might be coming just from the little acid they have, all near the bottom, with water on top. Since the charger isn't getting things going, maybe tipping to mix what is there will be something it can grab to and improve?
Note the highly scientific battery expertise there. Or first kill a chicken and let seven drops of fresh chicken blood fall on the positive posts of each battery--not the neg posts, or it won't work.
Did I mention we need a battery guru or two to help out here? :(
A stray thought---A charger will supply other loads first, then anything left over goes to battery charging.
Any chance the WFCO is supplying amps to something else in the rig and that's why you aren't getting any amps to the battery bank?
Only time I have with this, the guy's 6s were down near flat, but my Vector charger (does 14.6) was able to start (so the batts had at least 4 volts or the Vector would not have started--if that happens use jumper cables first, then switch to the charger)
Amps began very low and slowly rose and voltage slowly rose over the first couple hours. Then things got normal and amps started to taper again as normal. I think you can get away with doing that at least once and the batts will recover, like leaving the lights on in your car.
I don't know what the correct answer is here, IMO your amps should be rising slowly. T2R suggested not too much voltage, but how much is that? Time for a battery guru to help out. Maybe start a new thread on this to catch somebody who knows? Probably not many people following this thread anymore.
Looks like they want Vabs to be 14.22 (2.37) and fully discharged SG is 1.124.
But then they say do a "finish" near the end of the absorption stage to 2.65 = 15.9 So you will be twiddling the pot during a recharge, although it will max at 15.5.
Good luck with that for the average RVer and his typical converter :(
Looks like PowerMax is right to have the adjustable voltage feature on all their new converters coming out (LK model) that goes to 15.5, although even that is too low for some battery specs it seems.
I suppose the other converter brands will have to respond to all these higher battery voltages one of these days. I can't see how the fixed three-stage converter that is no good for anything can last in this situation. Going to make it hard for the average RVer who just wants to push a button and go have a beer!
"They started at (isolated) 11.5v which is close to Crowns claimed 50% SOC even though SG read 1.120"
I haven't looked at Crown specs, but Trojan uses 12.1v for 50% at 1.172SG. My Interstate and Exide 6s show similar numbers at 50% (as confirmed by AH count etc) Hard to believe 11.5 is near 50% with Crown.
Trojan has 10% SOC as 11.51V. They have 30% for SG 1.124 Another chart shows 1.120 as Zero % SOC.
The batteries are acting like they have low capacity. Agree with second opinion on the SG, but... Voltage can be not bad and still have low SG "depending." IMO just leave them on a charge for a day or two like T2R said, and see what happens. This will take lots of time.
Confirm the WFCO is getting over 115v just to eliminate one thing.
When I take my 6s down to 50% for a test at their 20 hr rate, they get to about 11.7 loaded, with SG about 1.190 and I stop. Voltage bounces back to 12.1 after a while confirming the SG 50% marker.
I have no info on what your batts have been doing for the last few months or how old they are etc to explain how they got this way, but IMO the thing to do now is just do a best attempt proper "recovery" which will take a day or three, and then see what's what.
You don't need to go back to 50% to show the 75 amper can do 75. Forgot to mention this earlier.
Once you have battery, you can test the 75 amper by using an inverter draw of say 80 amps and watch the Trimetric when you turn on the 75. Amps should go from minus 80 to minus 5, indicating the 75 amper is doing 75.
What you've suggested was my original thinking. Fixed higher voltage near the batteries for a faster charge using the generator. The WFCO still does the shore power type maintenance when available. The WFCO's plugged in now to get that 100%SOC / 1.275SG back. If 14.8v is good isn't 15v better? :-) And an occasional 15.5 to equalize?
Still want to see something closer to 75a instead of 32.
Yes you still get to twiddle the pot, but not with a chisel.
You won't know if it will do its proper 75 amps constant amps in Bulk until you have a battery bank to test it on. You need the batts at say 1.200 for near 50% and then see how it goes. With short fat wires to the battery and near 120v you could see 76-78 amps who knows? With low 120v you don't get the full amps of course, but it will do some.
BTW, if you do find the unit is not working right, just call Errin and he will look after you. (As long as you don't go around saying PMs are no good etc. :) ) This is all good feedback like they wanted in case there are design issues they can correct.
Thanks...a little less PO'd. Good thinking...on your part anyway. All the way clockwise is 13ish and the other way is 15.5+. All I care for is the fixed adjustable. (oxymoron?) I would have gotten the dial/led meter less 3 stage if it had been available....and would likely recommend that. Think they'd trade me?
Also, not that it can be fixed but I see what needs to happen with that switch but don't understand what mechanism works it.
Thank goodness it works! So you now have a basic ADJ except the little pot instead of the knob on top. If you don't care about three stage and the hole for the pot is big enough, just put the lid back on and tape over the switch hole.
So if you have that as your only converter, you still need to play with the pot, but if you have the original rig's converter, I suggest you leave the PM3-75 at 14.8 and just use it for fast charging. Reason is I don't know how much that little pot can take if you keep twiddling it. Use the original converter for 13.6 on shore power--which is how I do it, but I have a 5er with lots of room.
Set at 14.8 it does Bulk and then Absorption (for as long as you like) then you stop the generator. So you don't need to set it at 13.6 afterwards because you have no 120v anyway. :)
Before doing anything, see what you are set at now if anything--it has to be something. Put a voltmeter in the output terminals and plug in the unit. Green light should come on. Turn the pot and see what voltage range it has.
If it acts like an ADJ should you are in business. If not, then let's see what to do with the switch. I will check how that works mean time.
EDIT--that switch has six pins underneath. The centre moving switch part goes to either end. Don't see that moving part in your photo, but it looks like (be careful you match the back with the back and front with the front pins-- I think--) you can run something across between the middle pins and the right hand pins (looking towards the circuit board as though through the hole---the right set is for single stage on mine.
Yep. Green LED. It was in a blind spot on the back...by the fuses as you said. Now for a hole.
If it has four rivets for the lid each top corner, you drill them out and replace with metal screws. Actually two screws kitty corner will hold it.
So eventually, once you get the batteries sorted out, we should be able to get back on track. EDIT---oops no need to test the new charging profile--you are off the hook! See below.
OK forget what I said before about the new models. :)
All the new models are LKs like yours. You can special order an external pot and voltmeter etc like before. They still sell the older models.
It seems the LK's new three stage has 14.6ish boost for half an hour (was 15 minutes) then drops to 13.6. If you don't like that you can use the pot to put it back to 14.6 for as long as you like. You can swap back and forth 3 or 1 stage.
Or you can just switch it to single stage and use the pot to set voltages. (same as the ADJ models before)
(It was the previous ADJ that they yanked the three stage and made them single stage with external pot---IAW they made the previous ADJs out of existing 3 stagers :) )
EDIT--look for the new LKs and manual for it on PowerMax website in May. You can get them from PM direct now, and dealers will have them as they see fit--maybe sell their old style ones off first. Whatever.
I'm gonna go see what I can take apart so's I can drill a bigger hole for the switch....th pots hole's OK. Where the charger's at now I'm now unsure which way the switch is ??
Yes, you need to take the lid off (four screws) and look at the switch and see how big of a hole you need so you can operate it.
I am confused about you not having the LED lamp (lit when 120v power is on) AND you have the switch as well as the pot. I am getting more on that.
OK--it seems if you have an LK then you must have that lamp AND it has two holes and the switch will make it a three stage OR a single stage, which is worked by the pot. Please confirm exactly what it says on the label for the model type. and look again for a little lamp maybe by the three fuses? A photo or two would be great too!
OK, do you have a PM3-75LK and does it have an LED lamp?
If so you have three stage or single stage that adjusts with the pot.
Let me know what you have and I can find out more about it.
On the holes that are too small---on the prototype I had, I had to take the lid off to see what was there to understand what was going on with the switch and pot. I got mad at it and drilled way bigger holes in the lid's side so you can see what is there and what you are doing.
My feedback had a lot of notions of potential mounting problems for where it could go in an RV so you could get at the holes and see what you are doing. I like the external ADJ pot knob on the previous models way better, but even there you have to get at it. Works ok as a portable out in the open.