BFL: Which is it?
It was both:
pre-mod it would not recognize the batts were still down around 55%, so amps would taper.
post-mod it doesn't seem to understand what cv means.
So if it stays at 45 amps till voltage reaches about 14.3 when amps then taper and voltage carries on up to 14.8 by the time voltage is down to zero, you can use that. Just declare Victory now before they attack again :)
You can still use the 5 amps per battery marker to stop the charge at 90% SOC with voltage about 14.5.
For example, on a 215Ah bank at 50%, it will start around 13v / 46a. During the 15 minute thing, volts will rise to about 14. The unit shuts down, then comes on and continues from where it left off. At some point later (I would have to check my notes) amps will begin to taper, but the volts might be somewhere around say 14.3. The volts finally get to my 14.8 setting right around the time amps level out.
So it starts at 45a stays there for 15 minutes, then restarts at 45amps and stays there till it starts to taper? Before, you seemed to say it tapered the amps right after the 15 minutes when starting at 50% SOC. Which is it?
The voltages you are quoting looks more like the Vector's profile where it tapers closer to 14v, but then voltage continues to rise while amps taper. See that ugly graph again where it shows the Vector amps and volts. Note the Vectors beat the PM3 set at 14.6 but now the PM3 is at 14.8 they are about equal for time to do a 50-90.
Edit--yes like the 1093 which is a Vector profile
The voltage that counts is the loaded voltage it gets down to when you try to run something. That's when voltage drops below inverter low voltage shut off. However,
The fancy inverters like yours have other settings that might be at play here, and there can be things go wrong between inverter and its remote too based on some reports here on the forum. I don't have a clue about that side of things, sorry.
Maybe the repair crew messed up your settings. Or
Does anything work at night that should work from the inverter? If only the receptacles don't work but the microwave does work, then it's about the distribution of the 120v output from the inverter to the rig. Maybe it didn't get put back in right when it was out for repair.
lol, Yeah, that kinda got put on the back burner. I'm just not sure what they can do for me at this point. The pm pulls 9a, while my peak 40 only pulls about 6.5a, and apparently the vec1093 pulls about the same. And I'm limited for ac current, so I can't even pair up the pm with anything; not even my 20a gopher, until later in the charge cycle.
So, I guess they could send me a 60 amper, like I originally paid for, but that would probably just get stored as a back-up, anyway. And besides, the lid would be coming off it the moment it arrived, so...?
The PF corrected 75 should draw about the same as the non-PF 60, and not much different in price. But I have no idea how it would go now for warranty of course.
If it now goes to 14.8 holding at 45 amps all the way to 14.8 and then holds 14.8 while amps taper, you could use that for something I guess.
After solar goes dark, the battery voltage goes down too not just the current from solar.
The inverter needs voltage from the battery to work and has a low voltage shut off. If your wires from inverter to battery are not fat enough for their lengths, or if you don't have enough battery to hold the voltage up with that inverter draw when the battery is starting out at less than full (which it acts more like full with the solar backing it up in the daytime) then you will go below that voltage shut off when trying to run big things off the inverter.
One of the other members here, I think it was jrnymn7, modded a Boondocker 45. As I read his account of it, it still drops voltage as soon as it hits the target voltage, but the whole curve is higher in voltage. So instead of 14.6 dropping to 13.6, it's say 15.2 dropping to 14.2. BFL, you say your modded PM3-100 just stays at the 14.8? Just by setting the internal pot? Is the internal pot still present on the new models? On all sizes, or just the big guns?
He has a weird mixed up thing that is not proper so can't use that as an example of anything. Should be a warranty issue, off forum for the gory stuff between customer and seller.
Meanwhile, it did show that the PM4s are different from the PM3s for what happens when you change the voltage with the internal pot, which they both have. So my experience is with the PM3 and I cannot say if you can do the same with the PM4. The PM4 has that 15 minute fixed time in boost that seems to get in the way.
Boatandrv claims to be selling PM3s still at low cost too, but his blurb makes them sound like PM4s. I would pin the guy down on just what they are if buying in hopes of getting a PM3 you can modify for sure.
oh yeah, now I remember you saying that before, thanks.
But the feel is decent, not too choppy or fast?
It works for me. It is not choppy and you can go through the voltage range. If you go past the number you want just turn it back a little. Getting to two decimal places using a multimeter takes tinier twiddles :)
While camping I just use the one decimal place installed voltmeter on the lid. The Trimetric is only to one decimal place anyway. Of course it will show one decimal place different from the converter's meter due to voltage drop, different rounding off amounts, whatever.
No point getting too fussy there.
BTW, are you ever going to try to get warranty on that "75" of yours?
By quality I mean is it simply a large knob connected to a tiny blue pot?
I ask because I'm a little disappointed with the tiny screw that comes on the turnigy. In the pic, it looked fairly substantial, but it's really quite small. Definitely only a slotted eyeglass driver would fit. The pot appears to be similar to the small rectangular blue pots on those mex gizmos.
It is a knob on top of the lid which has a wire under it going to the top of that vertical circuit board where the little blue pot (like on your PM4B) goes but the little blue internal pot is not there. I don't know where the actual pot is, might be right under the knob on the underside of the lid.
Ignore the broken thermistor, got that fixed now :)
I'm curious about the quality of the potentiometer randy's using.
If it is like the one on my PM prototype, I can say it works. What do you mean by "quality?" It takes about half a turn to go through its range and you can pick a voltage to sit to what your meter shows to one or two decimal places.
I marked some commonly used voltages around the knob with a marker pen so I can set a higher "converter voltage" when it is showing less than that during battery charging in the Bulk stage.
When already connected to the batts, before turning on the unit, the meter shows battery voltage, and turning the knob does nothing because the unit is still off. (Do not turn the unit on first then connect!!! Thermistor time!) So using the marks, set the desired converter voltage, then turn the unit on.
If I have set converter voltage too low for being cold out and amps start to taper too soon, I can raise the converter voltage a bit and amps go back up to what I would expect.
This is from the Power Max 75 Site
75 amp 3 Stage Charger
Automatic three-stage battery charging maintains your battery's life with three nominal voltage output models:
* 13.2 Vdc range "float" mode
* 13.6 Vdc range "absorption" mode
* 14.4 Vdc range "bulk" mode
* Electronic current limiting automatically shuts down power during overload or short-circuit conditions.
* Quiet operation in a wide range outputs. Convenient deck mount installation.
The PM3-75 Amp converter/ charger is a versatile, advanced power source solution.
Some of you are familiar with this unit. Voltage rises slowly as batteries charge to 14.4 volts. After this unit reaches 14.4 volts how long does it stay at 14.4 volts before it decides to do something weird?
-An Educational Moment-
It drops to 13.6 as soon as it gets to 14.4. See my ugly graph of that with the 100amper.
Similar to the Iota which drops to 14.2 15 minutes after it gets the batts to to 14.6 (converter 14.8)
That is why I modified my PM3-100 amper to go to 14.8 using its internal pot. Now it gets the batts to 14.8 and stays there forever till I shut it off. ( I use the trailer's converter at 13.8 or a little 2amp charger I have that holds forever at 13.4 to Float)
With the PM adjustable, you can do that with the external knob. When it has done the job at 14.8, change it down to 13.x for Float
Note that Randy's PMs have different specs from regular PMs and PMBCs.
If your charger only does 40a, then on two 27s, it will take about two hours to do a 50-80. If you keep going, then in another hour you will get from 80 to 90. Three hour 50-90.
I would prefer a two hour 50-90 but that takes a 70 amp charger on two 27s, which will accept that perfectly.
The PD/Onan issue just means the PD will do fewer amps but not that many less.
One way to solve this would be a PowerMax 75a adjustable voltage model from Randy, but first make sure it is PF corrected so it can run on a 15a circuit, then consider the cost. You can do anything if money is no object!
Money is always an object. :)
Less than $100 would be sweet. Less that $200, tops. Cables not included.
I'm just looking to be able to blast some AH in, in the event of non-sunny days off-grid. I figured C/5 was a good number of amps to charge with, and two hours is about all I want to run that noisy, smelly Onan.
I'm not a battery pamperer though. I like what people say here, "my batteries work for me, not the other way around". Mine spend too much of the year idle, which is probably a bigger issue than a few hard charges per year.
I still say get the 75amper and stop fooling around--as long as Randy confirms it has PF correction so it will run on a 15a circuit. So it is $20 more than your $200 limit. You will soon forget all about that in real life.
I'd lower the voltage and let the solar help the battery run the inverter. The volts will come down either way.
if the inverter is to run the microwave for a few minutes just turn off solar for a minute to let voltage drop then start microwave and turn solar back on. If the inverter load is too light to keep voltage below 15 with solar on, that's another thing.
Almot, the pipe at noon is, "Hands to dinner"--- joke added---"officers to lunch" :) One of those class things from the UK like "pants" vs "trousers" and on a raincoat, belt (lower class) or no belt (upper class)
Don't forget to "calibrate" your new Solar30 so you know what voltage it will go to above what you set it at.
The T-1275s like to be at 15ish for a good while after they get that high and since they don't gas much, don't lose water much. But meanwhile at that time of day, around supper time, you want to use the inverter for things, so that means keeping the voltage under 15v so the inverter won't alarm off (some have higher limits than 15)
So it is a conflict you have to work around at the time. Disconnect solar, run the inverter, connect solar back up. Or leave solar at 14.9 (which might mean set it at 14.6 or whatever :) )
BTW it is amp hours not amps--you keep doing that!
Randy does have a clue for sure, but not all Boondockers are the same. Mex probably means the adjustable voltage ones. The regular ones get the batteries to 14.6 and then drop to 13.6 for the rest of the recharge.
This is not very good for generator charging, but most people are on shore power and also there is an idea out there among many that they want to be "gentle" with the batteries. The customer is always right! :(
Years ago Randy was posting how you could get to the internal pot of a Paramode and adjust the voltage. He said guys in the desert were doing that. He and the PowerMax guys have been looking at ways to make it easier to adjust the PowerMax too without having to open it up and get at the tiny little internal pot.
They finally got onto this external knob idea as with my prototype from early 2012. PM has had that as an option on their PMBCs ever since and Randy now has his own version.
One of my ugly graphs shows the regular PM charging profile and time taken compared with adjusting the absorption voltage so it stays at 14.6 instead of dropping to 13.6. it also has some Vector graphs in there so it is "busy" but work real hard and you can get all the info :)
Define "getting to float" before saying what SOC will be. Depends how long at absorption, which all depends on the charging profile of the various chargers being compared, and the charging rate which determines what the SOC will be when first hitting Vabs.
The BATTERY SCIENCE rules for charging a depleted 12VDC battery in a short three hours time is to hit it with 14.4VDC for two hours and then 13.6VDC for an additional hour.
That last hour at 13.6V is where solar comes handy. Pretty much any panel will generate enough amps to keep it at 13.6V.
This scientist would leave it at 14.4 (14.8 actually) till the battery is charged never mind the time, then and only then drop to 13.x (where x depends on temperature) float.
I suspect Roy has been reading too many PD converter blurbs. :)
You can put the 1093's clamps on any pos and neg post you can get at. In fact you can put the pos clamp on a pos post and the the neg clamp on the rig's frame like it says to do :) You can leave the solar on while you are charging with the 1093.
You can probably rearrange the battery links so your most "balanced" pos and neg are up front.
If you get a Trimetric then its shunt neg will go to the neg battery post and you will need to connect the 1093's clamp to the outer end of the shunt for the Trimetric to show what the 1093 is doing along with the solar neg and the rig's negs.
You can solve a lot of that by balancing the batteries and run a set of wires from the proper posts to a pos bus and the shunt as the neg bus. One guy with a four battery tray like that put two holes in the "roof" of the compartment where the tray is and ran the wires up through the holes to the busses. That way he didn't have to worry about getting the tray all the way out anymore.
BTW the little gen will run the 1093 but won't have much left over to run anything else at the same time until amps have tapered down quite a bit from the initial 40 amps.
Also the 40 amps will take a long time to recharge four batts from 50-90%SOC maybe 6 hours. My 100 amp charger can do that in under three hours but needs a bigger gen of course. Its the old story, noisy big gen for a short time or quiet small gen for a long time (unless you have a big Honda which is quiet and fast)
I believe one can multiple the hours of discharge at a certain load to get capacity at that load.
86 ah @ a 5A load, 72 ah @ 15A load
However, we don't run the load to battery death, we stop short of that and the battery recovers to be able to run more, so the capacity figure for the load in such tables is lower than you get in real life.
RVers run a mix of high and low amp loads all day, so the battery capacity rated at the 20hr rate is about right for a two-battery bank with about 11a as the rate in many cases.
If the RVer averages less than the 20hr rate, then his bank capacity is more than it is rated for thanks to Mr Peukert.