I would ditch the on-panel charger; get a $20 e-bay PWM charger and mount within a foot or so of your battery. With one 120 watt panel, I'd set up so that I could bypass the charger and tie directly into the battery when I knew the battery was below full charge.
Yes. Panel-direct till it gets to 15v (if it ever does that day) and then connect the controller so the fridge etc does not get over-voltaged. So no concerns about a too-low set point.
Also if you will be away from the trailer that day when you think the battery voltage will hit 15v, then you can leave the controller on to prevent over-voltage (which is what it is mainly for anyway)
The 15 ft panel to controller distance with a portable, aimable panel is a difficulty unless you can put the panel on the roof of the RV.
You need the panel on the south side of the RV and even then you are limited to 180 degrees if that. The sun goes around more than that (46 degrees more on 21 June) so the trailer is blocking off the sun part of the time.
It is even worse if you have the panel near one end of the trailer with awning and slide sticking out. You have to switch sides or ends where the panel is at some time during the day. Except you might need to put it in your neighbour's site to achieve this.
It all gets complicated depending on your options at the site, but in general for a ground mounting and a 30ft long trailer, you need to get that panel much farther away from the trailer than 15 ft. I find 35ft is restrictive but doable where we camp.
As mentioned , you can avoid all that trouble by placing your portable panel up on the roof so it can see all around, but now you have other issues to contend with. (contraption time! :) )
I didn't find that, ISTR it was tenbear from a previous thread.
IMO you can overdo the shortening of the controller-battery wires at the expense of practical convenience, especially with a TT where the batteries are out on the tongue and you want the controller under cover, but with cooling air too. It is easier with a 5er.
If farther away than idea, you can still get some help by using the trailer frame for the neg path so at least some of the "wire" is fat.
It is all about the voltage at which the controller starts to control, so if you want 14.6v battery for that, and you have 0.1v drop to the controller at the amps you will get to by the time you get to 14.6, then just set the controller at 14.7 instead.
Does the power company charge for KWH or KVAH? Does the KillaWatt measure KW or KVA (some can measure PF, ISTR) We don't want to compare prices using different amounts. Does it come out right with lights but not dryers? (Of course I am only asking in the true spirit of inquiry )
You need the controller somewhere between the panel and batteries. You can arrange your desired amount of voltage drop on each side of the controller by choosing fatter or thinner wire for the lengths you have.
Also you can make up for voltage drop at the battery-controller end by jacking up the controller's high voltage set point for where it starts controlling.
this is a good guide for some of that work.
Ten years ago I let the battery in the Honda3000 run down and did not replace it. I just use the pull cord ever since. But I would have had to use a trickle charger to keep that battery up between using the gen since the gen does not get enough run time or used often enough to keep the battery up.
The gen rides in the back of the truck so a couple years ago I got the idea of using the truck battery to start the gen so I wouldn't have to use the pull cord. I did run wires from the gen's inside battery compartment to hang outside the gen and I keep the ends of those wires covered when not in use (wire nuts)
I made an adapter to go from the slide-in camper plug the truck has (behind the cab and in front of the box) over to the wires I added to the gen. So with that plugged in, the electric start worked.
Since that worked, I don't see why if there were a proper battery in the gen, that you couldn't attach a trickle charger to those added wires hanging out and keep the gen's battery charged.
BTW I gave up on my electric start method even though it worked as it was too much bother with the adapter, and am back to using the pull cord, but the wires that I added are still hanging out of the gen.
The fan could be replaced with a computer fan, it is that sort, but you can't mount it inside-- it goes in a slot. The fan frame housing would have to be just the right size to go in the slot and hold there. You would end up mounting the new fan externally, so might as well just mount the original fan externally.
RJ, I did not find what exactly was making the noise against what to know just how to cure it. There is not much you can see or get at with it installed in the slot. Best thing would be just install it externally against the vent hole instead of inside it. The red and black wires will reach through the vent easily.
Mine has a noisy fan and I was worried, having read here about some troubles with that. I took it apart and it was the fan housing when stuffed into its slot rattling on something. Perfectly quiet fan when out of the (padded) slot. It is not screwed down. I could not figure what was actually making the noise or find a quiet position in its slot, but at least it was nothing that was going to make the charger not work.
It looks like a good fix for the noise would be to take the fan right out and mount it externally with screws or use any other similar fan. I have the fan off my broken Paramode converter that would work there. Not bothered by the noise enough at the moment to do that now I know it is harmless.
I cannot remember a failure from a cold start with any of the different size thermistors, only with a hot restart.
However, since the converter runs ok after the thermistor has blown, which I have seen with a hot restart and the lid off so I can watch the thermistor go up in smoke; then with the cold starts and the lid on so I can't see the thermistor, I cannot state for sure that the thermistor did not blow after a cold start and just keep running so nothing seemed wrong.
The converter with the big fat thermistor did not start in Nov after not being used since Sep. It worked ok in Sep, but taking the lid off in Nov, there was the thermistor as shown in the photo. I have no idea when that happened or how many times the converter worked ok while the thermistor fell apart to the point the converter would not start at all.
I have seen smoke after hot restarts that came from the thermistor. Sometimes after the smoke event the converter has died with the thermistor burning right up. Other times there is just a little smoke and a brief red spot and the converter keeps running at full amps. I have never seen smoke after a cold restart.
The general advice which I am taking, is to just not do any hot restarts, and also to clamp on first, since clamping on second is similar to a hot restart.
My suspicion now is that if I do that, it doesn't matter much which size thermistor I put in there, so I might as well use these ones I have on hand and not buy any more of a different size. Unfortunately I have 5Rs and 2Rs so if I do need to cover for 3R, then I would have to put two of the 2Rs in series to make a 4R if I want to use them or else it is wasted money ($3.00 each !!! :) )
EDIT--there is also the problem of the hit and miss just what part of the a/c cycle you happen to start up in, so it may not be possible to draw any conclusions from observations of smoke/no smoke based on whether it was a cold or hot start.
Salvo, no call for being so nasty.
In any case, ISTR he already did estimate 30a to go with the 170 and came up with 5.7R, while Ken used 50a to come up with 3.4R. My previous post seeks clarification on where the 30 or 50 or any other number comes from. 85 would let you use 2R. Seems to have to do with the diode bridge specs.
On that Salvo used the inrush limit spec of 300 to get 1/2 an ohm for R, so there is a conflict over which part of the diode bridge's specs to use to go with 170v peak to get Min R.
How about this sort of looking one, under the big heat sink overhang on the right by the fan, marked, "D25XB 60 B 7508"
That is a pretty durable device, your other part.
For a 25 amp part, it looks like it can handle about 50 amps for 100 cycles and I would probably stick with 50 amps as a conservative number.
Getting back to this, where did that 50a come from anyway? (I see the 60 number for part is not a rating just an identity)
If I want to use my 2R thermistor, then if I get my amps to go with the 170 from where that 50 came from, then I would need to use 85a.
Why can't I use 85 instead of 50? If I did, would I get 60 cycles instead of 100 before it failed? Cycles of what anyway?
The 170v comes from peak volts RMS on 120v line voltage, ? , so that means every time you do a cold start, the voltage could be anything from peak to zip which means in rush may be small or great each time.
So whatever thermistor I pick, I could do several starts and it would work every time but that proves nothing, because it may be that I never caught it at peak inrush, but the next time I could and it could blow? So just because it works great after a repair, that proves nothing?
Meanwhile we do see my thermistors blowing but no harm to the diode bridge, or at least not so you would notice. Which brings us back to the spec about handling stress for 100 cycles. A cycle of what? Does that mean you get 100 starts and then anytime after that your diode bridge might fail? Converters are supposed to last years and years so that can't be right.
(I have not forgotten the comments that the production 100amper design for the straight converter version may not work quite right for the same thing used with variable voltage where perhaps higher inrushes might occur. They might need two different designs, no idea. Might hear something about that from them or not. )
Looking at 3 different converter manufacturers surge current limit resistance:
Parallax: 2 ohm
Progressive Dynamics: 1 ohm
Iota: No thermistor, ac source resistance and converter input resistance is adequate.
None of these are failing! Their surge current limit is perfect in protecting all parts.
Tell me again why do you want 5 ohm?
I don't care what R it is, I just want one that won't blow! :)
BTW the spec here for that 350a was at 50hz, not 60, and I don't know what it means for half cycle or whatever that is, where you are not talking about real cycles or whatever---arghhhh!
I have some 325R020s left over and some 322R025s but no 355R25s, so I keep waiting for someone to say (besides just Salvo (ha ha) ) that I can use either and it won't matter. since the 5R020s do blow at times, I would like to try the 2R025s I have, but am scared to when PowerMax has gone to the 5R.
Yes, if this is your typical capacitor peak charge circuit, then the diode bridge is the only part at risk. You must keep the surge current less that the diode rating. If the diode has a 350A surge rating then you need a current limiting resistor greater than:
R = 170V/350A = 0.5 ohm
Please remind me, on a cold start, with the capacitors unloaded, is the diode bridge at risk at all?
Ok so these are the diode bridge specs. (D25BX60) I can't follow the argument here what to use for amps and the 170v. Ken wants to use 50a , back a bit from the 60 number--but is that 60 amps??? and Salvo wants to use the big number threshold to arrive at a way lower R.
ISTR the actual thermistor requirement is to hold back a certain amount of amps to the diode bridge out of the total inrush, so the bridge stays under its limit. But we don't know the total inrush so how can we subtract the diode bridge's limit, whatever that is really, from the total, to see what the thermistor's minimum R must be to hold back that much current?
BFL, the diode bridge is in series with the capacitors.
BTW, I was going to mention this since we are talking about inrush current and a possibly faulty converter. Do you have or know about a dim-bulb tester? It might be a good tool to use in a case like this where components are failing. You can build one for less than $10 and has saved my bacon a couple of times. I'll try to fond a link to a well made one.
Not a clue, sorry. I can understand there might be other components causing my problem , except it has happened with two different 100ampers. Also they work just fine with cold starts even with broken thermistors as long as not too badly broken it seems. This makes me think the other components are ok.
The 100amper with the broken MS35-5R025 thermistor that would not even start, fired right up with a new thermistor (it has an SL32-5R020 at the moment--might have to change that, we'll see) so I don't think the rest of it is damaged.
There remains the issue that if I only do cold starts, the thermistor will eventually fail from accumulated overheating from:
-running steady state with too high an R value, or
-too many inrush hits where it holds ok for a while then can't take any more
This is a really good discussion, with differing opinions, so I am now well armed to ask questions of tech support. They are working on a reply, so that might clear things up--or not! :)
They are mistaken in regards to needing the thermistor to limit capacitor inrush current. These capacitors can easily take inrush current that's 100 times the steady state current (13A).
The person who wrote the patent was probably not the designer. I've had a patent issued, but I didn't write it.
Most likely the designer did the same calculation I did.
Rmin = 170V / I_diode_surge-max
Interesting, the PD patent shows a surge current thermistor of 1 ohm.
I see they use a 20a, 400v diode bridge, where mine is a 25a 60. Not sure what that means for what the thermistor needs to do to protect the bridge.
However it says the thermistor is to protect the unloaded capacitors at cold start. It has three 850s instead of my two 1200s.
I missed the PD's output DC amps size etc that the specs for those parts goes with. Mine is a 100amper with 13a steady state input.
So what does that all mean wrt the risk to the diode bridge as asked about in my previous post?
PT you could be right, but I think I will leave well enough alone. Perhaps a plate in one cell is stripped of sulphate but so thin it has not long to live or some such. I am not sure why I even care if all cells are the same SG. I know their voltages in series add up, so as long as that total is enough, who cares? :)