PD9245C-14.8

I was told the "production" models of the 100 amper now all have those big 5R025s like my prototype adjustable's. However, my prototype (based on a PM3-100)also has the new front end layout, which it looks from the other photo that the regular PM3-100s now have too.

I don't know where the shop is where they get the big thermistor attached on the regular models now. Are they back-fitting PM3-100s left in stock? (PM but not Randy still sells PM3s even though PM4s have since come out) Do the PM4s get theirs OEM in China?

The legs on those are really fat so I can see why they don't drill new holes in the board but get them stuck on from on top which takes a bit of fiddling, winding the old thermistor's thin leg on top around the cut-off fat leg and soldering it all. It works ok but it does look sort of ugly.

I would like to see inside a production OEM PM4-100 and see how they got the thermistor on the board, but of course I have no "need to know." :)

Here is the 100 amp powermax adjustable model interior whose thermistor had obviously been replaced too:

Fifteen minutes is about right...

For a Flashlight battery...

"I like your idea as well and yes its a no brainer, however the powermax does not have any way to force it to the bulk charge mode or even have an LED/indicator that shows what charge state it is in."

PowerMax and Iota converters go into boost every time at first so you don't need an indicator like that. (They stay in boost for 15 minutes, then drop to Absorption voltage if the batteries are already well up in their charge, or stay in boost longer if the batteries need more of a recharge.)

You can usually tell (see below for an exception) what "stage" a PD is in by observing the voltage, so you don't need the lights unless there is no voltmeter handy. Those lights would have to be where you can see them, which depends on your rig's set-up.

There is one grey area when you might not be sure the PD converter is in boost. If the battery is low and you turn on the converter, battery voltage might only spike to something like 13.4 volts and start climbing from there. You might have to wait until battery voltage rises past 13.6 to know for sure you are in boost and it will continue to rise to 14.4. The lights would help with that, but again, not needed with PowerMax or Iota.

BFL13 wrote:

lbzya wrote:

KJINTF wrote:
It's a simple modification to increase boost voltage from 14.4 to 14.8 or almost anything you desire. Pin #5 of the micro controller is connected to a 32.4KOhm resister - drop the value by several hundred Ohms and the Boost increases - Simply solder a 60KOhm across the resister in question.

Do you happen to have any pictures of this modification? I am going to purchase a pd9270 from best converter and would like to be able to charge my Trojan batteries at their recommended charge rate of 14.8.

You could just as well get the adjustable voltage 70 amp PowerMax Randy sells and set it to 14.8 or whatever you like. (EG, at 32F, 14.8v becomes 15.2v to get the same results as 14.8 at 80F) Adjustable is the way to go!

Also the PowerMax 70 amper is PF corrected so it doesn't take as much of a generator as the non-PF corrected PD 70 amper does.

However if you insist on the non-adjustable converter version, you might want the PD with its Charge Wizard instead of the PowerMax depending on what charging profile you need. "It depends" (as usual)

IMO it is a "no-brainer" to get the adjustable voltage converter that can do it all with less generator required!

I like your idea as well and yes its a no brainer, however the powermax does not have any way to force it to the bulk charge mode or even have an LED/indicator that shows what charge state it is in.

Yes, your 5R25 with the fat legs is attached on top like my prototype was instead of having the legs right through looks like.

The older PM3s (I have one) have the thermistor over by the heat sink where yours has that wire across (bottom left of the picture)that used to be RT1's spot. Where the big thermistor is now (bottom right) was a second smaller coil same as that one beside the thermistor. Some other things different to.

Photos page 7 of 43 here

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/26979020/srt/pa/print/true/pging/1/page/7.cfm

Note I had already replaced the thermistor on the earlier model PM3 but I blew it too. Now has the 2R25 which is holding. It seems the trick is to use a 25 not a 20.

So they dumped one coil and used a bigger thermistor in that redesign. I have no idea what they have done since, but they do keep making improvements.

I don't take the lid off anymore on my adjustable, because the wires underneath from the lid down to the board are short and it is too easy to break one. Then it is a bugger (for me) to solder the wire back on the board where it goes. So the lesson is to leave the lid on! :)

BTW, as you must know, that little blue box upper right in your photo is the "internal" voltage pot. I made mine to be 14.8 instead of reading 13.6v Now it charges the batts up to 14.8 and then stays at 14.8 forever till I unplug it. Love it! :)

The adjustable version I also have, has the blue box spot remoted to underneath the knob on the lid. This is the wire that can come off if you remove the lid and get it too far from the rest of the unit.

Somebody here tried that blue box adjustment on his PM3, but his had the new (from late 2013?) "15 minute thing" which mine doesn't have. (that makes it go to boost every time instead of only when the batts are low like a WFCO routine) So when he set his to 14.8, it first went to 15 something high in boost (the pot adjusts all voltages) before it would then settle at 14.8. So the 15 minute thing makes it awkward for doing what I did. The PowerMax sales guy (not really a tech) said he thought to disable the 15 minute thing, you had to snip R1, but that would also kill it for having any "stages" but he wasn't positive about that R1 snipping idea.

Anyway since then Randy has his line of "external" adjustables, so all is now good and we can keep our lids on. :)

Understand the PM3-Series is now discontinued
They are simple to modify and easy to repair
Looks like mine has the "Factory" thermistor modification

KJINTF wrote:
BLF

A while back you posted a thread regarding a blowup thermistor on one of your converters.

Was that Converter a PowerMAX PM3-100?

The reason I ask, Just received one requiring service and noticed an aftermarket thermistor was soldered in from the top. Remembered you mentioned your soldering ability and wondered if it was your old converter.

The real problem was a shorted FET which is a simple low cost fix for a 100amp converter.

Yes it was. I still have mine though. PowerMax says they have since upgraded their thermistors. Haven't heard of any troubles since.

The prototype adjustable 100 they cobbled together in 2012 had the big 5R25 thermistor's fat "legs" attached to the thin legs of the original smaller thermistor that had been clipped off.

My repair job was to drill through the circuit board and poke the legs of the new thermistor through to get the thing down to the right height to fit under the lid, and then solder above and below, and clip off the legs sticking out underneath. I am really bad at soldering so I was lucky the thermistor was located where I could get at it by itself on the board.

I have also used a 2R25 thermistor with thin legs which seems to work as well as the big 5R25 with the fat legs, so I don't have to drill such big holes for the fat legs. Problem solved so far.

The big 5R25 thermistor in the prototype was bigger than the regular PM3-100 had back then, but I still managed to blow its thermistor. I blame "hot restarts" and also clamping on the 12v after turning on the 120v input was mentioned by guys here as a possible cause, where that is harder on it.

Now I make sure the 12v is attached first, and if the Honda gen conks out right after starting, I don't immediately restart it and so get the converter back on while the thermistor is still warm. (I have revised my Honda start to prevent that too--now let it warm up for a couple minutes before plugging in the 100 amper so now it doesn't conk out. If it is cold out like 35F, I also start with eco off then turn eco on a bit later after it is all running ok. No more conking out and no more fried thermistors either.)

I reported on my thermistor tests some time back. What was strange to me is that the converter still worked ok even though the thermistor was partly damaged. I got several starts out it before it got so damaged the converter would not start any more. The big black disk first gets a crack or two and it can even show a red hot spot glowing before shutting it off. Pieces fall off. It still works! But when enough pieces fall off, that's it. :)

BLF

A while back you posted a thread regarding a blowup thermistor on one of your converters.

Was that Converter a PowerMAX PM3-100?

The reason I ask, Just received one requiring service and noticed an aftermarket thermistor was soldered in from the top. Remembered you mentioned your soldering ability and wondered if it was your old converter.

The real problem was a shorted FET which is a simple low cost fix for a 100amp converter.

That's the big question. Is it fixed? If not, it will probably take an hour before it gets to 14.8V.

smkettner wrote:


I would be curious if amps still sag as PD is known for.