OK, I came across two graphs posted here. Both happened to be in Salvo posts but I think one originated with Bigfootford. ANYWAY...I'm sure each graph has been discussed and dissected on its own. I'd be interested in opinions as to which setup won a hypothetical 2 hour race. Graphs shown below. What I think I see is this.IOTA 55, 2x GC nominally 225AH, 50% SOC, C/4 charging rate:First 60 minutes: approx 50AH (to 72%)61-90: +11.5AH (to 77%)91-120: +6.8 AH (to 80%) (ignoring efficiency losses)Total 68AH into 50% 225AH batteryPD9260, 2x Grp 24, nominally 170AH, 50% SOC, nominally C/3 rate:First 60 minutes: approx 42 AH (to 75%)61-90: +12.5AH (to 82%)91-120: +9.5AH (to 88%)Total 64AH into 50% 170AH batteryNot apples to apples. But close enough to draw conclusions? To me it seems like the PD did better. No, it never delivered its rated amps. But in 2 hours it pushed almost as many AH as the IOTA, but into a much tighter box. Am I wrong? Too close to call, you pick em? Batteries too different to be able to say?source post for IOTA graphsource post for PD graph

Hi snow,As you said--very close. Close enough that there is no reason to move from a PD to Iota.Btw my PD 40 amp has never ever done more than 37 amps when in "boost" mode. That includes times when I was running the water heater from the old MSW inverter.I do "see" 125 amps from the Magnum inverter/charger. It can do so from a single 15 amp shore power cord.I have not yet tried running the PD and Magnum at the same time.

I'd like to see a race 1.200 to 1.280 similar batteries, in minutes elapsed.Of course, this would mean, I'm a meanieThis is a real life simulation of generator charging elapsed time which is not hypothetical.

MEXICOWANDERER wrote:I'd like to see a race 1.200 to 1.280 similar batteries, in minutes elapsed.Of course, this would mean, I'm a meanieThis is a real life simulation of generator charging elapsed time which is not hypothetical.What model batteries? And what charge controllers and what Voltages? I think you'd be pretty pleasantly surprised how well that Mega Watt 30 amp set with 8 gauge wire and 15.0V and a 2 foot run to the battery does, time wise. I'd be guessing 5 or 6 hours on a pair of GC-2's. You have to wait a couple of days on the SG to catch up, 3 days worth? It's getting the SG over about 1.265 to 1.280 that eats up most of the time, in my observation. It's just slow going there, you should be running a c/20 rate at the top charge portion, 10 to 11 amps charge rate fixed at 15.0V fixed. Huge waste of fuel spinning a generator for those last 15 points.IMHO, that's what it takes at the end to get that 1.280, if the plates are not sulfated at all.

Go a little big on the PD, 60+ is fine. You need 60 if you want to get 45.A little less on the IOTA, 45 amp is fine. Bulk less than an hour seems a bit much to me.JMHO.With a poor connection PD might be favored as it will hold 14.4 volts for 4 hours and can be reset. IOTA will get tricked and drop voltage to 14.2 fairly quick.Mostly a draw as both are excellent.

You can do better than that with a PD if you use really fat and short wires between it and the battery. However it will taper like that with only a little longer wire while some other actual constant amps chargers will do constant amps in the Bulk stage.http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27651123.cfm

IOTA graph vs PD graph | Good Sam Community

BFL13
Explorer II
Nov 07, 2014
Salvo wrote:
Why is there no warranty for the PM3? Varistors blowing up?

They still list them as one of their products with a 2 yr warranty.

http://powermaxconverters.com/pm3.html

2 yr warranty here (note their 75 is PF)

http://www.boatandrvaccessories.com/powermax-pm3-75-12-volt-75-amp-converter-charger.html

Randy has a 3 yr warranty on his, but AFAIK he doesn't sell PM3s anymore. He sells his version of the PM4 line.
Salvo
Explorer
Nov 07, 2014
Why is there no warranty for the PM3? Varistors blowing up?
BFL13
Explorer II
Nov 07, 2014
jrnymn7 wrote:
pm3 arrived today. i'll do at least one 'normal' charge for comparison, and then the mod, so probably by next weekend.

Mine would not go into boost unless just under 50%. ISTR with the 458AH bank it had to be at least down 235 and 225 wasn't enough

Will you be able tell if that one is PF corrected?
jrnymn7
Explorer
Nov 07, 2014
pm3 arrived today. i'll do at least one 'normal' charge for comparison, and then the mod, so probably by next weekend.
Snowman9000
Explorer
Nov 07, 2014
Salvo wrote:
They think pwm is a special Iota design feature. Pulse width modulation is used in all converters to convert the 170V rectified ac down into the 13 - 14V range.

Interesting, thanks!
Salvo
Explorer
Nov 06, 2014
They think pwm is a special Iota design feature. Pulse width modulation is used in all converters to convert the 170V rectified ac down into the 13 - 14V range.
Snowman9000
Explorer
Nov 06, 2014
Salvo wrote:

And... those guys at the boat forum discussing pwm, don't know what they're talking about.

How so?
BFL13
Explorer II
Nov 06, 2014
They did to the Iota what I did to my PM3. So it stays at the high Vabs till you shut it off instead of dropping to 14.2v. No longer a converter either.

However Iota has always had that jack to plug in that thingy which is also the same jack you plug the IQ4 into. What is new here is that they seem to have altered the little thingy so it will do 15.4 too.

Anyway you can get all the same thing as that with your own Mod-PM3 for half the cost.
Salvo
Explorer
Nov 06, 2014
No problem going down to 13.5V

BTW, I would stay away from a manual charge. The IQ4 addition charges the battery extremely fast. There's not much to be gained.

And... those guys at the boat forum discussing pwm, don't know what they're talking about.

smkettner wrote:
Salvo wrote:
You can increase by 0.1V to get Vabs = 14.3V and Vfloat = 13.7V.
Can you go down? 14.1 might be tolerable to have 13.5 float in hot areas.
Snowman9000
Explorer
Nov 06, 2014
Backwoodssolar sells an IOTA 55 which can run at 14.8 or 15.4 or whatever you might need in the normal range. There is no IQ4 and no float mode. So it is manual charging. They use the plug in jack to enable this somehow. I got this info over the phone from them.

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