Converter Performance

[ScottBrownstein]

When boondocking, I have always blamed the 20 feet of #6 in my coach for maxxing out my 70 amp converter at 36 amps or so, even when I force it into boost mode. However, looking at the specs from Progressive Dynamics, I see that they rate a PD9270 at 70 amps at 13.6 volts. I find no spec on the current capacity at 14.4 in boost mode. Has anyone ever seen better performance in boost mode from their converter?

[WolfWhistle]

Hey Scott, I am looking at the specs on the PD4590. It shows voltage at max load is 12.6 volts and no load voltage at 13.6 vdc. I have never measured it other than to function check it. I actually use a solar and Magnum inverter charger for charging duties and when trigger voltage is reached (12.4)... because solar can't keep up. Magnum states this model is 100 amps at 25 degrees C. That is all I can find. When Bulk mode is entered, the Magnum current rises to the 80 amps (the limit I set) at the start which fairly quickly begins dropping as voltage rises to absorb set point. I think it's putting out about 20 - 25 amps when 14.8 set point is reached. But, its been awhile since I've paid attention to it. My camper is in the shop with another Dometic A/C failing, but when its back, I'll look at what the 4590 does.
WW

[ScottBrownstein]

This is what I am getting right now. Planning on upping the feed line to #1, connecting directly to the battery and putting a chassis ground within a couple of feet from the converter. Hoping for something better than this, but I doubt I will see much more than 40 amps at boost voltage.

[rockfordroo]

Remember that the 70 amp output is what the converter is capable of supplying to ALL the loads, i.e., lights, water pump, battery, etc. The actual number of amps to any load is a function of the voltage at the load and the loads resistance. The number of amps your battery, as just another "load," will draw is related to the voltage at the battery and the battery's state of charge. You could increase the size of the conductors to the battery from #6 to, say, #1. This will increase the voltage at the battery by about 3%, which will increase the amperage by about the same 3%. But as the battery charges its internal resistance increases and the current flow will drop.

Here's a voltage drop calculator where you can see what wire size changes will do for you:

Voltage Drop Calculator


So going to a larger wire will improve things some, but if you're expecting your converter to put all 70 amps to the battery, you're expecting too much.

[johnbryanpeters]

Scott, what are you measuring with? Nice graph...

[ScottBrownstein]

Have a data logger that connects to the serial output of my Trimetric and use it for all sorts of empirical designs. I used the Trimetric's second battery at the output of the converter and the current and voltage at the battery are from the standard Trimetric measurement points. The only thing the converter was feeding was the battery and I imputed the line resistance from the current and voltage drop shown.

Thinking of "moving my batteries" by rewiring with #1 from the rear converter to the bank, but wondering what I will get. Certainly won't be 70 amps at 14.2 volts.

[johnbryanpeters]

Originally Posted by ScottBrownstein

Have a data logger that connects to the serial output of my Trimetric and use it for all sorts of empirical designs. I used the Trimetric's second battery at the output of the converter and the current and voltage at the battery are from the standard Trimetric measurement points. The only thing the converter was feeding was the battery and I imputed the line resistance from the current and voltage drop shown.

Thinking of "moving my batteries" by rewiring with #1 from the rear converter to the bank, but wondering what I will get. Certainly won't be 70 amps at 14.2 volts.

Thanks. I would be interested in the details, specifically what data logger and how you got the serial data into it. I have the TM-2030RV-F, but have not gone through the learning necessary to process the serial output.

[rk06382]

Originally Posted by ScottBrownstein

This is what I am getting right now. Planning on upping the feed line to #1, connecting directly to the battery and putting a chassis ground within a couple of feet from the converter. Hoping for something better than this, but I doubt I will see much more than 40 amps at boost voltage.

I don't know about your system but on my FR3 I also have a PD9270. The 6AGW wires first go to the 12VDC power panel. Then it goes to the shutoff, then to the battery bay.

In the battery bay it passes a 50 amp breaker before getting to the battery. I will never get 70 amps to the battery if it goes through a 50 amp breaker.

Have you looked to see what size breaker you have?

Just food for thought.

[ScottBrownstein]

I think my breaker is slightly larger, but with that long path, it would never get to more than 40 amps anyway. I am going to move it so that it goes directly to the bank and I have a 1000 watt inverter piggy backed to it as well. I also dislike the fact that the disconnect has to be on to charge the bank.

Just wondering what I will get but I am convinced that PD won't push that much anyway since they are rated for 70 amps at 13.6 and they don't have enough guts to push that much at 14.3. Either way it will shorten my genny run times.

[rk06382]

Originally Posted by ScottBrownstein

I think my breaker is slightly larger, but with that long path, it would never get to more than 40 amps anyway. I am going to move it so that it goes directly to the bank and I have a 1000 watt inverter piggy backed to it as well. I also dislike the fact that the disconnect has to be on to charge the bank.

Just wondering what I will get but I am convinced that PD won't push that much anyway since they are rated for 70 amps at 13.6 and they don't have enough guts to push that much at 14.3. Either way it will shorten my genny run times.

I choose to install a Inverter/Charger with both shore & genny connections. My Samlex will go as high as 100 amp charge. It was just installed in the compartment next to battery bay. I am programing the settings for my Battle Born LiFePO4 batteries.

[Skyliner]

It is easier to run romex with 120 V AC to a converter moved next to battery bank then running heavy gauge wire.

[rk06382]

Originally Posted by ScottBrownstein

When boondocking, I have always blamed the 20 feet of #6 in my coach for maxxing out my 70 amp converter at 36 amps or so, even when I force it into boost mode. However, looking at the specs from Progressive Dynamics, I see that they rate a PD9270 at 70 amps at 13.6 volts. I find no spec on the current capacity at 14.4 in boost mode. Has anyone ever seen better performance in boost mode from their converter?

Back to the original questions about the PD9270. Has anybody installed the remote for the PD92201V Status Remote?

AMAZON: Progressive Dynamics PD92201V Status Remote Pendant for Inteli-Power 9200 Series Charger/Converter $14.74

[ScottBrownstein]

Originally Posted by rk06382

Back to the original questions about the PD9270. Has anybody installed the remote for the PD92201V Status Remote?

AMAZON: Progressive Dynamics PD92201V Status Remote Pendant for Inteli-Power 9200 Series Charger/Converter $14.74
Attachment 172049

Yes I have and it works well...as advertised. Wouldn't be without it boondocking.

[ScottBrownstein]

Originally Posted by Skyliner

It is easier to run romex with 120 V AC to a converter moved next to battery bank then running heavy gauge wire.

Of course it is, from a purely electrical standpoint. However, there are good design reasons on many FRs for the power bay to be in the rear and for the converter to be there along with at least one inverter. In addition, there is no dry, protected space near the batteries.

However, what's the big deal about 15 feet of #1 ga cable? A voltage drop of 120 mv, less than 1%? $30 worth of cable? There are guys out there with 4/0 where 1/0 or even #2 would have worked just as well. That is what they make good DC cable for.

[rockfordroo]

Before you do anything rash, do the math with the calculator I posted in Post #4. But don't look at the end result. Look at the result with the #4, then look at the result with the #1, and subtract them. You want to look at the amount of difference (i.e., the improvement gained by going from #4 to #1). Then decide if that small amount of improvement is worth the effort.

For example, using #4, copper, 12VDC, 20 ft long at 30 amps, the voltage drop is 0.3 volts. Changing just the wire to #1, the voltage drop is 0.12. So your wire change effort will really only buy you 0.3 - 0.12 = 0.18 volts at the battery.

[ScottBrownstein]

Wow...I found another guy here who doesn't own copper futures!!! I agree, did the math already. Switching to #1 AND grounding at the converter will cut the round trip more than by a factor of 2, more like a factor of 3, since I skip going to the panel as well.

I never overdo wire gauges, otherwise I would be talking about 4/0...like the rest of them.

Thanks for taking the interest.

[WolfWhistle]

Scott, excellent idea to use Battery 2 to monitor the converter / charger. I am curious how my 90 amp converter will do, as soon as I get it back from Camper's Inn. When I went to 50 amps and the 4590, I ran #1/0 from the B+ bus near the inverter charger / batteries to the converter and if memory serves it is 17 feet A to B and a short #1/0 to the frame directly below the converter. I had it laying around and thought what the heck. The PITA was reducing wire gauge to fit the converter lugs. I think I did this by using both sets of lugs on the converter and 4 AWG and spliced them to the #1/0. I used two of these suckers.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

WW

[ScottBrownstein]

Right, Kendar (new owner, bought it from Ralph) at Bogart liked that idea as well. He has been helpful when I have questions that go deeper than the documents. I have been lobbying him to upgrade the color scheme on the RV version so that it looks a little nicer in a modern coach. He has his work cut out for him but I keep him appraised of what I am doing. There is a lot that he could do to compete with Victron et al, especially with the level of interest in RV and general solar power.

Obviously I am a big Bogart/Trimetric fan, especially the more I know about them.

[Newfiestang50]

Originally Posted by Skyliner

It is easier to run romex with 120 V AC to a converter moved next to battery bank then running heavy gauge wire.

Yup....i just installed my new Xantrex inverter/charger right next to battery bank for that same reason.