PD 9260 how long to charge?

[brulaz]

I've heard that people with the PD9260 (or similar) use the pendant to force the charger to stay in boost mode (14.4V) while running their genny. To get Max charge with min gen time.

Ok, but how do you figure how long to leave it in boost?

Say, in my case, I've depleted the batteries by ~50%, that's 100Ah that needs to be put back in the batts.

The PD9260 is 1000W with output of 13.6 VDC, 60 Amp according to the docs.

How long would it take to recharge the batts at 14.4V?

Or instead of guessing, do you use something like a Trimetrics meter to measure Ah in and out?

[Wayne_Dohnal]

I'm basing what I say on this statement in the Charge Wizard patent:

"In Auto Boost the power converter will run for a maximum of eight hours unless the battery voltage rises above 14.0 volts in which case the power converter will run for four hours after the 14.0 volt level is detected. If the power converter runs eight hours without exceeding 14.0 volts, the power converter switches to the Normal Mode."

If reality differs with this, I defer to reality, plus it looks like my statement about the converter not measuring the output voltage is (as Richard Nixon famously said) "inoperative".

[BFL13]

Wayne Dohnal wrote:

AFAIK (not much) if the PD goes to 14.4 by itself at the start of the recharge, it will stay at that for the time it takes to get the batts to about 97% then drop to 13.6, even if that time is less than four hours, say three hours.

Even if the PD converter measured output voltage and/or current (which it doesn't) to determine SOC, how would it know if its power was going into the battery or running DC loads in the RV? Without measuring voltage and current at the battery it is clueless as to the battery's SOC. It's all timer-based for a particular example battery of an assumed size, assumed SOC, and assumed temperature. If you're not running the generator for more than a few hours, and it's not obnoxiously hot, my algorithm is to run in boost mode whenever the generator is running.

Scroll down to Salvo's post of Fisherguy's results. Time was way less than four hours and seems to be related to SOC

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/24655789/srt/pa/pging/1/page/10.cfm

[tenbear]

tenbear wrote:
I have an ammeter in series with my 115AH marine battery. When the ammeter drops to 5A, I turn off the genny. I think this is better than checking the battery voltage, but is similar since the voltage change is basically due to the resistance of the converter to battery wiring.

That's why I replaced the OEM #8 wire with #4.

BTW, I don't believe that running other 12v equipment while charging the battery will increase the charging time unless you exceed the 60A rating of the 9260 converter. The converter will put out more current while maintaining the 14.4v it sends to the battery. That assumes the converter to battery wiring is feeding only the battery.

[tenbear]

I have an ammeter in series with my 115AH marine battery. When the ammeter drops to 5A, I turn off the genny. I think this is better than checking the battery voltage, but is similar since the voltage change is basically due to the resistance of the converter to battery wiring.

That's why I replaced the OEM #8 wire with #4.

[Wayne_Dohnal]

AFAIK (not much) if the PD goes to 14.4 by itself at the start of the recharge, it will stay at that for the time it takes to get the batts to about 97% then drop to 13.6, even if that time is less than four hours, say three hours.

Even if the PD converter measured output voltage and/or current (which it doesn't) to determine SOC, how would it know if its power was going into the battery or running DC loads in the RV? Without measuring voltage and current at the battery it is clueless as to the battery's SOC. It's all timer-based for a particular example battery of an assumed size, assumed SOC, and assumed temperature. If you're not running the generator for more than a few hours, and it's not obnoxiously hot, my algorithm is to run in boost mode whenever the generator is running.

[BFL13]

The above method will tell you the usual time to get your own bank to 14.4 with your own converter. But what SOC do you think you are at when you first reach 14.4?

As you see in the ugly graph above, the SOC you are at then, depends on your charging rate. (charging amps/AH capacity of bank)

If you use a higher charging rate you get to 14.4 sooner at a lower SOC so you must keep charging while amps are tapering to reach your desired SOC. (this is still faster than using a lower charging rate and getting to 14.4 at a higher SOC as you can see in the ugly graph above)

BTW, the PD bumph states it gets to 90% SOC in Bulk. As you can see, this would only be true if you used a very low charging rate such as 10%. You want a high charging rate when on generator time, such as 25 -30% (higher than that gets you into the vertical part at the left and diminishing returns for time, so 30% charging rate is about it really.)

So if you have two batts, you can get good value from a 70 amper and if you have four batts then you could use a 140amper. Of course more amps means you need a big enough wattage (VA really) generator to run the charger(s)

You can see that with two batts and a 60 amper you will not save much time going to a 70 amper for doing a 50-90. However if you had four batts, your 70 amper is going to be very slow. Generator time is all about charging rates.

[otrfun]

Had the same questions myself. I'm far from an expert on the matter, but I did manage to figure out a way to determine charge times that work reasonably well for my purposes.

I recorded the voltage at the batteries with them 100% charged with the PD9260C in boost/bulk mode. I usually get a voltage very close to 14.4v. To establish a baseline, I purposely discharged my batteries to 50% (12.2v) with the converter turned off. Make sure there's no load on the battery when you make the 12.2v reading. Again, with no load on the system, I turned on my PD9260C in bulk/boost mode and recorded the voltage. At the start of the charge the voltage on my TT is typically 13.5v - 13.6v (YMMV). I made voltage readings every 15 minutes until the voltage got very close to 14.4v. Using these readings, I'm able to determine (accurate enough for my needs anyhow) how long I need to run my generator to obtain a given state of charge. Note, if you load the system during the charge (appliances, lights, etc.) it will lengthen your charge times vs. a charge with no load.

I'm sure those with much more knowledge on the matter will chime in more accurate ways, but this has worked reasonably well for me.

[time2roll]

brulaz wrote:
To get Max charge with min gen time.

97% is a bit beyond "min gen time" IMHO.

[BFL13]

AFAIK (not much) if the PD goes to 14.4 by itself at the start of the recharge, it will stay at that for the time it takes to get the batts to about 97% then drop to 13.6, even if that time is less than four hours, say three hours.

But if you manually put it to 14.4 it goes by a timer for a fixed four hour run at 14.4 and then drops to 13.6 regardless of the state of charge.

So if you think you are at 97% after three hours having used the manual method, then you can use the manual method to put it to 13.6 yourself. If it is not to 97% by the time the four hours is up and it drops to 13.6 you can hit the button again to finish the job at 14.4.

[brulaz]

Thanks folks. As usual the forum has been a big help.

In summary, to replace my 50% depleted 210Ah battery bank back up to 90% with the PD9260:

1) using the graph, go for 2' 20" at 14.4V
2) using the approx. 105/50 = ~2 hrs at 14.4V
3) Another recommendation: 2hrs at 14.4V then 1 hr at 13.6V
4) Monitor voltage. When 14.4V is reached, continue charging at 14.4V for one more hour.

I'll give it a go, monitoring V and Time and see what happens.

There does seem to be a difference of opinion as to what/when the PD9260 will do after being forced into bulk mode. Will it eventually detect that the batteries are close to 90% full and switch out of bulk earlier than I want or just keep on going at 14.4V? I'll keep an eye on that too.

Cheers!

[time2roll]

I recommend charging for one more hour after the converter hits the 14.4 volt target.

[RoyB]

If you have a SMART MODE BAttery charger with ay least DC Current between 17AMPS to 20AMPS DC available then any deep cycle battery will charge up somewhat like PROGRESSIVE DYNAMICS states in all of their brocures...

"Progressive Dynamics ran this test on the amount of time it took a PD9155 (55-amp) converter/charger set to three different output voltages to recharge a 125 AH (Amp Hour) battery after it was fully discharged to 10.5-volts.

14.4-VOLTS (Boost Mode) – Returned the battery to 90% of full charge in approximately 3-hours. The battery reached full charge in approximately 11 hours.

13.6-VOLTS (Normal Mode) – Required 40-hours to return the battery to 90% of full charge and 78-hours to reach full charge.

13.2-VOLTS (Storage Mode) – Required 60-hours to return the battery to 90% of full charge and 100-hours to reach full charge."

battery science at work here - not many ways to get around the times listed above.

The battery will demand how much DC current it will draw from the charger. Doesn't matter if you are using a 60AMp or 80AMPS battery charger as the each battery you are charging will only draw 17-20AMPS each when hit with up to 14.4VDC charging voltages.

My three 12V 85AH Interstate batteries in parallel seems to charge at 52-53AMPS DC from my PD9260C Converter/charger and they get to the 90% charge state in approximately three hours time.

If you use more than 14.4VDC charging voltages then you will run the risk of boiling out battery fluids when being charged for a few hours. Starting out with 14.4VDC for two hours then dropping back to 13.6VDC for another one hours time period will give you the 90% charge state and NOT boil out any battery fluids.

Roy Ken

[RoyB]

oops

[wa8yxm]

Who knows how long to BOOST charge your batteries.... The Wizard knows (Sorry Mr. Cranston)

Though the 9260 is capable of 60 amps. Rarely will you get full output.

Here is a formula, you will need to plug in the proper numbers, Amp hours are at the 20 hour rate.

(Total amp hours) * (100%-(State if charge)%) = (amp hours to replace)
(Amp hours to replace)/50 is a good estimate.

Example: pair of GC-2 230 amp hour at 60% state of charge

230*(100-60)% = 230 * 0.4 = 92 amp hours

92/50, a bit less than 2, so 2 hours (you may round)

Seriously though, the Wizard may take over when the proper level is reached even if you initially overrode it and forced bulk.

From the point where it goes to absorption, another 2-4 hours to fully charge, but if you are boondocking,,, You may wish to skip that last 10 percent SOC.