Help choosing the right converter/charger?

I guess the OP is done, so it is ok to address Roy's concerns.

"I have been using three each GP24 85AH batteries and I have found my total demand from the batteries when first starting my 14.4VDC Boost charge will demand right at 52-53AMPS DC when first hit with 14.4VDC when they are at the the appx 50% charge state....

I see this 53ADC Current for about 15 minutes and then it starts tapering back and in an hours time it will be down to around 8AMPS DC Current demand."

1. There is no such thing as "demand." There is "acceptance." In fact, 220 AH or so worth of battery bank will easily accept well over 70 amps of initial charging.

The 53 amps you see is just the "60 amp" PD converter being its usual lame self in not being able to do its rated amps, and in addition not being able to maintain them at a constant level for the entire bulk stage. Too bad , so sad, it is what it is. Think of it as a 55 amper, being optimistic.

2. 15 minutes before tapering is a sure sign you do need new batteries, which is happening , so that is the good part! (55 amper on a 255AH bank (3 x 85 )with a 55 amper would be at constant 55 for about an hour before batteries reached Vabs and started to taper the amps)

3. Your new bank of four 6s (440AH) will easily take 150 amps or so of initial charging, so there is no sweat about the 60 amper. With just the 2000w generator, which would struggle to run a 75 amper, you should keep the 60 amper. Only get more amps worth of charging for less gen time if you happen to get a bigger size of generator.

You are stuck with a longer gen running time with the 60 amper, but it could be more cost effective than buying a bigger gen and a bigger amp charger, as long as the campground will let you keep running the generator. ( ISTR that is an issue where Roy camps, same as it is here in the provincial parks)

BTW a 50-90 on 440AH will take about 4 hrs and 40 minutes with a 55 amper (Roy's 60 doing what it does)

Clarified
" Specs: 20 hour discharge = 215 AmpHrs, 5 hour discharge = 157 AmpHrs, 6 hour discharge = 156 AmpHrs . Wired series/Parallel "

joem789 wrote:
The PD4655V is a bit pricey to me. But probably well worth it. I wouldnt mind going with one cheaper. But I am not certain how much cutting I would need to do without going with the drop-in upgrade.

That is the one you want if you have a 73XX. Best Converter has a remote specifically for it so you don't have to crawl on the floor to see the mode or take manual control.

You can use any deck mount converter as a portable charger if you are willing to go outside and set up for the battery charging. You just use a cut- off end of #4 copper (or fatter cu-al) jumper cables. Ends go in the converter outputs and you clamp onto the batteries.

I do that with a PowerMax ADJ 100 amp charger on four batteries. I kept the 7355 converter in place for when on shore power. It does that very well.

Thanks for the advice about the Boondocker. I think I will stay with the 55 to 60 amp range. My camper already has a 45 amp. But I am sure it doesn't juice up the wire like the new one will. I am unsure what size wire comes off the batteries running into the camper. I am sure it is whatever is standard on a single battery TT. The PD4655V is a bit pricey to me. But probably well worth it. I wouldnt mind going with one cheaper. But I am not certain how much cutting I would need to do without going with the drop-in upgrade.

45 amp is fine plugged in. On generator I would go at least 55 amps and right up to 80 amps would be great for fast bulk charging four batteries. However you need to review the charging circuit before you go above 45 amps. Common #10 or #8 wire is too small to go big on the converter. Even if the wire does not burn up the voltage drop will cripple the fast charging of any three stage converter. I recommend #4 wire with anything above 45 amps and possibly mounting the new converter close to the battery if possible. PD 9280 deck mount would work great.

www.bestconverter.com/PD-9280C-80-Amp-RV-Converter

Yes if you want the converter to fit in the existing position you may need to stick with 4645, 4655, 9260 converters.

Do not let Randy sell you a Boondocker unless you want a manually controlled unit.

I wouldn't be afraid to put a c/5 charge rate into those batteries. That would be an 86A charge. They may not always be low enough to take that. I would say anything between 50 and 90 amps should be fine. When charging from a generator instead of the grid I think a bigger charger and thus shorter gen. run time is better. A 4 kW generator shouldn't have a problem running even a 100 amp charger.

I have the same problem here with my latest planned battery system upgrade. I have the PD9260C 60AMPS COnverter/charger

I have been using three each GP24 85AH batteries and I have found my total demand from the batteries when first starting my 14.4VDC Boost charge will demand right at 52-53AMPS DC when first hit with 14.4VDC when they are at the the appx 50% charge state (Around 12.0VDC). This is around 17AMPS DC current for each of the three GP24 12VDC batteries in parallel.

I see this 53ADC Current for about 15 minutes and then it starts tappering back and in an hours time it will be down to around 8AMPS DC Current demand.

Then the PD9260C will go to the 13.6VDC Charge mode for the next two hours which will bring my three GP24 85AH Interstate batteries back up to their 90% charge state.

My new battery bank will have two groups of 6VDC GC2 batteries in series that will give me around 440AHs at 12VDC. I was hoping to find out how many DC Amps the groups of 6VDC batteries in series will demand from the charger.

My PD9260C is perfect for using my 2KW Honda generator providing 120VAC when camping off grid so hoping I will be ok using the 60AMP converter/charger. I am also hearing that the GC2 batterie like the Trojan T-105s which I am going to be using wants to see 14.8VDC boost charging voltage. I will only be providing 14.4VDC so I am planning all will be fine but will take a little longer to get from the 50% charge state to the 90% charge state.

I haven't got my batteries yet so will have to wait until I do to see if my planning on keeping the PD9260C is going to be ok...

The most I hear from other folks is that they use the PD9260C with their GC2 batteries and it works just fine haha

I will know more this coming spring when I can afford to purchase the four each Trojan T105 batteries for my new metal battery box setup...

this is what my three GP24 Interstate Batteries look like in parallel on my POPUP trailer tongue area...


Roy's image

If they were 12VDC batteries like my 85AH GP24 Interstates I would say base your converter/charger on having enough capacity for suppling 17-20AMPS DC Current for each 12VDC battery in parallel if you want to gain the 50% to 90% charge state in a three hour period of charging... If your total current is less that the 17-20AMPS DC current per battery the batteries will still charge just take longer to happen... This has been my experience at any rate...

Roy Ken