Hello all,I am trying to figure out what the max power output of a PD 9145 converter is before its brain decides there is an overload condition- and also, what it does to solve that.through my experimentation, I have attached short chunks of #4 wire with lugs directly to my 2 golf cart batteries, brand new, discharged to about 50%. With my DC clamp meter, I measured 47 amps @ 12.6 volts when i plugged in the converter to an ac outlet. The charge wizard pendant had also been installed on the unit.My question is, just how low will the converter output voltage get in order to control current to the max 45 amp output. The paperwork says the converter's full load current is rated at 45 amps and about 12.6 volts. I understand the fact that at the batteries state of charge rises, so will the converter voltage until max 14.4 is reached at full current, and then the battery demand will taper.So what if someone has maybe 4 or six golf carts which will demand significantly more than 45 amps if heavily discharged? surely the converter would have to drop to maybe even 12.0 volts or lower to control the charge current from climbing past max output. Would the PD9145 simply consider this overload condition if the batteries demanded too much current at a voltage below the 12.6 min spec? And does the converter shut off completely at this point?

Great question. I have not seen an answer. I have also never read a issue of a smallish converter overloading and shutting down even with a large battery that needs significant charging.Reality is that as you go below 50% the internal resistance of the battery is climbing fast so the demand does not increase as much as you may think. If you would to get 90% discharged you may not even get 45 amps into the batteries.I can say my 35 amp WFCO will charge my 4x GC2 just fine from 50% and even less.

I don't know about the PD 9145, but battery chargers in general are current sources, not voltage sources. They output a fixed current. As the voltage rises, they'll sense that and then begin to taper off the current until it's fully charged. They may then switch to a constant voltage mode to maintain a float voltage. So with more batteries, the current would stay fixed at 45 amps, but it would take longer for batteries to charge.

I am using a P9260C 60AMP Converter/Charger here and have two banks of GP24 12VC Interstate 85AH batteries, One battery bank only has one working 12VDC Battery in it.I will run down my batteries to around 12.0VDC over night and when I first fire up my generator running the PD9260C Converter/charger I will see 14.4VDC on my BATTERY MONITOR PANEL reading both selected battery banks and my DC CURRENT meter is reading around 53-54 DC AMP. This is telling me my selected batteries are demanding around 18AMP DC current each when first hit with 14.4VDC. This sets in this mode for two hours showing 14.4VDC and DC current starts tapering off after around 15 minutes. The DC current slowly tapers back to around 8AMP DC CURRENT in the two hour period. After two hours the PD9260C switches to 13.6VDC and the DC current drops to around 6AMPs DC. It will remain in this mode for about an hour and then gets to it 90% charge state. If no current drain is being detected from the trailer side then the PD9260C will drop back to 13.2VDC but as soon as current start being drawn then the PD9260C will revert back to it 13.6VDC mode.This is basically what I see each morning on my battery monitor panel when camping off the battery banks. Pretty much follows the battery charging chart shown in the PD9260C manual.Roy Ken

Batteries do not demand current. Batteries accept current, and only if it is available to them.You can have a hundred 1/2 dead batteries, and the 45 amp PD will just take 100 days to charge them at 45 amp max.Now if you get into a demand situation, like dumping a 60 amp load on a 45 amp converter, well,.... just don't do it, ok,....because something is going to break,.....and I'm not sure what.

The converter has a max power and that's it. It does not "overload".Within that max power, you get its rated amps at the spec voltage which in the PD's case is 13.6 volts. It will have some extra power so you will get more at the start, but the PD has some circuitry thing where it can't quite hold 45 amps at 14.4 volts so it tapers the amps a bit at the start in 14.4v mode. some other converters and chargers can hold their rated amps steady "constant current" until the battery reaches the set absorption voltage. then amps will taper once voltage is held constant in that stage.The exact way it all happens for different chargers is called their "charging profiles" and those vary among brands somewhat.The PD and the other brand converters will do a little more amps than the "name" size. Eg my 7355 will do 56 amps, my old Paramode 55 did 60, and my PowerMax 100 does 103 given low resistance paths to the battery.So don't worry how many batteries you are trying to charge. As was noted earlier in the thread, it will do 45ish amps max no matter how big the battery bank is.EDIT--RJ, the 60 amp load will be on the battery not the 45 amp converter, so all that happens is your battery will get 45 amps in while that 60 amp load is running for a net loss of 15 amps. Nothing will break.

Progressive Dynamics - max current before overload

14 Replies

RJsfishin
Explorer
Mar 29, 2015
Batteries do not demand current. Batteries accept current, and only if it is available to them.
You can have a hundred 1/2 dead batteries, and the 45 amp PD will just take 100 days to charge them at 45 amp max.

Now if you get into a demand situation, like dumping a 60 amp load on a 45 amp converter, well,.... just don't do it, ok,....because something is going to break,.....and I'm not sure what.
RoyB
Explorer II
Mar 29, 2015
I am using a P9260C 60AMP Converter/Charger here and have two banks of GP24 12VC Interstate 85AH batteries, One battery bank only has one working 12VDC Battery in it.

I will run down my batteries to around 12.0VDC over night and when I first fire up my generator running the PD9260C Converter/charger I will see 14.4VDC on my BATTERY MONITOR PANEL reading both selected battery banks and my DC CURRENT meter is reading around 53-54 DC AMP. This is telling me my selected batteries are demanding around 18AMP DC current each when first hit with 14.4VDC.

This sets in this mode for two hours showing 14.4VDC and DC current starts tapering off after around 15 minutes. The DC current slowly tapers back to around 8AMP DC CURRENT in the two hour period.

After two hours the PD9260C switches to 13.6VDC and the DC current drops to around 6AMPs DC. It will remain in this mode for about an hour and then gets to it 90% charge state.

If no current drain is being detected from the trailer side then the PD9260C will drop back to 13.2VDC but as soon as current start being drawn then the PD9260C will revert back to it 13.6VDC mode.

This is basically what I see each morning on my battery monitor panel when camping off the battery banks.

Pretty much follows the battery charging chart shown in the PD9260C manual.

Roy Ken
Roadpilot
Explorer
Mar 29, 2015
I don't know about the PD 9145, but battery chargers in general are current sources, not voltage sources. They output a fixed current. As the voltage rises, they'll sense that and then begin to taper off the current until it's fully charged. They may then switch to a constant voltage mode to maintain a float voltage.

So with more batteries, the current would stay fixed at 45 amps, but it would take longer for batteries to charge.
time2roll
Nomad
Mar 28, 2015
Great question. I have not seen an answer. I have also never read a issue of a smallish converter overloading and shutting down even with a large battery that needs significant charging.

Reality is that as you go below 50% the internal resistance of the battery is climbing fast so the demand does not increase as much as you may think. If you would to get 90% discharged you may not even get 45 amps into the batteries.

I can say my 35 amp WFCO will charge my 4x GC2 just fine from 50% and even less.

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Progressive Dynamics - max current before overload

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