Battery charging voltage is low

[anditg]

The PD4045 installed in Jayfeather 19H does not deliver the required charging voltage to my battery. The roundtrip wiring resistance between the PD4045 and my battery is relatively high (~0.035 ohms). This amount of wire resistance causes a 0.7 Volt drop when drawing 20-amps. That amount of voltage drop (0.7 Volts) is significant when charging batteries. Has anyone else had this issue? I am considering the purchase of an external battery charger that I connect directly to the batteries. Thanks, -Mike

 

[DanNJanice]

The PD4045 installed in Jayfeather 19H does not deliver the required charging voltage to my battery. The roundtrip wiring resistance between the PD4045 and my battery is relatively high (~0.035 ohms). This amount of wire resistance causes a 0.7 Volt drop when drawing 20-amps. That amount of voltage drop (0.7 Volts) is significant when charging batteries. Has anyone else had this issue? I am considering the purchase of an external battery charger that I connect directly to the batteries. Thanks, -Mike

You could use an external charger, but I think you will find that to be a bit of a hassle. Better would be to find the caused of the voltage drop. Remember, since you see that drop when charging, you will also see a drop when running only off of batteries (IOW, boondocking), which could actually be a bigger issue. I would check ALL connections between the battery and the convertor. Including frame grounds, terminals, fuses, and wire sizes. Since it is a small trailer, it might even be possible to just run new larger wires between the battery and convertor.

 

[us71na]

20 amps is a pretty high charging current are you sure the battery is any good? It sounds like you may have a shorted cell. What voltage are you actually seeing at the battery when it is charging?

 

[Mustang65]

Try pulling your main 30 amp fuse by the battery.. let it sit for an hour or 2.... and take a voltage reading of the battery with no load on it.

The battery should be between 12.6 and 13.2 volts.

Then put put the fuse back in and take a reading with no charge controller just the TT load.

Then turn on the TT's charge controller on. What is the battery voltage.

If you have a large load on the battery, pull all your 12vdc fuses in the panel and start replacing them one at a time to see which one has a large load on it

The

 

[RoyBraddy]

I would just run a 4AWG cable between the converter/charger unit and the battery. You will most likely add a second battery soon anyway... Having two batteries really make a difference when camping off trail...

ANCOR Marine cable can be purchased in 25-foot spools from ebay sales stores for around $50. This cable is very flexible... Also get a couple of ANCOR type RING TERMINALS and once you figure out how long your cable needs to be you can take it any number of automotive stores and have the ring terminals crimped in place with weather tight adhesive heat shrink ends...

The three smart mode charging DC VOLATGE should be 14.4V-13.6V-13.2V... coming from your PD4045 with a capacity of 45AMPS DC Current. A typical battery fully charged state should read 12.6-7VDC...

Roy Ken

 

[anditg]

Thanks to all for the quick and great advice. I will check the connections and then probably install a #4 wire from the PD4045 to the battery. I will feedback any info I discover on the connections. -Mike

 

[anditg]

I am finally finished diagnosing and partially remedying this voltage drop issue while charging the battery. I installed a 20-ft #6-AWG directly from the PD4045 to the battery box ... replacing the 10-ft 8-AWG + 10-ft 10-AWG that Jayco had installed. I also replaced the ground lug from the trailer frame to the battery negative.

I still have about 0.4 Volt drop when drawing a 20-amp charging current. This remaining voltage drop is primarily caused by the switch and the in-line fuse I have at the battery box. This voltage drop diminishes as the charging current falls off ... so I am thinking maybe it will not be a big problem ... it will slow the charging a bit ... but eventually the battery will see the full charging voltage ... and that might be OK.

The more interesting issue is that the PD4045 only gets switched to the full bulk charging voltage (14.4 Volts) when the battery voltage is <11.7 Volts. But I like to charge my batteries when the voltage falls below 12 volts. Fortunately I discovered that if I operate the electric tongue jack for a few seconds while plugging the trailer into the generator (or other power source) ... the battery voltage drops ... and the PD4045 switches on to the full 14.4 volts ... and stays at that level after stopping the electric tongue jack.

I may still purchase an external charger as a backup or for when I need quicker charging.

Thanks again to all for the advice, -Mike