Converter operation

[samTummo]

I installed two Duracell 6v Golf cart batteries at 12v, 235ah. Also an Aili v/a/ah/capacity level. I watched my WFCO 8955, in my 2015 FW Cherokee Limited, charge it at 13.65v at 9amps, then 2amps, then .5 amps in about 24 hours. All readings had 3 digits after the decimal, hence the +- after readings. Assuming the batteries were close to full when purchased, it was topping off the charge. After 24 hours, still charging at +-13.65v, +- @.5amps the battery disconnected read 13.11v after about 4 hours of rest.

The questions I have are, I thought the converter was a three stage and the voltage would change from 14+v, to 13.6v, then 13.3v. Is my converter working correctly?

And should my batteries read 13.11v At rest, or are they overcharged?

Thanks in advance, Samtummo

[TitanMike]

Originally Posted by samTummo

I installed two Duracell 6v Golf cart batteries at 12v, 235ah. Also an Aili v/a/ah/capacity level. I watched my WFCO 8955, in my 2015 FW Cherokee Limited, charge it at 13.65v at 9amps, then 2amps, then .5 amps in about 24 hours. All readings had 3 digits after the decimal, hence the +- after readings. Assuming the batteries were close to full when purchased, it was topping off the charge. After 24 hours, still charging at +-13.65v, +- @.5amps the battery disconnected read 13.11v after about 4 hours of rest.

The questions I have are, I thought the converter was a three stage and the voltage would change from 14+v, to 13.6v, then 13.3v. Is my converter working correctly?

And should my batteries read 13.11v At rest, or are they overcharged?

Thanks in advance, Samtummo

Were voltage readings take at the battery or from the converter end? That would include any electrical source like a cigarette lighter type power port.

It sounds like you are experiencind the well known shut down of bulk rate due to voltage drop from converter to battery.

Only two cures. A larger wire betwern converter to battery or move converter clise to battery. The latter usually requires a new, floor mount converter.

[tomkatb]

4 6 volt interstate batteries. Standard rv charger.

First camp out of the year. Batteries at about 12.1 volts after winter in Ohio.

Plugged in. Converter never went into bulk mode. About 48 hours charging at About 13.8. The shifted to 13.1. Recording voltmeter.

Current voltage over 12.6. Been that way for years. Often wondered about heavier cables between the converter and batteries.

My converter has only gone into bulk one time. Dealer turned on a closet light. We found it a month later.

Also wondered about a better converter.

[samTummo]

Originally Posted by TitanMike

Were voltage readings take at the battery or from the converter end? That would include any electrical source like a cigarette lighter type power port.

It sounds like you are experiencind the well known shut down of bulk rate due to voltage drop from converter to battery.

Only two cures. A larger wire betwern converter to battery or move converter clise to battery. The latter usually requires a new, floor mount converter.

The Aili meter is the only draw on the batteries when isolated with cutoff switch. The readings of the converter were at the batteries. Does the resistance in the inadequate feed line increase with the heat of the wire?

Thanks TitanMike
Samtummo

[samTummo]

What would be the most economical way to replace the converter out line? What size wire? The converter is about 30’ from the batteries.

Samtummo

[TitanMike]

Originally Posted by samTummo

What would be the most economical way to replace the converter out line? What size wire? The converter is about 30’ from the batteries.

Samtummo

For 30 feet I'd first find the size of the lugs where your existing wire connects to the converter. If the power center and converter is a WFCO, the positive connection is at the bottom of the circuit board that has all the fuses. Remove the cover and you'll see it. You can measure by removing wire and then gauge the lug with the non cutting end of drill bits. When you get the size just consult an online AWG wire dimension chart.

In my TT I used #4 awg welding cable I bought on Amazon. Not terribly expensive and various lengths are available. ON your RV I would go with the absolute largest wire that will fit the lug described above.



I didn't try to follow the existing wire in my TT, I just routed it down from the converter, through the floor, and ran it along the frame. To protect it from chafe or cuts I inserted the wire inside a piece of industrial air hose. 1/2" ID is easy to feed the wire through.

Crimped lugs can add expense unless you have a crimper or a friend does. I spent about $35 for a cutter/crimper set (crimper looks like bolt cutters) along with some crimp connectors, again all from Amazon.

Don't forget to get enough of whatever wire to upgrade ground connections at the frame on both ends.

You might also consider changing Converters and get a floor mount that cam be mounted near/next to the batteries. You'll still have the job and expense of running some romex from the circuit breaker feeding the converter to it's new location.

[babock]

Originally Posted by tomkatb

Plugged in. Converter never went into bulk mode. About 48 hours charging at About 13.8. The shifted to 13.1. Recording voltmeter.

What makes you think it never went into bulk mode? How much current was it charging at?

[babock]

Originally Posted by samTummo

The questions I have are, I thought the converter was a three stage and the voltage would change from 14+v, to 13.6v, then 13.3v. Is my converter working correctly?

The way the converter works is as follows:


1) Bulk mode is constant current mode. It puts out as much current as its max spec until the converter sees 14.2V or so on its output.


2)Then it switches to absorption mode. For converters, that's a constant voltage of 13.6V until the current drops to a small amount.


3) Then it switches to float mode. As long as there is little current it stays in this mode.


The problem is if you have a lot of voltage drop between the converter and the battery, under high current conditions in bulk mode, the converter may see its output go up to 14.2 and knock it out of bulk. The battery voltage, however, never makes it to 14.2.


A lot of people think their converter was never in bulk because they never see over 14V. The voltage drop is the reason for that. Also, you only see 14.2 in an instant. During the bulk phase, your voltage will be much lower and rise as the battery receives constant current.