One charger not working

[Jon Wehrenberg]

Jim,I am almost certain that Liberty charges in the auto start mode by time(6 hours) and not by voltage,they assume that if the generator runs for 6 hours the batteries are fully charged.

Jack, if that can be verified then the starting voltage can easily be modified with a resistor in the sense circuit. (Our guy Peter V can probably figure out the value of the resistor if we stop picking on Marathons).

The only problem then is the question about the six hour run time. It won't hurt anything except burn more fuel than required.

[jack14r]

You are right Jon,on my last trip I noticed that the generator auto start did not activate until the voltage was below 22 volts,this is by all gel battery manufacturers far below their 50% discharge point.I was told by the owner of watchdog Russ Churchill that Liberty did their charging by time.Jon,what do you think would be the time to charge 6-8D AGM batteries if the auto start were activated at 24.2 volts and my chargers are set up for 18 and 10 amps of incoming AC,I can change the outbacks to charge the AGM batteries to 100%.I can change the voltage and time for bulk as well as float.Bill at Liberty said that he would help me change the watchdog program but he has not gotten back with me yet.The newest watchdog has web pages in it that can be modified by the user with a computer but it will not plug into the older watchdog.Bill is trying to get it to plug and play with the old system.

[truk4u]

Jack,

I just finished some inverter updates and new AGM's and here's a couple numbers for you relating to Lifeline:

Charge - 100%
Bulk/Absorbtion - 14.3
Float - 13.2

On my CC and Marathon with large battery banks, 3+ hours was about the normal charging time to get to float. My Liberty gets there in about 2 hours with 125 amps DC charging that steps down as batteries charge. My start point is 12.2.

Keep us posted on the Watch Dog settings, mine is probably too old to easily change the start voltage.

[jack14r]

truk,I will try to call Bill tomorrow and see if he has made any progress yet.

[jack14r]

I called Bill at Liberty and he said he was still working on getting electronic applications(watchdog) to agree to modify the older style unit.I also asked if there was any way the newer unit would plug and play in place of the old unit,he said he did not think so and that the new unit had not been very reliable.At the end of the conversation we talked about charge times that I want and he said that he would call watchdog again and call me back.

[Jon Wehrenberg]

Jack,

We would have to do the math on time based on how the inverters are set up and this may vary per individual.

I have my inverters set up for the lowest charge rate. We rarely dry camp, or if we do I leave my generator running. No sense dragging it around with me If I will not use it. Others only want to run the generator when the batteries need charging. So rather than me changing my dip switches to a different charge rate i prefer to leave them and then I know I can plug in at a campground, run a bunch of electric stuff on my 120 V AC circuits and not trip the 50 amp breaker.

You may want to modify the time, and set the rate of charge to the preferred 18 and 10 amps. I think the timing is going to be based on when the autostart kicks in, and what other 24 V loads you are using.

If autostart kicks in when you are using your tivoli lights and you have other inside house lights lit the batteries have a fairly good sized load. But if autostart kicks in when the coach is dark you have very little load on the batteries. I almost think this is something that can be tested. Run the batteries down to your target voltage, kick on the generator and see how long it takes to fully charge them, both with the lights on and without.

I think Truk has the right start voltage. (double it for yours)

[jack14r]

Jon,I have done some calculations and without any loads I think that 3 hours is enough but the safe bet would be 4 hours.Bill confirmed today that the watchdog uses time as the charging parameter.

[GDeen]

The Trace system on my Marathon shows a time set by the user for bulk charging. It is currently set at 3 hrs. The Marathon owners manual however says it charges on bulk until the batteries reach a threshold voltage.

Also noticed that after a power problem at Kerrville caused us to draw the batteries down, inverter #2 was in bulk charge mode longer than #1 which would seem to indicate it is not a set time.

Any comments from the Trace / Marathon guys on this?? Need to carve out a couple of days to read the Trace manuals and figure it out.

[Jon Wehrenberg]

Gordon,

This site is a wealth of information and if you follow the information here your batteries will last a long time.

The chargers should get out of bulk charge as soon as a voltage threshold is reached. It is important to charge to the correct voltage, but it is also correct to step down as soon as that is reached.

http://www.windsun.com/Batteries/Bat...ting%20battery

[GDeen]

Thanks Jon.