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Batt Charging:Does 50a make a difference?

August 21, 2012, 10:42:13 am

The weather up along the Great Lakes has been nice enough that I had been happy with 30A. No AC required at night and often cold..

We tried to stick to our "drive 3 hours, stay 3 days" regime, thus alternator charging relatively often.

Then we spent 6 days way back in the woods, drove 80 miles, and spent 7 days in the City campground in Marquette, Mi. All on 30A.

Symptoms:
When I went to start the coach ('96 295) in Marquette the dash voltmeter was in the questionable below 12V range and I had to use the boost switch.

We drove 4 hours to De Pere, WI (just outside of Green Bay).

A short time after arrival the dash meter was above 12V (I expected the alternator to have done that).
The new campground is 50A
I checked the start batts with my voltmeter - 12.67.
I checked the Trick-L-Start device - Maintaining.

Today , 2 days later, the start batts read 13.4, as I expected them to in the absence of problems.

Status:
I haven't as yet checked the connections to the Trick-L-Start.
The Battery connections are nice and tight.
I haven't gotten out the wiring diagrams as yet.


Questions:
Is there a reason that the Inverter/Charger would act differently if on 30a than on 50?
I can't imagine it.
Why might the Trick-L-Start not charge the start batts?

When will it get cooler back in Texas?

thanks for suggestions.

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Re: Batt Charging:Does 50a make a difference?

Reply #1 – August 21, 2012, 11:47:06 am

20/30/50A should make no difference on your battery charger/inverter, providing it did not trip the breaker at the power source. I have had mine trip a 20A if the house batts are low when you plug it in. Sounds like you may have a engine charging system problem, after a 3 hour run I would expect to see the chassies battery readings some where around 13.2-13.8 V when you first shut the coach off. Your trick-L start unit will have a hard time keeping your batt's up if the alternator is not working correctly.

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Re: Batt Charging:Does 50a make a difference?

Reply #2 – August 21, 2012, 02:09:50 pm

If you are changing locations after boondocking for three days (no electrical hookups) and expecting your batteries to reach full charge in three hours, I believe you are expecting a lot.  If you are trying to recharge, three discharged coach batteries plus a probable discharged engine battery in just three hours of running it is a big job that would take longer than that.
Is there a reason you are not using your diesel generator to charge the batteries prior to moving?

Need more detailed information:
When you were in the woods for six days, were you hooked up or just running off the batteries or charging with the diesel generator?

Do you have an 8D starter battery or what?

What equipment are you using to monitor both of your battery systems? 

Check the output of the 120v outlet where your Trickle Start is plugged in and verify that you have voltage to it when operating on only a 15 amp or 30 amp pedestal.  Some rear outlets only work on 50 amp hookups.

My guess is that you only have a 130 amp alternator.  Or do you have a 160 amp?

Are you now on a 50 amp pedestal in De Pere

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Re: Batt Charging:Does 50a make a difference?

Reply #3 – August 21, 2012, 07:34:20 pm

RE: "Questions: Is there a reason that the Inverter/Charger would act differently if on 30a than on 50?  Why might the Trick-L-Start not charge the start batts?"

Temperature compensated battery chargers, like almost all of us have in our coaches, lowers charge voltage when temps increase and increase charge voltage when temps decrease.

When the battery with the temperature probe is about 100 degrees, charge voltage decreases to about 13 volts.

Trik-L-Start and other similar devices, charge start battery bank at about a half volt lower than house battery bank.
13 volts minus 1/2 volt is about 12-1/2 volt, which is too low to charge house battery bank.

Much of the country is seeing 100 degrees in battery bays, so it looks like global warming can now be blamed for the starvation of batteries around the world.

Also batteries may charge to about 80% of capacity in several hours, but may take 24-48 hours to fill up that last 20%.
Battery chargers will work equally well on 20, 30 or 50 amp shore power.

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