Battery condition?

[Cowdog353]

Will be camp host at Sprong Creek campground on Lake Hebgen west of west Yellowstone park from June 1 until? .

Anyone have any information about this campground?

if your up this way stop by and say hello.

i understand there is a vault tolilet , no electric and no water on site. Water available down the road?

i will be on solar with genset backup,  wish me luck

Jim

 

[Cowdog353]

I have (2) 6 v 225 ah batteries with 280 watts of panels controlled by a trimetic sc2030 and with the rv 2030 battery monitor.   My question is, or better ear yet I am asking for your opinion.

i started with a 100% charged batteries which showed 12.8 v without charger on or sun providing any voltage. I started a 7 amp coffee maker and watched the voltage drop to 11.1-11.2 while brewing. After the brew cycle the voltages returned to 12.7v.. The percent of charge started at 100% and dropped to 98 % .  I repeated this again with a kurg type coffee brew and again voltage drop was same with another 2% drop in charge left. 

I am thinking the voltage drop to be excessive..  Your thoughtS.   I don't know the history of the batteries. 

 Your thought opinions are appreciated 

jim

[Chad Heiser]

Older/weak batteries can have significant voltage drops when under load and then rebound when the load is lifted.  Even new batteries will drop under short heavy loads, but the drops you are recording seem excessive and make me think your batteries are somewhat old/weak.

[Lou Schneider]

Is your coffee maker 7 amps at 12 volts (84 watts) or 7 amps at 120 volts (840 watts) through an inverter?

If it is the latter, the load on the batteries when the coffeemaker is brewing is more like 70+ amps and what you're seeing sounds perfectly normal for a good pair of 6 volt batteries.

[Cowdog353]

It a little over 6.5a AC which showed about a 80a DC load to the inverter.

thanks for the replies.

[Kirk W]

8 hours ago, Lou Schneider said:

If it is the latter, the load on the batteries when the coffeemaker is brewing is more like 70+ amps and what you're seeing sounds perfectly normal for a good pair of 6 volt batteries.

I suspect that Lou has it nailed. Our Kureg shows 1500 watts at 120V which would be 1500W ÷ 120V = 12.5A 

EDIT:   Looks like we doubled. Remember that when you use 120V power supplied by an inverter, the power used remains the same but the passage through the inverter is a multiplier. The formula above stays the same but the supply voltage drops from 120V to only 12V and so the amps required increase by the same factor. In your case, the 6.5a at 120V become 65a at 12V. In the real world it is probably near the 70A that Lou suggests because there is some conversion loss.