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Old 07-17-2007, 02:56 PM   #15
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Quote:
Originally Posted by campadk
Hi jd,

I checked the Link 10 manual, and although a bit on the vague side, it does as you mention, say the AH rating to use is based on discharging over 20 hours. I believe you are basing the AH rating on a 20A rate instead of 20 hour rate... that is were we have some confusion, and thus your AH rating is lower.
I think you're right. I usually get these math things all messed up. Now I have to re-think these SRM-24s...

Quote:
If the battery is somewhat linear at the lower rates, and the battery is rated at 16.4 hours @ 5A then that would equate to 20 hours @ 4.1A, which in both cases is 82AH which is what my understanding of the rated AH for these batteries.
This was exactly my first calculation...then I let a buddy talk me out of it I'm liking this approach better than my posted one, thanks!

Cheers,
-jd.
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Old 07-17-2007, 03:25 PM   #16
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Just did a bit more research jd...

I do believe the CEF is simply the charging efficiency. Since charge efficiency is higher when the battery has a lower charge, and less efficient when the battery reaches full, I'm not sure how fussy about CEF to bother with. I'm using the default of 90%. Some documents suggest charge efficiency is about 95% when the batteries are at a low charge state.

Its the Peukert's equation that dictates how many AH's you actually get based on how quickly you draw down the battery.

ie for the SRM-24's at lower currents such as 5A or less you can expect 82AH, however if you draw down at a 25A rate you only get 57.5 AH.

Based on the Xantrex manual charge, for the SRM's that would be about 1.3.

Now considering we have 2 batteries in parallel, then this could be incorrect since half the current is drawin from each battery. Based on this, a 1.25 figure would be more accurate.

Then again, in the real world since we are never drawing much more than 5A for any extended period, its probably useless getting fussy about Peukert's since it won't even be noticeable on the Link 10

Am I making my life to complicated? LOL
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Old 07-17-2007, 03:34 PM   #17
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my take on CEF

Quote:
Originally Posted by campadk
Hi jd,
I take it the CEF somehow comes in to play to calculate efficiency when you start drawing higher currents. I understood the CEF however to be an indicator of charging efficiency though. ie you may put back in 50AH, however due to loss to heating and resistance, only 45AH will actually be available to take back out of the batteries.
Ok, having embarassed myself on the Ah rating, let me take a stab at the CEF thing.

I think that if all you ever do is charge to full, use the batteries, charge to full, etc...then the CEF is irrelevant. This is an unlikely situation when dry camping.

I think a representive CEF is needed to accurately determine the state-of-charge when you don't fully top off the batteries -- a more common situation when actually camping and depending on your batteries.

The auto-calculation of the CEF is helpful because over time the batteries CEF changes. The older they are the less efficient they charge, in general. Thus, I assume the monitor uses the discharge characteristics to perform an accurate CEF recalculation.

So, since you've figured out the Ah rating (for both of us), and the CEF is recalculated from time to time to account for wearing batteries, we can both count on our monitor's percent-full reading, even when we only partially charge them when camping. Yay!

Q: do you have a temerature sensor, too?

Cheers,
-jd.
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Old 07-17-2007, 03:38 PM   #18
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I wish...

...sure wish I could somehow flag some of my earlier gibberish as just that, so other's aren't led astray by trash-logic...
-jd.
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Old 07-17-2007, 05:09 PM   #19
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No.. no temperature sensor.. I thought that was going a bit to far

That was no jimberish.. it was 'workin it out'... I'd hate to revisit some of my older posts all over the Internet LOL.

Next project is solar.. I figure on an AM100, 130W panel.. but thats next year, along with fold up bikes.

I've heard rumours.. (actually I have a scan of a letter) that the powers that be, may be re-evaluating the usage of generators at state parks... maybe we'll be limited next year to generator run time! maybe we'll have to pay a generator tax!.. maybe we'll have to prove our units are quiet and non-polluting. I'm going to stay ahead of any issues, and dive right into the world of solar
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Old 07-17-2007, 07:03 PM   #20
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Quote:
Originally Posted by campadk
Next project is solar.. I figure on an AM100, 130W panel.. but thats next year
Cool! where, exactly?
Can you fit one AM100 + one AM65 end-to-end above your main awning rail...?
Boy, this is starting to get off topic. I'll watch for your new thread

Cheers,
-jd.
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Old 07-17-2007, 08:34 PM   #21
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Yah... dragging this thread off topic a bit.. but I think we all covered the direct connect pretty much to the end didn't we?

Not putting the solar panel up on top. I don't trust that me (or anyone for that matter) isn't going to mess it up and I'll have leaks.

Besides a panel that I can adjust at ground level makes more sense to me. Something to tinker about with
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Old 07-17-2007, 08:57 PM   #22
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I have both a 1000i Honda. When we bought it, I asked the salesman about using the DC output to charge a battery. He said that since it was unregulated that he would not use it. He recommended plugging a battery charger into the generator to charge the battery. I have used this many times to charge my boat batteries when camping.

For our trailers, I just plugged the trailer into the generator and let the inverter do its job.

Jeff
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Old 09-04-2007, 11:15 AM   #23
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I was wondering, as a newbie to generators an travel trailers, where you store the generators? I was told i can't mount one, even a small one, on the tongue, but i don't really want to lift them, either, as i'm not that strong or big. Your thoughts would be most appreciated.
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Old 09-06-2007, 06:16 PM   #24
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Quote:
Originally Posted by chandles
I was wondering, as a newbie to generators an travel trailers, where you store the generators? I was told i can't mount one, even a small one, on the tongue, but i don't really want to lift them, either, as i'm not that strong or big. Your thoughts would be most appreciated.
Where and what size you carry depends on what you want them to do.

I'll use Honda's for my examples.

I have a eu1000 that I use for battery charging. Usually in Winter as the furnace is a battery drainer. It's light and small and has a sealing gascap. It's usually in a milk crate in the back of the truck or in the trucks rear seat.

Lots of folks use two eu2000's with a paralell kit so they wind up with a 4000.
in summer to run the A/C, fridge, microwave etc. Several have mounted them on the tongue and many carry them in their vehicle. They really are not that heavy.

I also have a eu3000 that once again is in the back of the truck for Summer A/C use. It is a tad heavy. I've seen them wheeled up ramps and horsed in. Something like a Spitzlift is a one handed no effort way to load.

Others have mounted all sizes of Gensets by adding a hitch to the front of their vehicle and mounting on hitch trays. Neat way to go if you don't have a truck.

Really it comes down to what you need for your kind of camping.
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