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Old 05-04-2014, 08:38 AM   #21
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Herk, I will do that. I am pretty sure the battery "boost" side of the system works, as I had to use that a couple of months ago. I believe that system travels through the isolator from the picture of the isolator manager. The other really strange thing is that recently when I turn on the ignition key, I get nothing. If I turn the key in the opposite direction (left) and then right again, the ignition works. I looked behind the ignition switch, only 4 light red wires coming in, and none of the wires were loose. Since I installed the upgraded remote controller for the inverter, that ignition system problem appears to have gone away, but I haven't driven it enough lately to be sure. Craig
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Old 05-04-2014, 11:19 AM   #22
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Originally Posted by boowho View Post
And I'm still curious as to why my batts willl drop from 12.7+ to 12.2 after running the inverter for less than 4 hours at a 9 Amp draw. I previously thought that it was because my original batts were completely "cooked", but now I have 4 brand new Trojans and I still don't get the capacity I think I should.
Boowho??
Question...how do you KNOW that :
A) You have only a 9 amp draw for 4 hours?
B) Your real battery voltage is 12.2?
Are you using a real battery monitor (like a trimetic or victron) or clamp meter or something else for your measurements?

One thing I can say is that when you are using something with a decent amp draw for a while...it will pull down your voltage below what resting voltage is...after the load is off it will slowly creep back up...so be sure to give it a couple of hours with NO LOAD before you determine that it is at 12.2...I'd be surprised if it isn't really at 12.4 after letting it rest.
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Old 05-04-2014, 11:58 AM   #23
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Herk,
Lots of good info.
Thanks,
Tom
X2..... Now if I can just under stand it!!!

boowho??
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Old 05-04-2014, 12:11 PM   #24
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Originally Posted by camaraderie View Post
Question...how do you KNOW that :
A) You have only a 9 amp draw for 4 hours?
B) Your real battery voltage is 12.2?
Are you using a real battery monitor (like a trimetic or victron) or clamp meter or something else for your measurements?

One thing I can say is that when you are using something with a decent amp draw for a while...it will pull down your voltage below what resting voltage is...after the load is off it will slowly creep back up...so be sure to give it a couple of hours with NO LOAD before you determine that it is at 12.2...I'd be surprised if it isn't really at 12.4 after letting it rest.
A) that's what was showing on the Magnum panel. 9 AMPS. There may be additional loads on the batts that don't go thru the inverter, but I would think they'd be fairly light.

B) again, that's what was showing on the Magnum panel. 12.2

With regard to the the voltage creeping back up, or the range not being linear, I understand that. However, next morning my slides would BARELY pull in, especially the front two hydraulic ones.

Thanks for you interest/info/suggestions. (to everyone, actualy)

Boowho??
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Old 05-04-2014, 12:13 PM   #25
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Originally Posted by boowho View Post
X2..... Now if I can just under stand it!!!

boowho??

Here is one that is "Zoom-able" so you can follow the traces.
Herk
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File Type: pdf Georgetown-Battery Connect Center.pdf (318.6 KB, 16 views)
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Old 05-04-2014, 12:28 PM   #26
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Originally Posted by boowho View Post
A) that's what was showing on the Magnum panel. 9 AMPS. There may be additional loads on the batts that don't go thru the inverter, but I would think they'd be fairly light.

B) again, that's what was showing on the Magnum panel. 12.2

With regard to the the voltage creeping back up, or the range not being linear, I understand that. However, next morning my slides would BARELY pull in, especially the front two hydraulic ones.

Thanks for you interest/info/suggestions. (to everyone, actualy)

Boowho??
So a couple of things are going on here:

Accepted at face value, 9 amps for 4 hours is 36 amp hours.
A typical OEM battery is about 70 amp hours at 100% charge

12.2 Volts DC equates to a 60% of capacity battery (assuming it was "rested" when tested. (or about right for an unstressed battery when tested).

When a deep cycle battery is "stressed" (asked to provide more than 5 amps), the capacity to deliver amperage decreases rapidly (see attached graph). This graph is for a 100AH battery, but you can use the plot as a percent of capacity for any battery.

If you ask a 50 or 60% charged battery to deliver the 15 or so amps a slide requires (more if the slide is loaded near its maximum capacity), you can see how the battery voltage will rapidly decline.

If you enter the graph at 100% = your 60% discharged battery and demand 15 amps, the available capacity will be reduced an additional 40% (or so).

This equates to a deliverable voltage of a battery at 25% (or less) capacity or around 11.5 volts under load (or less).

Hope this helps to see what is going on.
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Old 05-04-2014, 12:28 PM   #27
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Herk,
I'm not sure that the schematic for a Georgetown would be the same as for a Berkshire. I have found that there are differences in Berkshires even though they are the same model and same model year.
Tom
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Old 05-04-2014, 12:31 PM   #28
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Herk,
I'm not sure that the schematic for a Georgetown would be the same as for a Berkshire. I have found that there are differences in Berkshires even though they are the same model and same model year.
Tom
The schematic should be "representative" of the process. Locations and values may be different, but the process is identical for troubleshooting.
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Old 05-04-2014, 12:31 PM   #29
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Originally Posted by boowho View Post
A) that's what was showing on the Magnum panel. 9 AMPS. There may be additional loads on the batts that don't go thru the inverter, but I would think they'd be fairly light.

B) again, that's what was showing on the Magnum panel. 12.2

With regard to the the voltage creeping back up, or the range not being linear, I understand that. However, next morning my slides would BARELY pull in, especially the front two hydraulic ones.

Thanks for you interest/info/suggestions. (to everyone, actualy)

Boowho??
Bill,
Was the coach plugged in overnight when your slides barely pulled in? If so, something else must be going on that would cause them not to charge.
Tom
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Old 05-04-2014, 12:39 PM   #30
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Bill,
Was the coach plugged in overnight when your slides barely pulled in? If so, something else must be going on that would cause them not to charge.
Tom
I got the impression he was boondocking...
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Old 05-04-2014, 12:46 PM   #31
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Herk,
you may be right. I went back to the Boo's first post in this theread an it does sound like he was bookdocking.
My mistake.
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Old 05-04-2014, 01:18 PM   #32
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Originally Posted by boowho View Post
And I'm still curious as to why my batts willl drop from 12.7+ to 12.2 after running the inverter for less than 4 hours at a 9 Amp draw. I previously thought that it was because my original batts were completely "cooked", but now I have 4 brand new Trojans and I still don't get the capacity I think I should.

Guess I'll try equalizing next, but since the batts are less than 3 months old, I doubt that will help.

Boowho??
Sorry Boo.
I missed the 4 Trojans.
What is the total AH of the bank?
Are they 4 12 volt or 4 six volt?

There has to be more than a 9 amp draw going on to deplete a 200 or more AH stack in 4 hours. Is your battery computer (ammeter) set up properly?

Here is how the Trimetric is hooked up (a shunt on the ground terminal).
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Old 05-04-2014, 03:36 PM   #33
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Sorry Boo.
I missed the 4 Trojans.
What is the total AH of the bank?
Are they 4 12 volt or 4 six volt?

There has to be more than a 9 amp draw going on to deplete a 200 or more AH stack in 4 hours. Is your battery computer (ammeter) set up properly?

Here is how the Trimetric is hooked up (a shunt on the ground terminal).
Total stack (4 x 6V) gives 440AH at 12 volts. Considering a max drawdown at 50%, I should have 220 AH available. My "battery computer" is part of the Magnum 1200 watt inverter; at least as I understand it.

The Magnum as a control panel with about a "zillion" settings. As far as I know, I don't have anything that looks like what your picture shows. I did find the BI-directional isolator relay that was mentioned before. It's directly behind the CHASSIS batteries.

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Old 05-04-2014, 03:42 PM   #34
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Total stack (4 x 6V) gives 440AH at 12 volts. Considering a max drawdown at 50%, I should have 220 AH available. My "battery computer" is part of the Magnum 1200 watt inverter; at least as I understand it.

The Magnum as a control panel with about a "zillion" settings. As far as I know, I don't have anything that looks like what your picture shows. I did find the BI-directional isolator relay that was mentioned before. It's directly behind the CHASSIS batteries.

Boowho??
So you have 220AH 6 volt batteries, right?
What model Trojans do you have?

Could you give me an idea of the Magnum model number?
The Magnum may not be "seeing" all the amperage being drawn from the battery bank.
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Old 05-04-2014, 06:46 PM   #35
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Unless you added a splint at the main battery cable when you installed the new monitor, you are only seeing the amperage used by the inverter. This will not account for any of the 12v power in the coach. That would include the water pump, lights or refrigerator (of its not a residential one). From my personal experience, when our inverter broke last year and wouldn't charge the batteries, a 6 amp battery charger wouldn't keep up with the drain during a normal days use.

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Old 05-04-2014, 07:38 PM   #36
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Bingo..I think Herk & Beipers nailed it... you are not measuring full coach loads is my guess OR you have negative wires that bypass any shunt you have for measurement.
My suggestion would be to duplicate your 9 amp load conditions...i.e. same readout on the Magnum from the same sources. Then clamp meter your main battery positive and take a reading. If it is significantly diffferent ...you might want to install a real battery monitor (like the trimetric) using a shunt off the negative terminal for ALL negative connections.
For you to be reading 12.2 you must have used somewhere around 220 a/h at 12V.
I assume the slides barely pulling in the next AM means you were still running a load below 12.2V when you woke up as even at 12.2 the slides should work normally.
Once things start slowing down you have to be getting around the 80% discharge area. On the evidence... getting to 12.2V in 3 hours means you were pulling somewhere around 50-70 amps...which sounds pretty absurd. Something weird is going on. I'd do a specific gravity check on each cell of your 4 batts to insure that a bad cell is not causeing problems. Next step would be to figure out the real amperage being used with a clamp meter or battery monitor.
Do you have the residential fridge...and was it running during this period? That's about the only thing I can think of that would normally pull down that kind of amperage if it was warm on start up and ran most of the time. I assume you weren't trying to run your A/C's off the batteries...as that would do it too.
A real puzzle.
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Old 05-04-2014, 08:21 PM   #37
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So you have 220AH 6 volt batteries, right?
What model Trojans do you have?

Could you give me an idea of the Magnum model number?
The Magnum may not be "seeing" all the amperage being drawn from the battery bank.
Trojan T-105 Plus....... all 4 replaced together about 3 months ago.

Inverter is Magnum MM-1212 with the optional "super" control panel.

I do understand about some of the current from the house batts NOT going thru the inverter, so without an additional "battery computer" I will not see current being drawn by "native" 12 volt devices. My fridge is not household there does not draw thru the inverter; however, it does have cooling fans that run whenever the cooling unit (propane) is running. What else may be pulling off the house batts is somewhat unpredictable. My mascerating toilet is 12 V and of course all the LED lights.

Further, even when the inverter is not furnishing 110, there is still some draw on the batts; in other words the inverter itself draws some current, even when idle.

I THINK I understand everything that's been said so far. Perhaps I did get a bat with a bad cell, even though they're basically brand new. I will test that tomorrow with a load tester. Electrolyte on all 12 cells is where it should be and has been since they were installed.

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Old 05-04-2014, 09:23 PM   #38
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boowho...I think you understand things well based on your post. Most inverters are wired to batts directly but not exclusively...i.e they are an add on to the existing 12V system and are NOT the only draw on the system. So...the 9 amp reading you are seeing on your 1212 represents ONLY the amps the 1212 is drawing and converting to 120V at that moment in time...as your PANEL manual clearly states. So...assuming your 1212 is working correctly...and your batteries are nearly dead in the AM ...either the batts have a defect or something is putting a BIG amp draw on them...bigger than anything you mention would. I would use a turkey baster rather than a load tester to test the batts...you want to find a CELL that is out of kilter with the rest of them. Take a specific gravity reading of EACH battery fill hole. This is what you need:

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Old 05-04-2014, 09:28 PM   #39
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Boo

Dumb question. Were you running your lp furnace when you experienced your low voltage? It looks like from your other posts you've experienced cool weather lately.

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Old 05-05-2014, 06:51 AM   #40
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http://www.forestriverforums.com/for...aws-17300.html

Note how much power incandescent lights require. After the inverter, the furnace, then lights are the biggest near continuous DC draw in the camper.

At over 2 amps, a single dual bulb light fixture can kill a normal battery overnight. (I forgot one in the front storage compartment once and woke up freezing when we normally have plenty of power - 150 AH).

I have since converted everything to LED.
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