2619, Designs for Review (with questions).

[rickst29]

First, here's a sketch of our somewhat "piggy", and MANDATORY, night-time electrical requirements:

CPAP, approx 8 hrs @ 60W = 480 Watt-hours
Evening Lights, etc = 3 hrs @ 60W = 180 Wh.
Bathroom visits and "etc" = 1 hr @ 100W = 100Wh.
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total mandatory: 760 + 15% power losses (inverter for CPAP, wire losses, etc.) ~ 900 Wh.
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Batteries:
At 12V, this corresponds to 75 Amp-hours. My 2619 has two group-24 battery boxes on the front (Swing Hitch). Although expensive, I tentatively plan for 2 * "Concorde "Sun Xtender PVX 1040T" (nominal max capacity of 104 Ah each.) When lowered, the 2619 shell prevents taller or wider batteries in this location.

Are there other batteries which I should consider with the 2619?

Panels And Charge Controller:
If I use 100W panels and assume near-perfect weather conditions (4.5 hrs per day, 77% net efficiency SWAG from the "Icarus calculation") the each panel yields a bit less than 350 WH. I need 3 of them in perfect conditions. 4 would be more realistic, and support some daytime electrical usage simultaneousl with charging the batteries. In an ultra-cheap PWM configuration, 4x100W Panels + Controller costs about $700.

Or, I could spend about $1100 and get a really high-end MPPT controller, allowing use of 24 Volt panels instead (2 * 240W). That's more like 5* 100W "12V" panels, providing a generous amount of extra power for daytime use (running an air cleaner; playing the Stereo, and etc.)

I'm inclined to blow the money - it's "like" getting a 5th 100W panel included (cutting the "effective price difference" to just $350). It simplifies the wiring and mounting a lot (less wire and connectors saves some money as well); It looks WAY better, leaving the roof a lot less crowded.... And it gives much better battery management.

Those components would be something like:
2 Suniva MVx240-60-5-501 http://www.suniva.com/documents/MV%2...%2002%2028.pdf for about $580

and the Morningstar Tristar MPPT-60 for about $520. (Why not the 40A? Because the 60A includes the Ethernet Web Interface, for use with my $35 Raspberry Pi computer.)

Comments? Thanks in advance.

[ShrimpBurrito]

First of all, if you replace your interior lights with LEDs, you can reduce your power requirements for light to virtually zero -- my LEDs generate at least as much light, and draw only 10% of the power (about 150 mA, IIRC). The ones I have plug into the existing sockets, are circuit boards that shine only downward, and require no retrofitting. And since lighting represents a major part of your power requirements, I would do that first. Assuming most of the "bathroom etc." visit power requirements are also lights, your 280Wh drops to 28Wh, which at 12VDC is only 2.3Ah. That's nothing.

Additionally, look at the "brick" that supplies the power to your CPAP, and perhaps the jack on the machine where the power supply plugs into, and you may find that your CPAP machine runs on 12VDC. If that's the case, make an adapter for it with a cigarette plug on the other end, and you gain back your 15% inverter loss.

I have 2 Trojan T-105s (total combined capacity of ~220Ah), and while camping with a guest that ran a CPAP, we had plenty of power reserve after 2 nights of use, including using the CPAP heater. I think you will find that the 60W requirement is the max; when the heater is not running, it's significantly less. I could be wrong though as that was several years ago. But even if it drew 60W constant, you still should have plenty of power to get you through 2 nights.

I can't comment on the solar setup, but my Trojan T-105s have been great after 6 years. I don't think I'll need to replace them for at least a few more years, although I have taken good care of them. And they are half the price of AGMs last time I checked.

Dave

[rickst29]

Originally Posted by ShrimpBurrito

First of all, if you replace your interior lights with LEDs, you can reduce your power requirements for light to virtually zero -- my LEDs generate at least as much light, and draw only 10% of the power (about 150 mA, IIRC). The ones I have plug into the existing sockets, are circuit boards that shine only downward, and require no retrofitting.

Dave, do you remember where you bought these things? I realize that your Trailer might be in storage, so I'm not going to be if your answer is "not sure, and can't look..."

Originally Posted by ShrimpBurrito

And since lighting represents a major part of your power requirements, I would do that first. Assuming most of the "bathroom etc." visit power requirements are also lights, your 280Wh drops to 28Wh, which at 12VDC is only 2.3Ah. That's nothing.

Indeed, the lighting load becomes insignificant.

Originally Posted by ShrimpBurrito

Additionally, look at the "brick" that supplies the power to your CPAP, and perhaps the jack on the machine where the power supply plugs into, and you may find that your CPAP machine runs on 12VDC.

Bravo, it is 12V! At 60W, I'm not sure that I want to go through a cigarette adapter - but there are many other kinds of plug/socket pairs which could hold together tighter, and provide higher current capacity too. (IIRC, TM's own cigarette lighter sockets are fused pretty low, at either 3 or 5 Amps each.)

Originally Posted by ShrimpBurrito

I have 2 Trojan T-105s (total combined capacity of ~220Ah), and while camping with a guest that ran a CPAP.... And they are half the price of AGMs last time I checked.

I looked at them, but they are too tall and too wide for the 2619 A-frame. (Between the propane tanks and the front shell in "down" position, there's no room in either of these directions. The only direction with any room for increased battery size is the "length" along the rectangular base.)

They also aren't very well tuned for accepting the fast, high-current solar charging process: In the Trojan lineup, the 24-AGM would be the correct battery for deep-cycle solar, and that Product lies in a nearly identical (and much less attractive) "Ah per dollar" as my Concorde choice. (The 1040T is about 20% "more" battery, in weight and capacity, at about 20% more cost.) them. It's about taking in the high charge current without overheating - not about "maintenance free".

Great post, you nailed it on the 12V CPAP. But I have another big consumer, which I didn't mention: The fridge. This is somewhat "optional" but very desirable functionality:

My Norcold is re-wired, so that 12V operation is independent of the Norcold's own "mode selector" switch. As you know, the "thermostat" dial is basically a direct connect into the propane needle valve -- if you set the dial to a high enough value (e.g. 5 or 6 ) to keep the Fridge cool in the early evening, your beer, lettuce, milk and everything else freezes by just before dawn -- when the ambient temperature is much lower, and your setting is now far too "strong".

I don't like wilted lettuce, or frozen milk. And exploded beer, that's simply TRAGIC.

In powered camping sites, I run the fridge on 120V all the time. (Like the new 12V circuit, this is now controlled by a PT100 thermocouple, we just set the Norcold temp control to "6" and let the PID turn off the power when the temp approaches 34). But in the Boonies, we will want to use propane at a relatively low-power "don't freeze in the morning" dial setting, with DC electric adding heat to make up for the "too low in the early night" propane flame. (Adding electric heat, according to PID and thermocouple rules.)

That will probably be at least 2 hours @ 120W, another 240Wh -- so I just ate up most of the savings which you created by switching to LED lights. But your ideas allow the same config(s) to run MORE STUFF, I'm thrilled!

[rickst29]

I just bought this kit: http://www.ebay.com/itm/Complete-Kit...item41709288fb
VMP on these panels is 18.9V, a bit high for 12V with a PWM charger - I'll actually get only 14.4V (bulk voltage mode) * 5.3 amps * 2 panels = 153 watts, minus battery cable losses too. But I "Sniped" it at a pretty deep discount.

With only 10.6 Amps at the best of times, it doesn't make a lot of sense to invest in exceptional batteries either - and they could be stolen of the forward, unenclosed frame mount of the 2619 anyway. I'll just buy a pair of el-cheapo WalMart "24DC" Everstart Marine batteries.

Any suggestions, where to mount the PWM charge controller controller for a 2619 front shell installation?

[LoveToCamp]

I mounted my controller on the front of my shell, about 12" above the bottom of the shell. I have a front window, so I made sure I was not right where my window crank is. Controller is sheltered from water while on the road, as it is under the front shell. It is under the front bed at camp, so it is sheltered while open, also.

I ran the wires straight down, and through a hole in the frame, below the front. Then, two wires went street-side through holes and zip-ties, and two wires went to my battery on my tongue.

If you are concerned about losing your batteries while in a storage lot, I had a chain locked around my battery. Granted, bolt cutters will cut chain easily, but if you are not at a public storage yard, I wouldn't worry about battery theft. Just me, though.

[ShrimpBurrito]

Originally Posted by rickst29

Dave, do you remember where you bought these things? I realize that your Trailer might be in storage, so I'm not going to be if your answer is "not sure, and can't look..."

Sorry, I just saw this thread with your questions. Yes, I bought them from Command Electronics. All the details are in this post:
http://www.trailmanorowners.com/foru...mand#post78605

Originally Posted by rickst29

Bravo, it is 12V! At 60W, I'm not sure that I want to go through a cigarette adapter - but there are many other kinds of plug/socket pairs which could hold together tighter, and provide higher current capacity too. (IIRC, TM's own cigarette lighter sockets are fused pretty low, at either 3 or 5 Amps each.)

Actually, the cigarette lighter socket in my TM is rated for 7 amps, which is 96 watts at 12VDC. So that would be plenty for the CPAP. The CPAP our guest used was also about 60 watts, and we used it for several nights powered in that socket with no ill effects (via an inverter, actually).

Originally Posted by rickst29

They also aren't very well tuned for accepting the fast, high-current solar charging process: In the Trojan lineup, the 24-AGM would be the correct battery for deep-cycle solar, and that Product lies in a nearly identical (and much less attractive) "Ah per dollar" as my Concorde choice. (The 1040T is about 20% "more" battery, in weight and capacity, at about 20% more cost.) them. It's about taking in the high charge current without overheating - not about "maintenance free".

Where have you read that Trojans (the T-105s and the like) aren't well tuned for being charged by solar setups? Most battery literature I have read, including the windsun.com site and Trojan's site, say deep-cycle batteries should be charged at no more than the C8 rate (or sometimes the higher C10 rate). At the C8 rate, a 2-cell T-105 bank can be charged at 26 amps. Is your solar array putting out more than that? Looks like the setup you just described above is only ~12A (153W).

Originally Posted by rickst29

Great post, you nailed it on the 12V CPAP. But I have another big consumer, which I didn't mention: The fridge.

Ah yes, can't help you there. And I too hate frozen beer. Had a whole case explode on me when I left some out in Utah in January overnight a few years ago. Bad scene. Maybe use a cooler?

Dave

[rickst29]

Originally Posted by ShrimpBurrito

....
Where have you read that Trojans (the T-105s and the like) aren't well tuned for being charged by solar setups? Most battery literature I have read, including the windsun.com site and Trojan's site, say deep-cycle batteries should be charged at no more than the C8 rate (or sometimes the higher C10 rate). At the C8 rate, a 2-cell T-105 bank can be charged at 26 amps. Is your solar array putting out more than that? Looks like the setup you just described above is only ~12A (153W).

Yep, no problem with this setup, or even the full 200 watts - which I could get with a switch to MPPT. (Max would be close to 15A in that case).

I started this Thread with a proposal for vastly more PV power basically, 2 * 240W (24V panels). In that kind of configuration, 35A would not be impossible - and that could lead to temp sensor "throttling" of the Bulk charge cycle, unless I also did a big upgrade to the battery bank.

[rickst29]

Originally Posted by LoveToCamp

I mounted my controller on the front of my shell, about 12" above the bottom of the shell. I have a front window, so I made sure I was not right where my window crank is. Controller is sheltered from water while on the road, as it is under the front shell. It is under the front bed at camp, so it is sheltered while open, also..

The Front of the front shell is outside, in the weather, during travel - do you mean that you mounted it on the fixed TM vertical panel behind the lowered shell, and underneath the bed when opened up? Or do you mean that you're on the inside of the moving shell?

Originally Posted by LoveToCamp

I ran the wires straight down, and through a hole in the frame, below the front. Then, two wires went street-side through holes and zip-ties, and two wires went to my battery on my tongue.

If you are concerned about losing your batteries while in a storage lot, I had a chain locked around my battery. Granted, bolt cutters will cut chain easily, but if you are not at a public storage yard, I wouldn't worry about battery theft. Just me, though

I'm not worried, now that I've decided to stay with cheap batteries. At the beginning of the Thread, I was thinking about an upgrade to very expensive batteries.

[LoveToCamp]

Misspoke. I meant the front of the bottom shell, which is covered by the front shell during travel. As you say, it is behind the lowered shell, and underneath the bed when open. Definitely not on the inside of the moving shell.

Sorry for the ambiguity.

[rickst29]

Thanks for clarifying that - I'm going to copy your configuration.