Attention a Electrical Sleuths

Hey y'all,

This from has been an education blast!
At last i'm settling in on a strategy for resurrecting my Hawk's refrigeration and battery system and will start with introducing refrigeration venting where there is now all but non.
To achieve the Dometic's recommended 36 Sq. inches, I am thinking of adopting isotherm's upper and lower vents if they fit the Hawk without cutting into the tubing frame. I would also like to bring in some sort of filtering to reduce the infusion of dust from the miles we put in on gravel roads. We might as well add a switch activated pancake fan for days of extreme heat or when fridge side must be exposed to sun for periods of time.

Our 80-90 watt panel is to be replaced with 2-100 watt panels. I had figured on Zamp's (FWC 's choice) but have been comparing them to Renogy and Grape solar after recent recommendations. Not keen on accepting marketing claims at face value, I'd like to hear from first hand users why one might be a better suited product than another. And then there are choices between Monocrystalline or polycrystalline panels to choose from. Specs seem very close with either composition panel but are they the same in real world boon-docking?

The Hawk is pre-wired for my current panel and unless the wire gauge is insufficient I should only need to upgrade the controller and attach the new panels. I see no need to buy a complete prepackaged kit unless there is something I have not considered.

Lastly, I think both Exide AGM batteries need replacement. Every technician that tested them verified their good condition. And perhaps some sort of auto cut off may have salvaged them, once they were run down individually one failed more quickly than the other.
Optionally, once other improvements were in place they could be run to actually prove themselves in use. If they are to be replaced, it needs to be a deep cell battery intended for extended power usage not a startup style battery. I have liked what I've read about a particular Interstate model but have not been privy to any real world experienced users.

Any input or concerns on finer aspects of this plan coming from experienced users would be appreciated.

Ted
 
Ted,

I believe our Zamp controller is good to 400w..not certain about the FWC wiring...darn good question; cuz even with the 160w on roof and 80w portable, I would quickly add another 160w to roof if the weight didn't make raising the top problematic...

But we need to get some miles on our systems before knowing if need more of anything...well, except time! Never enough of that.. :D

What batteries will you buy?

Phil
 
Terrapin said:
To achieve the Dometic's recommended 36 Sq. inches, I am thinking of adopting isotherm's upper and lower vents if they fit the Hawk without cutting into the tubing frame. I would also like to bring in some sort of filtering to reduce the infusion of dust from the miles we put in on gravel roads. We might as well add a switch activated pancake fan for days of extreme heat or when fridge side must be exposed to sun for periods of time.

I added a thermal switch behind the frig to turn the fan on at 80°. Fan draws ~ 0.1 amp so I just let it run all the time (as opposed to only when the compressor is running). Blowing air out the top is gives better cooling than drawing air in the bottom.

Filtering will reduce airflow so you will have to recalculate how much venting you need based on the filter's restriction (fans can mitigate this problem). I just use screening (to keep bugs out), drive very dusty roads at times and just blow/vacuum the area out once a year. Cooling fins should be cleaned periodically anyway (the are dust magnets).

Our 80-90 watt panel is to be replaced with 2-100 watt panels. I had figured on Zamp's (FWC 's choice) but have been comparing them to Renogy and Grape solar after recent recommendations. Not keen on accepting marketing claims at face value, I'd like to hear from first hand users why one might be a better suited product than another. And then there are choices between Monocrystalline or polycrystalline panels to choose from. Specs seem very close with either composition panel but are they the same in real world boon-docking?

Panels are comodity items now; I don't see much difference in brands. I have only had experience with Renogy.

Poly is older technology. Poly panels are not as efficient as mono so the panels are larger (and heavier) for a given output. Rumor has it that poly panels give more output in cloudy conditions. Both work well. I have used 2 X 100W Renogy mono panels for 2 years and am happy with them. I would steer clear of flexible panels as they haven't worked out all the bugs yet. My two 100W Renogy rigid mono panels added 32 lbs to my roof.

The Hawk is pre-wired for my current panel and unless the wire gauge is insufficient I should only need to upgrade the controller and attach the new panels. I see no need to buy a complete prepackaged kit unless there is something I have not considered.

I used 8 feet of 4 AWG wires from my junction box on the roof to my controller to my batteries. I am very happy I did. Voltage drop from panels to controller is less than 1%. My batteries are usually back to 100% by 11 AM. IMO the 10 Ga wire supplied is undersized for parallel wired panels (3+% voltage drop).

http://circuitwizard.bluesea.com/#


Lastly, I think both Exide AGM batteries need replacement. Every technician that tested them verified their good condition. And perhaps some sort of auto cut off may have salvaged them, once they were run down individually one failed more quickly than the other.
Optionally, once other improvements were in place they could be run to actually prove themselves in use. If they are to be replaced, it needs to be a deep cell battery intended for extended power usage not a startup style battery. I have liked what I've read about a particular Interstate model but have not been privy to any real world experienced users.

All the batteries in a system should be replaced at the same time, preferably with new batteries manufactured at the same time. Otherwise the new batteries will degrade to the state of the old batteries in the system rather quickly.

6 volt golf cart batteries are the cheapest true deep cycle batteries. I like FLA batteries as I can check condition periodically with a hydrometer. Any deep cycle battery(s) should weigh in the neighborhood of 120 lbs per 12V-200AH (another reason to like 6V; mine are 62 lbs each, much easier to handle). Some here insist on venting non-sealed batteries. I don't think it is an issue. YMMV

My build (including solar) is in my signature, if you are interested.

jim


Any input or concerns on finer aspects of this plan coming from experienced users would be appreciated.

Ted
Click to expand...
 
Jason- Thermostat switch is a great idea and I am going to add one. After a day with the fan running my fridge seems to be running much better.


Sent from my iPad using Wander The West
 
Choose the t-stat switch setting with care. I thought that I had, but missed. Adjustable would be good. I *think* 100°F as it's lowest setting might be good. I have a manual kill switch in that circuit too. That way they aren't running when the camper is just sitting in the yard & the fridge is off.
 
I power my two pancake fans (.15A each) off the power wire of the original fan that Dometic installed on the back of the fridge condenser coil. That way the extra fridge fans run only when the factory fan runs, which is when the compressor is running. I checked wire size and current draw and was well within limits. This was much simpler that any thermo switch or manual switch, in my opinion.

During planning stages I was concerned about adding additional electrical draw to the system (my goal was to reduce draw by increasing efficiency) but in reviewing test results posted by WTW member Dr. J., my concerns were alleviated. If I recall his results, the addition of two fans lowered his overall electrical fridge use by about 30%.

I have the full width factory vents lower and upper and installed the fans within the framing of the camper at the top, so they pull cooler air from below and are not physically within the 'air duct' so they wouldn't reduce the passive air flow if they were to fail for some reason. They have been functioning as planned for about 1.5 years now.

This is the best mod I ever did, reducing electrical use by 30% on the largest draw. A four pack of fans from Amazon (2 spares) and the alum. angle I mounted them with them with set me back about $30.
 
BATTERIES
Admittedly I'm shy of using flooded batteries in my living compartment.
Their location in my Hawk would also expose all other electronics and wiring to the gases.
I've see plenty of corroded battery environments with floods batteries and both my wife and I feel quite anal about keeping the Hawk environment clean and tidy. I'm willing to pay the extra money, accept lower performance and exercise the care required to keep the AGMs.

Ever hear of "second hand smoke?"

An excellent reference for anyone exploring solar is "Handy Bob's" blog.
He favors 6v flooded batteries but his usage does not include an interior like our pop-ups.
He makes very convincing arguments for his beliefs and use of specific products.
He's a fun read as well.

Bob thinks highly of Trojan batteries although again, he specifies flooded type.
While on the road recently, I became desperate and was looking to buy some Trojans (batteries). I spoke with a battery dealer who had dropped Trojan AGMs because of too many failures and returns. He had instead switched over to the Interstate line which may or may not be a fully truthful argument. We did drive to the Interstate distributor in Carson City with the idea of buying new batteries. They tested our Exides and said they were fine.
What's a consumer to do?

After working in the world of advertising, I'm very skeptical about any stated position and acknowledge that individuals as well as companies feel strongly about promoting their product/brand. One needs to research and decide what might be best path or product for their needs.
So to answer your question, I've not decided on battery brand. I buy into Bob's argument that the industrial 6V batteries like used in carts are more robust and hold a deeper charge but they are flooded and heavy. We're I to have an outside location for batteries I'd probably go that route. But I don't.

The FWC dealer in Tigard, Oregon has 6V AGM batteries that have the same tall footprint as the cart flooded batteries. They tout them as an AGM equivalent of the golf cart batteries and I think they may fit in our space. However, I've never heard of the brand, cannot find a track record and feel I'm a Guinea Pig enough having purchased an unvented refer and inadequate solar panel. Additionally the big 6v batteries are very heavy and if by chance you loose one, your system is dead.

Boondocking to me is not only compact but lightweight. We'r not building the Titanic after all and the best may not be the best.


Sent from my iPad using Wander The West
 
DesertDave said:
<snip>
A four pack of fans from Amazon (2 spares) and the alum. angle I mounted them with them with set me back about $30.
Click to expand...
DesertDave, can you please provide a link to what you purchased? Thank you. If you have already provided this link elsewhere, my apologies.
 
Terrapin said:
BATTERIES
So to answer your question, I've not decided on battery brand.
Click to expand...
There are only 3 major battery manufacturers in the US!

Quoting Consumer Reports

"Most aftermarket car batteries sold in the United States are made by three companies that build them for retailers: Johnson Controls, which supplies more than half of the market, Exide, and East Penn. They are sold under various names and built to the specifications of retailers, so performance can vary. Most stores will test, install, and match the right battery to your car’s needs. Here are the major brands and where they are sold"

Lots of info on who makes what, but the problem becomes what was true last month may not work out this month as retailers jump from manufacturer to manufacturer :(
 
I agree, if there had been something that went live with our fridge starting to run & turned off when it quit I'd have sure used it in one fashion or another. There wasn't, hence the t-stat switch.

My admittedly undereducated take on it is that the heavier the deep-cycle battery, the better it will work. We have a pair of Trojan T-125's that I've let suffer some. Not used to this wet cell stuff, they've gone dry enough to expose the plates twice now. They are in a vented plastic enclosure inside, up front. Am looking at group size GC2 AGM's to replace them.

I'm not sure that the phrase "aftermarket car batteries" is all inclusive. It may be, and it may not. Since Trojan doesn't appear to make common starting batteries they may actually make their own and be exclusive of CU's comment. No idea myself.
 
Desert Dave - I am also interested in the specific fans you installed. And is it possible to get a picture of the install locations?
 
ntsqd said:
My admittedly undereducated take on it is that the heavier the deep-cycle battery, the better it will work. We have a pair of Trojan T-125's that I've let suffer some. Not used to this wet cell stuff, they've gone dry enough to expose the plates twice now. They are in a vented plastic enclosure inside, up front. Am looking at group size GC2 AGM's to replace them.

I'm not sure that the phrase "aftermarket car batteries" is all inclusive. It may be, and it may not. Since Trojan doesn't appear to make common starting batteries they may actually make their own and be exclusive of CU's comment. No idea myself.
Click to expand...
A true deep cycle battery is constructed differently than a starting/marine battery. Starting batteries have porous lead plates to give more surface area to release electrons fast under heavy starting loads. Deep cycle batteries have solid lead plates to offer more bonding sites for electrons but cannot release them as quickly as a starter battery. That is why I said that deep cycle batteries are HEAVY: lots more lead. Marine batteries are a compromise, porous lead but not as porous as a starting battery. Lots of marine batteries are labeled 'deep cycle' by marketing. They are much less tolerant of deep discharge. You will not get as many charge/discharge cycles out of them. Starter batteries do not tolerate deep discharge.

Reasons I chose FLA batteries:
  1. can quickly check their condition with a hydrometer
  2. can replace lost fluid
  3. very tolerant of equilizing
  4. cheaper than AGM
  5. a vented battery box is easy to construct
Just because two batteries come from the same contract manufacturer doesn't mean they are equal. Each reseller has their own specifications for components and construction.

Hope this helps

jim
 
Terrapin said:
BATTERIES
Admittedly I'm shy of using flooded batteries in my living compartment.
Their location in my Hawk would also expose all other electronics and wiring to the gases.
I've see plenty of corroded battery environments with floods batteries and both my wife and I feel quite anal about keeping the Hawk environment clean and tidy. I'm willing to pay the extra money, accept lower performance and exercise the care required to keep the AGMs.

Ever hear of "second hand smoke?"

An excellent reference for anyone exploring solar is "Handy Bob's" blog.
He favors 6v flooded batteries but his usage does not include an interior like our pop-ups.
He makes very convincing arguments for his beliefs and use of specific products.
He's a fun read as well.

Bob thinks highly of Trojan batteries although again, he specifies flooded type.
While on the road recently, I became desperate and was looking to buy some Trojans (batteries). I spoke with a battery dealer who had dropped Trojan AGMs because of too many failures and returns. He had instead switched over to the Interstate line which may or may not be a fully truthful argument. We did drive to the Interstate distributor in Carson City with the idea of buying new batteries. They tested our Exides and said they were fine.
What's a consumer to do?

After working in the world of advertising, I'm very skeptical about any stated position and acknowledge that individuals as well as companies feel strongly about promoting their product/brand. One needs to research and decide what might be best path or product for their needs.
So to answer your question, I've not decided on battery brand. I buy into Bob's argument that the industrial 6V batteries like used in carts are more robust and hold a deeper charge but they are flooded and heavy. We're I to have an outside location for batteries I'd probably go that route. But I don't.

The FWC dealer in Tigard, Oregon has 6V AGM batteries that have the same tall footprint as the cart flooded batteries. They tout them as an AGM equivalent of the golf cart batteries and I think they may fit in our space. However, I've never heard of the brand, cannot find a track record and feel I'm a Guinea Pig enough having purchased an unvented refer and inadequate solar panel. Additionally the big 6v batteries are very heavy and if by chance you loose one, your system is dead.

Boondocking to me is not only compact but lightweight. We'r not building the Titanic after all and the best may not be the best.


Sent from my iPad using Wander The West
Click to expand...
I just got back from a 600 mile road trip and 3 days with my new mods to my fridge. Huge improvement and kept my freezer below 10 degrees and my fridge around 35-37 degrees. I can't say for sure what fixed it as the larger vent, fan, as well as direct wire 8 gauge kit happened all at once. But it certainly fixed my problems and after two full days I still had over 12 Volts when I plugged in at a Koa. I'm sure I could have made it another full day before I ran to issues. I'm going to add solar and copy drJ's set up. Then my Honda generator will always stay home. Good luck and keep us posted on your progress in fixing your solutions.


Sent from my iPad using Wander The West
 
Grandby,
OK, into it now. Adding upper and lower vents with access for cleaning. I'll add at least one quiet fan to run in unison with the one attached to the fridge compressor. I notice your fridge looks to be incased with a tufted looking insulation. Could you talk about that?

Thanks,

Ted
 
Terrapin said:
Grandby,
OK, into it now. Adding upper and lower vents with access for cleaning. I'll add at least one quiet fan to run in unison with the one attached to the fridge compressor. I notice your fridge looks to be incased with a tufted looking insulation. Could you talk about that?

Thanks,

Ted
Click to expand...
hi Ted, mine had the insulation in it from the factory. I'd say it's mostly like a dynomatt type product.


Sent from my iPad using Wander The West
 
Guys,
As you have read, my Hawk was delivered with no outside venting for the Dometic 110 fridge and only about 12-15 sq inches inside. Undoubtedly this was at the root of my electrical cycling problem. With some great help from Jason (FWC Rep from Azusa Ca/Tigard, Or) FWC is installing new venting. After searching around the forum and deciding additional exhaust fans seem prudent, I purchased 2-120mm Arctic PWM fans with dual ball bearings. They will mount at the top of the upper vent and
be wired direct to run in concert with the fridge fan. I'll be needing to seal up the old interior venting and while at it will add additional insulation. I've noticed some have filled much of the space behind their units with foam and other insulation materials.
Is there any reason why I cannot fill this negative space as long as I keep the condenser clear and a well directed passage for air to enter the bottom vent, pass over the condenser and smoothly onto the new dual fan exhaust setup?

Thanks,

Ted


Sent from my iPad using Wander The West
 
Terrapin said:
Grandby,
OK, into it now. Adding upper and lower vents with access for cleaning. I'll add at least one quiet fan to run in unison with the one attached to the fridge compressor. I notice your fridge looks to be incased with a tufted looking insulation. Could you talk about that?

Thanks,

Ted
Click to expand...
Hi Ted,

Wondering if you ever were able to get everything fixed and working correctly. I found the wiring coming out of the fridge to have the fan run only when the fridge fan was running but I was to worried about adding more load to the system then it was made to handle. So I have mine wired to a toggle switch along with a heat switch that turns the fan off once the temp is below 80 degrees. It has worked really well the two weekends I have taken it out since the repairs.
 
Terrapin said:
I've noticed some have filled much of the space behind their units with foam and other insulation materials.
Is there any reason why I cannot fill this negative space as long as I keep the condenser clear and a well directed passage for air to enter the bottom vent, pass over the condenser and smoothly onto the new dual fan exhaust setup?
Click to expand...
The specs for your refrigerator should tell how much space is needed around and behind the condenser. I would not violate that. Unless you can put the insulation up against the back of the refrigerator I don't think it does anything.

jim
 
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