fireball
Explorer
Pulling air in or blowing air out. ?
100+ ambient Temp - ARB 50qt - 100 watt solar panel - Not enough?
- Thread starter dstock
- Start date
Pulling air in or blowing air out. ?
13 hours into my power consumption test, An Engel 32 and a NL 72 fridges set at about 34 and freezer set to about 0, Units in the shade (garage) and both have protective shells. 49Ah consumed. After 24 hours, 70Ah total. Average is about 3A each when they are running at the same time, 6.42Amps. Temps range in the 84-92 range.
http://www.disco3.co.uk/gallery/thumbnails.php?album=35750
http://www.disco3.co.uk/gallery/thumbnails.php?album=35750
Last edited:
geordie4x4
Observer
That is interesting and I guess it depends on the controller. I have a Morningstar 10 controller and it has a little temperature sensor on it. The instructions say it should be mounted as close to the battery as practical and the temperature is used as a voltage compensation for I think, lowering the charge as the battery heats up. I assume this is to protect the battery but surely would reduce the charge capacity. So I figure with this temperature compensated regulator it is better to keep the battery and regulator in a cool place together.
The other reason that I thought that it was better to have the regulator close to the battery is that the panel is putting out higher voltage than the battery requires, say 17V. I thought it is therefore better to have the higher voltage travel the greater distance which results in less voltage drop. But maybe this theory is only relative to much higher voltave than this? Then the regulator lowers the voltage to the charge voltage which the battery gets with little or no voltage drop through a much shorter run of wire to the battery.
geordie4x4
Observer
I'm interested as to which fan you used? One to move a lot o fair with little restriction o rone to provide more pressure against a restriction?
I am thinking of fitting one down on the air vent grill of my fridge but the first little computor fan I tried had so little force when there was a bit of restriction that I did not bother to go ahead and fit it. SO maybe a better fan is needed for me too.
geordie4x4
Observer
OK so 10 ft gives you a reasonable distance to move the panel around, probably with minimal voltage drop. I do wonder how much the temperature thing actually makes unless the regulator is really hot and the battery is then limited in charge.
I am thinking that when I put my new roof top tent on, I might just go with 2 by 100w panels and not have to worry about all this to fine tune and maximise output.
I am thinking that when I put my new roof top tent on, I might just go with 2 by 100w panels and not have to worry about all this to fine tune and maximise output.
If there is room, absolutely install 2. On a cloudy day like today, I was getting less than 50 watts from 500 watts of panel.
The temperature sensor mounts on the battery at the terminal on the Morningstar system. The battery manual I got suggested mounting it center of the side of the battery. The charging profile is adjusted based on temperature, at least on the controller I'm using. Some controllers have provisions for a voltage sensor. This allows for actual voltage without losses in your wire, again adjusting appropriately the charging profile to account for the difference.
If you have a short run (under 12.5') you can use the MS temp sensor, and cut it in half (it's 25') and use the other half for the voltage sense wire. If you have no voltage drop in your charging wire, then you can probably get away without the voltage sense.
For example, here is an excerpt from Battery University
As with all gelled and sealed units, AGM batteries are sensitive to overcharging. These batteries can be charged to 2.40V/cell (and higher) without problem; however, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages). Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell), and a direct replacement with a sealed unit could spell trouble by exposing the battery to undue overcharge on a long drive. See Charging Lead Acid.
AGM and other sealed batteries do not like heat and should be installed away from the engine compartment. Manufacturers recommend halting charge if the battery core reaches 49°C (120°F). While regular lead acid batteries need a topping charge every six months to prevent the buildup of sulfation, AGM batteries are less prone to this and can sit in storage for longer before a charge becomes necessary. Table 1 spells out the advantages and limitations of AGM.
The temperature sensor mounts on the battery at the terminal on the Morningstar system. The battery manual I got suggested mounting it center of the side of the battery. The charging profile is adjusted based on temperature, at least on the controller I'm using. Some controllers have provisions for a voltage sensor. This allows for actual voltage without losses in your wire, again adjusting appropriately the charging profile to account for the difference.
If you have a short run (under 12.5') you can use the MS temp sensor, and cut it in half (it's 25') and use the other half for the voltage sense wire. If you have no voltage drop in your charging wire, then you can probably get away without the voltage sense.
For example, here is an excerpt from Battery University
As with all gelled and sealed units, AGM batteries are sensitive to overcharging. These batteries can be charged to 2.40V/cell (and higher) without problem; however, the float charge should be reduced to between 2.25 and 2.30V/cell (summer temperatures may require lower voltages). Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell), and a direct replacement with a sealed unit could spell trouble by exposing the battery to undue overcharge on a long drive. See Charging Lead Acid.
AGM and other sealed batteries do not like heat and should be installed away from the engine compartment. Manufacturers recommend halting charge if the battery core reaches 49°C (120°F). While regular lead acid batteries need a topping charge every six months to prevent the buildup of sulfation, AGM batteries are less prone to this and can sit in storage for longer before a charge becomes necessary. Table 1 spells out the advantages and limitations of AGM.
Last edited:
geordie4x4
Observer
I see that some of the regulators, particularly the larger capacity ones, have a separate location to hook up a temp sensor on a lead. This is so you can put the sensor on the battery for better real battery temp. But as far as I understand, this is mainly for when the battery is under the bonnet and hot from the motor, to protect it from overcharging and over heating.
You might be able to find out more from Morningstar as to how much difference it makes at the sort of temperatures you are likely to have for the battery and the panel location.
Regarding a fan, it would be great if you could set it up to vent hot air and draw in cool but I was thinking along a much simpler line. I was thinking a fan to simply move air inside the car to reduce hotspots right by the fridge.
A solar powered and thermostat triggered fan would be pretty nice, though... set it up to come on when the in-car temperature gets over X degrees. not a bad idea.
A solar powered and thermostat triggered fan would be pretty nice, though... set it up to come on when the in-car temperature gets over X degrees. not a bad idea.
geordie4x4
Observer
Thanks unseenone, It is a rainy day here so looks like I have some more reading to do.
geordie4x4
Observer
Good idea, I have seen some neat little ebay digital temperature switch and relay units for cheap enough to try out.
http://www.aliexpress.com/w/wholesale-temperature-switch-thermostat.html
Which model 10? -- I find it amazing you were able to speak with someone, they never returned my call the one time I called. If they are telling you something at Morningstar they should know.
I haven't seen a huge temperature difference to ambient, but I am also not putting huge charges into the battery. Under the hood, yes, definitely. You have to modify the PS30 to get both temperature and voltage senses, but they provide instructions to do it. I'm not sure about your model.. or installation. There probably is such a thing as overkill as well. I got more keen on trying harder to extend the life of my batteries. I got two years out of my last Yellow Optima. This is most likely due to poor charging habits, and the fact I'm in TX and it gets HOT here. That battery is in the engine bay as well.
A friend in Australia sent me a picture of his temperature sensor. He noted that in Australia, they generally fasten it on the cable near the battery post. It looked like a sensor cased in rubber. He's traveling around your area currently, I think he's skipping Perth, in Marble Bar at the moment.
I haven't seen a huge temperature difference to ambient, but I am also not putting huge charges into the battery. Under the hood, yes, definitely. You have to modify the PS30 to get both temperature and voltage senses, but they provide instructions to do it. I'm not sure about your model.. or installation. There probably is such a thing as overkill as well. I got more keen on trying harder to extend the life of my batteries. I got two years out of my last Yellow Optima. This is most likely due to poor charging habits, and the fact I'm in TX and it gets HOT here. That battery is in the engine bay as well.
A friend in Australia sent me a picture of his temperature sensor. He noted that in Australia, they generally fasten it on the cable near the battery post. It looked like a sensor cased in rubber. He's traveling around your area currently, I think he's skipping Perth, in Marble Bar at the moment.
Last edited:
wrcsixeight
Adventurer
Sorry, I thought the link took it right to the fan I used.
Noctua Nf-f12
http://noctua.at/pdf/infosheets/noctua_nf_f12_focused_flow_web.pdf
These are great at pushing air, quietly, through a restriction.
Just saw they have an Industrial version which is water and dust resistant, and spins at 500 more rpm for 0.075a and moves 71 CFM.
There are obviously fans which can move more air, this one moves a fair amount for very little electricity consumed. If the Fridge has a danfoss compressor, the compressor controller can handle powering 0.5 amps of fans, that switch on only when the compressor is running. So it could power 10 of these Noctua Nf-f12 fans if someone were so inclined. The fan which came on my Vitrifrigo consumes0 .12 amps and moved ~71 cfm and was pretty loud. So I saved 0.07 amps just by switching to this fan
I moved the Noctua to the other side of the condenser so it is pushing air into it, rather than sucking air through it. Much quieter The Duty cycle after doing this dropped a few points. Makes it easier to clean the dust off the blades too. The Noctua is rated at 53 cfm, so less than the provided fan(~71cfm), but had no negative effect on performance. In fact the opposite, when combined with the cooling unit tunnel.
Here is what the Danfoss cooling units look like.
On Chest style danfoss powered fridges, the cooling unit will look like this. The condenser can be different, but the electronic controller is attached to the compressor, though I guess an extension cord can be installed to relocate it. I made a tunnel to force all the fan's flow across compressor and controller after being forced through condenser.
Here is the other side. I could not have moved the fan to the other side if I did not add 3/4 inches extra insulation to the fridge body, and to the cabinet interior as well.
While I have added a 40mm fan to the interior, the Noctua is the only fan I have moving air through the cooling unit, or near it. It pulls ambient air from the floor below my front loading fridge, and pushes it out either a vent in the van body with no chance of recycling preheated air, or into the adjacent vented cabinet in winter time.
If your danfoss powered fridge is an AC/DC version:
http://www.ra.danfoss.com/Technical...f_electronic_unit_ac-dc_04-2009_ei100g402.pdf
If your danfoss is a DC only:
http://www.ra.danfoss.com/Technical...nit_101n0600_12-24vdc_08-2011_dehc100m602.pdf
These will show you how to hook an additional fan to be controller by the danfoss controller, to run only when the compressor is running.
Hope this helps
Best to exhaust hot air from the high point in the vehicle but there should be a passive inlet somewhere down low to replace the air sucked out.
Moving hot air around inside the vehicle will do little/nothing for fridge efficiency.
dstock
Explorer
Had a little time to do some checking on things over the weekend.
On the plus side, I tested the voltage from the battery back to the end of the ARB cord that plugs into the fridge and had no voltage drop.
On the solar panel side, well, things were not so encouraging.
I swapped out the 14-16 gauge wiring for a short length of 8 gauge wiring. Even going direct to the battery bypassing my harness completely, the Watts UP meter only averaged about 30 watts from the 100 watt panel. Once or twice I saw close to 50 watts for a few seconds. This was at high noon with a cloudless sky.
So then I tested the output of the panels themselves which are listed on the backside of the panel at +-17.6 volts. Both panels were slightly above that in the 18-19 volt range.
The question now remains, why aren't I getting full power out of the panels/charge controller or at least averaging half of their rating? Is it a charge controller issue? Am I reading the info off the meter incorrectly?
I don't like the fact that the charge controller doesn't have ring terminals on it, the wedge the wire in and tighten a screw method doesn't seem very efficient to me. Others with this same panel don't seem to be having the same issues but wondering if anyone has really tested theirs using a meter.
Where do I go from here?
On the plus side, I tested the voltage from the battery back to the end of the ARB cord that plugs into the fridge and had no voltage drop.
On the solar panel side, well, things were not so encouraging.
I swapped out the 14-16 gauge wiring for a short length of 8 gauge wiring. Even going direct to the battery bypassing my harness completely, the Watts UP meter only averaged about 30 watts from the 100 watt panel. Once or twice I saw close to 50 watts for a few seconds. This was at high noon with a cloudless sky.
So then I tested the output of the panels themselves which are listed on the backside of the panel at +-17.6 volts. Both panels were slightly above that in the 18-19 volt range.
The question now remains, why aren't I getting full power out of the panels/charge controller or at least averaging half of their rating? Is it a charge controller issue? Am I reading the info off the meter incorrectly?
I don't like the fact that the charge controller doesn't have ring terminals on it, the wedge the wire in and tighten a screw method doesn't seem very efficient to me. Others with this same panel don't seem to be having the same issues but wondering if anyone has really tested theirs using a meter.
Where do I go from here?