Amp hours

[David]

Double post

 

[SternWake]

3 minutes on , 3minutes off is a 50% duty cycle. I.ve never seen my vitrifrigo exceed 40% And that was when loaded with warm goods on a warm day. Average is about 22%.

not only does hot air need to escape up top, but that rising air needs to pull cold air from below.

Norcold developed the reputation as never cold due to their installment in boats qhere they were not ventilated properly. In some cases not at all. Later models were designed so that the condenser could not be cutoff from air flow.

apparently a
most all Norcold s manufactured in the last two years are using danfoss compressors. Raplacing the louder less efficient sawafuji compressor. If you want that fridge to last and not suck your battery dry. You need to let that condenser and compressor breathe free and easy. Utilize convection currents. I used to have a small low draw silent computer fan blowing upward across the passive condenser. One time its wiring was compromised ans the duty cy le shot up noticeably

I cant stress the ventilation aspect enough. Not just for a power onsumption factor, but an interior temperature and compressor longevity standpoint

 

[David]

This one is a pretty old unit, but it does get cold. It will get frost on the freezer section. I think I'll likely add a computer fan on something like that to fore more airflow through the cabinet.

 

[SternWake]

If my Vitrifrigo ran a 50% duty cycle, It would freeze everything solid.

If your finned passive condenser is flat on the back of the fridge. You should have no more than 1 inch of open space behind it. This will help natural convection currents to draw in fresh cool air from below.

Meaning there has to be somewhere for cool air to come from, below.

A fan down there blowing cool air into the condenser space will work wonders.

It need not be a high airflow fan. In fact you pretty much want something very quiet with very little current draw. it can be as low as 5 CFM and be extremely effective as long as it is pulling ambient air and pushing it into the condenser compartment.

Computer fans vary wildly for how much air they put out for how much current consumed and noise made.

I've found Noctua fans to be rather impressive in the noise and currrent consumption areas.

Not the cheapest fans, but they have a 7 year warranty.

I replaced my 120mm condenser fan provided by Vitrifrigo, with a Noctua NF-f12. It draws less than half the current of the stock fan, and is quieter. I made it so it pushes air through the condenser, rather than pull it through it. My condenser looks like a small car radiator or auxiliary transmission cooler. These fans are quieter and work better when the resistance is in front of the fan blades, not behind them.

On my 2/12/25 amp Schumacher charger. I replaced the very loud and annoying 40mm provided fan with a Noctua 60mm:
http://www.amazon.com/Noctua-60x25mm-A-Series-Bearing-Premium/dp/B009NQMESS

These Noctuas come with 2 " low noise adapters" which are just inline resistors to reduce fan speed ,current consumed and airflow and noise. I actually used both inline and it draws 0.02 amps and I can only hear it, if I put my ear right up to it. It still moves more air than the original fan.

I did not use any low noise adapters on my 120mm Noctua. Other fridge Mods I did was add a fan to the interior:

and make a shroud to funnel all airflow through the condenser,

across compressor and compressor controller and either out a louvered vent in the conversion van sliding window in summer, or into the adjacent cabinet space in winter.

Danfoss compressors are nice because one can control the compresssor speed, as well as add additional fans to activate when the compressor does, upto 0.5 amps worth. It could power 10 of my 120mm noctua fans for total overkill and ~530 CFM.



I also have added extra insulation around the sides(3/4 inch foam board, two layers. and insulated the cabinet and the airflow path. Improvements could be made to the door, in terms of insulation.

My interior fridge fan runs 24/7. It consumes 0.03Amps. It does not make the fridge use less energy, but it does allow it to cool things placed within much faster, which can allow me to take advantage of a solar surplus in the afternoon a little bit better. I can crank the fridge up to 4 just after noon and then back to 2 at sundown and then the duty cycle is Much much less for several hours afterwards.

The interior fridge fan also evens out the internal box temps dramatically. Without the fan temps will range from 32 to 44 according to my IR thermometer in different areas.

Without the fan running I need to use a setting of 4 of 7 to keep the interior at 38 or below some areas will climb to the mid 40's. One wants the fridge to be 40 or below, Some say 39, some say 41. With the fan I can use a setting of 2 of seven to keep everything about 33F.

These modifications are hardly necessary. The compressor on my fridge can power a fridge 3 times bigger so it is just coasting along.

The Norcold is more challenged. I had one, with extra insulation, with forced airflow in and out, and the danfoss cools faster and uses less battery to do so, and makes 1/4 the noise. I was seriously bummed when it failed. but the Vitrifrigo is just such a better fridge, and it took real well to my modifications to increase efficiency

 

[David]

Figured I'd update again now that it's been a bit of time. After figuring out the ventilation issue, the fridge still cycled on a lot. After playing with the setting dial, I noticed it cycled a lot less when on the lower settings.

I had it on the highest when it was cycling too much. I lowered the setting and everything stays cool enough and it now probably cycles less than half of what it did on the high setting.

I'm still dealing with more overcast days than not, but I haven't had to unplug the fridge at all. It seems I'm averaging 2 cloudy days for every so so decent sunny day. Due to this my 200 watts of solar is not ideal but it skimps by as long as I'm careful of any extra usage.

I originally planned on a 300w system and I think that would be much better than what I have now. When it's lots of good sunny days, the 200w is more than enough, but when having 2 to 3 overcast days in between a single good sunny day, 200w is just not enough.

I think I may eventually look around for some smaller panels that I can add upstairs to get me closer to 300w. I can't fit another 100w but maybe I can fit 2 x 40w or something like that.

 

[SternWake]

Well, make sure the fridge is maintaining sub 41f temps, everywhere inside.

Yeah, it is hard having too much solar. I find 200 watts is sufficient most of the time, but a couple cloudy days and the battery(s) are cycling in that range where they just go lower and lower voltage each night despite having the same amp hours removed from them. I think of this as progressive capacity loss after days of not getting up near 100% daily. It seems a full day of sun, perhaps with a morning alternator blast assist is needed to "reset" their performance, and I gauge their performance by the voltage they can hold by the amount of Amp hours removed from them, and an occasional specific gravity reading on the Flooded battery.

This time of year there is plenty of sun where I am at, and I have a solar surplus, and am looking for ways to use the extra power.
As I type this my AGM battery is holding 13.07 volts and has not seen any charging source, or loads( besides engine computer memory) for a few days.

My flooded battery, as I type, is taking 3.5 amps at 14.5 volts. Once it requires less than 1 amp to hold 14.5, it will go into "float mode" which I have set at 14.7v. The amps will keep tapering down to 0.3 or so to hold 14.7 till the panels fall into shade.

The highest temp my IR thermometer can currently find in my fridge is 31.5f. It is on a setting of ~2.2 out of 7. I could certainly lower the setting further, for less battery consumption, but do not need to, and 2.2 of 7 ensures sub 35f temps in 90 degree ambients, so I do not have to bother moving the dial twice a day.

 

[David]

Yea with lots of sunny days I have zero issues and always an excess of power. However I've rarely had that over the last month. Yesterday was sunny but was very cloudy and the 3 days prior to that it was overcast with very little sun. Today yet again is overcast with sprinkles of rain..

Due to this, I've been stuck between 75-65% charge for several days. I'm sitting at 65% right now (2x type 31 AGM) and the next two days are also expected to be cloudy with chances of rain and won't be til Wed that it's a good sunny day...

It's been like this since I left FL which is crazy..but guess it comes with the time of year. Seems more like New England weather than being in Texas.. However on the plus note, the one sunny day I just had it was 85 degrees, so at least with no sun the weather is cooler lol.

 

[SternWake]

Well, if you are driving daily, it is a shame you do not have your house batteries wired to accept alternator current. The alternator can do a good job at bringing them to 80% pretty quickly if the cabling is sufficient.

I've found that even shorter drives, when the battery is depleted, can really help replenish it. Letting the solar take over after even a brief morning alternator blast, is when I see the highest retained voltages overnight.

BUt 65% to 75% is not freak out territory. After a week or 10 days without getting above that, perhaps I'd be getting edgy about it.

Most would not, then again most have no idea what state of charge their batteries are actually in, nor their remaining full charge capacity, nor when they are approaching that area in which the batteries can not meet their overnight needs.

 

[akrvbob]

This is a classic example of why whenever I'm asked how much solar to buy I always say as much as you can afford! There are times when "Too much" is barely enough.
Bob

 

[David]

This is a classic example of why whenever I'm asked how much solar to buy I always say as much as you can afford! There are times when "Too much" is barely enough.
Bob

Well I had designed my system to be 300w but it was for a class b that I started with. When I switched to the westy, I couldn't squeeze my third 100w panel up there, so had to go with 200. It's doing it, but days like today I just skimp by.

 

[SternWake]

I started with a 130 watt Kyocera panel, and it was enough at first, but then I started using my laptop more, and conserving less.

So I added a Unisolar 68 watt panel. Now between Mid March and early October I usually have a significant surplus. I was very wasteful last night streaming video on one laptop and updating the other(XP) while playing the stereo and placed a gallon of warm vegetable juice and a six pack of warm beer in the fridge. I used 50 amp hours in 8 hours, but now the batteries are at 14.5v and requiring only 2.2 solar derived amps to hold them there. And I am charging this laptop, have 4 fans, 2 lights and the stereo running music from my charging Android phone. The panels are making 8.3 amps. They could make about 10.5amps right now if they need to, like when the fridge kicks on. I have not used grid power in weeks, except when working. Hard to run a table saw from battery power.

I do have a few sections on my roof for some smaller panels, but I doubt I will go for more as opposed to finding ways to conserve more/ use less.

If you cannot fit any more solar on the roof, and cannot or will not take advantage of other charging sources, then conserving more is the only real option, If you are regularly hovering in the 50% range or below. A Mppt controller might be able to squeeze more electrons from the available solar if you do not already have one.

If the fridge is the biggest electrical consumer then savings can be found there, but perhaps not without fairly major modification. Really unless is is much bigger than 2.5 cubic feet it should be using well under 30 amp hours per 24 hours in upto 90 degree ambient. More than this consumption points to an issue, either condenser ventilation or poor door seals or just inadequate box insulation. Or you are just leaving the door open for far too long and putting warm items into it too regularly.

When I visit friend's houses I cannot believe how they treat their fridge. They will open the door and walk away for a few minutes, or just leave it open while they pour milk or something, and I can feel the cold air pooling at my feet from across the kitchen. A few years back there was a power outage for the whole county for a while, and I could not believe how long my friend's wife was leaving the door open on the fridge. It should not even have been opened it in such a situation.

Funny how neighbors were coming to me with their perishables asking me to store them. Like more stuff than my fridge could ever fit.

As I said before the fridge condenser and compressor needs to be bathed in ambient air. It cannot sit around in air it itself has already heated. Keeping the van interior cooler helps greatly. The Door seals, especially on an older fridge are highly suspect. Doing the dollar bill test on the seals, and adjusting the door to fit tighter can significantly decrease battery consumption. My Old Norcold was bad in this regard, requiring adjustment every six months or so. Trying to stuff too much food inside would leave the door cracked open at the bottom, and sometimes it stayed in this alignment even when unstuffed. The door was too flexible.

Also a big mass of Ice built up on the cold plate decreases efficiency. Regular defrosting the evaporator plate will restore lost efficiency. The Ice builds up much faster in humid weather. Do not use any sharp tools on the evaporator plate to speed the defrosting

I originally built my cabinet around the Norcold, and extra insulation, but when that fridge failed I still had the extra room for more added insulation on the Vitrifrigo, and perhaps a little more than the Norcold. I was also able to better bathe the condenser in coolest possible ambient air. Anyway the Vitrifrigo cools better, faster for less battery consumption and that is keeping the interior at sub 35f temps where with the Norcold I aimed for sub 39f.
I hope it lasts a long time.

If you have a Westy, and are a member of 'The Samba' forums, those guys know the best way to route wiring to the house batteries for alternator charging on VW platforms, but I personally think their Yandina or Gowesty combiners/separators and cabling are a little undersized for the task. Some are concerned with overwhelming the alternator with depleted batteries when using fat cabling, and this is a legitimate concern. More in some vehicles than others

But still, like solar, any alternator current, is better than no alternator current.

Other conservation measures are avoiding inverter use whenever possible. Charging USB devices by inverter is very wasteful, and laptop DC to DC "car adapters" if available, use much less electricity than an inverter powering the provided power brick.

 

[akrvbob]

There are options if you are out of roof space, but only for boondockers and if you have some interior space to give up.

1) Flexible panels can be rolled up and stored anywhere then laid out on the ground.
2) Folding suitcase panels can be stored in many places and then set out hen you set up camp.

They cost more per watt but offer a good option. But, not for stealth city dwellers, they'd give you away or be stolen..
Bob

 

[David]

There are options if you are out of roof space, but only for boondockers and if you have some interior space to give up.

1) Flexible panels can be rolled up and stored anywhere then laid out on the ground.
2) Folding suitcase panels can be stored in many places and then set out hen you set up camp.

They cost more per watt but offer a good option. But, not for stealth city dwellers, they'd give you away or be stolen..
Bob

I already filled up my extra space with a folding kayak..

However I don't think this Westy will be my permanent rig. It's nice for what it is, but I'd rather build out my own interior and I'd like a more modern engine. This is pretty much my extended road trip van for the next 6 months or more.

When ever I head back to FL, I'll finish putting together my 4x4 vanagon that I first bought. I was in the middle of putting a modern engine in that van and building it out as a camper but I came across this Westy and did a quick engine swap, installed solar, fridge and a few other things then hit the road a tad over a month after buying it.

My plan is to use this van until the other is on the road, then sell this westy. Who knows by that time maybe I'll sell them both and try something else.. I'm kinda like that.. If I could figure out a way to get 20mpg out of a full size 4x4 van I'd be all over it.