[Travlin]

Yeah, I'm not sure how they would measure everything without sending it all through the shunt. At one place on the page it indicates reading 100 Amps, and at another it mentions 14 gauge wire. At 100 amps the 14 gauge wire could be called a heater, a welding rod, or, maybe just a fuse. It won't be wire for long. ha ha



If you want an accurate assessment, all the current flowing in the system should be measured. This is the purpose of the shunt being placed near the battery on the negative lead. Everything used will go through it. Measuring the difference across its small resistance reveals the necessary data to determine the answers.


If you might want a Bogart for a discounted price there may be one in the classifieds.

 

[Ben]

Finally finished (almost) and tested the kitchen cabinet, I just need to make the countertop now.. no big deal I just need some time... oops..

As you can see it follows the same theme as the driver side cabinet (see previous posts)..

Report from the week-end :
- having a fridge is soooo cool ! (pun intended), I basically took the food and ice creams from my home fridge, dropped it in the van, added a couple beers, GO !
- having a fridge (my fridge) drains the battery... I believe so ... : I left Friday after work, started the fridge while the van was still getting some sun (I know, I should have started in the morning.. I'm not that organized..) while I was packing the van. Saturday morning the solar controller was showing 12.6V on the battery. Oh please note that I don't have those fancy battery monitor YET... so battery SOC is guesstimated from battery voltage. 12.6V should reprensent +-80% SOC, that's fine ! A bit cloudy during the day but not that bad, the solar controller was showing some good charging activity. Sunday morning 12.4V.. hum.. that's weird I was hoping the solar panel would fully recharge the battery during the day so I was expecting 12.6V again the next morning, + I didn't really spent lots of time with the lighting ON, maximium 2 hours I'd say.. the Maxxair was running 1/3 speed all week-end though. sunday a bit cloudy in the afternoon but overall lots of sun, charging was good ! But this morning (monday) it was showing 12.3V when I woke up, that's a good drop.. no lighting yesterday night, and I turned the fan OFF in the middle of the night...
So yeah, after 3 days I felt like the solar panel (295W) was not enough to recharge the battery (230 AH) at 100%.. a bit disappointing and surprising at the same time.
What I noticed is the fridge doesn't cycle, it looks like it runs 100% of the time to maintain its temperature, I never heard it start or stop, always on. It's a 2nd hand fridge (Dometic/Waeco CR50) I got from a trucking company, might be 10 year old but the temperature test they gave me was OK.. it showed it could reach and keep its temperature, but it didn't show if the fridge was running full on to achieve that, which could explain the energy consumption..
Anyone with this kind of fridge can tell me if his fridge cycles on/off or if it's running all the time ?

Since for now I'm relying 100% on solar and winter will arrive soon (even less sun available), I need to address that.
First I know I have to buy a real battery monitor to accurately control the SOC and how the energy is used.
Then I have a 120V charger for the house battery, a good one (Samlex 1230UL) but I never installed it. I used it to keep the battery charged while I was building the first cabinets of the van. Since I already have that, I plan on sourcing a 12V/120V converter and plug those 2 back-to-back to recharge while driving. A battery-to-battery charger would have been my first choice since I don't know yet how I will prevent the "converter/120V charger" combo to drain my van battery if I forget to turn it off... but it's pretty expensive.
A simple isolator might do the trick for charging though, I know it's not the best way to charge since you never achieve the 100% SOC like a real multi-stage charger, but if it can help me "refill" the battery to let's say 90% then the solar takes care of the rest.. it might be enough.
Any thought ?
Also do I really need a pure sine inverter to plug the 120V charger ? I don't need 120V for anything but the charger... which will convert it back to 12V DC anyway..

 

[orton]

Something is not right.

I have a 85 liter refrigerator and a 300 watt solar panel and have no problem getting back to 100% before noon on a sunny or even overcast day.

The refrigerator runs about half the time in 70 degree temperatures. What temperatures were you camping in?

Overnight with just the refrigerator running I am at 95% SOC in the morning with a 255 amp-hr battery.

What is the voltage of your solar? Do you have a MPPT solar controller?

I have a hole in the floor so that with the open Maxxair gets enough air flow without running the fan.

Do you have LED lights.

 

[Ben]

It was around 80 degrees (F) almost all the week-end, and around 65 at night.

I use a MPPT solar controller (Tracer 4215), if I remember correctly yesterday in full sun the panel was giving me around 35V, and the controller made it a 13ish V for charging.

I too have a hole on the floor for the Maxxair to pull "fresh" air from outside but I still have to run the fan (even on lower speed) for the air to flow enough.
I also added a small computer fan on the back of the fridge so the compressor doesn't get too hot.
And yes of course my lights are LED
What I'm sure of is the fridge is running full time though, I would hear it at night it was cycling.. and as the week-end passed, the fridge was less and less full, that could explain even more energy to keep it cold..
I really need a battery monitor to have serious data about all that.

Something is not right.

I have a 85 liter refrigerator and a 300 watt solar panel and have no problem getting back to 100% before noon on a sunny or even overcast day.

The refrigerator runs about half the time in 70 degree temperatures. What temperatures were you camping in?

Overnight with just the refrigerator running I am at 95% SOC in the morning with a 255 amp-hr battery.

What is the voltage of your solar? Do you have a MPPT solar controller?

I have a hole in the floor so that with the open Maxxair gets enough air flow without running the fan.

Do you have LED lights.

 

[bicyclist]

Yes, you do need a monitor. If the battery is discharged to the point that it was showing 12.3 V, I would expect the charge controller to be pumping out way more than 13 ish volts. Something is not right with the charge profile.

I've had 3 fridges over the past few years, each larger than the last. All of them cycled on and off. Like Dave, I have an 85 liter fridge, now, and have almost identical performance.

 

[Ben]

My guess (and hope..) is that the solar is OK and maybe when I had a look at the display (early afternoon) the battery was already full again and in "float" mode.
On the other hand, the fridge was running non-stop and since I was slowly eating all the content of the fridge it had to run even harder and harder to keep the temperature, hence the lower voltage day after day when I was waking up...

I just pulled the trigger on a Victron BMV-712... might give me a better understanding of everything.
Can the Victron monitor show me a graph with how much was pulled/pushed in the battery along the time ? (on the phone through the bluetooth thingy ?) so I can know if the fridge cycles or runs constantly for example ?
And also can it differenciate what is pulled from the battery (loads) from what the charger "gives" to the battery ? of does it just gives the sum of "loads" (negative AmpHr I guess..) + "charge" (positive AmpHr).


Orton -» I do have a special question for you since you're the one who supports the "inverter+charger combo" to replace a B2B charger... Does a charger absolutely needs a pure sine inverter to operate ? (the inverter won't be used of anything else.. in theory...)

Yes, you do need a monitor. If the battery is discharged to the point that it was showing 12.3 V, I would expect the charge controller to be pumping out way more than 13 ish volts. Something is not right with the charge profile.

I've had 3 fridges over the past few years, each larger than the last. All of them cycled on and off. Like Dave, I have an 85 liter fridge, now, and have almost identical performance.

 

[orton]

Orton -» I do have a special question for you since you're the one who supports the "inverter+charger combo" to replace a B2B charger... Does a charger absolutely needs a pure sine inverter to operate ? (the inverter won't be used of anything else.. in theory...)

Do not know the answer. I would call the manufacturer of your charger to get an answer.

SOC meter: My Magnum remote has the ability to show all kinds of information but I just leave it set to SOC. I have no control over what the system does so no need to look at the information. I can control what I do based on the SOC. If needed I can use the shore power charger with power from the vehicle powered inverter, not use the microwave or not heat shower water using the house battery/inverter.

 

[bicyclist]

My guess (and hope..) is that the solar is OK and maybe when I had a look at the display (early afternoon) the battery was already full again and in "float" mode.
On the other hand, the fridge was running non-stop and since I was slowly eating all the content of the fridge it had to run even harder and harder to keep the temperature, hence the lower voltage day after day when I was waking up...

Based on the fact that it's a second hand fridge of unknown age, I'd guess that it might just be old and tired like me. Might just be a little low on gas.

 

[pricklypear]

Finally finished (almost) and tested the kitchen cabinet, I just need to make the countertop now.. no big deal I just need some time... oops..

Picking up on this old thread. I was hoping you could post some photos of your finished build? I guess i'm five years too late but I would like to see it. Also, wondering where you sourced the side rails you used for your sliding bed? How has it worked out for you?