A battery drain experiment

[Rossue]

Haved used the now fully converted Transit van for a few outings and our Goal Zero 3000X wasn't cutting it...lasted only 2-3 days max. That is running an Isotherm Cruise Elegance 130 and an induction cooktop, and a Propex propane heater. All the other systems run off the van's dual 70 AH AGM batteries.

Pulled the following off of repardise.com:
Isotherm states the Cruise 130 Elegance chews up 418 watts in 24hrs. This is based on ISO standards ( ISO 15502:2005 and EN 153:2006):

Operation on 12 V with +5°C in the refrigeration space, ambient temperature +25°C

In van builder/dyi camper-guy speak, that works out to 1.45Ah. Here's our math: 418watt / 24h = 17.4Wh 17.4Wh / 12V = 1.45Ah

The Goal Zero is 280 amp hours so this clearly did not make sense given that the induction was used maybe 30 minutes a day at 500 watt draw. The Propex heater uses 1.4 A continuous draw and that too was used maybe 30 minutes/day.

Even with a low sun the two 195W panels should have helped us with the above for more than 3 days. Goal Zero has shipped us a new unit and hopefully that will take care of it, yet am a little concerned now and doubt I would want a larger compressor fridge that this one in the trailer.

[Hawkeye Ed]

Originally Posted by Rossue

Haved used the now fully converted Transit van for a few outings and our Goal Zero 3000X wasn't cutting it...lasted only 2-3 days max. That is running an Isotherm Cruise Elegance 130 and an induction cooktop, and a Propex propane heater. All the other systems run off the van's dual 70 AH AGM batteries.

Pulled the following off of repardise.com:
Isotherm states the Cruise 130 Elegance chews up 418 watts in 24hrs. This is based on ISO standards ( ISO 15502:2005 and EN 153:2006):

Operation on 12 V with +5°C in the refrigeration space, ambient temperature +25°C

In van builder/dyi camper-guy speak, that works out to 1.45Ah. Here's our math: 418watt / 24h = 17.4Wh 17.4Wh / 12V = 1.45Ah

The Goal Zero is 280 amp hours so this clearly did not make sense given that the induction was used maybe 30 minutes a day at 500 watt draw. The Propex heater uses 1.4 A continuous draw and that too was used maybe 30 minutes/day.

Even with a low sun the two 195W panels should have helped us with the above for more than 3 days. Goal Zero has shipped us a new unit and hopefully that will take care of it, yet am a little concerned now and doubt I would want a larger compressor fridge that this one in the trailer.

Rossue, you are absolutely correct that the information you found about the Isotherm Cruise 130 makes no sense. The first clue is the statement that is consumes "418 watts in 24hrs." Watts is an instantaneous power measurement, not a measurement of energy consumed over a certain time period; that's watt-hours.

According to the Isotherm Cruise 130 page on west marine.com, the refrigerator consumes "5 Amps at 12 Volts DC." That's 60 watts (5 amps x 12 volts). If the refrigerator ran constantly for 24 hours it would consume 1,440 watt-hours (60 watts x 24 hours). But if it only ran 29% of the time it would consume only 418 watt-hours in that 24 hour period which is perhaps where that 418 number came from.

According to goal zero.com the Goal Zero 3000X has the capacity of 3032 watt hours. (Their chart of run times also makes the mistake of using the abbreviation of "Wh" for watts, so no wonder people get confused.) So theoretically if your Cruise 130 only runs 29% of the time and uses 418 watt-hours in a 24-hour period, it should run by itself on your Goal Zero for a week (3032/418=7.25 days).

Take another look at your induction cooktop calculations. You say it draws 500 watts running half an hour a day. Five hundred watts is a pretty low setting for an induction cooktop. Even at a medium-high setting portable induction cooktops draw 800-1,000 watts. You might want to get a Kill-A-Watt or some other AC energy meter to measure the AC draw for a typical cooking session. Then add another 10% or so considering that the cooktop runs on AC which means you're also using extra battery power to run the Goal Zero's built-in inverter. Assume 1000 watts for half an hour run of the cooktop. That's 500 watt-hours (1000 x .5) right there, draining about 1/6 of the Goal Zero's capacity every time you use the induction cooktop for half an hour.

As you point out, your Propex heater doesn't use much energy, maybe 20-25 watts or so when it’s running which would equal 10-12 watt-hours of energy usage when you run it for half an hour.

One day’s worth of usage using these figures would be somewhat less than 1,000 watt-hours (418 for the refrigerator, 500 for the cooktop, 12 for the heater), So the Goal Zero 3000X would seem to last for three days before it empties. If you’re getting less than that, see if the refrigerator is running more than 29% of the time or if your induction cooktop is drawing more power than you estimate.

Good luck and let us know if you get different results with the replacement 3000X.

[rubicon327]

Originally Posted by Rossue

In van builder/dyi camper-guy speak, that works out to 1.45Ah. Here's our math: 418watt / 24h = 17.4Wh 17.4Wh / 12V = 1.45Ah

Check my math but I think something is up with the units. I think they really mean 418Wh over 24 hours. Watts per 24h doesn’t make sense. So that is an avg of 17.4 W. If you take the 17.4W / 12V nominal you get 1.45A avg draw that should then be multipled by the number of hours of operation. So if the fridge ran 24 hours per day you’d be looking at 34.8Ah.

[I see Hawkeye Ed provided a more eloquent and informative response. Bottom line - the confusing units are throwing the math off]

[Brian B-P]

Originally Posted by rubicon327

Bottom line - the confusing units are throwing the math off

That's generous. In fact, the blatantly incorrect units published by the morons at Goal Zero make meaningful communication impossible.

I wouldn't buy this sort of equipment from a company which can't even keep watts and watt-hours straight. But then, they're probably just slamming whatever components they can get cheapest from Alibaba into a box, so maybe it doesn't matter.

[Rossue]

The calcs were from reparadise.com not Goal Zero. You can see the whole article here: https://reparadise.co/product/isothe...-130-elegance/

I bought the Goal Zero at REI last June and have a year to return it. I hope I don't have to as building components is the other option and would rather not have to. These "solar generators" are becoming very popular with van conversions and Goal Zero has a lot to like from my perspective and after shopping the main competitors including Bluetti and Jackery. GZ has a reputation for very good Customer Service and so far I have experienced that first hand a few times, especially last week. Normally in a swap they send out the Hazmat Box and label you send your old one in and they ship out the replacement. I asked if I could secure a new one being sent out first with a credit card and they said they had my card on file from me buying a cable or something and two days later I received the new unit.

I like the Anderson Power Pole connectors for the solar input and for the refer 12V output. The display shows me was the consumption is- that's how I see 500 watts with an induction burner set on level 5- which is plenty to boil water (8 minutes for 4 cups) or to saute something. There are enough connections on the face so I didn't have to use a fuse block. So will report back after another test; keeping fingers crossed.

Edit- just ran the induction and it is 795-800 watts. Not sure where I got 500 from.

[Brian B-P]

Originally Posted by Rossue

The calcs were from reparadise.com not Goal Zero.

Ah, good catch - I wasn't paying enough attention. So just don't believe anything from the morons at reparadise.com.

[John in Santa Cruz]

I second hte motion re Goal Zero customer service. I had an older LED lamp from them, the Torch 250... it has a captive USB cord to recharge (also a solar panel that would take a week in direct summer sun to fully charge, and a hand crank generator which would take hours of cranking), and multiple lights, a nice warm wide soft floodlight with 2-3 brightness levels, a conventional spotlight/flashlight, and a red emergency blinker modes.... anyways the USB charging connector got flakey so I couldn't recharge it, and the rubber coating on the outsides got sticky (like so many things from about 10 years ago with that style of rubber-skin-over-plastic). I contacted their tech support via email, asking if I could get the captive USB cord, and they sent me a brand new Torch 500 current model for completely free without any hassle.

[Jack!]

Originally Posted by Mike Lewis

I ran an experiment on how fast my batteries drain.......
boondocking for weeks on end. Those who go out for a week or two might be okay with my setup.
Comments?

Thanks for your experiment! We get out trailer in Feb so no real use info about how our planned electric setup will work out. Goals similar. Boondocking a week or two without or minimal generator use.

Installing 4-100ah batteries, 380 roof solar on a mppt 50amp controller & a second mppt 30amp controller for a portable panel we don't have yet.

Will have the 3-way fridge on propane but based on your experiment looks like our setup will do at least a week of general power usage and perhaps almost 1.5-2 weeks with an added 200amp portable. We sized our controllers for the future & perhaps better panel tech.

Seems our setup in in the right ballpark based upon your experiment.

[rubicon327]

Originally Posted by Jack!

Thanks for your experiment! We get out trailer in Feb so no real use info about how our planned electric setup will work out. Goals similar. Boondocking a week or two without or minimal generator use.

Installing 4-100ah batteries, 380 roof solar on a mppt 50amp controller & a second mppt 30amp controller for a portable panel we don't have yet.

Will have the 3-way fridge on propane but based on your experiment looks like our setup will do at least a week of general power usage and perhaps almost 1.5-2 weeks with a 200amp portable.

Seems our setup in in the right ballpark based upon your experiment.

Mike's experiment had a 4.15A constant draw. If you have your fridge on propane and only misc DC loads / minimal inverter loads you should be able to go indefinitely without charging on generator if you have decent output from that much solar. Just for some context we have a 400AH lithium battery and no solar and could have easily gone 3+ weeks with just lights, furnace, phone charging and occasional microwave use on inverter. Trailer was setup as a steelhead fishing basecamp outside Erie, PA. Furnace turned down and minimal load during the day while fishing.

[David Hendrickson]

Your assumption of 4 amps is pretty close. With 400 ah battery bank that would give you 100 hrs or 4 days of run time in total darkness. I'd like to think the sun will shine tomorrow to that's not realistic. You also aren't considering the compressor fridge doesn't run 24/7. It cycles on and off just like the residential fridge you have at home. You're over thinking this.

[Mike Lewis]

I ended my battery drain experiment on December 19. I shut everything down so that I had a remaining parasitic load of about an amp or less. My 400Ah capacity battery bank was at 26% state of charge then.

Since then I've had all kinds of weather, which is desirable for experimenting with solar charging. I had sunny days, stormy days, overcast, etc. The only anomaly was that the temperatures were unusually warm.

It took until today, December 29, for the battery bank to reach 100% charge. That's ten days; longer than I thought it would take. FYI

[hotfishtacos]

Well, I just had to chime in on the statement, "A compressor refrigerator is not practical for extended boondocking." Not True! I have one of the first compressor refrigerators I installed in my 19' years ago and I can go boondocking with plenty of power as long as I have sunlight. My system has 3 solar panels with four 6 volt deep cycle AGM batteries and, for example, I was boondocking 5 weeks including the entire month of October, 2018 in Lee Vining, CA with no problem with no hookups. Used the onboard 4-speaker stereo system constantly, using power for lighting (LEDS), coffee grinder followed by Mr. Coffee Maker on the Inverter for 30 minutes each morning, when water pump off and on during the day, CPAP system at night with humidifier, Cell Phone Power Booster going online in the evening with 2 tablets, etc...no power problems ever. I believe the 4 batteries give me more than enough capacity between charges and the three panels are plenty for replenishment. My duty cycle for my 7.3 cu ft refer is around 50%....2.6 amps/hr. I am generally fully charged up by 9:00AM-10:00 AM every day...and I did not feel it was necessary to align my solar panels for optimum power production so I left them flat the entire trip.

We especially like camping in Wyoming, Montana and Idaho during the spring and fall and I will adjust my solar panels for optimum power production during these seasons when that far north. When adjusted like this my solar power improves by at least 30% - 40% and is still plenty to support the compressor refrigerator.

During those few times I have no sun for several days I need to run my generator to refill the batteries....not very often.

[rubicon327]

Originally Posted by Mike Lewis

I ended my battery drain experiment on December 19. I shut everything down so that I had a remaining parasitic load of about an amp or less. My 400Ah capacity battery bank was at 26% state of charge then.

Since then I've had all kinds of weather, which is desirable for experimenting with solar charging. I had sunny days, stormy days, overcast, etc. The only anomaly was that the temperatures were unusually warm.

It took until today, December 29, for the battery bank to reach 100% charge. That's ten days; longer than I thought it would take. FYI

I did some rough math accounting for 50% output of a 355W array due to flat panels and low winter sun. Figured on 5 hours of actual peak production to account for slightly shorter winter days and variable weather. If you were using 24AH per day and trying to recoup 300AH into the battery I came up with ~10 days. Maybe just a coincidence but I think my math is good.

[John in Santa Cruz]

i'm about to install 400AH of 12V LFP (a pair of SOK 206AH's), and I'm getting a Norcold n2175, which says 7 amps running 'normally' and 5 amps in 'night mode'. so if thats an average of 6 amps, and its running 50% of the time in extremely hot weather (a reasonable assumption), my 400AH should be good for at least 4 days without any solar or AC or tow vehicle charging. in moderate weather, I expect a 25-30% fridge duty cycle, that will last at least 5 days.

now, I also figure, with 360 watt flat rooftop solar, in GOOD sun, a heavily discharged 400AH battery will take about 4 days to fully charge. in the winter, a lot longer. Worse case, I add another 360W 40V panel (60 cell), but finding room for that could be challenging. maybe the 2nd panel will be a home made folder with a powerpole connectorr into the trailer system, so I can optimally aim it for better pookah.




(thats my factory 160W panel)