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#1

condor22
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From: Adelaide, SA
Joined: 16 December 2013
Posts: 1,382
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05 July 2018 03:41 pm

So, the purpose of this thread - I covered a fair bit of theoretical information in my thread on Bush Power.
https://www.prospectingaustralia.com.au … hp?id=9156

During the course of working out what I'm using from my van battery when bush camping, I thought it might assist others to note what the "real world" practical loads are. Of course this will vary slightly with individual needs and gear, but there are some constants or similarities.

The first part of the thread will concentrate on what we prospecters use. I already have a power consumption list of my caravan gear i.e. lights, TV, pump, heater etc and will post that following the test results. If others have other real world figures (not rated loads) please post, keep in mind that rated loads don't always match actual

I'll give my setup, the test parameters and then the results. I'll be using my caravan battery for the test, but I could equally do this from my auxilliary 4x4 battery and get very similar results. The specific battery size will not affect the results as all of the following are very low load charging, so wether you have 60AH or 300AH won't matter.

3 users like this post: 7.62marksman, Trash, Diggerman60

#2

condor22
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From: Adelaide, SA
Joined: 16 December 2013
Posts: 1,382
Member
05 July 2018 03:43 pm

My setup -

A fully charged 130AH AGM battery, cigarette lighter socket outlets at a nominal 12VDC and USB power outlets connected to the van battery outputting a nominal 5VDC (some are 1.0 amp some 2.0 amp output) and a BM PRO battery monitor that will give amps used and voltage.

Test parameters -

The van battery is fully charged, however, the 240VAC charger is OFF and the Solar panels are also OFF. During the test the battery will not be under charge.
There will be no other van systems, i.e. TV, lights etc used during the test. The only loads will be the items under charge. When the chargers are turned off the battery is at 13.8VDC, which is Float voltage, so it will be left for a time until it stabilises at its "at rest" voltage of approx 12.9-13.0 volts.

2 users like this post: 7.62marksman, Diggerman60

#3

condor22
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From: Adelaide, SA
Joined: 16 December 2013
Posts: 1,382
Member
05 July 2018 03:45 pm

The following items will be under charge using their relevant charge connector; From 12VDC cig socket;

  • GPX5000 Battery

  • SDC2300 Minelab Ni-MH C cell 5,000mAH x 4

  • Uniden 5W Handheld UHF UH076SX 7.4VDC Li oN 850mAH

From 5VDC USB;

  • Detech Wireless Headphones

  • Detech Tx module

  • Detech Rx Module

  • Samsung Galaxy S4 mobile

  • Telstra ZTE T96 mobile

  • Telstra WiFi module

To simulate use, all of the above items have been switched on for 5 hours to drain some of the battery capacity. Each item will be briefly placed on charge separately, to assess current draw and then all items in total. I expect some items will have a negligible reading and as the BM PRO reads to 1 decimal place in both volts and amps, that cumulative values will increase i.e. 2 values of 0.14 amps will each read 0.1, but added together will read 0.3.

I am currently discharging the above gear and keeping the van battery on charge. They will then rest overnight and I'll do the charge test tomorrow and post when done. smile

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#4

condor22
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From: Adelaide, SA
Joined: 16 December 2013
Posts: 1,382
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05 July 2018 04:03 pm

Re the time operating -

The charging loads that I will measure, for my gear, will be much the same, wether I have used them for 5 hours or 10 hours (assuming they last that long, lol).

The primary difference is obvious in that, the longer you use something, the lower the State of Charge (SOC). It then equates to time, as to how long each item will take to be fully charged.

What I can confidently say is that; If all of the above were placed on charge from a van or auxiliary battery in the late afternoon, left overnight to charge, they would all definitely be fully charged by breakfast the next day and with no ill effect to the source charging battery SOC.

Whilst I do these tests I'm adding another for my benefit - I have a 150W PSW Inverter and also a 240VAC Ultrasonic Ring Cleaner. I know it works from the Inverter, but don't know what the load on the van is, so I'll test that and post the results.

Plus whilst I have the Inverter in use, I'll connect the noted equipment to it to do a comparative test as I have 240VAC chargers for all of them. I expect a significant difference.

Last edited by condor22 (05 July 2018 04:03 pm)

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#5

Nanjim
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From: Perth
Joined: 22 March 2014
Posts: 469
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05 July 2018 06:46 pm

condor22,

This is going to be very interesting...

Cheers Nanjim
Jim


APLA Member. A bad days prospecting beats a good days work anytime....

#6

condor22
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From: Adelaide, SA
Joined: 16 December 2013
Posts: 1,382
Member
06 July 2018 01:58 pm

Ok, first lot of results - needs some other info, but, not to keep you in "suspenders" smile the results first;

1530845403_power_use.jpg

I ran everything for at least 5 hours to run their batteries down, I switched off the van charger last night, no solar and no loads. This morning the van battery was at 99% charge, 13.0 volts, zero load and 17 deg C. Of all of the gear tested the only device switched on was the Samsung S4 cos it has the battery monitor, but it was at 23% charge. It was only connected to van battery to check its charge rate, then disconnected.

The column marked "DIRECT" were the charge amps when connected directly to Van 12 VDC or through the USB charge socket which is powered from the same Battery. All readings were taken individually as I don't have enough outlets to run everything at once.

The column marked 240VAC/Inverter = a Projecta 150W PSW Inverter running the 240VAC charge adaptors for each item.

more...........

Edit - Of note, Batteries in items such as phones, WiFi, Laptops will take longer to charge to full if the device is on at the same time.

Last edited by condor22 (06 July 2018 02:44 pm)

1 user likes this post: woomera

#7

condor22
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From: Adelaide, SA
Joined: 16 December 2013
Posts: 1,382
Member
06 July 2018 02:10 pm

Of Note -

I have a cig socket bucket that has 2 skt outlets + 2 USB outlets and LEDS that show battery condition. When connected to my van it's residual power usage is 0.1 Amps with nothing else connected. (So a small cost on battery power).

However, the Inverter plugged in, switched on, but nothing connected uses 0.4 Amps residual. (A slightly higher power cost).

I also tested 2 other items that have no direct 12VDC connection, but can be run from the Van battery -

1. Toshiba Satellite Laptop - Internal Battery @ 19VDC. I use a 12VDC 150W Power supply (Jaycar) to power/charge. If the laptop battery is fully charged, the power supply draws 1.5 Amps, if it is not charged then it uses 3.5 Amps to run and charge the laptop. What I normally do here is; Use the laptop in the evenings from its internal battery, I get about 2-3 hours dependent on what it's doing. I then leave it on charge during the next day, switched off and with solar on. That way solar is recharging it, not the van battery.
Note - The 150W inverter will not run the 240VAC laptop power pack/charger.

2. A 240 VAC Ultrasonic Ring Cleaner - run from the inverter draws 4.5 amps. But, if only on for about 6 minutes total = < 0.5 AH.

1 user likes this post: woomera

#8

condor22
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From: Adelaide, SA
Joined: 16 December 2013
Posts: 1,382
Member
06 July 2018 02:24 pm

CONCLUSIONS

1. It is very obvious that running/charging anything directly from a 12VDC battery, that can be run, uses much less power than powering an inverter to do the same with their respective 240VAC adaptors. (in fact, nearly 1/3)

2. Most of the items in my list will fully charge in less than 6 hours and I would never be charging all of them at once. i.e. If I ran my SDC with wireless the total charge rate is 0.7 AH, the wireless would take about 3 hours max = 2.1 AH. The C cells might take another 3 hours = another 2.1 AH = total of 4.2 AH. My phones only get charged every few days etc.

3. I have 2 sets of C cells, so I can charge what I use today, tomorrow when I have solar and use the other set. I can charge all of the listed items from my vehicle whilst driving, or at lunchtime when having a break. Again as much about how you do it as when or where.

4. Managed properly, by selecting what and when, the daily load of charging can be as little as <6AH.

NOTE - The conclusions I draw or statements made, are what I consider correct for the equipment I have and the methods I use. Individuals need to consider these factors for their circumstances as they may and indeed will be different to mine.

Last edited by condor22 (06 July 2018 02:25 pm)

1 user likes this post: woomera

#9

condor22
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From: Adelaide, SA
Joined: 16 December 2013
Posts: 1,382
Member
06 July 2018 02:41 pm

As an addendum to the above, I recently completed a 7 week trip to the GT all bush camping. I ran a diesel heater for 12-15 hours (I leave it on overnight, but lower the temp.) Watched some TV, used the laptop, lights etc. as well as charging gear. The maximum power use I recorded was 30%, the average was about 25%.

Having a 130AH battery (3 way fridge) this equates to between 39AH max to the average of 32 AH.

Although I have 200W of Solar, I also carry a 2kVA generator as I use it to heat the hot water system and use the microwave, both to conserve LPG as I only have 2 x 4.5kg bottles.

So if it's running, (not every day) I turn solar off and the 240VAC van charger on, to top up.

I mention this, to reinforce what I stated in my Bush Power thread, that "It is better to have more than one option when bush camping as circumstances can change." i.e.

The sun don't shine, you have a LPG leak, the genny won't start, something breaks, fails or perish the thought, gets stolen. It can make the difference between sticking it out for the whole trip or having no choice but to go home early.

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#10

nucopia
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From: lake mac , NSW
Joined: 07 July 2015
Posts: 2,150
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06 July 2018 02:51 pm

Brilliant post Condor, very interesting and informative!
Thanks thumbsup


every day is an adventure
NAPFA Member

#11

goldtruck59
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Joined: 29 July 2013
Posts: 1,405
Member
06 July 2018 03:01 pm

Good report and findings condor.
Interesting about charging direct from battery rather than the inverter although it makes sense re using less power.
My set up I am considering for our project will vary with the smart system from Redarc which will automatically switch to the best available power charging source and money dependent, I will use lithium batteries. I also have 450w of solar panels.
Hopefully like you, I have a genset and whatever situation I should be able to enjoy extended off grid stays.
I also went where possible for inverter technology.

GT smile


PX Ranger Super Cab , GPX5000, Dog called Nugget, wife called boss.
From Near Bendigo

#12

condor22
Member
From: Adelaide, SA
Joined: 16 December 2013
Posts: 1,382
Member
07 July 2018 06:05 pm

Goldtruck - Sounds like a good setup, the Redarc smart system is all about charging the house/van battery system.

My main point in this thread is about what and how you use that van battery. So mainly for others and you if you like, an inverter is used to provide 240VAC out bush and needs to be understood to be used effectively. The size of inverter is definitely an individual thing and varies depending on what you want it for, what you have to drive it, how you replenish the battery that drives it and all of that needs to be considered as a whole system. I've seen so many out there with large inverters, small to medium battery capacity and "jerry rigged" charging wondering why they have battery problems. But I'll try not to repeat what I've already detailed in my other thread., lol.

It sounds like you are on top of all of this as although you don't state your battery capacity, 450W of solar and the Redarc system is a great start.

Strictly my opinion for what I have and need - As I mentioned, it seems ridiculous to charge low voltage, low current battery operated devices using an inverter, or indeed any appliance that has 12 volt capability. The items I consider low voltage/current and usually have a 12VDC adaptor available are;

Any rechargeable battery in the group including - mobile phones, Ipads, Tablets, detector batteries, GPS rechargeable, Handheld UHF, E reader, mobile WiFi, any AAA-AA-C-D cells, 3.7 Li on rechargeable, torches et etc and or USB voltage.

Appliances such as TV, DVD, Satellite Decoder, fan, Laptops are all devices that can usually be run from a 240VAC adaptor or a 12VDC adaptor and all will use far less van battery on 12VDC than from inverted 240VAC.

So it then comes down to; do you want to run a microwave, washing machine, power tool, sleep apnoea machine or similar from 240VAC. How often do you need to do so, do you have a suitable generator, are you in a location that allows a generator to be used.

For me, I rarely go where I can't use my genny, and have alternatives if I do, I always carry it, as you never know when it's needed. The only devices I can not run from my van battery are the van aircon, I rarely go off grid in summer and have diesel heating for winter, the microwave gets used most days for less than 10 minutes and my ultrasonic cleaner, which I can run from a 150W inverter.

So, I came up with a rule of thumb for my use, the maximum inverter I am prepared to use on my 130 AH battery/200W solar is 150W (I might consider a 300W but don't need it). Anything else that needs more grunt and is very infrequent, gets the genny treatment.

As I mentioned previously it really is a personal thing; Work out what you need first - Then look at what options are available to provide that need - then look at what process you might wish to use to determine which of those options you spend you hard earned on smile and remember, You get what you pay for......

The one thing I will reiterate for others is the cost of doing business with an inverter - next Post.....

#13

condor22
Member
From: Adelaide, SA
Joined: 16 December 2013
Posts: 1,382
Member
07 July 2018 06:24 pm

Using the formula

A=W/V the key point is; For whatever 240VAC Watts you use - you will use the same wattage from the 12VDC battery + an efficiency loss.

In my experience, count on approximately 10% loss. The example below is my actual experience with my first vans inverter, which was a 300W PSW.

To provide 300W @ 240VAC (using the above formula) will give 300/240 = 1.25 A (which is not huge and i.e. not enough to drive my laptop power supply)

The battery cost is again A=W/V which is 300/12 = 25 A. Then add about 10% = 2.5 the total amp draw on the van battery is 27.5 amps. The resultant cost on the battery is then multiplied by time.

Here's a real world example - disregarding battery capacity, you have a 850W microwave (that's its output) it uses 1200W of 240VAC to run and you have a 2,000W inverter.

1200/240 = 5 amps @ 240VAC, however, 1200/12 = 100 amps at 12VDC. You run the microwave for 6 minutes = 1/10 hour, multiply 100A by 1/10 = 10AH + 10% =11AH.

So you use 11AH to run this microwave for 6 minutes, which on a decent size battery bank is no problem. Monitor how many times you might do this.

The key thing to note is; the 100 amp draw on the cables between your battery and the inverter. They should be as short as possible, of the correct gauge to handle not only this load but the maximum rating of the inverter = 166 + 10% = 178amps and properly fused.

#14

condor22
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From: Adelaide, SA
Joined: 16 December 2013
Posts: 1,382
Member
07 July 2018 06:28 pm

I forgot to mention that unlike a cold cranker start battery that produces large current for short times, a deep cycle is more geared to moderate loads for lengthy times, so....

Dragging a huge current although for shortish times to power a large inverter, will reduce its overall cycle life compared to not using an inverter.

#15

goldtruck59
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Joined: 29 July 2013
Posts: 1,405
Member
07 July 2018 10:02 pm

Hi Condor

This is some of my set up. I will be able to run most things that I need.

3 x 100ah Lithium batteries
1 x Redarc BMS1230S2
1 x Redarc 2000W inverter
1 x Redarc Low voltage disconnect

I am hoping this in conjunction with my solar and genset will see me enjoy plenty of off grid camping.

Enjoyed your articles.

GT smile


PX Ranger Super Cab , GPX5000, Dog called Nugget, wife called boss.
From Near Bendigo

1 user likes this post: condor22

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