More on Bush Power

[Nightjar]

DD,
My panels in series are hooked up to a Morning Star gizmo, don't ask me the details but do know a PVM wouldn't handle it so upgraded.
Weeks in the bush away from the grid and caravan electrics never let us down over past 10+ years. (On second pair of AGM's)

 

[Ded Driver]

Morning Star is the trick Nightjar. this explains it
https://www.morningstarcorp.com/products/sunsaver-mppt/
Sun Saver MPPT Controller "Converts 36v or 24v PV arrays"
& the ProStar MPPT is rated to Max. PV Open Circuit Voltage (Voc)
120 Volts (without damage to unit)
I hadn't looked at these units before

 

[condor22]

Ded. A good bit of advice, like most things, doing the research instead of blindly hoping for the best is always safer.

Even the best of us can have a brain fade. I remember years ago (well over 20) when I first bought my Engel, I had a Ford Station Wagon, no Aux battery and an after market alarm system installed. The fridge was plugged into the cars battery, not the IGN. At that time we always stayed in van parks, so it was ok when driving and when we parked up, I'd run 240V out to car and plug the Engel into mains power.

We went to Copley past Leigh Creek toward Arkaroola and I remember it was pretty warm up there. Got to the van park, I got distracted, I won't say what, but forgot to put the Engel on mains. About 5.30 the next morning we were rudely woken by the car alarm going off and the headlights flashing on and off. The alarm module under the hood had a key isolator which I used, that shut the noise off, but not the flashing lights. After buggering around and not finding an easy fix, I disconnected the battery and went back to bed. (FYI, the alarm had its own siren and was it loud.)

When I got up, I found the main battery was totally dead and the remote locking not working. I called the local RAA guy out. Short story, cost me a new battery and not cheap up there. He and I spent over an hour getting the central locking working and the alarm back into sync. and no radio for the rest of the trip as the code was at home.

All because I thought, "it'll be ok" taking the easy way out.

(The alarm had a voltage sensing circuit that if it went too low or someone cut power, it would trip into alarm on it's own for a time period, so the fridge flattened the battery and well, the rest is history, lol)

 

[Jaros]

Easy to do once you reach a destination. Might be a good check list in the camper to make sure everything is set and running well. The same checklist can be applied to make sure that you haven't forgotten anything.
Happy Camping-Sat Tv and all.

 

[Nightjar]

Been there done that, came home from a trip, transferred left over from fridges to home fridge.
Several days later got into cleaning up van, and during the process I checked the battery readout. Batteries dead flat.
Checked fridge, and yes had left it on 12V.
Connected 240V grid to the van and the battery charger didn't respond.
Removed both batteries from van and took them out to the shed and connected portable charger, still no response.
Broke out in a sweat at this stage (Batteries near new)
Remembered old advice from years gone bye about "jump starting a battery" so I connected parallel a fully charged spare battery I keep in shed to one of the flat ones.
Connected charger to the charged battery and it kicked in. Left it charging for about 1/2 hour then disconnected flat battery and connected charger.

Charging commenced and eventually was able to recover both dead batteries. These two batteries are now going into their 8th year.
We have used what Jaros mentioned in last post from that day on.
A "to do" list at beginning and end of each trip.
Also set the Morning Star to disconnect any load at 11.6V? (Would need to check to verify.)

CTX,
You're a battery man. How many dead batteries have you renewed and then found you can jump start them and bring them back to life?

 

[ctxkid]

CTX,
You're a battery man. How many dead batteries have you renewed and then found you can jump start them and bring them back to life?

about 50% will charge
an about half that live on :Y: with limited capacity
depends on how flat they have been , so many variables

 

[condor22]

Add to that - How old it was when it went flat, what DOC and how often, brand of battery, etc etc, lol.

I met a guy a couple of years ago with a camper, he had 3 batteries. One was a brand new 100AH AGM, the second was an 80AH at least 5 years old and the third another 80AH Optima Yellow even older. He had a portable solar panel plugged in and a genny but not a real good charger. He was running out of juice with the 2 x 80AH, so his solution was buy another bigger battery and add it to his bank. All he ran was a small 12V fridge, TV and a light or 2. I estimated his consumption at 35-40AH max, which is a little more than I run on 1 x 130AH and he had twice that.

Only weeks into using the setup, he was again running out of battery, they weren't holding charge and the voltage was definitely low.

I told him (politely) his mistakes were. Mixing old with new, mixing battery types, different capacities and not charging properly. He took a bit of convincing re battery ages as I told him simply that if one of his original 2 was near death, it would very quickly bring the others down to its level, including the new one.

Never did find out what he ended up doing as he gave up and went home

New batteries all round and a decent charger was the answer.

 

[ctxkid]

Playing in the sun waiting for the race

So close

?

 

[ctxkid]

It is a 30amp mppt

 

[Opalian]

Our van came with an auto changeover switch between Solar, 240V & 12V. The ute was wired and fitted with the rectangular type plug.
When we towed the caravan on a long haul and the fridge was running on 12v (draws approx 14amps) we noticed a slow drop off on fridge temp. (Wireless thermometer in cab)
I fitted an auxiliary battery activated via solenoid when ignition on.
Fitted a third deepcycle again isolated with a solenoid when ignition off. This battery runs the fridges on ute and was wired to the towing plug.
Long hauls the caravan fridge still warmed. (Van has two 110AH deepcycle.)
Next step ran two light duty welding cables from the deep cycle through a 100 amp fuse to an Anderson plug on tow bar. Same type of cables through to van batteries. (Again through another 100 amp fuse)
Now hook up the van connect both plugs and drive the thousand K's to our camp and the fridge remains at constant 2C
As soon as we stop for any extended time plugs are disconnected, van swaps to solar and we run fridge on gas.
Problem solved.

Yes. I had similar problem, and swapping the power supply cables from factory provided, to heavy ones did a job. DC power has its own specifics, it doesn't like thin cable, as the power runs only over the exterior part of the cable, not over all its dimension as it is the case with AC power. . But, since then, I changed my towing car to the diesel, and I swapped my Dual Battery system from the old car to the one I'm using now. Now back to work again, still a bit to do. Quite a bit of mucking around with all this, but saves a ton of money on electrician if you know what you are doing and follow the safety procedures.

 

[bicter]

DC power has its own specifics, it doesn't like thin cable, as the power runs only over the exterior part of the cable, not over all its dimension as it is the case with AC power.

Do you have any references to explain this?
I've never heard this theory before, the only case I'm aware of is skin effect at UHF frequencies and above, including radar wave guides.

 

[Opalian]

Fellas,
Reading between the lines of preceding posts am I correct in assuming you do not combine solar & alternator charging while travelling?
My set up has a permanent 64W solar on roof through a PVM to the accessories deep cycle battery.
The alternator is wired permanently but can be manually isolated if need be. Usually when I'm home and fridges are removed.

I don't want mine all linked, I would rather have each system as a stand alone system, reason for that is if one goes down then I can switch it over or off myself, In the beginning I found so many experts on camping forums all over the www. It just got too confusing because they all had their own Ideas So I gave up on the concept making it all work as One, If one thing goes down then I can switch it out in under 5 minutes and I don't have to pay an Auto electrician a couple of hundred bucks just to tell me it's knackered.

I got a 100w Panel which will soon become my portable kit being replaced by 560w fixed set up and then I have the genny so I can power my Big workshop charger or one of the many smart chargers that Annoy the living $(!% out of Me, and Finally I am adding a 500w wind Turbine, and then I could always add a back up supply from the truck if needed.

You need to run the dual battery system always separate from the solar panel, as their charging voltage rates are vastly different, then the charge regulators between them will not agree, and you will land up with lesser charge. The best, cheap, solution is to use manual switch to disconnect an alternator charging, or the solar panel charging when driving. There is difference in the rate of charging by alternator, which is just under 14VDC, (actually 13.8VDC or so) and solar panel which pumps about 18VDC, throttled down to 14,4 or 14.5V into the outlet to the battery. This is vastly different and the regulator will not accept the lower voltage from the alternator, even if the amperage is a lot higher. This is the way they are made. Best way, and cheapest, is to use a manual switch, or buy more expensive automatic switch type dual battery system, where power from the solar gets cut off right in the moment, the car gets started. I don't really know the exact process, as I'm not an electrician, but from the life experience I know it is better to run all these things separate if you wish to use the long time with no failures. The wind generator is great to work in combo with solar, as their regulators use the same, or almost the same voltage parameters and are used that way in the out of grit life situations at many small mining settlements and towns - especially on the outskirts of such towns, and at almost all remote Camp Sites. The wind generator makes a great solution for the overnight power top-ups, as generally there is more winds over the nights, early mornings and evenings, when the solar is not working anymore.

 

[Ded Driver]

Depends on the DC-DC charger, & if it is a multi-input.
My IDC45 prioritises Solar input 1st if its connected, then tops up with however much more is required from the alternator, if its connection is 'on'. So if Im getting 5A from the Solar Panel, it will also pull up to 40A from the Alternator, depending on which part of the charge cycle it is in, & how much is needed.

 

[Ridge Runner]

Fellas,
Reading between the lines of preceding posts am I correct in assuming you do not combine solar & alternator charging while travelling?
My set up has a permanent 64W solar on roof through a PVM to the accessories deep cycle battery.
The alternator is wired permanently but can be manually isolated if need be. Usually when I'm home and fridges are removed.

I don't want mine all linked, I would rather have each system as a stand alone system, reason for that is if one goes down then I can switch it over or off myself, In the beginning I found so many experts on camping forums all over the www. It just got too confusing because they all had their own Ideas So I gave up on the concept making it all work as One, If one thing goes down then I can switch it out in under 5 minutes and I don't have to pay an Auto electrician a couple of hundred bucks just to tell me it's knackered.

I got a 100w Panel which will soon become my portable kit being replaced by 560w fixed set up and then I have the genny so I can power my Big workshop charger or one of the many smart chargers that Annoy the living $(!% out of Me, and Finally I am adding a 500w wind Turbine, and then I could always add a back up supply from the truck if needed.

You need to run the dual battery system always separate from the solar panel, as their charging voltage rates are vastly different, then the charge regulators between them will not agree, and you will land up with lesser charge. The best, cheap, solution is to use manual switch to disconnect an alternator charging, or the solar panel charging when driving. There is difference in the rate of charging by alternator, which is just under 14VDC, (actually 13.8VDC or so) and solar panel which pumps about 18VDC, throttled down to 14,4 or 14.5V into the outlet to the battery. This is vastly different and the regulator will not accept the lower voltage from the alternator, even if the amperage is a lot higher. This is the way they are made. Best way, and cheapest, is to use a manual switch, or buy more expensive automatic switch type dual battery system, where power from the solar gets cut off right in the moment, the car gets started. I don't really know the exact process, as I'm not an electrician, but from the life experience I know it is better to run all these things separate if you wish to use the long time with no failures. The wind generator is great to work in combo with solar, as their regulators use the same, or almost the same voltage parameters and are used that way in the out of grit life situations at many small mining settlements and towns - especially on the outskirts of such towns, and at almost all remote Camp Sites. The wind generator makes a great solution for the overnight power top-ups, as generally there is more winds over the nights, early mornings and evenings, when the solar is not working anymore.

No I don't,

I am not running that type of system, I don't want my AUX batteries connected to the vehicles charging system because Alternators are not designed to charge flat batteries, They normally put out a high charge for the first 20 minutes or so and then they drop the voltage down to a nominal level, And depending on the SOH of the batteries excess charging can lead to Alternator failure.

 

[Nightjar]

Must have jagged a lucky set up?
My permanent solar on the cab roof charges the 110AH deepcycle through a PWM regulator.
The alternator also charges the same battery on the road.
I fitted this set up in my ute in 2002.
An ignition controlled isolator disconnects alternator/vehicle system when ignition is "off."
If it is a no, no can someone explain why it has functioned perfectly for all this time?

 

[BigWave]

DC power has its own specifics, it doesn't like thin cable, as the power runs only over the exterior part of the cable, not over all its dimension as it is the case with AC power.

Do you have any references to explain this?
I've never heard this theory before, the only case I'm aware of is skin effect at UHF frequencies and above, including radar wave guides.

bicter, you are absolutely correct. For DC, the current is uniform throughout the wire.
For AC, the skin effect increases the current density towards the outside of the conductor. This effect increases with increased frequency.
At 50Hz in copper, the skin depth (where the current has dropped to around 37% compared to the surface) is around 9.3mm, so there is no noticeable difference in current density in household ac wiring.
at 1kHz, the skin depth is around 2mm, and around 0.065mm at 1MHz. This is why Litz wire is used in better PI coils.

 

[bicter]

Thanks Bigwave,
I couldn't be bothered providing an in depth rebuttal of Opalians misconceptions.
I must admit to being a little confused where you refer to a skin depth of 9.3mm, whats that in reference to?

"This is why Litz wire is used in better PI coils." and also why TV antenna, VHF & UHF, are made from aluminium tubing

Nightjar,
It has functioned perfectly for all this time as I have a sneaky suspicion that you had very good advice over the years and followed up on it.

 

[BigWave]

Hi bicter,
Say you have a very large diameter copper wire carrying DC, the current density is uniform throughout the wire.
For AC however, the current is increased towards the outside of the wire due to increased "back EMF" towards the wire's centre. The current density decreases away from the surface. The "skin depth" is the depth at which the current density is ~37% (chosen as 1/E - the Naperian logarithm (2.718281828)) of that on the surface.-This skin depth decreases inversely to the square root of the frequency in non magnetic conductors. i.e.: at 4 times the frequency, the skin depth is roughly halved.
At very high frequencies, save money by making conductors out of tubes - the internal copper does nothing. At microwave frequencies, a thin silver plating on the outside of a stronger internal structure (even glass), is all that's required, although the silver should be protected in a pressurised Nitrogen environment (viz: as used in professional waveguides).
Sorry to diverge from the intent of this thread, but the question was asked.

 

[grubstake]

Must have jagged a lucky set up?
My permanent solar on the cab roof charges the 110AH deepcycle through a PWM regulator.
The alternator also charges the same battery on the road.
I fitted this set up in my ute in 2002.
An ignition controlled isolator disconnects alternator/vehicle system when ignition is "off."
If it is a no, no can someone explain why it has functioned perfectly for all this time?

I was just reading an article (https://www.solar4rvs.com.au/buying/buyer-guides/choosing-the-right-solar-charge-controller-regulat/), which I think covers this situation in its closing paragraph:

 

[Nightjar]

Nightjar,
It has functioned perfectly for all this time as I have a sneaky suspicion that you had very good advice over the years and followed up on it.

No sneaky suspicion here Bicter, have had many successes and failures along the road.
Mechanical engineering background here but enjoy experimenting with 12V, few blown fuses and burnt wires but still standing. :lol:

Thank you grubstake, rest my case. erfect: