Step Up Converter for Travel Buddy...

It would also assist and educate others if we all knew what you are talking about. Please supply some links to your "Travel Buddy" and your proposed "step-up converter."

You can use a 12v to 13.8V ( or 15V) DC DC step up Boost.

I saw a youtube video on how effective it was.

Step up converter.

And to the OP, yes, just leave it in the circuit, just make sure it is off in addition to the Travel buddy being off when not in use. It will draw a small amount of quiescent current.

https://www.youtube.com/watch?v=omAq_MfstRo

I'd be a bit weary about how long the element would last at 15V.

Peter,

A Travel Buddy is one of the many 12v ovens available these days. They are made in Australia and are the pick of the bunch!
Not just for heating pies, but the more adventurous do roasts & other delights too.

Bob

Allan, et al... The step up converter allows a greater current flow when the Travel Buddy oven is used at rest (batteries only, with no input from the vehicle charging system). I had presumed these were common enough to be familiar to most here, it seems I was incorrect.

The system does not consistently reach 15v with these converters, no need to be "weary" as far as I*'m informed. Could be wrong, though..

Cheers,
Mark

BTW Bob, it does excellent roasts and a decent loaf too! Nothing like pulling up for the evening with a hot meal ready!

Cheers,

Mark

Watch the video linked above. It seems to indicate higher voltage equates to less heating time, and thereby less overall power used.

I wonder if the 24V version would be better again?

Okay fair enough, the long heat up time no doubt is caused by the poor insulation in the oven so it seems you will save power there. Cooking is a different matter though, ie if you need to cook the item for 40 minutes then the oven has to run for 40 minutes, at higher temperatures the element is probably running nearly 100% of the time so the loses in the inverter then may factor in.

I'm surprised he didn't quote the totally Ah used to cook the pies at 12V and then at 15V for instances as then you would know exactly how many Ah you might save. Another aspect to consider is the wiring in your car, more current more power lost through the wiring if it isn't up to scratch. Also a lead acid battery will have fewer Ah available due the higher current draw though with only 2A difference probably not that much. Again surprised he didn't quote the total Ah to preheat and cook the pies as it would be much more informative or did I miss that?

The higher voltage though as he said will have an effect on the life of the element, in 12V absorption fridges for instance a 2V increase can have a considerable effect on element life so I would discuss with the oven manufacturer before raising the voltage to high.

Hi Leigh, all reports I have read and seen indicate that not to be the case. The increased inefficiency in power draw is outweighed by the more efficient pre-heat and cooking times.

The higher voltage affecting the element would be a minimal concern, as the power draw is similar to identical as when being used on the road (the whole reason for using the converter is to overcome the LOWER voltage when under battery alone)...

Cheers,

Mark

I had an 24 volt version 30 year ago, made by Lion, and it cooked a roast in 2 hours, in my road train, my wife would come along on the weekend trips, and do a roast for me in the oven on Sunday's. But it was a 15amp draw model. I never ran it without the truck running. God I miss those times, and those meals - best years of my life.

Watch the video Allan. According to that, which looks to be well-informed and comprehensive, the losses in the inverter are less than the losses in the oven, and in terms on the energy needed, it is more efficient as well as quicker.

These ovens usually won't work very well without the alternator running, so it does improve things.

Your other observations appear quite sound to me though.

Allan. I am a total mental gelding as far as auto electrics goes but reading thru this post made me wonder if having Travel Buddy turned on at a campsite where the 'feeder' battery is connected being fed by solar via a Redarc charger would negate the need to have the engine running.
Thanks.
OBJ

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Hi Jack,
Well, let's look at a hypothetical situation where you have a 100 Ah battery and a 200W rated solar in full sunshine.
The Travel Buddy draws 10 Amps (120 Watts) and the solar may contribute about the same so there will be no load on the battery at all. In reality, you may not get 120W from your solar when you need it, so the battery will need to make up the shortfall. On the other hand the solar may be contributing to the battery for more hours than the oven is turned on, so a balance may be achieved in battery level.
However, any solar contribution will help maintain the battery during oven use.

You can see that there is no firm answer to your question but certainly, having a solar contribution when the oven is on and the motor is off can be practical. Just keep an eye on the battery level and start the motor if necessary to complete heating the pies.

Thanks Allan, appreciate the clarification. We use the oven regularly and love it. Adds convenience and flexibility to our meal options (including avoiding the expense and poor food options at many service station stops).

I'm aware that the converter introduces losses but all reports/videos I have seen indicate an overall increase in efficiency due to improved preheat and cooking times. Efficiency is an often misused term. The system is more "efficient" if it safely and reliably provides the outcome I'm after, over the previous conditions...

From the responses so far it seems I am fine simply leaving the device connected when on and off alternator assistance, as the converter is simply allowing a similar voltage to the oven at all times (and closely approximating the voltage available when underway). Does that sound like a reasonable conclusion to you? I was asking the original question after seeing some who used the converters disconnecting them when underway. I couldn't see the reasoning behind that.

Cheers,

Mark

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Yes Mark, it is entirely reasonable to leave the converter connected and in operation at all times. It will maintain the design output voltage. It will introduce some small loss in efficiency compared to operating directly from the engine alternator but that is of little operational or economic concern.

Mark, you say "Efficiency is an often misused term" and I agree. As a practicing engineer I find it important to use correct terms but you are using "efficient" when it should be "effective". If some of the input energy is being wasted then that is a loss in efficiency. But if the system is configured to "provides the outcome I'm after" despite losses then that is "effectiveness". Some may consider this to be pedantic however it can be important to appreciate the difference when analysing and defining a system.

Hi Allan, I agree on the correct use of terms FOR THE DESIRED OUTCOME. ;-) . A discussion I have had (with, I have to add, some amusement) with my engineering friends and colleagues (one of whom is a lecturer in engineering). As a non-practicing philosopher (well, I exaggerate a little, I have not quite graduated yet, but have been studying the field of philosophy of science for decades)I have to disagree. ;-) You are using the term as you see it in your particular field.

So how do you define this situation (genuinely interested)? If I wish to cook a roast using the least amount of power using the system I have, which is the most "efficient", with or without the converter? As you say, there are "losses" (there are always losses) but which ones are the relevant ones appropriate to use?

The word efficient is simply that, a word, with varying definitions dependent upon context and perspective. In fact, from a linguistic perspective, there are few places words have definitive meaning without relation to context (scientific nomenclature being one and, even here, there are variances), as I'm sure you are aware.

I'd agree, though, effectiveness may be a clearer way to express this to this audience, but to me it is not sufficient.

Pedantic you were. In the context of your field reasonably so... I also used to analyse and define systems when working in quality and process management fields, I share your frustration with relevant terminology and its misuse!

Thanks for the help with the converter.

Cheers,

Mark

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Hi Mark,….. "using the term as you see it in your particular field"?….Well yes, we were discussing an engineering matter were we not?

Ah well, when it comes to actually cooking something to some degree of culinary satisfaction, there are many more considerations than simply conservation of energy. Not the least of these is cooking temperature and time in order to achieve the desired result. This is not a simple engineering matter and therefore beyond my field of expertise and comment.

To illustrate my perception of "efficient" versus "effective" I offer an illustration…….
It may be more EFFICIENT to have all traffic lights one colour, say red, in order to simplify inventory and gain buying economy, but it certainly would not be EFFECTIVE in operation from the point of view of traffic flow. However, maybe we could try all green lights?

Sitting here, typing slowly thanks to my wrist brace, after having someone pull out in front of my motorcycle at an intersection, I'd posit many couldn't care whether red or green!

;-)

Cheers,

Mark

Batts, I have more than sufficient battery and solar to use the Travel Buddy when not underway and, yes, we have also used it on battery alone more than a few times. The problem is we have noticed a considerable increase in both warm up and cooking times and I wanted to know why, hence my investigation into the step-up converters. No, I am not "overthinking things". Thanks for the concern though. ??

It is not that "something is wrong" with the set-up, it is a desire to have more efficient cooking times and overall more efficient power use (notwithstanding the losses through the converter itself).

Cheers,

Mark

There is a fellow that sells an insulated door for them and other things somervillemetalworks .com.au. My Travel Buddy is runing off a lithium battery so probably more consistent voltage supply. I was thinking a while ago if a small metal fan could be fitted to make it fan forced but they are what they are and better than nothing.

Hi Batts, I'm running off Lithium too, so was surprised at the difference in heating time. I'd imagine it would be worse with AGMs.

I saw a test of the insulated door and the verdict was.. meh... so I'll give it a miss for now. We find the oven, overall, is excellent though far from perfect (I notice more than a few are now moving to air fryers via inverter as a more flexible option) but wanted to make the most of batteries and still use the oven when off-grid. Hence the interest in the step-up...

Nothing like having hot jam donuts to share when you get to a fishing spot on a cold day! All of a sudden you're very popular.

Cheers,
Mark

I also had the oven running off 2 x 105ah agm batteries before I bought lithium over a yr ago can't say I was loking for or was expecting a difference in cooking time with engine off.

I thought cooking time was relative to the size of what your cooking and what temp the oven is set at. If the oven can not achieve the desired temp is one thing but it should with a little longer on time which again is only a concern if you dont have ample solar.
Having a higher voltage wont shorten the cook time just the preheat and duty cycle of the element.

Higher voltage doesn't help efficincy that's what everyone seems to agree on but Silkwood. He still says his runs better with engine on but how much difference 10min or 30min or more ? When looking at my lithium battery monitor I notice no difference in the amount of power the oven draws with engine on or off I just tried it to check.Mine is near the battery cut the oven power cord to around 1mtr fitted anderson plug and runs via the same multi fuse block that supplies power to fridge and light never had any problems . So why is yours different how far from the battery got a good plug connection maybe test the plug supplying power to the oven with a meter to see if voltage picks up with engine on.

Efficiency is using less power to achieve the same effect. By all accounts the step up converter does this . Please explain how this is not more efficient.

It's not "everyone but Silkwood".

If you want to make it a rant about how correct you are, go ahead. if I can use my oven with less time spent and less power used, I will...

My set up is fine, thank you. Nice presumption, though. And, yes, QLD, it is the cook time AND the warm up time which is improved. When you have put in the testing and the results, let me know how wrong I am...

I checked mine and there is a difference in time to warm up and cook when on battery only. Your view may differ.

This place gets worse by the year....

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Mark, you say… "Efficiency is using less power to achieve the same effect. By all accounts the step up converter does this." The step-up-converter does NOT use less instantaneous power. By raising the applied voltage it raises the current and hence raises the oven power. And I believe this is what you wish… more power to achieve higher oven temperature and shorter cooking times.

Just be aware that the manufacturer of Travel Buddy has chosen an oven heating element to suit a particular voltage. This is expressed as "12 volts" (nominal) but is more likely to be in the order of 13.5 volts. If you operate the oven at 15v then this 8.7% increase in voltage will produce 18% increase in wattage. That is, the oven element will operating at 118% of its design rating and certainly getting much hotter and with considerable extra stress on the element.

You have said that you are operating with a lithium battery. If charged correctly this will have a standing terminal voltage of about 13.5 volts and 14.3v when being charged. I would expect these voltages to be close to the Travel Buddy design so it would seem pointless to use a 13.8v converter. If on the other hand, you employ a converter with an output rated at 15v then you get enhanced oven performance but at the likelihood of shortening the oven's element life.

If your current lithium electrical system is not achieving an output of 13.5v then you have an inadequacy that should perhaps be investigated.

Incidentally, the use of a step-up converter will introduce losses as much as 8% which is why the converter housing is designed with heat-dissipating fins.

"Mark, you say… "Efficiency is using less power to achieve the same effect. By all accounts the step up converter does this." The step-up-converter does NOT use less instantaneous power. By raising the applied voltage it raises the current and hence raises the oven power."

It may use more power per hour. However, if the time is considerably shorter, you may be able to save on the overall power that is used.

Peter, I think you are referring to less energy being used. Not power.

Edit, apologies Peter. I think this is what you said. i don't take the quotation makes into account

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I think Mark has left the building".
lol

No, not left the building "LOL"...

Simply sick of the bull and the trolls. I have my answer (thank you, Allan), couldn't be bothered with the rest of the waffle...

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Ah Mark, glad your'e still here.
Despite all my training, experience has taught me that whatever works, it WORKS. So if it works for you then go for it. Maybe someday you will be able to let us know how it went. You can always MM me.
My son says his Travel Buddy works great. Maybe someday I will get one myself.

On my last trip, I had pre prepared some frozen meals, stews, and put them into my Travel Buddy Marine oven at 180 degrees for 1 hour. No pre heat time, the meals were hot after the hour. I was not checking voltage, amperage or watts, I just wanted a hot meal at the end of the days travel. I would pull up about an hour before I wanted to stop for camp, and put the meal straight from the freezer into the oven, and then travel on to my chosen camp site.

Macca.

Leigh it doesn't matter how much extra voltage is supplied the oven is set to draw around 10amps give or take a bit and it won't increase if the voltage supply is increased so no gain. I mentioned this previously as I have checked it with mine. The key thing here is if the battery/batteries are in good condition and are big enough to supply enough ah for the time required to run the oven plus whatever else is on like lights or fridge etc.

Batt's, does your oven have any current limiting circuitry in it to stop the current increasing to over 10 A if you increase the voltage above 14.5 V? If it does not, then your assertions are wrong. Have you checked your assertions by measuring the input current with input voltages in excess of alternator charging voltages? If not then how do you know you are correct?

Under the natural laws of electricity, if you have no current limiting device, when you increase the voltage above the designed voltage, your device will draw more current. When the current increases there will also be an increase in power and heat that is generated. That extra heat will reduce the warm up time and also cook your food faster.

Nothing I put in limits the power supply to the oven. All I've done is look at the lithium battery monitor in my car and the amount of amps the oven draws doesn't change at all when I start the engine. With the engine idling the voltage on the monitor increases and the alternator supplies 19amps to the battery but as mentioned the oven draws no more power so it won't heat up any faster that makes sense doesn't it. So my way of thinking would tell me that if someone oven does get an increase in current draw then I would say there may be something causing that like wiring or faulty battery etc. It seems pretty basic but I'm not an eleco.

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Sorry Batt's butPeter is quite right in what he has said. The oven is built with a heating element which will nominally draw 10 amps when supplied with 12 volts. There is no control in the oven to limit a rise in amperage with an increase in voltage. The current will rise in proportion to the voltage rise. That is why Silkwood wanted to use an external device to raise the voltage to his oven….. to increase the current and hence power to raise the oven temperature.

I fear that you are not making correct observations of your battery monitor. When your alternator begins to charge the battery the system voltage will rise a little. The 19 amps to the battery is the controlled charge rate and bears no reference to the oven consumption which will have also slightly risen with the charging voltage but the alternator will still be limited to a 19 amp rate, some of which will be going to the oven and the remainder will be applied to charge the battery. If you wish to observe the oven amps then you will need to independently measure the current in the oven circuit alone.

Ok my oven must be different to yours as it draws 10.5amps with engine of and 10.5amps with engine on don't know why that sounds complicated as I have mentioned it doesn't change. I did say the voltage increases with engine on and there is a battery monitor in the system so I can read how many amps I am drawing from the battery pretty simple that one to some but the rest of your statement has no bearing on anything I talked about maybe you read it wrong any way I'm out of this as it's getting over complicated for no reason.