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Discussion Starter · #1 ·
I want to add an inverter to my insight on the 12v side, I think doing it from the ima side would be overly complicated and risky so I'm willing to have lower efficiency for simplicity as I'm not using a lot of total watts. I'm wanting to power a small coffee maker so I'll need more power than the cigarette lighter socket can handle for sure, even the 12v ones that aren't really great tend to be setup for 12v rv which is 20a and that's more current than our socket allows.

I'm going to be going directly to the battery and then fusing it. I was told that the total dc-dc output is around 60-70 amps. For something that is only running for 5 minutes and only while the car is on with the headlights off how much is it going to hurt the under hood battery if I would put something like a 1000w inverter in and run a 900w Keurig on it? They take less than 5 minutes to make the coffee but bull dog expressed some concerns about hurting the 12v battery drawing it down in a way it isn't designed for.

Does anyone have any direct experience with 1kw inverters in the insight or should I really be looking more at the 500 or less watt coffee makers that aren't exactly what I want for various reasons?
 

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Your inverter is going to draw just over 80 amps continuous. That is pretty huge for an Insight 12V system. Most of the current will come from the dc-dc converter, but that output is dependent on engine speed. You would have to idle the car at some elevated speed to get close to the required output.

I'm kinda with Bulldog. I think you might well have problems. Bad as you dislike it, the 500W would be much safer. You'll need pretty large primary wire even for that.

I think your best bet would be the 12V RV units which would loose notthing to conversion efficiency and install dedicated wiring, and fusing, directly to the battery. Even then you need to run the engine while in use. JMHO
 

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Discussion Starter · #4 ·
That's probably not a horrible idea anyways. I had it blow one time on my old insight when I plugged in my phone charger
 

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I run a 750, which is still portable, has dedicated in rv and then I put on the cig adapter in a car, and those can handle a 2019 macbook pro 16, which can be high amp, but not the same type of load as a coffee pot :). I've upgraded the alternators in all of those cars, or converted generators to alternators, and upgraded the cig lighter wiring. I haven't done in Insight though since it only goes on trips as an RV toad.

Edit: Recommendation would be lower output inverter and a new accessory plug that can handle load, direct wired. I'd not go over 50 amp in any case though.
 

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My first impression was, yeah, that's a pretty huge, continuous load for the '12V system'. But then: I'm thinking that, if you're connecting the inverter straight to the 12V battery, and the 12V battery is charged, shouldn't the battery itself handle a lot of that load, so the DCDC and related 12V wiring doesn't have to do quite so much??

I mean, a fully charged 12V battery could probably power the coffee maker itself, couldn't it? Maybe something like this:

1000W/~9V (? -- voltage drop from ~12.8V) = 111 amps, 111 amps/~28Ah battery=4C...

Yes, that would be a tough load for the 12V battery, but near doable?

And then, the DCDC would try to prop voltage up to 13.85V. So, what would that entail, in terms of the load it sees?

hmm, I guess it would take over the whole load, as the voltage it's trying to hit is higher than the resting voltage of the 12V battery. I think that's the way it would work...

I'd bet you could take control of the WHT/GRN DCDC 'low power mode' wire - either bringing it high or low, whichever toggles the DCDC into low power mode - so that the DCDC would only try to prop voltage up to ~12.2V, not 13.85V. In such a case the 12V battery would handle some of that load and the DCDC would make up the difference... On the other hand, perhaps it wouldn't be enough - 12.8V to 12.2V isn't much of a drop, it seems, on a lead acid 12V battery, probably doesn't take much to induce such a drop...


It almost seems like you, or one, would be better off taking the car out of the equation and just using the 12V battery on its own, first, if you had a really good 12V battery. That 111 amp current for 5 minutes comes out to about 9Ah (111A X 5 min X 1hr/60min=9.25Ah)...

Let the 12V battery handle the job alone, then charge the battery back up with the car, which charge will be handled as it normally is, at normal rates...
 

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Discussion Starter · #7 ·
So like a little 12v battery and just leave it on a battery tender to keep it topped off and power that with the car?
 

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^ No, I was thinking a 'really good' 12V battery in the car, but leave car off, and then after coffee-making, start the car and let the DCDC charge it as normal.

BUT, I may be way over-estimating the ability of typical automotive lead acid batteries. I'm not really sure what they're capable of - I just did a quick search for max c-rate discharge etc. and the few hits I got and peeked at in the few seconds I glanced were very low values, like nowhere near 4C, more like under 1C (1C would be 28 amps for a 28Ah battery, stock Insight battery is about 28Ah as I recall)...

4C would be a walk in the park for Insight NiMH cells...

As I recall, Insight 12V starter load at about 130 amps drops 12V battery voltage to something like 9V, that's why I chose 9V... But that starter load is for seconds, not minutes.

100amps, or 111 amps, or thereabouts, for 5 minutes, is undoubtedly a very heavy load for a typical automotive lead acid. My guess is you could buy a special, higher quality lead acid that could probably handle it fine, maybe a deep cycle or something. Or better yet, a lithium iron... Those are expensive, all this might be overkill, etc. But, if you really want fast coffee in the woods, might be worth looking into some more.

Shoot, it might even be worth looking into using the electric motor output as a generator, I know there's been a few threads about that, but I don't recall what the verdict was.


edit: Just thought of something: If you really needed to go through the trouble of fitting an expensive 12V battery into the car to power your inverter - it wouldn't be worth it, at all. You'd be better off buying a small camp stove, boiling water on it, and using a cone-style filter to make your coffee.

IF one had grander woodsy-power fantasies, it would be cool to figure out something to convert electric motor output to AC 120V, or something.* But definitely not worth it for coffee.

*edit2: still thinking about this. Ran into this post that seems to suggest something really doable, mainly the first idea:

Based on some playing with an Insight with no IMA [electronics/pack I gather]:

-2 of the 3 phase outputs of the motor can power a 120V 1500W shop light, at just over idle. Rev the engine and you get up to 250VAC. Since it is AC, one could transform the voltage up or down as required.

Problem is that the voltage is engine rpm regulated. A 3 phase bridge rectifier connected to the IMA motor leads will yield a high current DC power source that varies between 80-250V depending on rpm.

Should present some interesting possibilities.
 

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So like a little 12v battery and just leave it on a battery tender to keep it topped off and power that with the car?
Going that route, you'd be looking at a decent sized deep cycle battery in the passenger footwell, or mount in the back where the spare is supposed to be. Either location you'd have to mount to the deck, they are heavy, that's a weight you want secured and not flying about in an accident!
 

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Discussion Starter · #10 ·
Yeah, might just get a heated pot, those take a while but I do long drives so it would work. They'll get to boiling in like 45 minutes off the cigarette lighter plug
 

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Discussion Starter · #14 ·
I like the makers so I dont have to make it but probably not a great option. Other option is to make coffee every night or morning in the hotel and use my thermos
 

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1st world problems :)
 

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Discussion Starter · #16 ·
I know, I'm mainly just trying to reduce my waste from getting a cup and lid all the time plus the cost adds up. Not that I can't afford it, just that it's kinda silly to have that cost for something and it's not even the best option. I frequently end up getting bad coffee from places since I travel so much I'm not always stopping at the same places.
 

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I know, I'm mainly just trying to reduce my waste from getting a cup and lid all the time plus the cost adds up. Not that I can't afford it, just that it's kinda silly to have that cost for something and it's not even the best option. I frequently end up getting bad coffee from places since I travel so much I'm not always stopping at the same places.
I hear ya. Unless it's overseas, my work travel for the last few years has been the motorhome. Before that all the work roadtrips were motorcyle. I got used to knocking back crappy roadside coffee quickly, but it was still a step up from 20 years of navy submarine coffee :)
 

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I'd buy the Makita one.

Sam
 
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