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Safe continous current draw for V6 3rd gen?

Discussion in '3rd Gen. Tacomas (2016+)' started by dschreib, Aug 30, 2020.

  1. Aug 30, 2020 at 4:30 PM
    #1
    dschreib

    dschreib [OP] Member

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    Does anyone know the safe continuous current draw for a V6 3rd gen? I'm adding a LiFePO4 battery with a charge controller (either Renogy DCC30S or DCC50S) and I'm wondering if 50A continuous draw is safe or should I stick with the 30A. The 400W inverter draws ~37A at max load assuming 90% efficiency.
     
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  2. Aug 30, 2020 at 5:45 PM
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    scotkw

    scotkw Well-Known Member

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    I'm doing similar except I'm going to boost the volts to 24, then send it back to a charge controller which will buck it to the volts it needs.

    As as far as amps, if hooked directly to original battery, I'd say staying within half the capacity of the alternator should be plenty safe. So half of 130 amps.

    If you're planning on drawing 30,50 amps from the fuse block, definitely a no on both.

    Only real issue is over heating the alternator at idle rpm. But at hwy speeds, alternator fan is ripping enough to stay cool at max amps. So as far as, can the alt and wire gauge handle it, yes it can handle 30 or 50. Guys with winches easily draw 100 amps for a couple minutes.

    I considered the 30 amp DC to DC charger you mentioned but opted to go cheaper with a boost converter and a renogy solar charge controller. Gives me more control/flexibility over charging parameters.
     
  3. Aug 30, 2020 at 5:58 PM
    #3
    dschreib

    dschreib [OP] Member

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    Which boost converter did you go with? I am considering a 1500W DC-DC Boost CC-CV model from China and a higher voltage pack to save money. A little nervous about the potential for the internal diode to fail to allow for full voltage (28v-50v depending on the pack) to be supplied to the car unless I add a reverse voltage protection circuit. Additionally, I would have to buck the higher voltage back to 12v to use the other inverter I have.

    Using surplus lithium battery backs with these cheaper components drops the system cost significantly from around ~$800 to around ~$200 for the initial setup.

    What is your total setup?
     
  4. Aug 30, 2020 at 6:22 PM
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    itr1275

    itr1275 Well-Known Member

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    For reference my 4runner has a 400W Inverter in the back so it can be done. I would make sure you have the proper fuses in there. I would not hook anything directly to your battery without a fuse or breaker.

    I would stick with the 30A and leave some margin. If it's that important to get your stuff charged that quickly get the right tool for the job and bring a generator or a power bank.

    To be honest 90% efficiency seem a bit optimistic. The efficiency is not a single number it's a curve based on current draw/load and temperature. At very little current draw efficiency will be very low. At higher temps it will degrade.

    These are random curves to illustrate a point. They are painting this picture. Notice that at full load the efficiency is much lower than at 30% but much higher than at 10%. It's not a single number nor a linear curve.
    [​IMG]
    What it looks like is this over temp. They may be showing you a number at 0C and not at 50C. BTW 5C is the temp inside the device not the outside air temp.
    upload_2020-8-30_18-17-32.jpg

    Given that this is all made in China and they don't give you current/temperature curves you have no way of knowing if that is 37A max @ 25C or 37A max @ 50C. Poor engineering and cheap components could mean it's 50% efficiency at room temp, unlikely it's that bad but possible.

    Also don't confuse 400W input with 400W output (like a vacuum cleaner, heater, or hair dryer). Input power (current draw*voltage) doesn't equal performance.

    Unless we have the characterization report, I would be conservative and assume it's 37A @ 0C and assume it will be much higher (like 50A) at room temp (remember it will be warmer inside the inverter and could easily be 40C or 50C.
     
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  5. Aug 30, 2020 at 6:41 PM
    #5
    dschreib

    dschreib [OP] Member

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    I assumed my Tacoma (your 4runner) is rated for 400W output from the inverter and was being generous about their efficiency. Realistically it is likely drawing over 40A as you stated! Since that is a factory item, I assumed at least 37A and likely 40A+ would be safe. I do not need above a 30A charge rate, but I would like to specify my system properly.
    My primary concern with the cheap boost converter running a higher voltage battery pack is that their diode may fail to a short configuration which allows the 28V pack to damage my car. I'm a bit stuck deciding whether to go for a cheap system or go for a nicer system. My budget is still a bit tight since I'm a PhD student (in electrical engineering, funnily enough) with a couple more years so I'm trying to debate which option is worth it is given that I don't need this system.

    This was prompted by someone scraping my car recently and not leaving their information which really bothers me. I was planning on doing this last time someone scrapped my previous car but assumed it was just bad luck. Now, I want 24/7 front and back dash cams. Since the pack is so large ~750Wh, it feels a waste just to use it for a dashcam and I know sometimes when I go camping, it's nice working in downtime or watching a movie at night.

    The high voltage system with cheaper components costs far less. To power an inverter I need one that can take ~33V max or buck it down first. Neither is ideal but the system costs only ~$175 with extra regulators to convert the higher voltage down to 12v. However, I do not believe the cheap regulator's efficiency and the stacking losses will hurt.

    Going with a Renogy charger (like https://www.amazon.com/Renogy-Battery-Batteries-Multi-stage-Charging/dp/B07Q4SVX3M?th=1) a LiFePO4 pack feels a bit safer and doesn't require these extra converters. However, it costs ~$500 to ~800 depending on how much feature-creep I fall prey to.

    Here are the two batteries for the lower end cost of both systems:
     
    Last edited: Aug 30, 2020
  6. Aug 30, 2020 at 8:17 PM
    #6
    scotkw

    scotkw Well-Known Member

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    Still testing/designing my setup. But I have that 1500 watt Chinese booster also. I plan to boost from truck batt to 16+v, just because the charge controller needs 2+volts over the battery volts before it will turn on. I've tried to boost to 24v batt then buck it down to 12v for return voltage. Almost like having starting batt and 24v Lifepo4 in parallel, switched between keyon and keyoff. It works but getting it to switch from 24v circuit when car is on to 12 when off is a headache. 24v inverters are way to expensive also, so I decided I only need to "boost" enough so i can charge lifepo4 to 14v or so.

    Here's my testing setup on top my pc, which is running off the lifepo4.

    In first photo, top left thing with fan and exposed guts is acting as the "truck batt+booster", AC to DC 24v supply. Then goes to that small 20 amp buck converter(silver fins) to control the current. Then to the renogy wanderer 30amp charge controller (30$) on top of the battery. Then charge controller sends it to the lifepo4 and the 1000w inverter(189$). The battery is about 20 amp/hr Chinese 32700 cells I put together (with a BMS for about $100). More cells on the way. Plan to go bigger. Thought about the prismatic cells like you linked to, not sure why I went 32700 instead. Other than maybe being able to package it in many shapes. I went lifepo4 over li-ion mainly for the safety. Little chance of fire with lifepo4. I accidentally charged one 3.2v cell with 24v!!! All it did was start crackling, felt hot, then popped, spilling out liquid and smoke. So over voltage test accidentally passed. lol. Only real issue with lifepo4 is charging them when temperature is below freezing. Not supposed to do that. So I'm also trying to work in a temperature relay that will heat the battery "area" until it can be safely charged.
    IMG_20200830_214331.jpg

    Second photo shows 11 amps going into the controller, 4.6 going into the battery, and the difference consumed by the inverter which my pc is plugged into. Can't wait for the TW gods to say, not safe, not UL listed, not built in USA, not smart, Im an idiot, why don't you just buy some thing made for this, dealerships are the end all know all of everything, blah blah blah. But like you said, shits to expensive. I just bought 100 amp/hrs worth of cells for 300$. The same "prepackaged" battery would run 900-1000$. That's fn retarded when you have the know how to do it yourself or want to learn to do it yourself. If one needs a warranty to feel safe, go ahead. But I'll take 3x the capacity for the same price. thx.
    IMG_20200830_214344.jpg

    3rd photo is renogy app for the bluetooth adapter. Monitor from there. All else can be hidden.
    Screenshot_20200830-225043.jpg
     
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  7. Aug 30, 2020 at 8:25 PM
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    dschreib

    dschreib [OP] Member

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    Why did you go with 32700 cylindrical cells over prismatic aluminum cased cells? Ir sounds like they are cheaper than the prismatic cells I'm looking at (about 500 dollars for 1kwh). Could you link them? Have you measured how well the cells capacities and internal resistance are matched?

    Laser cutting custom bus bars would make assembly a breeze and saving 200 dollars would be nice!
     
    Last edited: Aug 30, 2020
  8. Aug 30, 2020 at 8:41 PM
    #8
    scotkw

    scotkw Well-Known Member

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    Think I went 32700 because I was going to just need small system at the time and wanted the option to package it into what ever shape I need to fit the space I was going to put it in. Here's the cells I am trying. link

    Second guessing myself recently and thinking should have gone 60-100 amp/hr prismatics. If you need 60 amp hrs or more, Prismatic might be the way to go.

    I load tested the 1st set of 4 cells I bought. Didn't write any thing down but I wasn't disappointed with the numbers from what I can remember. I believe 3 amp load, 4 cells is series 12v, got 6 amp hours. So a lower, slower load might have made their 7 amphr claim. So not bad I don't think. Although the prismatics are known for 100 amprhr batts to get 100 amp hrs at 100 amps. So for higher amp load, prismatics are better at obtaining their capacity. Could be brand dependent also.
     
  9. Aug 30, 2020 at 11:09 PM
    #9
    itr1275

    itr1275 Well-Known Member

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    Toyota says:
    The maximum capacity of the power outlet varies depending on the position of the shift lever.
    • The maximum capacity is 120 V AC/100 W when the shift lever is in any position other than P or N.
    • The maximum capacity is 120 V AC/400 W when the shift lever is in P or N.
    The maximum capacity of 400 W can only be restored by turning the power outlet main switch off and then on again with the shift lever in P or N.

    You voltages are weird for being automotive. 28V/33V??? And 750 Wh is enough for an electric bike. So I'm sure I'm missing something in your project/question.

    A good source for info on stuff like this is www.hackster.io.

    Most dash cams have an impact sensor and will turn on (wake up) if they are bumped and run from a battery backup. I have Roav C2 Pro and you can set the sensitivity for impact. I turned it way down because it would go off when I closed the doors. It can sit for a week with no issues. When the car is off, it's not drawing any power.

    Don't get me wrong I'm on your side and think that people are pretty much dicks when it comes to other peoples cars. I've been sitting in the car and had people bang it with their door and deny the whole thing. But as for parking on campus - the sad truth is good luck. My wife worked at Stanford for years and they dinged her car six ways from Sunday. My advice is don't like your car too much if you live on campus, because no one else cares. Even if you record them, they will deny it and you would need to prove it was that person, not the vehicle. Then good luck on collection from a student. The campus police don't care. So, sadly, in the end it may be just a point of frustration for you.

    A good deterrent is to lift the truck a bit (1" will do) and get rock sliders that look like steps. The sliders are just about mid door level for most cars and are virtually indestructible. So they can run their car into it at 10 MPH and your damage would involve a $2 can of spray paint.
     
  10. Aug 30, 2020 at 11:28 PM
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    itr1275

    itr1275 Well-Known Member

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    LOL. If you are running fuses/breakers it probably fine. There are a ton of DIY power station videos out there.

    The only concern I would have, is you are taking this on the road, is impacts on the battery. There are containers to make arrays of batteries the will help. https://www.aliexpress.com/item/32807695647.html

    Although, I've seen people duct tape them together and they are fine. Mostly.

    BTW I've used the Ebay DC/DCs before and they don't last long. So if that's what you have you will want to have a few extras or design your own.
     
  11. Aug 31, 2020 at 7:09 AM
    #11
    dschreib

    dschreib [OP] Member

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    Those are some odd power ratings. At least we know ~40A is safe to draw while stationary but I'm not sure what to think about for driving. I feel like 20A-40A should always be fine given this information.

    The dashcam I'm looking at is a front/rear model and draws about 2W, drawing ~50Wh/day. I drive every other day for about 30 minutes Therefore I need a 200W charge rate. I've decided to go with LiFePO4 prismatic cells, just choosing 20A or 40A charging. I'm only going for such a large pack since I'm spending a bit of money on it either way. I do not need anything near this big for 95% of the time.

    I guess going with a 400Wh pack and the smaller charger makes the system much cheaper.

    That's a good point. I have only 1 door ding so far but this person must have scrapped the sides when pulling out at the beach. Do you have any small lifts you would recommend? My plan was to wait on this until after my power train warranty is up and my tire's tread is going out. Several times I've been worried about my rocker panels when going places to climb as well...

    I was looking at these sliders to save weight: https://greenlaneoffroad.com/toyota/tacoma-hybrid-aluminum-sliders-aa9sj
     
    Last edited: Aug 31, 2020
  12. Aug 31, 2020 at 8:17 AM
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    itr1275

    itr1275 Well-Known Member

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    Wow, those are nice sliders.

    I have a 2000 Tacoma and were were a bit more, shall we say less refined back then. Mine are 2" square steel tube welded to the frame and now permanently part of the truck. They are not Demello but the look similar to this.
    https://www.demello-offroad.com/tacoma-2005-2015-rock-crusher-bolt-on-sliders

    For those particular sliders it depends on what you want to do with them. Aluminum gear tends to be targeted for overlanding and rock crawling might be a bit of hard on them (it's a generalization I know). Rock sliders is they should be able to sustain an impact with the full weight of the truck. The Green Lane says "*Will protect vehicle from rocker damage but not designed to be used as a high lift jack point.". Will it protect from door dings, probably can you smash it on a rock, I dunno?

    A lift shouldn't void your power train warranty (in the US, I don't know about Canadian policies.). There are a dozen posts in the 4runner forums about this.

    Basically the dealer has to prove that the lift is the cause of the problem, then you would need to remove it to get warranty work done. However, the dealer also have the right refuse service as in "We don't work on customized vehicles". I would talk with your local dealer and see if it's an issue with them. Most of the dealer's here sell them with aftermarket lifts, which implies the dealership is taking responsibility.
     
  13. Sep 13, 2020 at 7:07 PM
    #13
    dschreib

    dschreib [OP] Member

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    Welp I went with a big pack, if I didn't again I would go much smaller. I feel a better way to go is a solar panel plus a smaller pack.

    The pack is 1.5kWh 12v LiFePO4 with a Renogy 12V 20A DC-DC charger. At 12V, the charger draws 30A. I'm hoping to splice into the tow circuit but I am not sure what the maximum current rating is?
     
  14. Sep 13, 2020 at 7:12 PM
    #14
    itr1275

    itr1275 Well-Known Member

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    Thanks for the update. Let us know how it works out.
     
  15. Sep 13, 2020 at 7:18 PM
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    dschreib

    dschreib [OP] Member

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    Thanks, do you know the current rating for the trailer circuit? Another thread shows a 40A fused battery charging circuit (figures attached). However, I do not see references to these in the 7 pin trailer hookup.

    big.jpg
    small.jpg
     
  16. Sep 13, 2020 at 8:14 PM
    #16
    itr1275

    itr1275 Well-Known Member

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    I've got this info from the "ax006t02 Trailer Wire Harness.pdf". It looks like 5A per leg. However, yours may be different depending on the year. upload_2020-9-13_20-13-33.jpg
     
  17. Sep 13, 2020 at 8:18 PM
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    caribe makaira

    caribe makaira Well-Known Member

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  18. Sep 13, 2020 at 9:00 PM
    #18
    dschreib

    dschreib [OP] Member

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    Is "+" the 40A charging circuit?

    tacoma.jpg
     

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    Last edited: Sep 14, 2020
  19. Sep 14, 2020 at 7:21 AM
    #19
    scotkw

    scotkw Well-Known Member

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    FWIW, do you have a BMS for the battery or at least a balancer? Its not super critical with LiFEpo4 if you balance them evenly initially, they will rarely go out of balance if kept within their voltage range. In case you didn't know, for an initial balance, put them in parallel and charge fairly slowly (1/4c) to their max recommended volts. Typically 3.65v. Leave on charger till amps drop to zero and all are at 3.65. Then can put into series and into service, and you're assured all where top balanced evenly.

    Curious about the the Renogy charger.... Is there a setting to limit output amps? or set a top voltage? That's one thing I need to fix on my test setup. If to many amps are input into my charger, it just errors out. I need it to limit the amps to the battery. I am currently having to limit the amps on the input side. To simplify things, I need the charger to handle to the limiting.

    I also use an old cpu heat sink with resisters as a load. :thumbsup:Works perfectly.
     
  20. Sep 14, 2020 at 8:03 AM
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    dschreib

    dschreib [OP] Member

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    Going to wire in my BMS today! I did the initial charge with a hobby charger (very slow going).

    The renogy charger has two current modes (20A and 2A?) And a variety of voltage settings for lead acid and LiFePO4.

    Going to setup some basic data logging with per cell voltages to a CSV tonight.
     
    Last edited: Sep 14, 2020
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