Announcement

Collapse
No announcement yet.

Dual battery setup for 2.8 1GD

Collapse
This is a sticky topic.
X
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Originally posted by LeighW View Post
    I had a lot of respect for Redarc once but over the past couple of years most of that has disappeared, once they would give unbiased advice, these days they are only interested in pushing their premium product. As an aside to this, if anyone is thinking of buying their DCDC/solar unit think again, their glossy states:

    "Solar input voltage range 9-28V (suitable for 12V panels only)"

    when you buy the unit and read the user manual it has minium turn on voltage for solar is 17.5V, people are having problems with the units not firing up when connected to solar panels, Redarc's response has apparently been "their units are designed to work with their panels" and apparently refusing to refund.
    A little late to the party, but this is a sticky thread and I figure other latecomers like me might also read it from start to end.

    They seem to have improved their sales literature now, perhaps as a result of your feedback? The sales glossy I have (2015) has a table of 7 of their chargers, 5 of which support solar charging. On all 5 of them they now clearly state:

    MPPT Solar Regulator: Yes
    Solar switch on voltage**: 17.5V
    Solar range: 9V-28V
    ** Requires unregulated solar panel

    The point is they have their own on-board MPPT so you need to connect a raw panel rather than a panel that has it's own on-panel MPPT regulator. The open-circuit voltage of most nominal 12V panels is typically in the low 20s, so well past 17.5V. I suspect when they told you "their units are designed to work with their panels" they meant to say "their units are designed to work with raw unregulated panels".... perhaps they did and by the time the story got related to you it'd been Chinese-whispered into that version. In any case, I see no evidence that they're "pushing their premium product". I just plugged one of these cheap-n-cheery $75 panels: https://www.whitworths.com.au/main_i...AbsolutePage=1 into their BCDC1225-LV and it lit up without any drama. The panel open-circuit voltage was at about 22V before I connected it. The charger was happy to move through its three stages (Boost, Absorption, Float) on the strength of a 40W source. At 4pm on a Gold Coast winters afternoon it was still pumping 26W into the battery from a nominal 40W panel so I'd say their MPPT is working pretty well.

    Comment


    • Originally posted by LeighW View Post
      The 2.8Ltr uses what is called a LIN regulator, this is controlled via the engine management system, it may be possible for Toyota to turn of the smart charge function if the know how.
      On the upside, we might only be a firmware update away from having regenerative braking enabled. Always keen to see if I can improve on this:
      Attached Files

      Comment


      • Originally posted by drivesafe View Post
        BTW, the reason for the 30 amp fuse on a 20 amp DC/DC device is because they are very inefficient at what they do and actually need to draw far more than 20 amps from an alternator, to supply the battery with just 20 amps.
        Well, another reason is that their output voltage is usually quite a bit higher than their input voltage (especially when installed in a 2.8L D4D), so even if they were 100% efficient you'd expect them to draw more current (at 13.6V) then they're outputting at 14.9V. You really need to compare power-in Vs power-out if you want to calculate efficiency.

        Starting the car after a typical night's camping for me and my BCDC1225-LV output voltage exceeds the input voltage (13.6V) within about 2 minutes. It will pump 25A into the aux battery all the way up to 14.9V as the aux battery slowly takes on charge (even as the alternator voltage drops down to 13.5V). Early on when their voltage paths crossed at 13.6V, the input current was 27.9A and the output current was permanently pinned at 25A, so I'd rate that at about 90% efficient. About 35 mins in it reached its peak power delivery of 14.9Vx25A while it's input was 13.5Vx30.2A which I figure is about 91% efficient. The charger was barely luke-warm throughout. In theory it will operate all the way down to an input voltage of 9V, so bring on regenerative braking I say. So far I've never seen my alternator output drop below 13.4V.

        After that the charger enters absorption mode, maintains the 14.9V and the current fairly quickly decays away. Drive long enough (maybe another 15-20 mins) and it will enter float mode where it just maintains 13.2V and at that stage the input current is about 100mA. That's probably more a reflection of how healthy my near-new aux battery is and how fully charged the previous two stages have got it; there really is nothing more for float to do. It'll stay like that for the rest of the day as you drive to your next location. As the fridge cycles it remains in float mode at 13.2V and simply supplies more current to deal with the fridge. Even if you shutdown and restart, it very quickly (less than a minute) gets back to float mode (assuming you weren't shutdown so long that it needs charging again).
        Last edited by dBC; 11-08-2016, 07:07 PM.

        Comment


        • Why fit any form of DC/DC device in the first place?

          If you set up properly from the start, then a DC/DC device, even a 40 amp unit, become a major drawback, not a benefit.

          If the auxiliary battery is an Optima, and the battery is in a low state, you can charge it to over 95% in an hour.

          A 40 amp DC/DC device will take more than 90 minutes to reach the same level of charge and a 25 amp unit will take well over two hours to achieve what the alternator can do in less than half the time.

          The advertising for these toys makes the sound good but the reality is that, in in the vast majority of setups, they are nothing more than a grossly over rated sales gimmick.

          Comment


          • Hi drivesafe, the main reason for using a DC/DC charger is to get full charge on AGM batteries.

            Comment


            • Originally posted by P W View Post
              Hi drivesafe, the main reason for using a DC/DC charger is to get full charge on AGM batteries.
              Especially in a 2.8L where there is no diode solution. If you're into really deep cycles, and you're in a hurry, then I agree amps matter more than volts, but my camping battery typically stays in the top 30% or so and trying to get that back up to 100% at 13.4V takes forever. Plus a lot of deep cycle battery manufacturers actually recommend you avoid big charging currents, so even if you are into deep discharges, you may find your battery lasts longer (even if your beers don't) by limiting the charge current to 25A or so.

              Comment


              • Originally posted by P W View Post
                Hi drivesafe, the main reason for using a DC/DC charger is to get full charge on AGM batteries.
                Hi P W and yes a DC/DC device can fully charge a battery, AGM or otherwise.

                But so can an alternator and they achieve it by getting the battery closer to a fully charged state in a much shorter drive time, so they do a better job, with out outlaying huge amounts of money in the first place.

                So again, why spend up big, when your alternator can do the same thing in a shorter time.

                Comment


                • Originally posted by dBC View Post
                  Especially in a 2.8L where there is no diode solution. If you're into really deep cycles, and you're in a hurry, then I agree amps matter more than volts, but my camping battery typically stays in the top 30% or so and trying to get that back up to 100% at 13.4V takes forever. Plus a lot of deep cycle battery manufacturers actually recommend you avoid big charging currents, so even if you are into deep discharges, you may find your battery lasts longer (even if your beers don't) by limiting the charge current to 25A or so.
                  Is this not a case of having to correct two wrongs.

                  If you buy the wrong AGM and then need to buy a DC/DC device to correct an error in the first place, that just does not make common sense!

                  Once again, get the correct battery in the first place, and you then end up with a far more efficient setup, for a fraction of the cost.

                  Comment


                  • So.. After reading all of this im still confused.. Which is the best option for a dual battery set up?!

                    Just want it mainly to run a Engel in the rear when Im doing weekenders, and some LED lighting..

                    Comment


                    • I don't think there's agreement on that, especially with the 2.8L engine and it's fairly low voltage alternator setting (and no diode solution to boost it), and it's difficult to do a direct comparison in order to get actual data.
                      Last edited by dBC; 24-09-2016, 06:32 PM.

                      Comment


                      • All the big 4wd companies and most auto electricians (at least around my area) recommend the use of some sort of DC/DC charger, so can they really be wrong. Both ways will get the job done, just one costs more, is better for your battery and is recommended by many.
                        [LEFT]Silver 150 Facelift
                        TJM Bullbar, Lightforce Genisis Spots, Dual Battery System with bits from everyone, Powerful 4x4 slider/steps, Kaymar rear bar, "Genuine" Roof Racks, MSA Seatcovers, Dashmat, Tint, LED Interior Globes, Bridgestone D697s [/LEFT]

                        Comment


                        • And the big 4WD companies and auto elecs wouldn't be telling you that because they make more money out of the Dc/Dc charger, would they?

                          Comment


                          • Originally posted by dBC View Post
                            I don't think there's agreement on that, especially with the 2.8L engine and it's fairly low voltage alternator setting (and no diode solution to boost it), and it's difficult to do a direct comparison in order to get actual data.
                            Hmmm Im at a loss!

                            Comment


                            • Well, people appear to have done both and report success so you probably won't go too far wrong either way. The debate comes down to how quickly the 2.8L alternator will charge your battery Vs a DC/DC charger and that's pretty hard to quantify. It also depends on the type of battery, and how deep a discharge cycle it typically sees.

                              I consider myself fairly neutral on the technology. I've run VSRs in cars with a descent alternator output voltage (Disco-II and a V6 120 series Prado) and I switched to a DC/DC charger for the 2.8L because of the low alternator voltage.... 13.4-13.6V is what I usually see out of the alternator. If you do deep discharges, and you need to do a partial recharge quickly, then VSRs are probably the way to go. If you do fairly shallow discharges and you're more interested in getting the battery back up to 100% in a timely manner, then DC/DC chargers are the way to go. Some report never seeing their camping battery fully charged with just an alternator (http://www.pradopoint.com/showthread...y-Guide/page42). You'll need to decide for yourself whether you believe that fancy colour graphic in the middle of that page, or the battery manufacturer's data quoted on the page after.

                              Comment


                              • Originally posted by REN470 View Post
                                And the big 4WD companies and auto elecs wouldn't be telling you that because they make more money out of the Dc/Dc charger, would they?
                                And also that most of them do not know the first thing about Dual Battery Systems and they are easily sucked in by the grossly exaggerated advertising hype.

                                Comment

                                canli bahis siteleri bahis siteleri ecebet.net
                                mencisport.com
                                antalya escort
                                tsyd.org deneme bonusu veren siteler
                                deneme bonusu veren siteler
                                gaziantep escort
                                gaziantep escort
                                asyabahis maltcasino olabahis olabahis
                                erotik film izle Rus escort gaziantep rus escort
                                atasehir escort tuzla escort
                                sikis sex hatti
                                en iyi casino siteleri
                                deneme bonusu veren siteler
                                casibom
                                deneme bonusu veren siteler
                                deneme bonusu veren siteler
                                betticket istanbulbahis
                                Working...
                                X