Page 2 of 2 FirstFirst 1 2
Results 21 to 37 of 37
  1. #21
    Join Date
    Oct 2016
    Location
    Polokwane
    Age
    55
    Posts
    1,115
    Thanked: 831

    Default Re: How long does a dual battery system really last?

    Jeep Grand Cherokee 2002 4.7 V8
    Conqueror Courage 2016

  2. The Following User Says Thank You to DC Polokwane For This Useful Post:


  3. #22
    Join Date
    May 2009
    Location
    Ruimsig
    Age
    57
    Posts
    6,138
    Thanked: 24356

    Default Re: How long does a dual battery system really last?

    Quote Originally Posted by DC Polokwane View Post
    I was advised, for longevity, to not charge a deep cycle lead acid battery with more than 10% of its capacity.

    Also that a deep cycle lead acid battery will only accept so much charge (amps) as it can absorb, no matter how much you throw at it.

    That an alternator does not run (push amps) at its maximum all the time but only supplies as much as needed by the system.

    Is this correct?
    Simplistically, yes. It produces AC whereas a dynamo or generator would produce DC. Alternators produce power according to the demand of the system.
    Estee = S T = Sean Towlson

    Total 4x4 Novice with no experience whats-so-ever

    ''Nothing makes the Earth seem so spacious as to have friends at a distance; they make the latitudes and longitudes''. H.D. Thoreau.

    Hummer H3 V8

    W.A.P Objectivist

  4. The Following User Says Thank You to Estee For This Useful Post:


  5. #23
    Join Date
    Oct 2016
    Location
    Polokwane
    Age
    55
    Posts
    1,115
    Thanked: 831

    Default Re: How long does a dual battery system really last?

    Jeep Grand Cherokee 2002 4.7 V8
    Conqueror Courage 2016

  6. The Following User Says Thank You to DC Polokwane For This Useful Post:


  7. #24
    Join Date
    Aug 2017
    Location
    East London
    Posts
    611
    Thanked: 346

    Default Re: How long does a dual battery system really last?

    National Luna website has a ton of info on all of this...simply put a Solenoid with a AGM traction battery will be better for a system where alternator supply >13.7V. Less than <13.7V, DC-DC.

    Charge will be much better first 3hours of driving with Solenoid...thereafter you can top up with Solar, which can be set to 14.4V to get the battery to 100%.

  8. The Following User Says Thank You to Jakkals. For This Useful Post:


  9. #25
    Join Date
    Aug 2019
    Location
    S.Antonio
    Posts
    67
    Thanked: 18

    Default Re: How long does a dual battery system really last?

    Quote Originally Posted by Peter1949 View Post
    Real life experience from a few years back:

    We did a just over 3 month camping trip through Southern Africa, mostly without grid power supply.
    When it was available it was only overnight most times.
    However we were travelling most days, being an overlanding type trip, son usually between 2 to 400 Km most days.
    We did stop at a few places for up to a week at a time.

    Our setup was similar to what you describe but we did have a 90 W Solar Panel & controller connected to two 105 Ah batteries while on site.
    While driving the alternator provided charging through the solenoid setup as described.
    (The alternator does NOT stop charging the auxiliary after the crank battery is charged unless you have a blown fuse or the solenoid itself has failed.)

    Running off the system was a National Luna 50 L Weekender camping fridge usually set to between -7 and -3 deg C depending on ambient temperature.
    This ran 24/7 with thermostat control.
    Ambient during the day fluctuated between 20 to 44 deg C, nights usually around 20 to 24 or so.

    In addition we charged a laptop, two tablets, satellite phone, camera as needed but usually while driving.
    We did have a 1 000 W inverter due to a requirement for my CPAP which ran an average of 6 - 7 hours nightly. (At the time 12v was not an option.)

    So most likely a greater load than you would have.

    Under those conditions ....

    After 1.5 months the one battery failed and needed to be replaced (They were not new at the start of the trip, but were fully charged).
    The fuse between the alternator and aux. system had failed, so the batteries had only been getting charge from the solar panel during the time until we realized that there was a problem. (Not sure - maybe 3 or 4 days).

    We continued to use the same system for a few years after that trip for shorter ones but usually with at least some grid power available most of the time.

    The one battery lasted approx. 8 years, the other (Original) another three years.

    There are a LOT of variables there, but maybe that will give you a starting point for your own decisions.

    Enjoy the trip.

    Thank's Peter, very much appreciated. If everything goes as planned, should be one first 1- 1/2 month trip next september 2022 through Damaraland and Kaokoland and a second 2 - 1/2 months from Kgalagadi through CKGR, Moremi/Savuti, Hwange and back from Caprivi.

  10. #26
    Join Date
    Oct 2013
    Location
    Centurion
    Age
    64
    Posts
    2,455
    Thanked: 977

    Default Re: How long does a dual battery system really last?

    Quote Originally Posted by Hedgehog View Post

    I have heard that it is relative to the speed the alternator turns..

    For example, on a game reserve you drive at low speeds, my solenoid system was useless in this situation, and my battery would discharge to flat while running my 50l fridge, on the second day..
    Alternators generally produce their rated output at about 6000 alternator rpm. Most vehicles have about a 1:2 ratio which implies at 3000 rpm for the engine the alternator is turning at the rated output. If not many loads are on in the vehicle one can already have 16-24A charging rate at idling of 900-1000 rpm.

    So the statement is true but only up to about 3000 engine rpm. No need to rev higher than this.

    Interesting to note of your experience with solenoid vs DC-DC charger.

    What is interesting to note is after a motor home rental company changed all their vehicles to solenoid from DC-DC they found far less customers complaining about flat batteries.

  11. The Following 2 Users Say Thank You to ekkekan For This Useful Post:


  12. #27
    Join Date
    Apr 2021
    Location
    Pretoria
    Age
    35
    Posts
    102
    Thanked: 103

    Default Re: How long does a dual battery system really last?

    The entire reason people spend extra money on a smartpass when installing CTEK dc-dc chording systems is to allow the system to bypass the fancy dc charger and use the alternator direct to the battery, to make use of the alternator for the bulk charging phase, and then switches back to the ctek for the topping charge, making use of the higher voltage that the DC-DC can achieve.

    so, essentially, a smartpass just cuts out all the high tech stuff, and gives you exactly what you would have with a soleniod for the majority of the time you are driving.

    so if in Hedgehogs case he is using a d250s with a smart pass, then his claims make sense, but without a smartpass or similar, I really donít understand how itís possible that it charges faster. The physics just donít make sense - I however only got a B for science in matric, so that isnít saying much

  13. #28

    Default How long does a dual battery system really last?

    Just a side note and interruption here Ö

    Technically a dc to dc charger is a misleading term used in the industry. It doesnít create current or voltage to charge. It just regulates it from an alternator or a solar

    OP - it would be helpful to you by understanding Ohms law as well as considering the purchasing a battery tester (not a multimeter) so that you can monitor SOC and SOH. If you arenít the owner of the battery then definitely check the SOH of the battery before you go. It will indicate general battery health.

    Interestingly nobody has covered the solar panel side of it in this thread yet.

    The battery tester is cheaper than vrot meat and food because of no battery power to run the fridge.

    Sorry for this side note and off the point interruption.
    Last edited by Therackermann; 2021/05/13 at 08:13 PM.

  14. The Following User Says Thank You to Therackermann For This Useful Post:


  15. #29
    Join Date
    Feb 2009
    Location
    Pretoria
    Age
    45
    Posts
    4,787
    Thanked: 963

    Default Re: How long does a dual battery system really last?

    What everybody is forgetting, is the size and make of the aux battery.

    if it is a high cycle, then there is no way a dc2dc setup will beat a solenoid/alternator setup -unless as stated, if a C-Pass or similar device is also incorprated.

    If it is a deep cycle, the dc2dc charger will win as the alternator wonít get it past 80-90% SOC not being able to reach the required volt level required for the aborption stage.
    Nico Swart

    Triton 2.5DiD D/C with SS
    ZS6NJS

    One day, or Day One. You decide. Tomorrow is promised for no one!

  16. #30
    Join Date
    Apr 2010
    Location
    Port Elizabeth
    Age
    70
    Posts
    1,413
    Thanked: 1020

    Default Re: How long does a dual battery system really last?

    Quote Originally Posted by DC Polokwane View Post
    a Well designed (for your application) dual battery system could last indefinitely
    Absolutely with the emphasis on Designed four 'your' Application

  17. The Following User Says Thank You to Peter Betts For This Useful Post:


  18. #31
    Join Date
    Oct 2016
    Location
    Polokwane
    Age
    55
    Posts
    1,115
    Thanked: 831

    Default Re: How long does a dual battery system really last?

    I was taught (maybe incorrectly?) that charging a deep cycle battery is like baking bread, its a slow process and shouldn't be rushed. One can not simply turn the oven to 600ļ and be done in 3 minutes!

    For longevity a deep cycle battery wants a slow charge and slow discharge, it shouldn't be charge at more than 10% of its capacity meaning a 105ah deep cycle battery should not be charge with more than 10amps. (Presumably the same applies for discharge?)

    For longevity a deep cycle battery must not be discharged more than 50% and only 20% discharge is even better.

    For longevity a deep cycle battery doesn't like excessive heat.

    Assuming the above is correct, how does that impact DC-DC vs Solenoid charging?

    Charging a deep cycle battery with a DC-DC at 20amps might still be alright but pushing it to 40-80amps through a Solenoid system is probably not?

    The point I am trying to make is that charging batteries take time, especially deep cycle batteries, by rushing the process some damaged can be done to the battery.


    .
    Last edited by DC Polokwane; 2021/05/17 at 07:50 AM. Reason: Spelling
    Jeep Grand Cherokee 2002 4.7 V8
    Conqueror Courage 2016

  19. #32
    Join Date
    Oct 2016
    Location
    Polokwane
    Age
    55
    Posts
    1,115
    Thanked: 831

    Default Re: How long does a dual battery system really last?

    Quote Originally Posted by Peter Betts View Post
    Absolutely with the emphasis on Designed four 'your' Application
    Yes, as long as "your" setup produces more amps than its using you can carry on indefinitely.
    Jeep Grand Cherokee 2002 4.7 V8
    Conqueror Courage 2016

  20. #33
    Join Date
    Jan 2011
    Location
    Loevenstein
    Age
    56
    Posts
    25
    Thanked: 10

    Default Re: How long does a dual battery system really last?

    In 2012 I travelled to Tanzania, Kenya, Uganda, Rwanda, Burundi and back. It was a seven week trip. Just the batteries. Could camp for three days without hassles with 40 liter Engel at no 1 setting. Everything was charged while driving. It was a 15 000 km drive. You can isolate the main battery if you are worried or load an extra removeable battery, one of those in a box. I think it is not necessary to overthink. Adapt as you go. Keep cost low, if they see you with to many paraphernalia you become a target. Keep your weight down, the lighter the load, the less chance of something breaking.

  21. #34
    Join Date
    Feb 2009
    Location
    Pretoria
    Age
    45
    Posts
    4,787
    Thanked: 963

    Default Re: How long does a dual battery system really last?

    Quote Originally Posted by DC Polokwane View Post
    I was taught (maybe incorrectly?) that charging a deep cycle battery is like baking bread, its a slow process and shouldn't be rushed. One can not simply turn the oven to 600ļ and be done in 3 minutes!

    For longevity a deep cycle battery wants a slow charge and slow discharge, it shouldn't be charge at more than 10% of its capacity meaning a 105ah deep cycle battery should not be charge with more than 10amps. (Presumably the same applies for discharge?)

    For longevity a deep cycle battery must not be discharged more than 50% and only 20% discharge is even better.

    For longevity a deep cycle battery doesn't like excessive heat.

    Assuming the above is correct, how does that impact DC-DC vs Solenoid charging?

    Charging a deep cycle battery with a DC-DC at 20amps might still be alright but pushing it to 40-80amps through a Solenoid system is probably not?

    The point I am trying to make is that charging batteries take time, especially deep cycle batteries, by rushing the process some damaged can be done to the battery.


    .
    Agree with most of this, save to say that NO battery likes excessive heat, be it from the charging itself, or external sources present and this will hamper charging (if this function is monitored by the charger) and if not, it will damage your battery if charged with too high amps. In this regard, high cycles was designed for this.

    Deep cycles not.
    Nico Swart

    Triton 2.5DiD D/C with SS
    ZS6NJS

    One day, or Day One. You decide. Tomorrow is promised for no one!

  22. The Following User Says Thank You to Die SwartKat For This Useful Post:


  23. #35
    Join Date
    Feb 2009
    Location
    Pretoria
    Age
    45
    Posts
    4,787
    Thanked: 963

    Default Re: How long does a dual battery system really last?

    Quote Originally Posted by Johan H View Post
    In 2012 I travelled to Tanzania, Kenya, Uganda, Rwanda, Burundi and back. It was a seven week trip. Just the batteries. Could camp for three days without hassles with 40 liter Engel at no 1 setting. Everything was charged while driving. It was a 15 000 km drive. You can isolate the main battery if you are worried or load an extra removeable battery, one of those in a box. I think it is not necessary to overthink. Adapt as you go. Keep cost low, if they see you with to many paraphernalia you become a target. Keep your weight down, the lighter the load, the less chance of something breaking.
    From this I assume that:

    1. You went during autumn/winter when it is obviously cooler;
    2. During three days stationary time, there was still some driving involved (such as game drives)
    3. You had high cycle/cranking batteries as the aux battery.

    Else there is no way a battery will last 3 days.
    Nico Swart

    Triton 2.5DiD D/C with SS
    ZS6NJS

    One day, or Day One. You decide. Tomorrow is promised for no one!

  24. #36
    Join Date
    Oct 2013
    Location
    Centurion
    Age
    64
    Posts
    2,455
    Thanked: 977

    Default Re: How long does a dual battery system really last?

    Some interesting comments here. Some guys have really great chargers that can charge a flat or nearly flat battery at 40A. For years I had an ammeter between alternator and start cycle batteries and never saw such high currents while the alternator could provide it. Even if the battery accepts 40A it is only for a short period without it generating a lot of heat.

    This relates to lead acid.

  25. The Following 3 Users Say Thank You to ekkekan For This Useful Post:


  26. #37
    Join Date
    Apr 2014
    Location
    Witsand
    Age
    63
    Posts
    461
    Thanked: 256

    Default Re: How long does a dual battery system really last?

    Regardless of whether the vehicle is fitted with a solenoid system (which is really only a time delay switch connecting the second battery to the vehicles alternator) or it has a DC-DC charger, 2 hours driving a day is insufficient ON ITS OWN to properly recharge the battery, and from one 105Ah battery in good condition you can only reasonably expect 10-12h of running in hot weather.

    Much is said on the solenoid/DC-DC debate and it is worth reading the NL research results on this, but basically, if the alternator puts out >13.7V (my LC 76 puts out 13.9V) then a solenoid type is just as good as a DC-DC charger. Take note though that most DC-DC chargers can accept a PV feed as well and will select the better feed of the two whilst on the move.

    So your choice is either to drive more (like 5h/day plus) or top it up with a PV panel and/or a AC-DC charger when you have access to ground power. Most hire vehicles have a ground power input and onboard charger anyway. An inverter will have no effect on this-its a DC-AC conversion device with its own losses and functionality issues.

    Batteries require care. Must not charge too fast or discharge too fast either. And if the battery has been misused before you get it, you could start with a dud and never recover. If in doubt, ask yourself why so many single battery systems are fed with 20A and not 40A chargers. Go 20A and save the battery.

    When I drive a lot (>5h/day) I have one 105Ah battery for each fridge (2) on solenoid, 200W PV through controller and AC ground supply charger. When on AC charger, run fridge on AC to save battery cycles. When doing long stops with caravan, I use a DC-DC/MPPT PV combo in the caravan because of the long line from the vehicle alternator. Same 200W panels and AC if available. My batteries seldom last more than 3 years.

    Good luck and safe travels.

  27. The Following User Says Thank You to rob wilson For This Useful Post:


Page 2 of 2 FirstFirst 1 2

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •