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Battery help

Discussion in ''How To' & 'Handy Hints'' started by Josht3, Jul 9, 2019.

  1. rstucke

    rstucke Well-Known Member

    Messages:
    1,013
    Location:
    Wamberal NSW AUS
    @drivesafe
    Ok I take your point between starter batteries and auxiliary batteries
    So if we use an aux battery for free camping for a few days and the voltage goes down to say 11.2v during that time. Is a 10-15amp smart charger good or bad for the operating life span for the battery? If it isn't what is best?
    Or am I reading what you posted incorrectly?
     
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  2. drivesafe

    drivesafe Active Member

    Messages:
    145
    Hi again rstucke, by “smart charger” do you mean a DC/DC device and if so, THEORETICALLY yes, in sorts.

    First off, most deep cycle batteries should not be discharged below 11.6v or 20% SoC.

    Next, a SLOW recharge with a low current DC/DC device would be good for the battery, but the problem is that you now have to drive for many more hours then you probably would, to allow the DC/DC device the time it needs to be able to fully charge the battery from a low state.

    With a Kombi and it’s small alternator, because DC/DC device are inefficient, ( they need more power going in than they actually charge the battery with ) you are going to waste valuable energy just to run the DC/DC device itself.

    Because a Kombi alternator runs at a constant 14.3v, which is the idea battery charging voltage, you are far better off charging directly from the alternator.

    While it is unlikely that you will drive long enough the fully recharge the battery, your alternator will recharge the auxiliary battery to a much higher state than a DC/DC device will, in the same drive time.

    This is important if you are moving from one free camping site to another, and trying to get as much used energy replaced during the drive between the two locations.

    Using a slower charging DC/DC device will most likely mean you will be forced to discharge your auxiliary battery even lower while at the second free camping site.

    If by “smart charger” you mean a 230VAC battery charger, then a low current charger is far better for your battery.

    For say a 100Ah battery, a 5 amp battery charge, while it will take much longer to recharge a battery, it will leave the battery in both a better state of charge and the battery will be in a better condition.

    Just a tip. Most people will charge a battery and then when the charger goes into FLOAT mode, they remove the charger. You are far better off leaving the battery in the FLOAT stage for up to 8 hours ( if time permits ), as this will actually recondition the battery by helping to reverse the effects of any Sulfation that may be building up in the battery.
     
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  3. rstucke

    rstucke Well-Known Member

    Messages:
    1,013
    Location:
    Wamberal NSW AUS
    @syncro
    It was combustion
    So if you really want to know the details
    Tom was the head teacher of heavy vehicles at Wetherill park (I was teaching in light vehicles across the drive)
    Heavy vehicles had the latest twin axle dyno, some prime movers, a number of plant machinery, scrapers, dozers etc and all diesel.
    The systems were 24v and the batteries were in wheelie carts so the storeman could maintain them.
    Tom was teaching plant mechanics one morning(around 1986 (I think)), grabbed a battery cart (which he maintained was not on charged but could have been taken off earlier that morning) and took it to a grader he was going to use in his class. What he didn't realise was the cabin light switch was left on in the grader (found after the event in an inquiry).
    When he connected the battery the small spark at the battery terminal from the cabin light circuit was enough to ignite the hydrogen/ oxygen mixture around and in the top of the battery.
    He was leaning over the battery at the time. The plastic shrapnel embedded in his face and neck, took his nose off and covered his overalls in acid.
    Ambulance was called, Safety shower came in handy, nose was wrapped in glad wrap and put in ice cold water (pretty traumatic for him and us).
    Toms nose was reattached and scars were cauterized with a fancy laser at the time.
    Took about 3 months till he came back to work, we all agreed he was a handsomer version of himself after his "face lift".

    I transferred to Miller college and then up the coast and some years later learned that Tom died of a heart attack doing what he liked bush running( for want of a better word) between Blackheath and the Jenolan Caves.

    So I've learned from this experience that sparks around batteries can cause explosions, be it a closed circuit in the system or dodgy connections. The percentage of combustible hydrogen doesn't work because oxygen is created at the opposite terminal at the same time during charging (basic electrolysis)

    I really didn't want to do this
     
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  4. rstucke

    rstucke Well-Known Member

    Messages:
    1,013
    Location:
    Wamberal NSW AUS


    I was basically meaning an ac charger for when the vehicle is sitting around between uses which you've answered in your post.
    I think most have an alternator connected to the aux via an isolator of some sort.
    Good to know about the 11.6v
     
    Last edited: Aug 15, 2019
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  5. syncro

    syncro Well-Known Member

    Messages:
    9,324
    Location:
    Southern Highlands
    I really think that this was an unfortunate one in a million accident to your friend. It would be near impossible to replicate. Just think how many die on the roads, but we all still drive.
     
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  6. Maccas

    Maccas Member

    Messages:
    50
    Location:
    Gosford
    Over the past twelve years, easily the most discussion I'm aware of amongst watercooled T3 owners concerning combustion avoidance, centres around the need for preventive maintenance of the 30 year old fuel delivery system. A bigger problem in aircooled veedubs.

    For Australia, I can't recall over the same timeframe any discussion or reporting of one or more actual incidents of combustion or explosion concerning a watercooled T3 camping battery, be it in a TRAKKA or any other OZ camper.
     
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  7. Barry

    Barry Well-Known Member

    Messages:
    3,660
    Location:
    Abbotsford NSW
    Isn’t the point of a deep cycle battery that it is better at going flat than my normal car battery?
     
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  8. AC-T3

    AC-T3 Well-Known Member

    Messages:
    961
    Location:
    Woy Woy
    Agree with them 2. My TRAKKA now has it's auxiliary battery under the passenger seat in the VW designed vented battery space.
     
    Mr Beckstar likes this.
  9. Mr Beckstar

    Mr Beckstar Well-Known Member

    Messages:
    1,017
    Location:
    Bateau Bay, NSW
    @Maccas the problem (or perhaps the good thing) is that battery explosions are rare. It requires all the wrong conditions to occur at the time of an ignition source. Rstucke’s Qld Mines article shows 37 reported explosions in 11 years throughout all of Queensland. There would be millions of batteries in Queensland by my estimate. Therefore, the chance of experiencing a battery explosion is akin to winning Lotto. However, with poor installation of the battery and disregard for safety procedures your chances of an explosion narrow down, but it doesn’t make it a sure thing. The question is, do you want to risk being one of the 37 in 11 years?

    My biggest concern is people getting hit by flying shards of plastic and getting covered in acid. I guess if the battery explodes whilst in a box under a seat, it’s providing a bit of protection to people and any damage would be repairable. In this case, ignition sources are limited to the battery itself or to the terminals coming loose, so perhaps it’s okay during operation - if not for risk of explosion damage, at least for risk of people getting hurt. But of course any gases generated will have trouble getting away. Therefore, if you go to connect/disconnect/connect jumper leads, make sure you ventilate the battery well before any connections/disconnections. As an extra safety measure, a fan positioned a couple of meters away and pointing at the battery to blow fresh air in would be good. I was always taught when connecting jumper leads to make the earth connection last and, where possible, make the connection on e.g. a nice clean bolt head on the body of the car (or clean metal on the engine) rather than at the battery. The idea is to make sure no sparks are generated above the battery where gas could be present. For the same reason, when disconnecting, remove the earth lead first which is hopefully connected somewhere away from the top of the battery.
     
    Last edited: Aug 16, 2019
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  10. syncro

    syncro Well-Known Member

    Messages:
    9,324
    Location:
    Southern Highlands
    I think that if there was serious risk then VW would have learned a long time ago as they have built many millions of vehicles with internal batteries. As we have read here that it can happen but it would be one chance in many millions. We are driving unsafe old cars that have a much higher risk of injury due to minimal safety, many body repairs, old seat belts and poor quality parts. Just look at the owners on here that buy tyres and shock absorbors on price.

    I think that we can give this one a rest.
     
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  11. drivesafe

    drivesafe Active Member

    Messages:
    145
    Hi Maccas, there are plenty of vehicles, not just Kombi campers, where auxiliary batteries are fitted in an unsafe manor, but this thread is not about what is already out there, it is about assisting the OP to avoid potentially dangerous practices, particularly where there is no need to increase the safety risk in the first place.

    While fitting his battery in the engine bay of his Kombi does not make his setup 100% safe, it does give Josht3 the safest POSSIBLE setup.

    By fitting his battery in an open area, Josht3 dramatically reduces the potential explosive capability of his battery, to its absolute minimum.



    Hi Mr Beckstar, rstucke’s document is not really an indication of how few incidents of battery explosions have occurred as the data specifically only relates to incidents that have occurred in the last 11 years in the mining industry itself.

    When you consider the stringent safety protocols that are in place in the mining industry, the document should act as a wakeup call for the RV industry, where no such safety requirements are mandated.

    This is very similar to the now mandatory safety standards for the use of inverters and generators on worksites in QLD and VIC came about.

    These safety standards were only introduced after 2 people were killed on QLD and VIC worksites but are now being enforced for any use of inverters and generators.
     
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  12. drivesafe

    drivesafe Active Member

    Messages:
    145
    Hi Barry, a little over 20 years back, the only batteries available ( at a realistic price ) were Wet Cell cranking batteries and these were used as cranking batteries, auxiliary batteries and house batteries.

    To get a decent lifespan from these batteries, you did not cycle them below 11.9v or 40% SoC.

    When reasonably priced Wet Cell deep cycle batteries came on the market, they also had the same cycle rate limitation of not taking them lower then 11.9v, but they had a much better throughput ( number of cycles down to 11.9.v ).

    In the early 2000s the first of the AGM “deep cycle” batteries came on the market. They were, and many still are, upgraded Standby Batteries, but they could safely be cycled down to 11.6v or 20% SoC.

    By around 2014, as most Wet Cell batteries were now Calcium/Calcium construction, and they too can be safely cycled down to 11.6v or 20% SoC.

    The two main differences between Wet Cell and AGM deep cycle batteries is that AGMs can be laid on their side or ends while Wet Cells must remain upright at all times.

    Plus, AGMs will have a maximum charge current limit, with most new AGMs being able to tolerate up to 35% of their Ah ( if it is a 100Ah AGM, then the maximum safe charge current is limited to 35 amps ).

    While Wet Cell batteries of all types are actually self-limiting, so you can apply any charge current and the battery itself will limit the absorption charge current, based on the voltage applied at the time.

    NOTE, there are some special AUTOMOTIVE GRADE AGMs, like Optima, that can safely absorb very high charge currents without harming them. Optima Yelowtop batteries can also be safely cycled down to 10.5v or 0%.

    There is a lot more to this subject, but the above, I hope, answers your question.
     

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