Hi all, I wish to run an anderson plug from the coupling area to the battery (fused) - does this need to go via the fuse box/BMS or direct to the battery etc .. ?? Just want to charge battery from the tug. Thanks DOS
Electrical Anderson plug to battery ?
- Thread starter dosmos
- Start date
Hi @dosmos , If you already have connections to your BMS (Setec or later type), then one of the wires from tug battery/alternator will be connected through the BMS. Unfortunately, the BMS has power diode in line to prevent any current from van battery being drawn when the high tug starter current is required. The connecting wiring is insufficient to carry such current, especially if tug battery is low and van battery is considerably higher. The power diode whilst protecting the connecting wiring will cause approx 0.7 volt drop in addition to other losses in transferring voltage/current from tug to van, losses which will prevent your van battery from receiving sufficient voltage to achieve a proper charge. Using a separate heavy cable with connections by Anderson plugs will reduce this loss but still needs to be isolated from the tug alternator when engine not running and also when wanting to start tug. A separate relay or better still, a VSR (voltage sensitive relay) will do this for you. But even then, if your tug has a "smart alternator", see attached, you will not see much joy. The only real way to achieve a proper charging current transferring from tug to van battery is with a DC to DC relay. This device takes any voltage from tug alternator and boosts this output to a usable charging voltage at the van battery. Eg, tug alternator/battery voltage IN to van wiring at say 12.6 volts is boosted to say 14.6 volts OUT to charge van battery. These settings are user adjustable.
I have attached several pieces for you to consider when trying to overcome this problem.
Attachments
What is the tug vehicle?
What is the current connection set up, 7 or 12 pin ?
What is the BMS system in your van?
Does your van have solar?
Most original set ups the 12v feed from tug will supply fridge as well as battery charge via whatever BMS system is fitted, an anderson to supply 12v to fridge is more important than 12v to battery as most vans now have solar so 12v for battery from tug is often not needed especially if you are doing off grid camping more than van parks, if your system requires charging from tug while driving then the set up isn't all that great for off grid use...... Many tend to spend big on tug charging systems not realizing their solar set up does the job better.
What is the current connection set up, 7 or 12 pin ?
What is the BMS system in your van?
Does your van have solar?
Most original set ups the 12v feed from tug will supply fridge as well as battery charge via whatever BMS system is fitted, an anderson to supply 12v to fridge is more important than 12v to battery as most vans now have solar so 12v for battery from tug is often not needed especially if you are doing off grid camping more than van parks, if your system requires charging from tug while driving then the set up isn't all that great for off grid use...... Many tend to spend big on tug charging systems not realizing their solar set up does the job better.
Hi,
your statements concerning a diode in series with the AUX input relate ONLY to the Setec BMS.
The BmPro J35 does NOT have a diode in series with the AUX feed.
Here is an excerpt from the J35 BmPro manual:
AUX INPUT (AUXILIARY)
The power supply input terminal “AUX INPUT” provides an alternative option for powering the loads and charging the caravan battery when mains voltage is not present. This input is powered from a suitable +12 V system (e.g. your vehicle). The voltage of this external DC power source must not exceed 14.8V.
This input is isolated using an internal relay, so it is strictly an input. J35 will never supply current to anything connected to this terminal.
Take care
Mike
Thanks for the update @mikerezny . These things are changing all the time and one needs to check before making any "rash" statements. It is good that there is now a relay incorporated into the later model BMS to prevent any power being taken by starting currents from van battery, and now no loss of charging voltage/current with a diode.
On that note, I had a good read on the link provided by @Johnanbev regarding the Projecta PM 200. It appears that even with the latest BMS, there is still the problem of tug alternator charge voltage.
The following is listed on page 7 of the instruction book for this BMS:
NOTE: The PM235J when charging from the vehicle battery, does not provide the 5 stage state charge. It simply takes whatever power and charging is available from the alternator.
NOTE: If your vehicle is fitted with a "smart" alternator, the VCR charge system (Variable voltage or temperature compensating), the VCR (VSR) charge system may not function correctly and a Projecta IDC25 charging system is recommended.
Shows how important it is to have current information.
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Hi @Boots in Action,
as far as I am aware, most BMS for vans have only the most simplistic facility for charging the van battery from the tug alternator.
Usually achieved by connecting the tug output to the van battery via a relay or an isolation diode. In both cases, the charging voltage is determined solely by the alternator voltage.
There are two explanations for this.
1: The better way would be to incorporate a DC-DC convertor into the BMS and thus remove the dependence of the van battery charging voltage and current on the tug alternator voltage. This would have been beyond the capabilities of early van BMS. And is probably outside the price range of the later BMS. Hence, why it has not been done.
2: I suspect that BmPro and Setec have also noticed with the increasing availability of solar there is now way less dependence on needing the tug alternator to charge the van battery. Hence, complex solutions to charge the van battery from the tug are not required. Especially in those cases where most camping is done on powered sites. Further, it makes economic and environmental sense to charge the van battery from rooftop solar panels if fitted rather than burn extra fuel to charge the van battery.
I do have 12V from the tug going into the Setec ST20 series III, but it is really not necessary, more just for completeness.
Our Falcon alternator usually runs at about 14.6V, which means 13.9V to the van battery allowing for 0.7V drop across the Setec isolation diode.
So, this just keeps the van battery on float and with such a small current drain it is not chewing that much more fuel. Especially in comparison to the 15A drawn by the three-way van fridge.
Here is one trick I do when camping in one place for an extended time. In the early days, I flattened the car battery when we stayed in one spot for 7 days with no driving. All the door opening, leaving the boot opened etc chewed a lot of power from all the interior lights. Solved that problem by getting into the car setups to turn off all internal lights.
But, I worried a little about having a flat battery, so I usually solar charge the car battery once or twice every 7 days.
Then I realised that if I left the van connected to the tug, charging the car battery would also charge the van battery. At the very least, it would supply enough power to supply any devices used in the van. So now, I leave the solar panel connected to the car battery quite often and thus keep both the car and van battery charged at the same time. Then connect the solar just to the van battery on some days to bulk charge it separately.
Probably a lot of overkill. But, when camping, there are a lot of brain cycles spare, so best to apply them to something useful.
take care
Mike
as far as I am aware, most BMS for vans have only the most simplistic facility for charging the van battery from the tug alternator.
Usually achieved by connecting the tug output to the van battery via a relay or an isolation diode. In both cases, the charging voltage is determined solely by the alternator voltage.
There are two explanations for this.
1: The better way would be to incorporate a DC-DC convertor into the BMS and thus remove the dependence of the van battery charging voltage and current on the tug alternator voltage. This would have been beyond the capabilities of early van BMS. And is probably outside the price range of the later BMS. Hence, why it has not been done.
2: I suspect that BmPro and Setec have also noticed with the increasing availability of solar there is now way less dependence on needing the tug alternator to charge the van battery. Hence, complex solutions to charge the van battery from the tug are not required. Especially in those cases where most camping is done on powered sites. Further, it makes economic and environmental sense to charge the van battery from rooftop solar panels if fitted rather than burn extra fuel to charge the van battery.
I do have 12V from the tug going into the Setec ST20 series III, but it is really not necessary, more just for completeness.
Our Falcon alternator usually runs at about 14.6V, which means 13.9V to the van battery allowing for 0.7V drop across the Setec isolation diode.
So, this just keeps the van battery on float and with such a small current drain it is not chewing that much more fuel. Especially in comparison to the 15A drawn by the three-way van fridge.
Here is one trick I do when camping in one place for an extended time. In the early days, I flattened the car battery when we stayed in one spot for 7 days with no driving. All the door opening, leaving the boot opened etc chewed a lot of power from all the interior lights. Solved that problem by getting into the car setups to turn off all internal lights.
But, I worried a little about having a flat battery, so I usually solar charge the car battery once or twice every 7 days.
Then I realised that if I left the van connected to the tug, charging the car battery would also charge the van battery. At the very least, it would supply enough power to supply any devices used in the van. So now, I leave the solar panel connected to the car battery quite often and thus keep both the car and van battery charged at the same time. Then connect the solar just to the van battery on some days to bulk charge it separately.
Probably a lot of overkill. But, when camping, there are a lot of brain cycles spare, so best to apply them to something useful.
take care
Mike
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@mikerezny, I think you have explained the situation perfectly , and unfortunately for @dosmos, he hopefully can see there is no easy answer, except to spend more cash, which may be for little return, if solar charging is a better bet. The only problem is that solar charging is not possible at night or semi-darkness, and still limited when travelling.
I think you are correct on point 1.
And point 2 is in line with @Drover,s thinking too if not on a powered site and free camping a lot. On a price basis, why would manufacturers provide a function that many (or most) would not use and not be willing to pay extra for?
You are most fortunate in having an alternator with that sort of voltage output and so do not suffer from the problems of later, more modern vehicles with more sophisticated charging alternators especially in diesel tugs.
We have not had any issues with the tug battery as we are rarely in and out of it, turning lights on etc when camping. Indeed, we never remain connected to van when camped - unhitched! Remember that if remained connected to tug, both van battery and tug battery will tend to equalise even if charging the tug with solar unless you are able to isolate each one.
Over the Christmas/New Year period, I still intend to remove my Setec ST20 Series III and look at replacing the power diode with a lower loss Schottky type. I will let you and @jazzeddie1234 know the results and if it is possible without too much problem.
Hi,
one other solution which might work especially if one already has a good 240V multi-stage battery charger.
Run a good sized connection from the tug battery up to near the van battery. Install a 240V inverter capable of supplying the battery charger.
Then use the inverter to power the 240V battery charger.
This would be a great solution if one already has a good battery charger and an adequate inverter.
In effect that mimics a DC - DC charger. Well, actually, I should patent the idea as a DC-AC-DC charger.
take care
Mike
one other solution which might work especially if one already has a good 240V multi-stage battery charger.
Run a good sized connection from the tug battery up to near the van battery. Install a 240V inverter capable of supplying the battery charger.
Then use the inverter to power the 240V battery charger.
This would be a great solution if one already has a good battery charger and an adequate inverter.
In effect that mimics a DC - DC charger. Well, actually, I should patent the idea as a DC-AC-DC charger.
take care
Mike
Lol,lol,lol,lol,,................................... bit more than .7v loss in that set up...........................
I like that plugging a panel in to keep the tugs battery up, my set up for the rear anderson power for my fridge works as a input to my battery as well, under the bonnet is another anderson which I can plug a panel in and charge the battery or plug a compressor in, the Jeep doesn't sit in camp for a week so battery doesn't go close, leave the radio on or accessories and it will auto shut down in 30 mins anyway...
BMPro and most of the modern whiz bang gear will select the best power source thats plugged in, son in law reports his van will select solar even when plugged into the tug as he asked me why did we go to all the trouble of setting up, I told it was a waste of money and that his panels would look after it....... but he does like gadgets.
BMPro and most of the modern whiz bang gear will select the best power source thats plugged in, son in law reports his van will select solar even when plugged into the tug as he asked me why did we go to all the trouble of setting up, I told it was a waste of money and that his panels would look after it....... but he does like gadgets.
Hi,
it may or may not be as efficient as a dedicated DC-DC charger.
However it would certainly supply a higher voltage to the van battery irrespective of the type of alternator installed in the car. Further, if a good 240V battery charger is used, it will be able to supply the correct bulk and float voltages for the van battery that is installed.
If one already has a good 240V battery charger, the extra cost of an inverter may well be much less than fitting a dedicated DC-DC charger which serves only one purpose. In contrast, a 240V battery charger and a 12V 240V inverter would have many many uses.
take care
Mike
Interested to see how that turns out. The mod I did with that small dc dc board is working pretty well for me - I added a small cooling fan that is powered from the output (setec aux input side) and now I can hear what the unit is doing based on fan noise/speed. It fires up when the ute altenator is producing enough volts and/or the solar on the ute has charged the 2nd battery (so gives surplus to caravan) which is exactly what I hoped for
Hi @dosmos , just because we gave you indigestion with our answers (sorry), does not mean it cannot be achieved. You will have to investigate the priority it has and the depth of your wallet to get around these things. Good luck and Merry Christmas.
PS. My 2011 Colorado does not have a "smart" alternator, but I am still going to see what/if a Schottky diode (voltage loss of only 0.2 volts) can improve things. The current power diode has a voltage loss of approx 0.7 volts. Stay tuned if you are still interested as I will do a separate thread on this experiment. Won't help you though if you have a "smart" alternator!! Cheers.