Hi again. New to me 2015 17.56. The battery in the van charges from the car. But requires both Anderson and 12 pin to be plugged in. Is this normal?
Electrical Battery charge from car
- Thread starter KevD
- Start date
No ................ usually the anderson does the fridge while the 12pin is left to do the 12v supply to van, could be an earthing problem or just weird set up, best way is to track each connection and see whats what, multi meter is handy... A simple test is to plug 12pin in, engine running, turn off battery switch in van, van lights should operate if 12pin supplying power which in turn should mean that when battery turned on it will be getting charged via the Setek......
Try to follow the Anderson cable to see where it goes, otherwise a check would be to again plug into tug, engine running, van battery off, confirm power at anderson then again at rear of fridge where the 12v terminal block is, of course if a fridge switch fitted this won't work. and do the same test with the lights.. the lights should come on with any one of the following 240v, battery switch turned on or connected to Tug and plugged in......
Try to follow the Anderson cable to see where it goes, otherwise a check would be to again plug into tug, engine running, van battery off, confirm power at anderson then again at rear of fridge where the 12v terminal block is, of course if a fridge switch fitted this won't work. and do the same test with the lights.. the lights should come on with any one of the following 240v, battery switch turned on or connected to Tug and plugged in......
Anderson is generally connected to fridge only. The 12 pin is not used to charge the battery in the van, it is only used to let the fridge know when the tow vehicle ignition is on (generally so slides can not be moved while the van is being towed and to prevent the fridge from automatically switching to gas and igniting as soon as the ignition is turned off. This way the fridge doesn't ignite next to a fuel bowser when your filling up.) If you want to charge the battery you will need to run another cable from the tow vehicle and fit a dc-dc charger (JHUBS are not a DC-DC charger). If you run a new cable it should be a minimum of 6B&S all the way from the car battery (4B&S would be better).
I beg to differ the BMPro series of RV management systems does take 12v from the tug via 12 pin or anderson, (personal preference) and doesn't require a seperate DC-DC charger in tug or van, it will charge the batteries via solar, 240v mains or 12v, the 12v supply runs to the Aux on the BMPro systems
On an auto fridge the D+ wire should be connected to a tug ignition supply of 12v to enable the fridge to see the tug is plugged in and in theory shut down when key is off, usually though its connected to the same fridge feed line, with the fridge disconnected by unplugging or a fridge switch relay operating a shut down the fridge will attempt to connect to LPG therefore a fail safe of 10 mins delay is fitted so that gas won't start in case the operator had a brain fart and didn't shut off gas at hook up, with an analogue fridge its not a problem as it require input to operate........
Of course if you have ample solar 12v charging from tug is redundant and a waste of money...
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Quoting BMPRO from https://teambmpro.com/products/lithium-compatible-battery-management-system-j35d/
"The J35 does not serve as a DC-DC charger. We offer the MiniBoostPRO, which is a DC-DC charger that can connect to the J35."
You will not charge any battery via the 12v lead on your 7/12 pin plug.
Personally, I use a 175amp Anderson plug for both fridge and Enerdrive DC-DC charger (both wires to one plug), via VSR on tug to prevent excessive load on alternator. When the van fridge isn't running I get 37amp from the tug to charge the van battery. Usually, it only takes a couple hours driving to recharge the van fully.
"The J35 does not serve as a DC-DC charger. We offer the MiniBoostPRO, which is a DC-DC charger that can connect to the J35."
You will not charge any battery via the 12v lead on your 7/12 pin plug.
Personally, I use a 175amp Anderson plug for both fridge and Enerdrive DC-DC charger (both wires to one plug), via VSR on tug to prevent excessive load on alternator. When the van fridge isn't running I get 37amp from the tug to charge the van battery. Usually, it only takes a couple hours driving to recharge the van fully.
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I quote from the document:
"J35D allows you to charge the caravan battery to the optimal charge level from 230-240 Volt mains, your solar panel (28 Amp, or three panels 450W total), or from any auxiliary input, such as a power generator or your vehicle. "
But they do cause confusion with their not a DC-DC charger.
I have found, the van wired from factory the aux is the feed from the tug and when I did the new tugs for 2 friends vans, it was fed from tug battery to draw bar, standard set up so they do charge.... What I think is meant and not very clear, is that the BM Pro will not act as a DC-DC charger and charge an aux battery pack to do that fitting their Mini Boost Pro DC-DC charger ($300) will enable an aux battery to be charged from the BM Pro unit, so your portable battery pack can be charged up just like the house battery, be handy while in camp for sure, you don't need a DC-DC charger in vehicle to supply the BM Pro, though if I had a smart alternator unit I probably would for ease ..... I think a unit costing over a grand if it was incapable of taking feed from tug without spending more $$$ would be a bit much.....
If my batteries required 35 amps to charge I would be worried actually.... and many a vans batteries are charged from the 7/12 pin plug including the fridge though I prefer any power to be via an Anderson Plug, far more efficient................
"J35D allows you to charge the caravan battery to the optimal charge level from 230-240 Volt mains, your solar panel (28 Amp, or three panels 450W total), or from any auxiliary input, such as a power generator or your vehicle. "
But they do cause confusion with their not a DC-DC charger.
I have found, the van wired from factory the aux is the feed from the tug and when I did the new tugs for 2 friends vans, it was fed from tug battery to draw bar, standard set up so they do charge.... What I think is meant and not very clear, is that the BM Pro will not act as a DC-DC charger and charge an aux battery pack to do that fitting their Mini Boost Pro DC-DC charger ($300) will enable an aux battery to be charged from the BM Pro unit, so your portable battery pack can be charged up just like the house battery, be handy while in camp for sure, you don't need a DC-DC charger in vehicle to supply the BM Pro, though if I had a smart alternator unit I probably would for ease ..... I think a unit costing over a grand if it was incapable of taking feed from tug without spending more $$$ would be a bit much.....
If my batteries required 35 amps to charge I would be worried actually.... and many a vans batteries are charged from the 7/12 pin plug including the fridge though I prefer any power to be via an Anderson Plug, far more efficient................
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Maybe their definition of DC-DC charging means to actually boost voltage (ie be able to take 10V in and convert it to 12+ for charging the battery). So if the voltage supplied is not sufficient to charge it will not be able to use it.
So I would say that J35D is a battery charger for Solar and Aux, that requires the input voltages to be above the charging voltage. In this case minimal voltage drop is required so that the voltage at the charger is at the required charging voltage or above. If not no or minimal charging will occur.
For it to be a DC-DC charger it would be able to use voltages below charging voltage and convert it to the charging voltage. In this case it is not as important to minimise the voltage drop and charging will still occur.
Noting that in both cases the power lost due to cable and connector resistance is power that is wasted, but in the first case may mean that charging doesn't occur at all.
So I would say that J35D is a battery charger for Solar and Aux, that requires the input voltages to be above the charging voltage. In this case minimal voltage drop is required so that the voltage at the charger is at the required charging voltage or above. If not no or minimal charging will occur.
For it to be a DC-DC charger it would be able to use voltages below charging voltage and convert it to the charging voltage. In this case it is not as important to minimise the voltage drop and charging will still occur.
Noting that in both cases the power lost due to cable and connector resistance is power that is wasted, but in the first case may mean that charging doesn't occur at all.
Well I had a good read of the manual again and it will charge from a tug via the AUX input, just like all RV BMS, if you have solar connected it will use both or just one depending on charge required, what it won't do is charge another battery pack , just like other RV BMS units... BM Pro have a DC-DC unit which will marry to the J35 to charge an aux battery pack ..... remember these systems will charge any number of identical batteries linked together, it will only see one battery as such but like other sytems it is unable to charge a seperate battery like an aux battery for an engel or whatever.... If you fit a DC-DC charger to your tug to charge a aux battery for your engel then it can't supply power to the van unless it has dual outputs or you piggy back the 12v supply from the aux to provide 12v to the vans BMS unit which will then charge your van battery... or even the fridge..... one battery type one charger you can't mix...
Of course the answer of "No its not a DC-DC charger" in the FAQ section is correct as the BM Pro is a RV Battery Management System and as such incorporates the functions of a DC-DC Charger, Mains Charger, Solar Regulator and a Power Distribution System, if you just wnated to charge the aux battery for a fridge you wouldn't by one of these...........
Of course the answer of "No its not a DC-DC charger" in the FAQ section is correct as the BM Pro is a RV Battery Management System and as such incorporates the functions of a DC-DC Charger, Mains Charger, Solar Regulator and a Power Distribution System, if you just wnated to charge the aux battery for a fridge you wouldn't by one of these...........
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If you want to partially charge a battery over a very long period of time from the tug, use the J35 and whatever size wire you can stuff into a trailer plug.
If you want to do it properly it would be a good idea to do some research on the voltage required to charge whatever battery you use (to full charge). Then calculate the voltage drop from your alternator with the size wires you have used (and remember the length for most calculators is from car to van and back to car i.e. double the actual length). If using 6B&S your drop will probably be about 1 volt (if charging at 20amps), to charge at 40 amps the voltage drop would be 2 volts etc... There is a reason why the alternator is at 13.6v or there abouts; and is right next to the starter battery with heavy cables.
The amount of Amps you use to charge the battery has nothing to do with needing the amperage to charge. The amperage just allows you to charge more quickly. the voltage is the important figure for a full charge. A good DC-DC charger will up the voltage to allow you to reach full capacity. The J35 is a very poor choice if you want to charge from the tug, and it will not charge to full capacity from aux.
In my situation, I wanted to bulk charge the van in the shortest period of time. My limiting factor being the alternator on the car. If my alternator allowed it, I would love to charge at 100Amps (Note: 300A/Hr lithium with 100A max charge rate)
Personally, I have two DC-DC chargers, a Ctek in the car for the drinks fridge and an Enerdrive in the van. The 37 Amps I get from the tug is in addition to the 14 Amps from the vans rooftop solar.
If you want to do it properly it would be a good idea to do some research on the voltage required to charge whatever battery you use (to full charge). Then calculate the voltage drop from your alternator with the size wires you have used (and remember the length for most calculators is from car to van and back to car i.e. double the actual length). If using 6B&S your drop will probably be about 1 volt (if charging at 20amps), to charge at 40 amps the voltage drop would be 2 volts etc... There is a reason why the alternator is at 13.6v or there abouts; and is right next to the starter battery with heavy cables.
The amount of Amps you use to charge the battery has nothing to do with needing the amperage to charge. The amperage just allows you to charge more quickly. the voltage is the important figure for a full charge. A good DC-DC charger will up the voltage to allow you to reach full capacity. The J35 is a very poor choice if you want to charge from the tug, and it will not charge to full capacity from aux.
In my situation, I wanted to bulk charge the van in the shortest period of time. My limiting factor being the alternator on the car. If my alternator allowed it, I would love to charge at 100Amps (Note: 300A/Hr lithium with 100A max charge rate)
Personally, I have two DC-DC chargers, a Ctek in the car for the drinks fridge and an Enerdrive in the van. The 37 Amps I get from the tug is in addition to the 14 Amps from the vans rooftop solar.
Noting that when sending charge voltage through a BMPRO BMS Aux input to the batteries, it does not put any limits on the voltage passed through, to the batteries. They will receive what ever voltage is received by the BMS. So to connect voltage to the BMS Aux input directly from the vehicle alternator could damage the batteries as there would be no voltage regulation...
IMHO, I don't believe that to be true. The tug alternator has its own regulator which is sensed from battery voltage . If it senses tug battery voltage at say 13.90 volts and peak charging voltage is set say at 14.0 volts, then all outputs to battery will be at regulator controlled voltage with reducing current (amperage). If two batteries are connected in parallel, then the alternator regulator will sense the mean voltage of both batteries and voltage charge accordingly. The battery with the lowest resistance to accept a charge (usually the lowest?) will accept more amperage until both batteries are approx equal and then both are charged at the appropriate voltage sensed by alternator regulator until fully charged or float settings are reached. Therefore the voltage received at the BMS will be the same voltage as alternator output less any losses in connecting wiring.
However, if BMS AUX is connected directly to an external charging system, which doed not have ANY regulating system, be it voltage and current control, then there will be problems with the battery. Indeed, the manual even states that any charging input from an outside source, eg generator, must be regulated as BMS does NOT have any regulating device via this input.
Most connections from tug to J35 are done via the tugs battery but the connection set up does apply to all the BMS systems I have seen in vans, in fact if you connect DC-DC unit to an un regulated supply it would frize as well...long time since I came across an alternator or genny that has a seperate regulator....
Well this block head would run it from the aux battery which is hanging off the Redarc, keep the cranker for the engine.
Mines on the 2nd but I'm told other wize the start gets better charge ive noticed not that I've towed my van much waiting so long and all .... ... the 2nd gets a hammering feeding the van fridge ???
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I run 2nd off 1st and 3rd off 2nd, with a 100 amp CTEC bypass between 1st and 2nd with a VSR between 2nd and 3rd, That way voltage drop between 3rd and 2nd will prevent 2nd from supplying current to 3rd when the alternator is off. As soon as the fridge or DC-DC in the van kicks in when the engines not running it turns off. 2nd AGM lasted 6 years, and was then replaced solely because the beer fridge battery dying on a remote holiday would have been catastrophic.
I'm just old school and like to keep the cranker in good nick so we start every time ...... my van has never flattened the starter battery, my design is foolproof in that regard as I could see no need for an expensive set up .......
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