I have a 12 pin flat plug/socket and - in spite of bridging two of the 30amp connectors for the fridge (2 +ve and 2-ve) and van battery charging - I still have pin discolouration from overheating after a few hours on the road. I am aware that an Anderson plug/skt would solve the problem but I would like to avoid having to fit extra plugs, etc. I have also checked the pin connections to ensure all the existing plg/skt connections are good. I recently saw a very solid looking (12 pin, I think) round plug on a friend's rig but have no idea of brand or availability. It seemed to screw together and I hope someone out there can point me in the right direction. I believe the large contacts on the round plug are rated at 35 amps which should do the job if that rating is genuine and not like the 25amp rating on my existing plug. I am using 8mm cable right through.
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Best regards,
Chris
Licensed Electrician, Electronics, Gaming & Computer Technician. Now retired and loving it!
The connector you describe could be military. I suggest you google ampenol, canon, or radial to see if there is a connector combo suitable. Maybe google high current multi pin connectors.
I would check the whole circuit, sounds like a low resistance/short someplace to cause burning and discolouration.
Good luck, here are a few more sites to peek at, these wont be cheap.
I'd just use an Anderson plug for the fridge and leave the battery charge one in place as it should not be carrying as heavy a current as the fridge plus when the house battery nears being fully charge the current will decrease.
Cheap and simple.
Gopod Luck.
If the pins are discoloured there is to much current going through them which will eventually melt the plug at the least opportune time , a miniature Anderson plug will do the trick.
Thanks for all the help. Looking pragmatically at the issue, I have decided to eliminate any further problems (as much as possible) by replacing the 12 pin flat plug - which should have done the job easily if the large contacts rating of 35amps per pole is genuine - with a large round 7 pin using pin 2 for van battery charging and a 50 amp Anderson plug for the fridge.
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Best regards,
Chris
Licensed Electrician, Electronics, Gaming & Computer Technician. Now retired and loving it!
Chris, I would be going the other way. The large round connectors are only rated to take the same current as the 12 pin flat ie 35 A. The battery is likely to draw more than that when it is well discharged, the battery is the one to shift to the Anderson connectors.
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PeterD Nissan Navara D23 diesel auto, Spaceland pop-top Retired radio and electronics technician. NSW Central Coast.
The battery is likely to draw more than that when it is well discharged, the battery is the one to shift to the Anderson connectors.
Peter, you have infinitely better electrical knowledge than I, but by my figuring (and guessing) I'd think that a fully discharged flat house battery would not receive the amps it could take when in series with the fully charged car battery. The car alternator will be sensing the car battery which will be higher than the flat house battery so will supply charger appropriate to the car battery.
Or is the theory that the car battery will equalise with the house battery and then the alternator will sense this equalised voltage/current.
Can you please explain and improve my abysmal electrical knowledge.
Denis, firstly look at this site. Look at the first diagram titled "Charging System Functional Diagram." You will note that all the regulator in the alternator does is to measure the voltage across the battery. It does not measure the charge current going into the battery (ie there is no current shunt at the battery terminal.) Without measuring the actual charge current going into the battery the alternator can not determine the charge state of the battery. Further down the page you will see a diagram labelled "Vehicle Charging Voltage Graph" This is the temperature compensation that alternators have built into them so they don't overcharge batteries as the temperature rises under the bonnet and heats up the battery.
Secondly, the batteries are in parallel, not series. The result is the vans house battery gets the full output voltage available from the alternator. When the motor first6 starts the house battery will be at its lowest charge state and the alternator will be at its highest voltage. After a few minutes the battery will take all it can get. The fridge on the other hand will settle down quickly to its 12 to 20 A, well within the range of the 30 - 35 A trailer connector range.
Quote "Or is the theory that the car battery will equalise with the house battery and then the alternator will sense this equalised voltage/current." With the motor running there is no interaction between the batteries. Both batteries are receiving a charge voltage far above their resting voltage immediately before the alternator starts charging.
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PeterD Nissan Navara D23 diesel auto, Spaceland pop-top Retired radio and electronics technician. NSW Central Coast.
Sorry, guys! I have to admit that I am far from being an expert on Battery charging theory, but I should have mentioned that my Avan is fitted with an Elektroblock EBL109 power control unit which is a sophisticated and robust unit containing separate multi stage booster/charging modules for 240 vac, 12 vdc and regulated solar dc input for house battery charging. For some insane reason, Avan only connect the 240v module. I have remedied this and everything works brilliantly, except for the van plug/socket contact issue. I have also installed a digital power meter and have tested the charge current when charging the house battery at 11.0 volts while under towing conditions and the charge current never exceeds 12 amps - which is just as well as the recommended 15 amp in line fuse has also been fitted. The Elektroblock also acts as a battery protection unit which disconnects the load before battery voltage drops below 10v. I have to agree with Peter that the current ratings for the 12 pin flat and 7 pin large round plugs are almost the same - depending on manufacturer - but I recall an auto electrician telling me a while back that (in his experience) the large round plug is much more reliable than the 12 pin flat. I also have a RedArc VSR fitted to my tug to protect the start battery. Denis mentions a fully discharged house battery. This is an absolute no no for virtually all types of batteries as few will ever fully recover from this state according to the experts who repair the Elektroblock units in the U.K. They pointed me to a very detailed and unbiased report on the whole RV house battery suitability question. For anyone who may be interested, here is the link:
Denis, firstly look at this site. Look at the first diagram titled "Charging System Functional Diagram." You will note that all the regulator in the alternator does is to measure the voltage across the battery. It does not measure the charge current going into the battery (ie there is no current shunt at the battery terminal.) Without measuring the actual charge current going into the battery the alternator can not determine the charge state of the battery. Further down the page you will see a diagram labelled "Vehicle Charging Voltage Graph" This is the temperature compensation that alternators have built into them so they don't overcharge batteries as the temperature rises under the bonnet and heats up the battery.
SNIP
Thanks for that Peter - I did look at the site but still a bit confused about how the regulator handles 2 batteries with different rates of charge - does it see 2 batteries as just a "voltage"?. Next time I drag the van out I'll monitor the charge applied to the house battery which I will make sure is down to about 12.2Vdc before connecting to the vehicle which will have a fully charged battery. My alt is 130amp so I'd expect to see at least 30 amps @ 2500rpm?
Thanks again for taking the time. Apologies for incorrect terminology.
Denis, I have not been ignoring you, just have not been on for a couple of days.
Charging two batteries from one alternator is a bit like feeding chooks. You just keep throwing out the feed and they take what they want. It does not matter how many batteries you have, one, two or many. The alternator just puts out power at a voltage fixed by what its internal regulator thinks the batteries require. The batteries just accept a charge current that largely depends upon their state of charge. The lower the charge level of the battery the more current they will suck in.. If the charge voltage of the alternator is not too high then the current will drop to a reasonable float current and the batteries will not get overcharged. The regulators in auto alternators are not very smart.
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PeterD Nissan Navara D23 diesel auto, Spaceland pop-top Retired radio and electronics technician. NSW Central Coast.
Thanks Peter - from what you say, it would be advantageous to run cables heavy enough to carry the current.....I might fit a 2nd Anderson connector dedicated to the house battery. Currently I'm just using one of the larger connectors on a 12 pin socket.
Understanding electricity would be easier if you could actually see it!
Regards
Thanks Peter - from what you say, it would be advantageous to run cables heavy enough to carry the current.....I might fit a 2nd Anderson connector dedicated to the house battery. Currently I'm just using one of the larger connectors on a 12 pin socket. Understanding electricity would be easier if you could actually see it! Regards
You don't need to see it, put your tongue on it and you'll taste it
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Yes I am an agent of Satan, but my duties are largely ceremonial.