Anderson Plug - Wire Size

Submitted: Wednesday, Sep 08, 2004 at 23:57
ThreadID: 121380 Views:11117 Replies:9 FollowUps:1
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I know that Anderson Plugs have been discussed before, and up until recently I couldn't really see the need for having one. The 6sq mm wires that connect through the trailer plug seemed to be working OK to me. While we were away with fridge problems I though back to Collyn's comment that my trailer plug connection was really only giving a token trickle charge from the alternator, so I went to an Auto Electrician in Katherine NT and enquired about and Anderson Plug. The boss recommended 8mm Diameter wire be used over the 10 metre length between the auxilary battery in car and the van batteries, with a 50 amp circuit breaker next to each end of the lead. I am happy to say that by using 8mm Diameter wires that when I test the voltage at cars battery coming off the alternator at 13.3 - 13.4 volts and then check the caravan batteries that they are the same voltage and there does NOT appear to be any voltage drop. When travelling the batteries are now always fully charged no matter what the weather conditions, and in National Parks where they have a ban on generators, they still allow the car to idle so I can charge batteries up in wet conditions if required. Some people say that 8 mm diameter wires are an over kill but I am more than happy with my set up and would recommend people getting a new van built to stipulate the size of the wires that BTi use on the van side, as from what I have seen they appear to be much smaller than what I have installed. Brian
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Reply By: Deleted User - Wednesday, Sep 08, 2004 at 10:02

Wednesday, Sep 08, 2004 at 10:02
Brian, Something doesnt seem right here ?? Your alternator should be putting out about 14.2 -14.4 volts. Are you sure you were measuring the voltage on the battery that was receiving the charge from alternator ? Was the BT solar input turned off when reading voltage ? It is common to talk about wire capacities in sq mm .. of the area the copper core covers. That way the varying insulation thicknesses are removed from the calculations. You can have a 6sq mm rated wire with 1mm thick insulation or 3 mm thick insulation. They can only carry the same current but one wire looks thicker than the other by far and can lead to thinking all is ok when it is not. It is worked out by simple area of a circle formula (22/7) Radius Squared, (pi r Squared) The largest wire able to fitted into a 50 amp Andersen plug is 5.5 mm diameter or approximate 25 sq mm. So your 8 mm wire must be the diameter including the insulation. It is also very hard to have no voltage drop over that length especially with the resistance of circuit breakers and the Andersen plug terminals. As an example My F250 Alternator puts out 14.43V at the terminal ... I have two aux batteries only about 4 metres away ...connected by 35 sq mm cable and one isolator. the voltage measured at the aux battery terminals 14.26 V ...a 170 Millivolt drop. You probably did the following but just in case .... Disconnect solar input ... disconnect load (or turn all circuit breakers off). Place multimeter +ive lead on alternator power output terminal. Place - ive lead on any battery earth lead or alternator casing .. start motor ...measure voltage (14.3 ish). Run back to BT batteries and measure voltage ...give us the results ? Regards Anthony Explore this Great Land ... Do it Easy ...Tow a Bushtracker
AnswerID: 564741

Reply By: Deleted User - Wednesday, Sep 08, 2004 at 10:03

Wednesday, Sep 08, 2004 at 10:03
Anthony, What if you used gold cables? would that be any better? HE HE! Macka ( just having fun)
AnswerID: 564742

Reply By: Deleted User - Wednesday, Sep 08, 2004 at 10:04

Wednesday, Sep 08, 2004 at 10:04
Actually, not much. Initially anyway. Though gold does have better conductivity, it would be a tad expensive & probably attract too much attention (along with that glittering front tooth of yours). There are some exotic cables available off the shelf from the top end hi-fi industry at $US1000/m, but they may not do much for you. In addition, there are not many outlets for liquid Nitrogen in the Outback, so keeping your ultra-low temperature Super-conductor system operating may prove problematic. On the other hand, you could get all the connectors (battery posts and clamps, Anderson plugs etc) finished with 100micron gold plating (triple dipped for better wear characteristics). Again, you wouldn't notice much difference at first, but the real advantage is the absence of oxidisation (which results in increasing DC resistance over time). This would keep your system operating at peak efficiency for years to come. The appalling lack of attention to this vital subject has been a matter of grave concern for some time now. It is extremely gratifying at last to find someone who has a modicum of sense and shows some interest in attention to detail (unlike the vast majority of unwashed diletants infesting this site, filling it with puerile, putrescent banter and self-important, BT-hugging waffle that is not at all concise). Your observations represent a great leap forward and will surely be recognised for the gems that they are and be quoted with deference for years to come. I salute you. (Reverential pause.) Griff the Awestruck
AnswerID: 564743

Reply By: Noosa Fox - Wednesday, Sep 08, 2004 at 10:05

Wednesday, Sep 08, 2004 at 10:05
Anthony, You are right again, , checked my wires, they are about 8mm dia on outside of insulation and estimated 5.5 to 6mm dia of wire itself. (It is still much heavier that what I saw on Roger Bunny's BT that BTi put on their Anderson Plug lead. The Alternator is putting out around the 14.3 volts, and by the time it gets to the auxilary battery in the rear tub of F250 it has reduced to about 14.2 volts because that battery is connected by very heavy cables. There probably is about 1 volt drop by the time it gets the next 10 metres into the van as most of the time the Pro Star shows around the 13.3 volts when it is connected to a running motor. I have seen the pro star showing above 14 volts but not sure if that is entirely from vehicle alternator or combination of alternator and solar. (The van is parked in the back yard at my daughters and the vehicle out the front so I don't have the oportunity at the moment to check it again while connected. I will get you to check at Copeton.) The main thing is that by running the vehicle the batteries soon come back to showing a full charge and green indicator light, and I am happy with the way it is working. Even if I don't understand all the technicalities with it.
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Reply By: Deleted User - Wednesday, Sep 08, 2004 at 10:06

Wednesday, Sep 08, 2004 at 10:06
Brian, The main objective with any Andersen plug is to fill the terminal with the max allowable wire to potentially carry as much current as is safe but effective....especially as the charge source in this case is a big'un. You have done this, so thats fine ! It sure sounds better than it was before and if its doing the job ....thats all you can ask. Possibly the weakest link in your system now might be the batteries ....something we can discuss in the warm sunshine of Copeton. [smile] Anthony Explore this Great Land ...Do it Easy ...Tow a Bushtracker
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Reply By: Luvntravln - Wednesday, Sep 08, 2004 at 10:07

Wednesday, Sep 08, 2004 at 10:07
Brian, From the discussion I am assuming that you have installed a 50 amp Anderson plug. Your suggestion to tell BTi to install the larger wires was one of the reasons I almost did not receive my BT! Steve is very against the larger wires and will try to convince a new buyer that hasn't any knowledge or hasn't reviewed some of our posts that they should not install an Anderson plug on the drawer bar. Glad you added the plug on the drawer bar. It was a shame to waste all of that free charging while the F250 engine was running. tgintl/jay We are currently exploring the vastness of Australia. Details of our adventure are posted at www.geocities.com/luvntravln. <o:p></o:p>
AnswerID: 564746

Reply By: Dusky - Wednesday, Sep 08, 2004 at 10:08

Wednesday, Sep 08, 2004 at 10:08
I have been in two minds about the Anderson plugs, but now that the F250 has been purcased, I agree that this is the way to go to ensure that BT batteries can be charged while on the move. Can someone please advise what are the appropriate rated cables, Anderson plugs, fuses and other equipment required to ensure adequate charging capability. Thankyou, Dusky
AnswerID: 564747

Follow Up By: Dusky - Wednesday, Oct 06, 2004 at 19:13

Wednesday, Oct 06, 2004 at 19:13
I asked the question below about the time that fellow boggers were leaving for Copeton and also at the time that the BT forum was in transition. Is there anyone that can provide some advice on this issue?

I have been in two minds about the ANDERSON PLUGs, but now that the F250 has been purchased, I agree that this is the way to go to ensure that BT batteries can be charged while on the move. Can someone please advise what are the appropriate rated cables, ANDERSON PLUGs, fuses and other equipment required to ensure adequate charging capability. Thankyou, Dusky
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FollowupID: 843888

Reply By: Deleted User - Wednesday, Sep 08, 2004 at 10:09

Wednesday, Sep 08, 2004 at 10:09
G'day Dusky, This topic deserves discussion in the NEW website (it should have a search facility) so it will help others if they need a reference. Are you in a hurry for the info ? I'm leaving for Copeton Sunday morn so am busy with all things "Packing" .... [CardboardBoxedSmile] We can discuss the formula to determine the cable size ...but .... the one thing you really need to determine is the amount of amps you expect the batteries to receive. The other thing to think about is the method of circuit protection i.e. circuit breaker, fusible link etc ... The new website is very close .... Regards Anthony Explore this Great Land ...Do it Easy ...Tow a Bushtracker
AnswerID: 564748

Reply By: Dusky - Wednesday, Sep 08, 2004 at 10:10

Wednesday, Sep 08, 2004 at 10:10
Thanks Anthony, the van is not due for delivery until May 05 so I have plenty of time. However, I would like to get this right and as there are BT owners and yourself there that have plenty of experience in this area I was sure that I would receive the right information. Regards, Dusky
AnswerID: 564749

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