Charging an aux battery in a trailer?

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Originally Posted by Teks

So, to those who doubt me - what do you think the maximum current is in a trailer socket? 5 amps, 10 amps, maybe 15 amps or more??
Back to you.

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Originally Posted by drivesafe

...as Inc has pointed out, that trailer contact terminals have a continuos current rate of just 10 amps ...
Cheers

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Just trying to get my post count up to avoid being flamed for a low post count when there are so many better reasons to flame me!! :D

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Originally Posted by Teks

Oh ye of little faith!

Anderson plugs are not the "be all" of connectors.

I have used the trailer socket on many cars and 4WDs over the last 20yrs to charge batteries in campers, caravans, boat trailers etc etc. The socket can easily cope with energised current. If it didn't, please explain how you are able to illuminate the tail lights and side lights of a caravan for example?

As for the cable to the socket and from the plug I would use 6mm sq cable and if this didn't fit the plug/socket simply splice in a short bit of 2-3mm sq cable. At the end of the day you are not going to get a gobfull of charge current over say 6-7m of cable anyway! At best the current will be around 10-30A at best which is OK anyway.

So, to those who doubt me - what do you think the maximum current is in a trailer socket? 5 amps, 10 amps, maybe 15 amps or more??

Back to you.

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Hi Teks, actually, Anderson plugs are THE “be all” until something better comes along.

As to using trailer plugs for high current applications, this has been done for many years and has worked but it depends on your definition of “works”.

Using these plugs will mean you will probably never fully charge the battery, if you even succeed to get much of a charge it at all and this means your battery life is going to be shortened.

As many have pointed out repeatedly, the maximum constant current capacity of these plugs is 10 amps and as such, you need to protect the whole circuit based on the weakest link in the circuit and this protection has to have a maximum tolerable current capacity that will enable the protection device to go open circuit before the weakest device in the circuit is damaged by too high a current flow.

Your circuit obviously doesn't have that protection.

You CAN get 30 amps through these plugs but you will be able to fry eggs on them while you do it ( that is, until they melt ), plus, the voltage drop that will occur will be of little use to the charging of a battery.

Try measuring the voltage at both your front battery and at the rear battery and see the just how much difference there is.

Cheers.

OK what have i missed:D

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Originally Posted by Redback

OK what have i missed:D

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Don’t rock the boat Baz, I’m trying to be polite ;)

Who me:angel:









































Never:whistling::whistling:

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Originally Posted by drivesafe

Don’t rock the boat Baz, I’m trying to be polite ;)

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And succeeding extremely well if I may say so.:angel:

My understanding is that most things that have a rating of some kind also have some margin for error ie they are guarenteed to work within that rating but will tolerate more. I suspect that this margin for error varies dramatically between manufacturers and also has been reduced over time as production facilities have become more accurate.

Tek has probably got lucky and has parts where the margin for error is big enough not to cause a problem especially if they were made 20 years ago. However someone buying components now to replicate Tek's setup might find they have parts rated the same but have less margin for error and find their wires melting, or worse, even though they have exactly the same setup according to the specs.

Hence why the design should be based on the specs of the parts, not what someone's mate has had work for years.