Cable lay out & recomendations

Hi Mike
Thanks for the info .From what you have said I assume that the anderson sb 50 will fit the 2BS cable( rated at 255 amp) ?Can I run the earth from the body or do I need to start closer to the battery?And does a circuit breaker do the same job as a fuse. I have a 50 A(may be not enough?) circuit breaker, which I believe will reset if things are ok, is this right.I have not heard of the power poles, what do they do?I will check out your link now.
There is one beer better than redback its the one I make! A true Bavarian wheat beer. If you head this way let me know 4-5 weeks in advance and I will prove it!
Niffty
Perth

The Powerpole is a smaller connector that can take 30 amps. One big benefit is that it is genderless like the SB50.

The SB50 can only take 6G - you would need to add ashort adapter tail.

. . . aaaahhhh a Haefeweizen,

Mike

Ahhh You know your beers!!Do you brew or do you comsume with a passion?
Niffty

I'll leave brewing to the experts - Redoak Brewery in Sydney do a very nice Haefeweizen.

Mike

Hi Sandman
All things come at a cost, In this case what powers the unit and what is the Amp consumption.Sounds to good to be True. Would it be cheaper to put a larger cable through?Its sounds like electrickery to me.But Im willing to learn.
Thanks Niffty

It doesn't break any laws of nature. You might input 30 amps at 12 volts amd get out 22 amps at 14 volts.

Voltage drop is less of a problem with AGM's - I have charged mine fully with 13.8 volts - it just takes longer.

Mike

Niffty,

I don't use one myself, but this technology is the most commonly adopted solution within the Caravan / Camper Industry.

What powers the unit?
The DC voltage from your vehicle's alternator.

What is the Amp consumption?
Whatever your battery bank in the camper can take, although the TwinCharge I mentioned has a maximum output to the batteries of 20 amps.

Sand Man, I supply both caravan and motor home manufactures and none of my customers use them. Thats not to say they aren’t being used but their benefits are limited to a very small portion of the market.

As pointed out, once the total battery capacity is 100 a/h or more, these devices are of very little advantage and then only where the battery bank has only been partially discharged.

An example, if a 200 a/h wet cell battery is discharged down to around 11 volts and then a 14 volt charge is applied, the battery can easily draw over 60 amps initially and over the next 4 hours will eventually drop to around 10 amp. These figures are based on experiments we have carried out on equipment we regularly work with.

The first hours charging drops the current draw to about 50 amps. The step up would take at least 2.5 hours to replace the same capacity.

It’s only when the battery has only had a small discharge that the step up will charge the battery to full charge quicker and then is still only a marginal improvement.

For the cost of one of these things, it would a greater advantage and a far cheaper cost to simply add another battery. At the end of the day you would have a much greater stored capacity, achieve in a much shorter time than these things could ever do.

And last but not least, most of these things are not very efficient so you are wasting power while using them.

Good quality high amp units that actually work, have a starting price of around $600 or $700

Hi Drive safe,
Yes I think circuit breaker are the way to go!Is 50 amp ok?I will plan on setting up more solar panels as Im all for green power but its turning out to be an expensive project right now. Next year when I have ironed out the bugs I will add another 100 watts or so.The batteries I have at the moment are 6 volt 220 Amh wet cells Supercharge Deep cycle hooked up in series(12 V).Next step is 440 Amh bank minus the losses.I know I will have fun keeping this puppie charged, this is the reason for getting the good oil from people like you with experience.In the mean time im stuck with fossile fuel. Thanks Niffty

save money and go to bogas or a welding supplier and buy the 25mm2 battery lead from them. Its heaps cheaper

Hi Norm
The cable I am using between batteries Is 32 mm2 rating. the sparkie assures me there is only one size bigger.This I think will be standard for the whole run.I will have to use the 175 andersons i think.Where did you take your neg lead from? Battery / motor.I can get the ctek 2500 for $590 which is the best price I have had with paying for freight.
Niffty

What some seem to forget when quoting massive cable sizes is that there IS a limit of current that the car's alternator can supply.
I see little point going above the max alternator output minus the Amps required to run the car electrics.
Find out first just how much juice you have on tap to feed back to your trailer. Then make sure you are not overloading the alternator by trying to demand more than it can supply. You can actually limit the charging current to the trailer batteries by using sensible cable sizes. That way you ensure you do not accidentally cook your alternator.
Klaus

Hi V8, the advantage of thick cable is more related to reducing the voltage drop between the alternator at the front of a vehicle and the battery in the trailer.

The longer the length of cable that the power has to travel along, the greater the voltage drop is going to be and the only way to reduce voltage drop by any segnificant amount, is to increase the thickness of the cable.

The Circuit Breakers will protect everything from current overloads.

what has been said is true but to ensure minimum loss over 6 to 7 metre to the trailer 25mm IS the way to go. I have taken a earth from the spare tyre holder with a lug and 8mm bolt and feed to the anderson from there. I have more than enough takeoffs from the battery

Yeah, I know all about voltage drop, but its also dependent on the current flowing through the wire.
Now, if you are in the habit of flattening the trailer batteries regularly then a 25 sq mm cable might be the ticket.

But, if you are like me and look after the batteries, which at present are in a trailerable yacht, then a 6 sq mm cable is perfectly adequate. The cable (2 wires) runs from the battery to a socket at the back of the troopy and from there to the boat. This size cable had no trouble keeping the 90Ah boat battery full while towing the boat for 5 days (3000km), running a fridge inside the boat and the boats electrics when it was used as a caravan every night at roadside stops. I doubt that the current ever needed to exceed 10 Amps to keep the boat battery happy.

Marc, the steel body of the car is a worse conductor than a 6 sq mm cable would be to the battery negative or to the body end of the negative strap.
Klaus

Hi V8, if you are using as little power as you are then you will probably get away with such thin wire but the first time you, for what ever reason, use more power than usual, you will find that your set up will now take days to get your battery up to anywhere near fully charged.

With thin cable, the time required to recharge a battery dramatically increases because of the combination of thin cable and the current load required will cause such a voltage drop that the battery will literally take days before the charge state of the battery rises enough to allow the current level to drop and therefore have an increase in the charging voltage start to get the battery to get towards a full charge state.

If this was to be repeated on a regular basis, the life of the battery would be servilely shortened, furthermore in niffy’s case, it sounds like he is going to be using his batteries in a big way so the quicker he can get his batteries charged up the better and thin cable just won’t allow him to do that.