Amps through the Anderson Plug

I believe a SB50 is rated at 50Amps. A SB120 is rated at 120 Amps.

saying that 50 amp anderson is rated at 120 amps is over simplistic and not correct.

Also universally bagging the chineese copies is not fair or accurate, nor is saying "most people" sell them.

The 50 amp anderson plug is rated at 50 amps continuous, it may be surge rated considerably higher than that at various duty cycles.

the better copies are as good as ....... but recently the Anderson distributers have done some work and sharpened their pencil ...... many companies like Jaycar now stock the genuine artricle at similar prices to what they had copies at previoulsy.

cheers

50 amps is the max current for when you are connecting or disconnecting two plugs.
Continuous uninterrupted rating is much higher.

Anyway, as pointed out the larger connector would be a better choice.

hi
The reality is it does not cost much more if any to use
25mmsq = 3B&s
or even
2B&s = 33mmsq

The idea is to get as much in as quickly as possible to reduce charge time
Also at 1.6 volt less than charge volts eg 14.2 -1.6 =12.6 Not much charging happening at that voltage . The lowest voltage you need to charge a battery is around 13.5volts .
The only way it HALF WORKS is at high amp charge the volts are low but as it ""eventually"" charges the batt volt will rise /current draw reduces and u get a good charge voltage .
This is why the charge cable needs to be of a decent size in order to charge batts in a decent time .

9mtrs 20mmsq cable .95 volt drop in theory 60amp load
9mtrs 25mmsq cable .7 volt drop 60 amp load
9mtr 35sq cable .5 v drop 60 amp load
This does not include volt losses across
fuses
c/breakers
VSR
solenoids

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Swampy, the OP Keith has said that he is employing Redarc LFP1240 lithium DC-DC chargers which will accept input as low as 9V whilst delivering an appropriate output to the lithium battery, so the 1.6 volt drop is not a factor in the charge voltage. Not that I would recommend running the system at 9V input!

I have one of your voltage boosters and it works a treat.
What is the capacity of the alternator on your tow vehicle?

Hi Keith,

Good to read your happy with your booster, the alternator is rated at 100A.

He has Lithiums they'll suck whatever you can throw at them.

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Hi Keith,

I would definitely use no less than the 120 Amp rated Anderson connector. And I would recommend the genuine "Anderson" brand if possible. There are 'cheap' copies on the market and I have experienced trouble with them.
One distorted the plastic moulding due to the pressure of the contact springs which caused the contacts to lose engagement pressure. The other housing cracked for no apparent reason.

Edit:
Your stated 1.6 volt drop is more than I would want. It should not cause your system to fail but may limit the delivered current. Nevertheless, give it a go.

Hell, that is one Mother of a system you are installing. It could almost solve South Australia's power problems on its own! lol
Please do post on here when you have used it and tell us how it copes.

Have you thought about not manually isolating anything and just running a smartpass setup to combine the solar/vehicle etc as required and smash both batteries? I am averse to having lists of things to do hence the fully automatic lean from me.

Solar 4 RVs mentioned the Smartpass but I am not smart enough to understand how it works. I'll talk to them again.
Keith

http://ctek.com/au/en/chargers/SMARTPASS

It joins all the dots in a system like the one you propose. The user manual link is at the bottom of the page. Not much to know.

There are plenty of ways to skin a 12v cat, the set and forget aspect appeals to me muchly.

One 400 amp battery will work better.

My auto sparky said the same thing. So I think I'll carry a spare alternator (about $1K for a really big one) and change the serpentine belt more regularly. I always carry a spare belt anyway. Or maybe just put the bigger alternator on and use the OEM as a spare. The bigger version comes from the USA, is a direct fit and will avoid having to put a stick on the accelerator to charge while stationary. Unfortunately it's a big job to change one.
Large alternators for 200 Series

Sounds like an expensive and complicated job just for an air conditioner..

When we get to the age of retiring and travelling around Aus, it will be after a lot of research as to best times of year for each region for the best temps.

I did write guesstimate, my Prado draws around 15A with the ignition on but without the motor running, add in fuel pumps once the motor starts, injectors etc it will be up over 20A.

The 200 series has a lot more electronics so I would imagine the drain would be considerable higher hence the much larger alternator in the 200 series compared to the Prado.

Thanks for the info HKB.
Just on the aircon subject, family commitments don't often let us pick and choose when we can be away. Hence the need for an aircon, which I do admit is a bit of a luxury.
The extra cost for a bigger electrical system is about $4.5K over and above what wI reckon would be required for a normal off-grid caravan of the same specs. Given that we may be living in the thing for months on end, I think it's expensive for sure, but worthwhile.

The Kimberley type system works very well. I can run my air conditioner from my inverter whilst using a Honda eu10i generator to charge the battery at the same rate that I am drawing power. The charger will do 65 amps if needed and my draw is approx 40 amps. The 1 Kva Honda will run a 50 amp charger so I just wind mine back to the level needed to balance the load..

Keith, I have Tortech TXF inverter chargers. They are transformer based and much more robust for going off road. They need a bit of room due to their size, weigh a bit, but have excellent features.

Batt's, they just overdrive the alternator with a smaller pulley to attain max output at lower engine revs.

Yes that would help even another 500rpm at idle would be handy at least. I expect there would be a limit as to how high you can go and if the idle needs to be adjusted to handle the load when stopped. I would like one for my old GQ as well but do you know any sites that sells pulleys ?

Usually for the average person it's not even a passing thought that they need a reasonable amount of revs to produce enough power to cover their needs until they discover their batteries aren't charging enough. just thought I'd ask to see if it has been taken into account.

Done some more research it can be done but you have to find out what your alternators continuous max rpm is then measure crank pulley & alternator pulley divide into each other that will give you the ratio difference eg: 3 to 1. So you can then figure out what rpm the alternator is spinning at which in the examples case that would be 3 times faster than the engines rpm so it may already be near max or you may have some room to play with.

Your cars alternator will normal produce its "rated" output at normal driving
speeds, there is no upper limit though, if you spin it faster it will produce more
than its rated output but you will decrease the life of the alternator.

Yes it will wear it out faster I also read it may cause component failure.

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"spinning it faster" it will not produce more than its "rated output". It may well produce its rated output at lower engine revs but the maximum rated output is always limited at design by the inbuilt current regulation. The OEM would have designed the system to allow full current out at normal driving speeds. This of course may be over-ridden at idle by late-model EMS controls for emissions reasons.

There is a bit more than may meet the eye in installing over-sized alternators or changing pulleys to increase rotational speed..........
1) The OEM pulleys and belt are designed for the original configuration and may not be adequate for an increased alternator rotational load. Belt slippage may increase and overcoming this by increased belt tightening reflects on point 2) below. Over-tightening will also increase bearing loads.
2) There are energy losses in any pulley/belt system and they may be more significant than you might imagine. These losses relate to the flexing of the belt around a pulley, much as a tyre on a road. They are present even when the alternator is not supplying current and will affect fuel economy which may be of some concern to you. A pulley of smaller diameter will always introduce greater losses due to increased flexing of the belt. Belt heating also increases which will reflect on belt life.
3) The very high output specifications of over-sized after-market alternators packaged into frame sizes no larger than the OEM alternators usually cannot be maintained continuously and duty cycle needs to be considered. Inherent losses within the alternator produce heat and larger alternators produce more heat. If they are packaged as per the OEM product they will obviously run at a higher temperature.
4) Increased load current from battery may cause consideration of increasing cable sizes. Beware of changing the negative cable from the cranking battery to chassis as this is often employed as a shunt to measure battery current for the benefit of the Management System. Changing the cable cross-sectional size will change the resistance and therefore the reported current value. This will affect design performance of the EMS.

Allan,
The stator resistance of the alternator is the primary output current limitation.

Alternators are generally rated at 6000RPm@24C after a stabilisation period, if you increase the RPM's the output will increase, a good quality alternator will be conservatively rated.

The other points you have raised are all valid and worth consideration.

A typical alternator output curve:

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Leigh,

You perhaps used an unfortunate example to make your refutation. The Delco 10SI alternator you refer to was released in 1969 and is way out of date. The OP, Keith, is talking about an LC-200 Series whose alternator is much more sophisticated.

My response above did generalise that the "output is always limited at design by the inbuilt current regulation". It seems that I must go further and detail that this regulation is inherently the impedance (not resistance as this is alternating current) of the alternator stator windings plus the action of the alternator regulator, now largely invested in the vehicle ECU. The ECU control is of course a function of the invested algorithm to satisfy direct load, battery charging, environmental requirements and alternator protection.
Even in modern non-ECU controlled alternators with in-built regulators, protection control for both over-current ant excessive temperature are incorporated into the incorporated regulator.

Thank you though for affirming my other points.

I did write typical, the same applies to most if not all alternators.

Modern alternators have temperature compensation, this can reduce alternator output current under overload conditions but this is not what its intended for and it shouldn't be replied upon for this purpose.

I have not seen a typical alternator regulator that has overload current protection, in fact all alternators I'm familiar with do not produce their maximum output until the regulator has dropped out?

Last time I spoke to Bosch regarding their alternators ratings they advised to de-rating to at least 80% for continuous operation at high loads, their common alternators have no internal overload protection. Denso advised to de-rate to 70%, again no internal protection against overload.

A quick check of the net shows statements that many regulators have over current protection but I have yet to see one that actually does, I would be interested to see the alternator your basing assertions on?

Over current protection in an alternator is pointless, the basic design of the alternator limits its maximum current to safe levels. This does not mean you can't overload the alternator though, an overload manifest itself as you wrote by a rise in temperature, if the alternator can't shed its heat load it could overheat and be damaged, this could be as a result of high ambient heat, the alternator being required to supply high outputs for long periods of times or combinations of thereof.

With regards to Land Cruisers, the only LC I'm aware of that uses a ECU controlled alternator is the new Prado 2.8Ltr, the alternator in the new Prado appears to be a LIN type, however Toyota appear to be either not using it or have coded the engine management system to emulate the previous models temperature controlled alternator as the outputs of both are nearly identical under the same conditions. There is no current sensor or smart charge functions yet.

Regarding the negative battery cable, modern ECU controlled charging systems generally use a hall effect device or other sensor to monitor the current flowing in the wire, hall effect devices detect the magnetic field generated by current flowing through the wire, other sensors such as terminal mounted units have shunts in them, if you can change the size of the cable it will not affect the current reading of these devices.