Thread: Power from White Plug to Anderson Plug

And here is the problem...
Some say the 12s can charge a camper battery no problems directly.
Some say it cannot charge it or it will take an eternity.
Some say DC DC chargers are required, others say they are snake oil.

Don't you just love forums!


Using an isolator, eg traxide and 6b&s from an aux battery to an Anderson plug is also well tested and used by many. Obviously works well and seems the safest option as it has the capacity to carry many amps,with near 0 voltage drop and will not deplete the cranking battery. Is it safest though because it is a very over-engineered solution. Running a white plug and cable from the 12s socket is certainly simpler and cheaper.

Originally Posted by Tombie

G'day Muddy

Option 4 is a Bad idea.

DC/DC chargers will take about 18-20hrs of driving to charge a 20%SOC charge (acceptable) battery.

No good for normal use.

I have had a DC to DC charger in my camper for about 5 years charging two 105 amp AGM house batteries while driving with 150 litre fridge running directly from the house batteries. AGM batteries still going strong due only to using a proper battery charger.

This is by far the best setup in my years of travelling.

DC to DC charger is putting up to 25 amps into the house batteries, and state of charge has never been below 97% according to my battery minor (control unit).

I don't have the voltage drop running from the alternator which even with big cable I use from the battery never exceeded 10amps to the house batteries.

So for me, I find your statement mostly inaccurate.

No hype at all....DC to DC chargers work if used for the appropriate purpose....from someone who uses them on 2 different trailers, and since using them, have never had to replace batteries like I did in the past with bulk chargers.

But agreed that if they are close to flat it will take a long time to get them back up, but at just under 10 amps coming in from the alternator without the use of a DC to DC charger, the rate of charge is even slower...and that's using big cable, almost too big to fit in a 50 amp Anderson plug.

Brett.....

I disagree..

Your statement of "my AGM batteries... Because of a proper charger"

You can't back that up with evidence.

I can back up mine - because they were going strong 5 years later... That AGM without a charger, using only the alternator, were going strong after 5 years...

Your batteries get 25a max.

Mine get whatever they need.

Your twin 130ah batteries at 20% SOC would require over 8 hours driving to get close to charged.

If you never run that low then you are lucky - you're not seeing the problem - it doesn't mean it's not there.

Camp in a spot for a week, get the batteries down to their lower safe limits and see how you go... A days drive might just get them close to full.

As for cost:
Redarc 25a Dc-Dc ~$600.00
Plug and wiring ~$25.00

Traxide isolator and h/d Anderson plug kit (batteries in trailer) $350.00 less AULRO discount.

One has a 25a limit the other 80a.
A 3.2x capacity.


I'm glad your system "works" for you. But it's expensive, unnecessary and actually limits your capability as opposed to other simpler more robust systems.

With your $600.00 you could wire the lot with an SC80 and Anderson and then fit a charger hard wired to the camper for when it's stored and still be in front $150.00

$425.00 (plus a battery) would get you the Anderson plug, 1 aux sockets in the cargo area and an aux battery in the vehicle. Same outlay and better functionality... Plus additional capacity that can be shared with the camper
House batteries or stand alone for charging phones, car fridge, camp lights etc.

Whilst the spin doctors continue to push these Dc-Dc units as the be-all-and-end-all when there is no need for them people will read the brochure, read a positive thread somewhere and believe the marketing.

In theory it all sounds great. In practice there's better suited, more economical systems.

Originally Posted by Tombie

I disagree..

Your statement of "my AGM batteries... Because of a proper charger"

You can't back that up with evidence.

I can back up mine - because they were going strong 5 years later... That AGM without a charger, using only the alternator, were going strong after 5 years...

Your batteries get 25a max.

Mine get whatever they need.

Your twin 130ah batteries at 20% SOC would require over 8 hours driving to get close to charged.

If you never run that low then you are lucky - you're not seeing the problem - it doesn't mean it's not there.

Camp in a spot for a week, get the batteries down to their lower safe limits and see how you go... A days drive might just get them close to full.

As for cost:
Redarc 25a Dc-Dc ~$600.00
Plug and wiring ~$25.00

Traxide isolator and h/d Anderson plug kit (batteries in trailer) $350.00 less AULRO discount.

One has a 25a limit the other 80a.
A 3.2x capacity.

I'm glad your system "works" for you. But it's expensive, unnecessary and actually limits your capability as opposed to other simpler more robust systems.

With your $600.00 you could wire the lot with an SC80 and Anderson and then fit a charger hard wired to the camper for when it's stored and still be in front $150.00

$425.00 (plus a battery) would get you the Anderson plug, 1 aux sockets in the cargo area and an aux battery in the vehicle. Same outlay and better functionality... Plus additional capacity that can be shared with the camper
House batteries or stand alone for charging phones, car fridge, camp lights etc.

Whilst the spin doctors continue to push these Dc-Dc units as the be-all-and-end-all when there is no need for them people will read the brochure, read a positive thread somewhere and believe the marketing.

In theory it all sounds great. In practice there's better suited, more economical systems.

I base my statement on experience! With and without DC to DC charger.

The amperage coming from the car, does not get over 10amp to the house batteries from my D4 and previous Patrol...fact. I get up to 25 amps from my DC to DC charger depending on SoC. Xantrex controller provides me with the current flow in/out and a whole host of other info.

80amps would be great....but will destroy my AGM's (not orbital AGM's) which don't like charging over more than 20amps each.

Brett.....

Brett, if you're only getting 10a from the alternator.. Something is wrong!

D4 alternators throw out 180amps (max) so more than enough to feed the house batteries.

The house batteries won't always draw max. Even the charger you have won't be running 25a very often if you are never running batteries down below 97%

That seems quite minimal as well.
2x105 = 210a/h = 6.3a/h drawn is 97% capacity. Running a 150l fridge with a say a Danfoss compressor you would pull that easily a day. Add camp lighting, tank pumps etc and I struggle to see your obtaining sub 97% figures.

Solar can make this happen, and a solar reg is dirt cheap anyhow. It's the only way to be camped longer and maintain that SoC without resorting to gen sets or long top up drives.


What you do have now too, is a better power system in your vehicle - smarter alternator and charging control which better matches to modern AGM batteries...

The playing field is different.

Originally Posted by discotwinturbo

I base my statement on experience! With and without DC to DC charger.

The amperage coming from the car, does not get over 10amp to the house batteries from my D4 and previous Patrol...fact. I get up to 25 amps from my DC to DC charger depending on SoC. Xantrex controller provides me with the current flow in/out and a whole host of other info.

80amps would be great....but will destroy my AGM's (not orbital AGM's) which don't like charging over more than 20amps each.

Brett.....

80amps is max. Batteries will pull what they need.. The battery dictates the rate if there's surplus to its needs it won't pull it...

What cable size did you have to only see 10amps? I'm guessing were talking independent cables not factory loom?

Your experience at the back of the vehicle is certainly very different to what mines throwing back there!

Originally Posted by Tombie

2x105 = 210a/h = 6.3a/h drawn is 97% capacity. Running a 150l fridge with a say a Danfoss compressor you would pull that easily a day. Add camp lighting, tank pumps etc and I struggle to see your obtaining sub 97% figures.

I have 180 watts of solar too.

97% SoC is during driving....batteries don't get below this during driving and running the fridge. Was a different story before the DC to DC charger.

Gets lower of course while camping, using led lights, pump, TV, 240v inverters, etc.

Last 350km return trip from Warren River saw SoC at 98% by the time I got home, after 5 days of camping.

Works for me.

Had Kalamunda autosparky check my Anderson wiring and was impressed in the cable size that I used, and confirmed amperage was about right.

Brett....

Thanks for your feedback Brett.

Good to have these discussions.