Charging camper while driving

Nomad_Nev · Veteran Member

Charging camper while driving

Brenda and Alan · Guru

My guess would be a computer controlled alternator that does not respond to charging aux. batteries. There are two fixes that i know of. One is to use a DC to DC charger to charge the trailer battery . (expensive) The other is to trick the alternator into increasing its voltage output and hence charge your camper battery. This is done by replacing the alternator fuse with a device called a"Microblade Voltage Booster" which increases alternator voltage by about 0.6 V. Price I believe to be about $35. Just did a quick search. They are available online from HKB Electronics which are a Vic. based company.

Alan

-- Edited by Brenda and Alan on Wednesday 6th of January 2016 10:39:49 PM

hako · Guru

We found we could boost the input to a battery we used to power the portable fridge by have the solar panels connected to the battery whilst driving - fitted them to the roofrack in a way that enabled them to be easily removed when camping.

Good Luck.

KFT · Guru

Our Navara has a computer controlled Alternator that will not recognise an auxiliary battery so we fitted a 40amp DC-DC charger that charges the aux battery in the back of the ute as well as the caravan batteries while driving.

The Redarc has a built in isolator and an MPPT solar reg so when the engine is not running it connects the 240 watts of solar on the roof of the canopy and charges the batteries.

A good solution for us and we think worth the money.

Frank

Nomad_Nev · Veteran Member

Thanks, yep thinking that i will need to look into the DC-DC route, the solar while traveling wont work unfortunately as we dont have anywhere to mount em.

PeterD · Guru

Brenda and Alan wrote:
The other is to trick the alternator into increasing its voltage output and hence charge your camper battery. This is done by replacing the alternator fuse with a device called a"Microblade Voltage Booster" which increases alternator voltage by about 0.6 V.

That fuse does not work on the new alternators. It was designed for the older Toyota alternators.

patrol03 · Senior Member

I would suggest you check the wiring circuit of your vehicle,find the connection to the ECU and disconnect it,You will find you will get full and constant 14.4 or 14.5 volts from the alternator just like the normal constant voltage alternator,and save yourself heaps. The wiring configuration to the ECU has been introduced by manufacturers to increase the "MPG"figures by putting less load on the engine and supposedly more attractive pollution figures. In reality my own vehicle,when I disconnected the wiring to the ECU,fuel consumption may have increased by 1L/100km if I could really measure it accurately when towing because there are so many variables,speed, wind and terrain etc. All my batteries are now fully charged all the time and the fridge in the van is producing icy cold frothies where previously my co-driver always complained that the freezer had defrosted on a long haul. After a long day my start battery is fully charged as is the auxiliary battery under the bonnet together with the van battery,the latter two being controlled by a Redarc SBI12. It is obvious that many fellow caravanners do have charging problems,and many of these problems are related to incorrect size of wiring,improperly made connections and poor earthing. I hope this may help some fellow campers.

-- Edited by patrol03 on Thursday 7th of January 2016 08:45:58 PM

Brenda and Alan · Guru

Peter D that is not correct they work on all current ECU controlled alternators on most if not all makes of vehicle, check their website for details.

Alan

Nomad_Nev · Veteran Member

Thanks for the comments so far,

After reading Patrols's comment i did a bit of digging and came across this, it seems redarc makes specific DC-DC converters to overcome this issue, the article also says you need to ground the earth to the car which i will check today as well.

www.redarc.com.au/handy-hints/tech_tips/new_vehicles_technology_can_affect_dual_battery_systems_charging_performanc/

patrol03 · Senior Member

Hi Nev,My comment has nothing to do with DC-DC chargers.It is about restoring your alternator to a normal constant voltage unit.Easy to do,costs nothing and no error messages from the ECU on the dash. 14.4 volts constantly with only the current dropping as the batteries reach their capacity.Fully charged batteries all the time with no capital outlay should be attractive.The Y62 Nissan owners worked this out some time ago.I suggest you are not digging in the right place.

Nomad_Nev · Veteran Member

I hear you and do understand, no idea on how to go about it on the jeep though, spent some time digging through the web with no luck.

The DC-DC charger fixes the same issue though, it takes the lower voltage from alternator and boosts it up, it does cost a fair chunk though so definitely prefer your option, will do a bit more digging and see if i can find a bit of guidance on the web of what cables to look for, but so far no luck

lawrie · Veteran Member

You want a setup like mine.
I tow my home built caravan with our 1933 ford V8,the 33 is still 6v pos earth,my caravan has two 12v neg earth batteries on board,they run the fridge and other stuff like the electric brakes and lights.
How do you keep those two 12v battery charged, easy drive a 40amp alternator with a fee belt off one caravan wheel,
so far we have done 32000klms with it with out a drama.
Lawrie

patrol03 · Senior Member

Workshop manuals for Jeep and other late model vehicles are available on e-bay cheaply in CD form,alternatively talk to the guys on the Jeep Forum.They may have worked a way to disconnect the alternator from the ECU.

03_Troopy · Guru

lawrie wrote:
You want a setup like mine.
I tow my home built caravan with our 1933 ford V8,the 33 is still 6v pos earth,my caravan has two 12v neg earth batteries on board,they run the fridge and other stuff like the electric brakes and lights.
How do you keep those two 12v battery charged, easy drive a 40amp alternator with a fee belt off one caravan wheel,
so far we have done 32000klms with it with out a drama.
Lawrie

That sounds like a bit of nifty engineering, I'd love to see some pics of that.

Nomad_Nev · Veteran Member

Thanks Patrol, will give that a go,

Yep, the alternator and belt does sound like a nifty way of getting charge

Hylife · Guru

<quote> I would suggest you check the wiring circuit of your vehicle,find the connection to the ECU and disconnect it,You will find you will get full and constant 14.4 or 14.5 volts from the alternator just like the normal constant voltage alternator, </quote>

*** I would strongly advise against this. ***

The modern alternator is NOT like the old style generator and chucks out anything from 80 to 150 amps. By removing the smart output function of your alternator you will possibly destroy your batteries (vehicle and house) quite quickly by overcharging.

Imagine putting an 80amp charger on your battery for 5 hours (assuming 5 hours drive time per day).

Smart alternators like smart chargers alter their output based on the terminal voltage of the battery. A DC to DC charger will present the necessary input resistance for your alternator to have it increase its output only as required until the terminal voltage increases and then the DC to DC charger input resistance will change the alternators output as the batteries come up to full charge and eventually will reduce to a maintenance charge rate.

Please go talk to an Auto Elect about this.

-- Edited by Hylife on Saturday 9th of January 2016 05:10:28 PM

03_Troopy · Guru

Hylife wrote:
<quote> I would suggest you check the wiring circuit of your vehicle,find the connection to the ECU and disconnect it,You will find you will get full and constant 14.4 or 14.5 volts from the alternator just like the normal constant voltage alternator, </quote>

*** I would strongly advise against this. ***
The modern alternator is NOT like the old style generator and chucks out anything from 80 to 150 amps. By removing the smart output function of your alternator you will possibly destroy your batteries (vehicle and house) quite quickly by overcharging.
Imagine putting an 80amp charger on your battery for 5 hours (assuming 5 hours drive time per day).
Smart alternators like smart chargers alter their output based on the terminal voltage of the battery. A DC to DC charger will present the necessary input resistance for your alternator to have it increase its output only as required until the terminal voltage increases and then the DC to DC charger input resistance will change the alternators output as the batteries come up to full charge and eventually will reduce to a maintenance charge rate.

Please go talk to an Auto Elect about this.

-- Edited by Hylife on Saturday 9th of January 2016 05:10:28 PM

Whether it's a 10A charger or an 80A charger, the battery will only accept what it wants in the way of charge current. More importantly the voltage is what matters. The diode in the alternator's voltage sense line should bring the output up enough (0.5V to 0.6V) without going too crazy. All the diode is doing is inserting a voltage drop into the line so that the alternator sees a slightly lower value than what is actually at the battery.

Dav4Cris · Senior Member

If you go the way of DC/DC charger make certain it is a 40amp job as a 20 will just take to long to charge your battery. In other forums one person has stated " use the alternator as it will give you the voltage which is what you really need to charge". So in reality you need to trick your alternator into supplying more volts 13.8 or above will do the job. These new alternators just don't supply the voltage to charge secondary batteries or van batteries. So if you can trick them into supply more volts then your batteries will be a lot more charged over a trip than before. If you fit a DC/DC charger then it will charge constantly at 40amps till the charger senses that the battery is nearly full then it will back off charge. I have a 40 amp DC/DC charger that I can set to charge at 13.8 or 14.6v so I run it at 13.8, this does me. Then again I also have 500watts of solar charging the van batteries the whole time I am driving so I always arrive at a campsite fully charged unless I decide 30 klms up the road that is a nice place we will stay here. LOL has happened a couple of times.

Jaahn · Guru

Hi,

On some modern vehicles with variable voltage alternators the function can be turned off by a command to the ECU via the diagnostic port. I suspect this is probably available in all vehicles but the dealers seem to be completely ignorant of these modern ideas when you ask them. Certainly the dealer software should be able to do this for testing at least. Try asking about it on your makes forum.

If the function is tuned off it becomes a standard system like we had for the past 50 years and the newer systems default to it anyway under some normal or even fault conditions. Using the full alternator output certainly works well in my older MH with a 110amp alternator. The solar does the non driving days. But if you need a boost just start the engine for an hour.

Cheers jaahn

Aus-Kiwi · Guru

The price of DC to DC charger ? Can go along way to fit or increase the solar panels ? An extra alternator with it regulator at or near battery so voltage drop in cabling isn't that big of an issue ..

oldtrack123 · Guru

Hi
A DC /Dc charger should be the LAST resort
First look at connecting cable sizes to minimize voltage drop.
Plus boosting the alternator voltage as others have indicated