Dual battery setup

Submitted: Thursday, Oct 31, 2019 at 21:28
ThreadID: 139261 Views:4140 Replies:6 FollowUps:4
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Hi all, I have a camper with the second battery enclosure at the back. Its charging from main battery via solenoid.
Is it possible to temporary move it to other vehicle & charge via cigarette lighter port?
Just want to run fringe on one trip in company car.
Thanks for help.
Cheers Jerry
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Reply By: Allan B (Sunshine Coast) - Thursday, Oct 31, 2019 at 22:55

Thursday, Oct 31, 2019 at 22:55
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Hi Jerry,

Cigar lighter ports are somewhat limited in delivery by their wiring size. Typically 5 Amps.
However, this may be adequate to keep the auxiliary battery charged enough to serve the fridge.
What type of fridge is it? Brand and model.
How many driving hours and how many parked hours will you be doing? This determines how much power the battery will demand from the cig port when the engine is running. I am assuming that the cig port is not energised when the vehicle is stationary.

Answers to these questions will enable me to estimate the power usage.
Cheers
Allan

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AnswerID: 628451

Reply By: RMD - Friday, Nov 01, 2019 at 07:30

Friday, Nov 01, 2019 at 07:30
In the company vehicle, if the battery and fridge running from it , is connected when you switch off the engine, the battery will supply voltage to the circuits you are trying to switch off with the ignition. That will deplete the battery even without the fridge using some stored charge. At a minimum you may need to religiously unplug the ciggy feed each time you stop the engine.
If the vehicle is a campus system which checks the ciggy drain at startup, it may go into error mode. If the vehicle has a smart, read dumb idea type alternator, the aux battery may not get charged fully even on a long run. A few unknowns there.
AnswerID: 628456

Reply By: HKB Electronics - Friday, Nov 01, 2019 at 09:46

Friday, Nov 01, 2019 at 09:46
If you run the fridge for a few hours and start the car it will most likely blow the fuse on the power outlet, as Alan pointed out the access fuse will only be 5 - 15A

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AnswerID: 628464

Reply By: Allan B (Sunshine Coast) - Friday, Nov 01, 2019 at 10:49

Friday, Nov 01, 2019 at 10:49
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Jerry, the other way of managing this is to transfer the fridge to the company car and power it directly from the cig port without involving a second battery.
It will depend on the wiring and fusing of the cig port but overcomes any Canbus system problems that RMD has pointed out. ( Canbus, not "campus", bloody spellchecker eh RMD? )

Using this method the fridge will only run when the vehicle runs and will warm-up progressively when the vehicle is stationary. But this may provide enough cooling for your needs, particularly if the fridge is set to a lower temperature to begin with and depending also on the quality of the fridge insulation. You could try it out at home to start with. A bit hairy but it may serve.
Cheers
Allan

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Follow Up By: RMD - Friday, Nov 01, 2019 at 13:50

Friday, Nov 01, 2019 at 13:50
Allan
Nah, I didn't re read and the BL#$dy Lenovo pad only knows campus not canbus . My fawlt, Will try to have the pads mental state attended to. I can't find how to turn off pre dicktive text.
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FollowupID: 902850

Follow Up By: Allan B (Sunshine Coast) - Friday, Nov 01, 2019 at 14:22

Friday, Nov 01, 2019 at 14:22
.

Well don't ask me. I don't even know how to spell "Lenovo".

Cheers
Allan

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Reply By: Jerry D - Friday, Nov 01, 2019 at 21:11

Friday, Nov 01, 2019 at 21:11
Guys, thanks for all the inputs, appreciated.
The car is 2019 Colorado & the fridge is compressor ironman 38L
When driving:
Plan is to use the fridge from the cig port while driving.
Charge second battery from another cig port (there are 2)

When stopping.
Starting the car before plugging it in fridge into the cig port??
When stationary run the fridge from the second battery (portable ~40kg but 5 years old?)
If in caravan park charge the second battery with 240 charger with fridge connected.

Hope it will work?
Thanks for all the advise & recommendations.
cheers jerry
AnswerID: 628486

Follow Up By: RMD - Friday, Nov 01, 2019 at 22:38

Friday, Nov 01, 2019 at 22:38
Jerry
While plugging in the fridge to the ciggy point may run the fridge OK, using a ciggy point or in fact ANY charge system from the battery which is being fed by a so called smart alternator, will see the aux battery not charge to it's full capacity and therefore will be fairly useless as a fridge backup supply. Unless a suitable DC to DC charger is connected to, and operated from the main battery and it's output connected to the aux battery, full charge of the aux will not be achieved.

Probably all OK if it was a normal alternator, I ran systems like that for years, although directly solenoid connected to the alt system.
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FollowupID: 902872

Reply By: Jerry D - Sunday, Nov 03, 2019 at 20:55

Sunday, Nov 03, 2019 at 20:55
Still need some help, please?

Arc pak specifications

An great feature for those struggling to find room for a second battery under your bonnet is the BUILT IN 7 AMP DC-DC 12V Car Charger that lets you charge up and run your ArkPak via your vehicle’s 12V socket.

Is it possible with my box, please? If I get DC-DC charger with 12v cig plug?

Cheers
AnswerID: 628518

Follow Up By: Batt's - Tuesday, Nov 05, 2019 at 02:20

Tuesday, Nov 05, 2019 at 02:20
Best to try it for a couple of days and see what happens before you go away it might work.
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FollowupID: 902968

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