12v Extension leads

Submitted: Saturday, Jan 16, 2021 at 10:06
ThreadID: 140983 Views:1799 Replies:9 FollowUps:6
Hi Everyone, I am looking at creating an extension lead with accessory sockets on each end to run lights or the water pump for the Joolca HWS.
Just wondering if there is a limit to the length these will work effectively?
5m, 10m, 20m????
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Reply By: Notso - Saturday, Jan 16, 2021 at 10:12

Saturday, Jan 16, 2021 at 10:12
Depends on the current draw. How many amps does the gear draw?
AnswerID: 634800

Reply By: Notso - Saturday, Jan 16, 2021 at 10:14

Saturday, Jan 16, 2021 at 10:14
There is a useful calculator here:

http://www.energymatters.com.au/climate-data/cable-sizing-calculator.php
AnswerID: 634801

Reply By: Allan B (Sunshine Coast) - Saturday, Jan 16, 2021 at 10:38

Saturday, Jan 16, 2021 at 10:38
.
There is no limit to the length, but for a given current the wire diameter needs to increase as the length increases. Losses in the cable mean losses to the delivered volts to the appliance which should be limited to no more than 0.5 volts. The wire also needs to be big enough to not overheat and cause damage.

Not hard to calculate the necessary cable size if the length and load is known but if we assume your maximum current is 10 Amps and the length of the cable pair is 10m then a cable size of 8 AWG would serve OK.

If you were to increase the length to say 20m then you would need a cable of twice that size which would be 6 AWG.

Cheers
Allan

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Follow Up By: HKB Electronics - Saturday, Jan 16, 2021 at 15:20

Saturday, Jan 16, 2021 at 15:20
As Alan wrote the length will be limited to how big a cable you can put in the connectors and how much copper you can lift:)

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Reply By: Member - Soft-Trailer - Saturday, Jan 16, 2021 at 10:51

Saturday, Jan 16, 2021 at 10:51
I've got the same HWS. I'd be a little cautious of using the car battery directly - once the pump came on/ off as it's meant to and after having a full battery (just driven 300km's) the battery was dead flat within 5 minutes. That sounds like a problem somewhere with the Joolca, granted, but it left me having to charge a V8's battery for an hour from a jump-starter module for enough cranking power.

I now have a RAPS system that I use exclusively for the HWS. I see Anaconda at the moment has a 40Ah Lithium battery pack, with Ciggie, Anderson, USB etc ports as well, going for $599 and it only weighs 6.5kg. For all the other various things this could be used for, I am going to get one of these and, again, have the HWS using this power so it's separate from the cars main battery.

I don't have a dual system, so perhaps this isn't an issue. I prefer the portability of these battery packs myself.
Lachlan

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Follow Up By: Allan B (Sunshine Coast) - Saturday, Jan 16, 2021 at 11:05

Saturday, Jan 16, 2021 at 11:05
.
According to the Joolca website they typically draw 5 Amps, so if run for your "5 minutes" that would be a consumption of less than 5 Ah from a battery of some 30 to 40 Ah delivery ability.
So maybe you have a problem with your battery?
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Allan

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Follow Up By: Member - Soft-Trailer - Saturday, Jan 16, 2021 at 16:06

Saturday, Jan 16, 2021 at 16:06
Thanks Allan. Yep, I am also sure it's a fault somewhere. To me it seems like a short in the joocla somewhere on the day (likely my fault), as the battery ran fine before and after (and was 18 months old). No issues since.

But it brought to me the idea of a small, lithium separate battery pack for a HWS. Can also take it into the tent to charge the phones or lights overnight, so found it handy. So much so that on my new vehicle I don't have a dual battery anymore, but have two lithium packs that fit in nooks in the car.
Lachlan

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Follow Up By: Frank P (NSW) - Saturday, Jan 16, 2021 at 16:12

Saturday, Jan 16, 2021 at 16:12
Lachlan,

If you don't get the fault fixed it's going to kill your small lithium battery pack either permanently with over-discharge if there is no protection against that, or prematurely flatten it. You haven't fixed the problem, just transferred it to a less critical place :-)

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FrankP

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Follow Up By: Member - Soft-Trailer - Saturday, Jan 16, 2021 at 20:22

Saturday, Jan 16, 2021 at 20:22
You're not wrong. I've brought the kit back from my farm (where I use it) and have been sussing out the issue over a few beers. I think I've found it (open wires in the submersible pump) and intend to fix it. It costs a lot less than the lithium battery so I am very anxious about it! Intention is to try it on a work vehicle first :)
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Follow Up By: HKB Electronics - Monday, Jan 18, 2021 at 14:02

Monday, Jan 18, 2021 at 14:02
Something not right, if the water heater flattened your cars starter battery in 5 minutes you would have smoke emanating from somewhere?

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Reply By: Erad - Saturday, Jan 16, 2021 at 17:09

Saturday, Jan 16, 2021 at 17:09
I bought a 5 tonne 12 V electric/hydraulic jack to jack my car (I have sever respiratory problems and have trouble jacking a car if needed), The lead on the jack was long enough to reach all the wheels on my Pajero, but not to reach the caravan axle, so I bought a 12 V extension lead from Ebay. I selected on which was supposed to be rated for 15 amps (they didn't say over what length though) and it jacked the caravan fine. Then I used it to run the air compressor and it blew the fuse in the plug. When I pulled the fuse out, it was only a 5 amp fuse, so I had to then go out and find some of the old style glass fuses and fit a 15 amp fuse into the plug. All good now
AnswerID: 634813

Reply By: Kazza055 - Saturday, Jan 16, 2021 at 17:54

Saturday, Jan 16, 2021 at 17:54
Anything like this, I make them up using Anderson plugs plus using reasonable size wire, e.g. to run a compressor.
AnswerID: 634815

Reply By: Member -Pinko (NSW) - Saturday, Jan 16, 2021 at 20:57

Saturday, Jan 16, 2021 at 20:57
Hi Marsa
If you have not got the gear to make up a 12v. extension lead a phone call to this Person will put you right.
andersonconnect.com.au
Living is a journey,it depends on where you go !
VKS 737 mobile 0049 selcall 0049

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Reply By: Member - Cuppa - Monday, Jan 18, 2021 at 14:14

Monday, Jan 18, 2021 at 14:14
If you are going to the trouble of making up an extension lead you may as well male it as heavy duty as you can to cover future loads.

We power our Tvan from batteries in the tow vehicle. Water pump, led lights, radio & a sirocco fan, plus an inverter to power my laptop.
The cable is 13mm2 (6B&S) & almost 10 metres long. Works OK, but still gets significant voltage drop when charging the laptop (7amps) - the voltmeter in the Tvan drops to around 12v whilst the one near the batteries still reads over 13v. (mind you there is probably 2 or 3 metres of original Tvan wiring after the extension cable which is lighter than the extension cable). Not an issue for us as we have plenty of battery & solar. 10 metres of 6B&S twin cable is not insubstantial & fairly heavy weight wise but is a good compromise for us. Going for lighter cable and/or greater length will see more voltage drop but if it gives you enough at the pump end to run the pump & you can easily re-charge that may suit you. .... but I reckon 10metres of 6B&S twin core with an andersen plug each end will be more versatile in the long run.
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Reply By: Member -Pinko (NSW) - Monday, Jan 18, 2021 at 16:56

Monday, Jan 18, 2021 at 16:56
You're right Cuppa,
My heavey duty extension is used for suitcase solar panels, compressor to reach all wheels, power to a campfire light on a tripod .
Cheers
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