Wires to thin or wrong batteries??

Submitted: Tuesday, May 11, 2010 at 20:05
ThreadID: 78400 Views:3727 Replies:11 FollowUps:12
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G'day all,

This question has haunted me for two years now and I need some direction.

Went to Cape York 2 years ago and borrowed a mates 110L Waeco fridge/ freezer.

Car stats: Standard factory dual (cranking) batteries in a 6 month old (at the time) 100Series L/cruiser. Had a redarc isolator put in before the trip. I ran the fridge off the aux power source outlet in the cargo area of the car. Fridge was full most of the time.

Now, whilst on the road the fridge worked a treat. Ran at the prescribed temperatures i.e about 5/-5 respectively.

As soon as we'd stop though, up she goes!!! (The fridge temperature that is). The fridge compressor use to cycle every minute or so to try and cool the insides down. The temperature got to 15C. Ruined all our cryovacted meat.

Afew on the trip said the batteries are insufficient and others said the wiring to the aux power outlet in the rear is too thin to cope with the load of a big fridge.

Can anyone help me out. Im in the market for a fridge now and need to know weather to replace the wiring to the power source or get chunkier batteries to support the load.

I hate long winded posts but needed to explain the details.

Cheers

The Dr




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Reply By: Member - Ed C (QLD) - Tuesday, May 11, 2010 at 20:19

Tuesday, May 11, 2010 at 20:19
Yes

;-))
Confucius say.....
"He who lie underneath automobile with tool in hand,
....Not necessarily mechanic!!"

Member
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AnswerID: 416324

Follow Up By: Lex M (Brisbane) - Tuesday, May 11, 2010 at 20:23

Tuesday, May 11, 2010 at 20:23
I agree. For a 110L Waeco - Yes and yes.
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FollowupID: 686437

Reply By: Wherehegon - Tuesday, May 11, 2010 at 20:22

Tuesday, May 11, 2010 at 20:22
My weaco did the exact same thing with the prado, the wires on the standard plug are too small, you need to run new wires direct from the battery, myn use to run ok while the vehicle was running but when I turned the motor off and left on acc the error light would come on the fridge. Hope this helps you out. Regards Steve
AnswerID: 416325

Follow Up By: Member - Toyocrusa (NSW) - Tuesday, May 11, 2010 at 20:26

Tuesday, May 11, 2010 at 20:26
Yep. Mine did exactly the same (Waeco CF 50) Heavier wiring fixed it but make sure you fuse the wiring at the battery as well. Bob.

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FollowupID: 686439

Reply By: Steve and Viv - Tuesday, May 11, 2010 at 20:30

Tuesday, May 11, 2010 at 20:30
The Waeco plug is fine it's the wiring from the front to the rear of the car that is the issue. As the wire is just to thin to carry enough current to allow the compressor to start. This is also why Waeco produce a wiring loom as this will over come the problem. As mentioned above, you can connect the fridge directly to a loom, I have done just that and run a dedicated 8mm loom By doing that I get 2.5 days out of my 105 amp battery.

Also. Did you check that the voltage regulator was set to low on the fridge. If it was set to high it would trip out very easy
AnswerID: 416326

Follow Up By: Member - david m2 (SA) - Tuesday, May 11, 2010 at 22:18

Tuesday, May 11, 2010 at 22:18
if the wire is not capable of taking the load why does the fridge work when on the move . would the load not be the same moving or stationary
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FollowupID: 686458

Follow Up By: Steve and Viv - Tuesday, May 11, 2010 at 23:35

Tuesday, May 11, 2010 at 23:35
Because the voltage is higher with the engine running (13.8 to 14.2) therefore it can supply the required amps. Once the car is off the battery rests and the voltage drops 12.6 12.8. The the compressor starts and draws it lower still and you then get the error light (1 flash repeating)
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FollowupID: 686472

Follow Up By: anglepole - Wednesday, May 12, 2010 at 09:12

Wednesday, May 12, 2010 at 09:12
Steve,

Power equals Voltage X Current.

More Volts less Current for the same Power.

Cheers
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FollowupID: 686487

Follow Up By: Fab72 - Wednesday, May 12, 2010 at 12:56

Wednesday, May 12, 2010 at 12:56
Could it also be that the cabin temperture goes up when the car is staitionary, further adding to the work of the fridge???
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FollowupID: 686505

Follow Up By: Steve and Viv - Thursday, May 13, 2010 at 11:39

Thursday, May 13, 2010 at 11:39
Yes, sorry anglepole, used the wrong term. I ,meant power, sorry
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FollowupID: 686635

Reply By: bks - Tuesday, May 11, 2010 at 21:38

Tuesday, May 11, 2010 at 21:38
I went all through this recently. make sure you rewire with the Waeco RAPS R12U kit. Then you know you have the correct size wire fittings and fuses. Its all ready made up and you can just use the old wiring to pull it through the chassis.

One of the members here gave me a good deal on Waeco.
AnswerID: 416332

Reply By: Dennis Ellery - Tuesday, May 11, 2010 at 22:22

Tuesday, May 11, 2010 at 22:22
Its a volt drop problem.
If you want to send me the model number of the Waeco or its compressor load and your length of cable run, I will do the calcs and size the cable for you

Regards Dennis
AnswerID: 416345

Follow Up By: ChipPunk - Tuesday, May 11, 2010 at 23:32

Tuesday, May 11, 2010 at 23:32
Trust Dennis, and the others.
It is a voltage drop problem due to high current through small cable.

When the vehicle is charging, the voltage typically jumps approx 1V to 1.5V which is enough voltage to run the Waeco. (IE - up to 14.4V at the battery; usually above 13.8V.)
Stop charging and the battery voltage quickly drops to below 12.8V - at least 1V less.

If the Waeco is set to the "low" cutout setting (10.7V), that suggests something like a 2V to 3V drop along the line...

Doubling the cable cross-section should halve that voltage drop.
Doubling the cable diameter (ie quadrupling it cross-sectional area) means 1/4 the voltage drop.
But that's where the cable calcs come in.
And ensuring a good low-resistance fused path from the battery.
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FollowupID: 686471

Reply By: OLD PETE - Wednesday, May 12, 2010 at 07:54

Wednesday, May 12, 2010 at 07:54
Hi Doc,
A very common problem with waeco fridges is a voltage drop in the actual fridge. The problem is in whats called the poli fuse. I know this because my fridge is currently being repaired at the moment by a 12volt fridge specialist at Doonside. The symptoms you describe are exactly what happened to my fridge after about two years of faultless running. If you live anywhere near Doonside you could take your vehicle to him, because the first thing he did when I arrived with my fridge was to load test the fridge battery & wireing in one test. It took less than 30 seconds, & in my case he determined straight away that the battery & wireing were OK to run a fridge from that point. He then went on to discover a faulty poli fuse. If you need his phone number let me know, you may be lucky & not have anything wrong with the battery or wireing.
AnswerID: 416363

Reply By: Alloy c/t - Wednesday, May 12, 2010 at 09:24

Wednesday, May 12, 2010 at 09:24
The Waeco 110 is just a taller version of the Waeco 80lt , both use the Danfoss BD50 compressor , correct wire size from battery to fridge is parramount to avoid voltage drop , the fridge has a switch next to the power input labelled , Eco - Normal - High , this switch controls the speed setting for the compressor -2000rpm -2500rpm -3000rpm and hit the Turbo button=3500rpm , nothing to do with LOW voltage as some suggest ,,,,,
Power usage is in the high range 64+ amp hrs per 24 hrs , ergo even a 100 amp hr battery is 'good' for only 1 day unless recharged.
No matter which brand / size fridge you have decided to obtain ,thicker wire both pos + neg is required direct [ with fuse] from the battery ,factory fitted power outlet /cig lighter sockets are like the proverbial t---- on a bull when it comes to fridges.
AnswerID: 416371

Reply By: PradOz - Wednesday, May 12, 2010 at 10:19

Wednesday, May 12, 2010 at 10:19
the Dr

Hi. As BKS in reply 4 above says, buy a Waeco Raps 12R-U2 unit. It is specifically made for Waeco fridges. Engel also make one for their branded fridges.

I fitted a Raps unit and fixed my dramas, and have since recommended a member from here at ExplorOz who is an authorised Waeco agent to bks and also another EO member. They cost around $119 plus postage (unless things have changed) and they come complete with everything you need and are very easy to install.

I would highly recommend you fit one and this should solve your standard thin wiring dramas that vehicle manufacturers put in so you are ready to fit your new Waeco fridge when you get it. If you want the details of the EO member here who supplies these (and other gear) let me know your email address and i will forward it onto him (no affiliation etc, just highly recommend his service, honesty and advice)

Information here: Waeco Raps 12R -U2 kit

cheers mick....
AnswerID: 416380

Reply By: youngharry52 - Wednesday, May 12, 2010 at 10:51

Wednesday, May 12, 2010 at 10:51
Hi Doc,

I agree with all that's been said, but I think you might do better with a dedicated deep cycle battery and a heavy duty cranking battery. I suspect that you you would be killing the cranking battery that you have been using for the fridge. I have just been through this exercise with a 200 series cruiser and actually installed a third battery under the bonnet in my previous 100 series. No room for a third in the 200....

Hope this helps.

Regards

Chris.
AnswerID: 416384

Follow Up By: Von Helga - Wednesday, May 12, 2010 at 16:41

Wednesday, May 12, 2010 at 16:41
If you could have removed the fridge from the rear of the car ( yes I know it's big) and connect it directly to the battery it would have confirmed most of the posts here.
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FollowupID: 686533

Reply By: Maîneÿ . . .- Thursday, May 13, 2010 at 14:22

Thursday, May 13, 2010 at 14:22
the Dr,
You have the answer with-in your question
is just a matter of narrowing it down even further

"Now, whilst on the road the fridge worked a treat.
As soon as we'd stop though, up she goes!!!
A few on the trip said the batteries are insufficient and others said the wiring to the aux power outlet in the rear is too thin to cope with the load of a big fridge"

As I believe this happened 2 years ago it's unfortunately not practical to recheck the situation now.

Because you have stated: "whilst on the road the fridge worked a treat.
As soon as we'd stop though, up she goes"

I would suggest it’s definitely the “standard factory dual CRANKING batteries” causing the problem :-)

Reason being, the battery would have been charged, because you’ve been driving and as soon as you turn off the ignition, stopping the alternator sending current to the battery system, also indirectly powering the fridge, you have only the battery to power the fridge and the fridge temperature goes up.

The cabling is the same when the alternator is powering everything or the battery, so I believe it’s not the major cause, although it may have *some contribution* which at this late stage can't be proven or tested.

Can I suggest the “standard factory dual CRANKING batteries” may have been run down and/or sulphated just once too often, causing them to not hold voltage?

Maîneÿ . . .
AnswerID: 416528

Follow Up By: ChipPunk - Thursday, May 13, 2010 at 19:28

Thursday, May 13, 2010 at 19:28
But even good batteries are still typically 1V to 1.5V down from the engine-running (hence charging) situation.
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FollowupID: 686698

Follow Up By: Maîneÿ . . .- Thursday, May 13, 2010 at 19:32

Thursday, May 13, 2010 at 19:32
ChipPunk,
What causes the situation where "good batteries are still typically 1V to 1.5V down from the engine-running" ?

Maîneÿ . . .
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FollowupID: 686699

Follow Up By: ChipPunk - Thursday, May 13, 2010 at 20:02

Thursday, May 13, 2010 at 20:02
Eh? No alternator!
As with the loss of any reasonable charging...
(Ignoring surface charge...)
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FollowupID: 686703

Reply By: Member - Graham H (QLD) - Thursday, May 13, 2010 at 14:32

Thursday, May 13, 2010 at 14:32
The wiring in the rear of a 100ser is definitely toooooo small to run a fridge

You need at least 6mm2 to stop voltage drop.

As stated a raps 12 will fix the problem I have one and have run my fridge in the car for the last 13months and have had no trouble

Im surprised you couldnt actually smell the wires running hot and it may pay to check that some of the insulation hasnt melted.

It would be extremely unlikely to be the batteries if the car was starting OK


AnswerID: 416529

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