Power Tank

Submitted: Monday, Nov 22, 2004 at 13:18

ThreadID: 18004 Views:5900 Replies:8 FollowUps:8

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Member- Starky

I am looking for something that will run a 45lt wacoe fridge/freezer over night while the vehicle is turned off. I have done a search on the forum but come with nothing, but I do remember someone posting something not so long ago.

We will be travelling throught the day and only need the power over night if we have to take a caravan site without power or do bush camping. The fridge usually holds its cold very well overnight during winter. I have had a quick look at the supercheap auto stuff and the bushranger power tank. Prices seem to range from $70 to $400. How good are these things?

Any advice from anyone would be helpfull.

Wayne

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Reply By: flappan - Monday, Nov 22, 2004 at 13:31

Monday, Nov 22, 2004 at 13:31

I doubt the SC ones would do it. I have one , runs my lights really well , but doesn't run the fridge to flash.

From memory , a mate got about 5 hours of fridge running out of one. You "may" be able to get away with it , at night , and on lowest setting , but doubtful.

I dont know how much better , if at all , the Bushranger one would be.

A few guys have made up their own. Battery Box with Meters etc from SC (about $70) , and fit either a deep cycle , or big starter battery. They then charged it like a defacto dual battery

AnswerID: 85373

Reply By: Member - Ross P (NSW) - Monday, Nov 22, 2004 at 13:42

Monday, Nov 22, 2004 at 13:42

Starky,

The battery packs are ok but it's the charging routine that causes the problem.
My experience with a small 24 AH unit is that with a standard accessory outlet (ie no wiring up-grade) I couldn't get enough charge into the batterry to get me through a hot NT summer night. It got worse as the trip went on.
Now, even with upgraded wiring to my rear accessory outlet, and the vehicle's charging system, the best you can achieve is approximately 80% charge after a fir bit of driving. Now if I stay above the recommended maximum discharge of say about 50%, my battery can deliver, at best, about 7 AH or 7 hours of deliverying 1 Amp. to an appliance. I also believe that charging the battery this way over an extended trip dlivers less and less useable power over time.
I would like to go solar but can't stretch the budget to the $1200 odd dollars it will take. My compromise has been to install a deep cycle battery in the car, rewire the rear accessory outlet, carry the gel filled 24AH unit as a back-up and charge both batteries using a mains operated "Smart" battery charger whenever I have 240V AC available.
My observation is that with my Ctek (Bainbridge Technologies) "SMART" charger in the 14.4V mode, I can get up to about 80% charge in about 8 hours but it takes another 48 hours or so the reach the fully charged maintenance mode.

Hope this helps,

Rosscoe

AnswerID: 85376

Follow Up By: Member - Ross P (NSW) - Monday, Nov 22, 2004 at 16:44

Monday, Nov 22, 2004 at 16:44

Starky,

I should point out that my deep cycle battery is under the bonnet of the car and the wiring includes a smart solenoid that prevents the cranking battery from being flattened.

I also tow an off road van which has an on-board (in a special vented compartment) 85 AH Deepcycle battery.

The 24 AH unit is sealed battery now used for powering lights etc or as a back up if my van battery gets to 50% charge.

I strongly recommend AGAINST using your cranking battery to power the fridge except when your driving. If you are running the fridge from the car battery it's best to have the power automatically disconnect from this outlet when you switch off the engine.
Nothing worse then hitting the starter and nothing happens, especially in the middle of nowhere.

FollowupID: 343966

Reply By: Noosa Bushtrackers - Monday, Nov 22, 2004 at 13:45

Monday, Nov 22, 2004 at 13:45

Collyn Rivers, will be able to help you in more detail, but if you check the fridge and see what the current draw is (probably about 4 amps/hour), and then allowing for the fridge to run on this battery for say 16 hours overnight at half the duty cycle, then the fridge would require 8 times 4 amps/hour = 32 amp hours to run fridge. It is my understanding that you shouldn't ever let a battery go below 50% of its rated charge so if you can get a power tank with over 70 amp-hours it should do the job, but one around 110 amphours will do it a lot better with more in reserve and less likely to damage battery.

Brian
Doing it tuff, Towing a Bushtracker.

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AnswerID: 85377

Reply By: Davoe - Monday, Nov 22, 2004 at 13:59

Monday, Nov 22, 2004 at 13:59

Why run the fridge off the battery pack? why not run the fridge off your vehicle, It should easily run your fridge overnight- If not your battery is stuffed. On the off chance your vehicles battery goes flat then start it with the battery pack

AnswerID: 85384

Follow Up By: Nudenut - Monday, Nov 22, 2004 at 14:11

Monday, Nov 22, 2004 at 14:11

yep Davoe I agree
its only a small fridge so it should be ok.....how ever a 2nd battery will ensure that the main is always available for starting the car and is good investment if main becomes U/S

FollowupID: 343934

Follow Up By: Robbg - Monday, Nov 22, 2004 at 15:58

Monday, Nov 22, 2004 at 15:58

The advantage of powering fridge, etc, from the starter battery, and having a power tank (or other battery pack) as a standby is that the tank can be float charged whenever the engine runs, thereby drawing minimal current and eliminating the need for thick wiring and anderson plugs. The tank would only ever be used to assist the starter battery if it was struggling. Only question is - what size tank (how many amp/hours) would be needed if it was to be used in this standby mode?

Rob.

FollowupID: 343956

Reply By: kiss'n'dirt - Monday, Nov 22, 2004 at 14:42

Monday, Nov 22, 2004 at 14:42

for the price of a powertank or a thumper you can buy an 90a/hr battery in a battery box and just hook it up with a 50amp anderson plug. why have a 40a/hr when you can have 90..

AnswerID: 85392

Follow Up By: Member- Starky - Monday, Nov 22, 2004 at 15:14

Monday, Nov 22, 2004 at 15:14

I thank evryone for thier assistance with this.

I do have a 660cca battery and battery box in my boat. I take it that this can be hocked up with the anderson plug and stored in the back of the Prado until needed. This battery would then be topped up when I have access to 240V. Can it be as simple as this?

Wayne

FollowupID: 343946

Follow Up By: flappan - Monday, Nov 22, 2004 at 15:24

Monday, Nov 22, 2004 at 15:24

Just a general comment.

You shouldn't be charging a wet cell battery in the back of a vehicle. Lets off gas.

If you are charging a battery like this , it should be a sealed one.

FollowupID: 343949

Follow Up By: Davoe - Monday, Nov 22, 2004 at 15:26

Monday, Nov 22, 2004 at 15:26

yes but get your batteries load checked often as they can have seriosly short lives alot only live for 18months- 2 years

FollowupID: 343950

Reply By: Member- Starky - Monday, Nov 22, 2004 at 15:55

Monday, Nov 22, 2004 at 15:55

flappan,

Thanks for your answer. That is exactly why I worded my post that way. I thought it was to simple. I have no idea what an anderson pug is. Is it an outlet plup or an input plug? If the battery and box was tied down in/on the camper trailer and only charged when 240 was availble then this would be the answer to my issue. wouldn't it? A 660cca battery should have at least two ten hour nights in it I would think. I believe it is about 110 amp hours?

Wayne

AnswerID: 85409

Follow Up By: flappan - Monday, Nov 22, 2004 at 16:07

Monday, Nov 22, 2004 at 16:07

Now we're talking.

Anderson plug is a fancy trailer connection (for want of a better description). Its able to handle up to about 50amp. Plenty for this type of application.

My setup , is simliar to what you are describing.

I dont have room in my vehicle for dual batteries , so my extra battery is on my trailer.

The cable for my battery , runs from the vehicle battery , through an isolator to the back of the vehicle , thru the Anderson Plug , onto the trailer , and to the 2nd battery. This battery gets charged once my starting battery gets to 13volts.

Mine is a Deep cycle battery , and the fridge and 12v lights etc, for my campertrailer run off this.

The DC battery doesn't charge so well off the vehicle , in a short period of time , so , a large starting battery would be better in this respect.

I will say NEITHER method , means the batteries will last a long time , but , I'm also not paying a fortune for batteries.

I'm just telling you what I have done , and it works for MY requirements. There are better methods (3 stage chargers , fancy 12v chargers Arrid Twin Charge) , but they are pretty costly.

FollowupID: 343958

Follow Up By: Member- Starky - Monday, Nov 22, 2004 at 16:25

Monday, Nov 22, 2004 at 16:25

Flappan

Thanks for that. I will keep it very simple as I already have the battery, battery box and charger. Not too much to extra to hump around as we travel very light. This will then keep me out of trouble and save me about $150 at least. I will forget about the power tank now.

This forum has to be the best advise and money saving device I have come across.

Thanks to everyone.

Wayne

FollowupID: 343961

Reply By: Richard & Leonie - Wednesday, Nov 24, 2004 at 21:48

Wednesday, Nov 24, 2004 at 21:48

I run my 40 lt engel off the car battery overnight. I have a new Exide Extreme battery which I think is rated about 70 amp hour. We do not have a dual battery system. We have just been away for a couple of weeks and travelled about 300 to 400 ks every second day with only local trips during the lay day. When I am driving I turn the frige up a bit so when we stop at night it is fairly cold. I then turn it down to maintain about 3 C. I have a Bushranger Power Tank which I fully charge before I leave home and only keep it just in case I do flatten the car battery. I have not flattened it yet. Mind you I have not been out when it has been really hot. If it is hot then the fridge will use more power and this might be a problem. As pointed out by others you will not be able to recharge a Power Tank with 4 or 5 hours driving. It takes about 24 hours. I did originally buy the Power Tank to run the fridge off and it worked well over night but I could never recharge it enough with driving to the next camp site. The next car I buy I will make sure I can put a dual battery system in.

AnswerID: 85792

Reply By: Willykj - Thursday, Nov 25, 2004 at 18:27

Thursday, Nov 25, 2004 at 18:27

Hi Wayne,

I bought a Waeco Thumper which I was going to use for my fridge (42L Bushman) but after some experiments I now use the Thumper for lights and recharging batteries etc - with small inverter - but overnight I leave the fridge on the car battery and have never had a problem. The THumper is m y back up for 4WD starting.

Recently had 7 weeks in Cape York using that system and it was great. The Thumper was fully charged on m y return and on some occasions I did not use the vehicle for 2 days & the 4WD battery was fine. It is a severe truck service battery.

Willy

AnswerID: 85912