Fridge size and current draw.

here are soooo many variables that you realy need to work on "worst case" and buy the battery for that..
The battery usage doesn't necessarily relate specifically to the fridge size.. The power draw down will vary depending on how oftwen the fridge needs to turn itself on to maintin the setting you put it at.. Whatw will effect how it needs to turn on is: How oftne do you open it, what is the ambient air temperature.. eh if it's hot all day , then perhaps it's worhth buying the carry bag which is insulated which will minimise the cold loss due to ambient temperature..

here are soooo many variables that you realy need to work on "worst case" and buy the battery for that..
The battery usage doesn't necessarily relate specifically to the fridge size.. The power draw down will vary depending on how oftwen the fridge needs to turn itself on to maintin the setting you put it at.. Whatw will effect how it needs to turn on is: How oftne do you open it, what is the ambient air temperature.. eh if it's hot all day , then perhaps it's worhth buying the carry bag which is insulated which will minimise the cold loss due to ambient temperature..
On the other hand by buying a 60 L you have the addedd advantage of a combo fridge/freezer.. the engel has an internal lid over the feezer which helps keep the cold in a little even when you open the fride for a tiny or 2...
In summary.. I'd go the 60L.. there actual power consumtion won't be all that different If you can afford it.. fridge space is never too much.. worst comes to worst you have to run the engine for a short time.. (the beauty of a hybrin battery is that although it doesn't haold charge as long as a deep cycle, it alos doesn't take long to charge (relativley speaking)... So in anut shell.. if you can afford a 60, I'd do it for the sake of having to run the engine.. which in reality,if you are doinga it of traveling will hapen anyway.. evne better get the fridge/freezer combo and you can really work some great efficiency by moving frozens into the fridge daily for next day etc.. (thats my 20c worth)

There are soooo many variables that you realy need to work on "worst case" and buy the battery/fridge for that..
The battery usage doesn't necessarily relate specifically to the fridge size.. The power draw down will vary depending on how often the fridge needs to turn itself on to maintin the setting you put it at.. What will effect how it needs to turn on is: How often do you open it and what is the ambient air temperature.. eg if it's hot all day , then perhaps it's worth buying the carry bag which is insulated which will minimise the cold loss due to ambient temperature..
On the other hand by buying a 60L you have the addedd advantage of a combo fridge/freezer.. the engel has an internal lid over the feezer which helps keep the cold in a little even when you open the fride for a tiny or 2... (not sure about Waeco)
In summary.. I'd go the 60L.. the actual power consumtion won't be all that different. If you can afford it.. fridge space is never too much.. worst comes to worst you have to run the engine for a short time.. (the beauty of a hybrid battery is that although it doesn't hold charge as long as a deep cycle, it also doesn't take long to charge (relativley speaking)... So in a nut shell.. if you can afford a 60, I'd do it for the sake of having to run the engine once in for a short time every couple of days.. which in reality, if you are doing a bit of traveling, will hapen anyway.. even better - get the fridge/freezer combo and you can really work some great efficiency by moving frozens into the fridge daily for next day etc.. (thats my 20c worth)

Damn I hate it when you press the enter button accidentally and the same post gets submitted sveral times.. Sorry folks...

One vendor has told you that you should go for a 40 litre fridge as a 60 litre fridge would draw to much current and one battery would not last 24 hours, is this true?.........
probably NO, if his fridge only lasts 24 hours on one battery it is not worth buying and taking away with you as it will be always running your battery flat and your food will often be in the dangerous bacteria area.

If you need 60 Ltr capacity get it, and get a third battery wired in parallel with the existing Aux battery, as you can't have tooo much battery power available, you will then only be drawing off the top of the two Aux batteries instead of just flattening one battery.

the vendor is just trying to make a sale as they know they’re more expensive than some others and are trying to get the price down by talking you into a cheaper fridge and also smaller than you may require... and yes you will regret it!

What fridge are we talking about?
Does it have a Danfoss compressor?
or is it a swinger?

My old EvaKool 65l (approx 12yo ) , runs for at least 2 days on a setting between 1/3 and 1/2 (enough to keep icecream frozen) on my smaller 55 a/h DC battery.

It doesn't have the benefit of newer technology so is pretty heavy on power draw.

ANY , new 60 odd litre fridge should run for 2 days at least.

Fridge draw compares to battery output!!!!

eg my engel 40 ltr _Affordable_Storage_Drawers.aspx up tp 2.5 amps per hour.

My battery is a cattapillar 220 amphour battery.

220 divided by 2.5 equals 88 hours of run time if my fridge is set to run non stop.( up to -22 C)

minimal setting on fridge will draw .5 amps per hour (wont keep the beer cold but the lettice won't droop) equald 440 hours.

the specks come with the fridge, do the math!!

If Ive got this wrong some body tell me

my battery will run an engel 40 for about five days plus as a fridge with icy cold beer all the time with out turning over the engine. (ive never stayed in the one spot for more than five days)

60 ltr engel _Affordable_Storage_Drawers.aspx allmost twice the amount of amps, (my old man has one) and works great.

The reason I liked the 40- less power draw, I can carry it on my own when it is loaded,(the 60 needs two), If i want more fridge space i can buy a twozone extention for the fridge.

Hi there I have read your post and was looking at others and thought that this may help you with work out how long your battery last as it does not seem that the amp hrs is strait forward.

I have left the orginal writer name on there

see ya
JAS095

Reply 2 of 9 posted 06 Oct 2005 at 07:15 - (AnswerID: 133230)
Mark T replied to the question

I would suggest that the lap top is shutting down as the voltage is dropping to a level that is below the laptops minimum to work. You can't "increase the amps".

What you need to do is to is measure the voltage at the laptop 's 12 volt connection and see what it is. You could also start the engine and run at around 2000 rpm and check the voltage then as the alternator will be charging. (Ensure your fan belt is tight though as many cars run around with loose fan belts which ensures under charging!)

Depending on how old and what condition your battery is in, the state of battery charge might come ino play here. If you're drawing 15 amps for some time out of the battery, then the voltage will drop simply because of the load. It all depends as I said on the state of charge and age/condition of the battery. My assumptions are based on heavy duty wiring and you state 6 MM wire which should be fine.

Your 115 amp hour battery.. many people think that you can draw 115 amps for 1 hour. Actually there are 2 rates, the 10 hour rate or the 20 hour rate. The 10 hour rate (best) means you can draw 11.5 amps per hour for 10 hours or the 20 hour rate means that you can draw 5.75 amps per hour for 20 hours.

Anyhow after all this stuff.. get a digital multimeter and measure the voltage at the laptop's 12 v power supply and see what you get.

Hope this all helps you and doesn't confuse.

Mark Taylor

I have both a 50 litre and a 80 litre waeco. The draw when cycling is around 3 amps for both. The amount of extra battery capacity is based on the operating conditions. The less ideal the conditions the more effort the larger fridge has to make. So how long the battery lasts is probably more to do with, whats in it, ambient temperature, exposure, ventillation and the big one - how often it is opened than necessarily the size.

As stated above come up with a balance between desired fridge capacity, required mobility (if any) (reply earlier advises this), how much room you have to accomodate a fridge, as well as how much amps you have. Finding more amps to run the thing is probably the easiest of all to do.

An 80 litre fridge in the right position (ie ventillated, shaded, insullated, minimally opened etc) will use less power than a 40litre fridge in the wrong position. IMHO.

Happy fridge shopping.