Can i run the fridge off battery whilst charging it

Submitted: Monday, Oct 12, 2009 at 16:11
ThreadID: 72953 Views:20253 Replies:9 FollowUps:4
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HI,

Just wondering if its possible to run a fridge off a battery whilst a generator is charging the battery.

We have an 105a/h thumper battery pack to run the 40 litre waeco so we can stay bush for a while. after a couple of days the battery will need charging. we have a little Robin R650 generator which is 550w to charge the battery,

something i never thought off is that the fridge would still need to be attached to the battery whilst its being charged to stop the meat getting warm. The generator only has 1 240v plug (no 12v plugs).

How does everyone manage to keep the fridge going and charge the battery if you are set up for a couple of weeks away from power.
Im not sure how to manage the fridge and charge the battery at teh same time.

Any help and ideas would be great, we are really new to all this stuff.

Cheers
Tony
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Reply By: CraigB - Monday, Oct 12, 2009 at 16:15

Monday, Oct 12, 2009 at 16:15
Yes, no problems.
AnswerID: 386712

Follow Up By: viz - Monday, Oct 12, 2009 at 19:03

Monday, Oct 12, 2009 at 19:03
Been doing it for years this way...

viz
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Reply By: Member - ross m (WA) - Monday, Oct 12, 2009 at 16:16

Monday, Oct 12, 2009 at 16:16
I run my fridge and recharge off a battery recharger,no problems. When you are using solar solar panels,you are doing the same thing.
AnswerID: 386713

Reply By: Member - Troll 81 (QLD) - Monday, Oct 12, 2009 at 16:16

Monday, Oct 12, 2009 at 16:16
No difference to the alternator charging while you are driving.
AnswerID: 386714

Reply By: Tony - Monday, Oct 12, 2009 at 16:22

Monday, Oct 12, 2009 at 16:22
Thanks everyone,

will the 550w generator handle it ok.
I have read that you sometimes need to add a 100w load to the generator to charge the battery, how do you know if you need to do that
AnswerID: 386716

Reply By: Member - Pesty (SA) - Monday, Oct 12, 2009 at 16:46

Monday, Oct 12, 2009 at 16:46
Tony it doesnt seem you know to much about all this?
The generator DOESNT charge the battery.
550w is the AC output of the generator.
The generator is for running a 240v battery charger, I suggest you get a 20- 25 amp smart charger, maybe a ctek 25000, and run it with the generator for an hr or 2 morning and night, depending on how hot the weather is.
Your generator will run one of these chargers ok.
If you can use a basic cheap multimeter, get one of those as well to keep an eye on the batery voltage, and try and keep it between 12v and 12.7v.
The fridge will happily remain connected to the battery while you have the charger running off the generator.

Cheers Pesty
AnswerID: 386723

Follow Up By: Tony - Monday, Oct 12, 2009 at 17:04

Monday, Oct 12, 2009 at 17:04
Thanks for the info

Sorry, I didnt word it right :)
What I meant was would the generator handle charging the 105A/h battery via a smart charger because its only a small size gen. Most posts i have read people have 1000w or more
I have posted a question regarding types of chargers earlier.

We were looking at either the Ctek 25000 or the ABR 20 Amp smart charger.
Cheers Tony
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Follow Up By: Member - John and Val - Monday, Oct 12, 2009 at 17:46

Monday, Oct 12, 2009 at 17:46
Tony - just to clarify Pesty's suggestion - As he says, the 12.0 to 12.7 range is good when the battery is supplying current to the fridge. Actually, down to about 11.6 volts is ok, and the fridge will probably cut itself off if it gets down to about 10.6.

When charging though, the battery voltage should be up around 13.4 to 14.0 and higher still for some battery types.

You might find our blog Electricity for Camping interesting.

HTH

John
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Follow Up By: Bob of KAOS - Monday, Oct 12, 2009 at 18:11

Monday, Oct 12, 2009 at 18:11
John

Excellent article. Many thanks

Bobv
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Reply By: DIO - Monday, Oct 12, 2009 at 18:41

Monday, Oct 12, 2009 at 18:41
Yes, of course it is OK no different than having the fridge plugged into the car battery which is generally being charged whilst you travel.
AnswerID: 386734

Reply By: Member - Doug T (NT) - Monday, Oct 12, 2009 at 22:59

Monday, Oct 12, 2009 at 22:59
Thi comes from the Engel owners guide, click on it to enlarge.

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.

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Reply By: Member - Mike DID - Tuesday, Oct 13, 2009 at 06:56

Tuesday, Oct 13, 2009 at 06:56
The only potential problem in charging a battery while a load is connected to it, is that the Charger can't detect when the battery is overfull ad overcharge the battery.

This is unlikely to happen here because you won't be leaving the generator on all day. Batteries have a reasonable ability to stay on 14.4 volt without damage.

If the battery starts gassing or getting warm, then you know it's fully charged.

This happens because Chargers drop from 14.4 fast-charge voltage, to 13.6 slow-charge voltage when they detect that the battery is drawing little current - if there's a fridge connected, the charger sees a high current every time the compressor cuts in.
AnswerID: 386821

Reply By: sapphireminer - Saturday, Oct 17, 2009 at 17:46

Saturday, Oct 17, 2009 at 17:46
Hi Tony
I use a power board and plug the 240v fridge plug into 1 and the charger into the other that way all the charge is going to charge the battery instead of some bleeding off to run the fridge I do this of a evening when running the genny hope this is of some help Regards Dave
AnswerID: 387496

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