Smartchargers

Over the weekend was using a 6 amp 3 stage charger to keep fridge going, but came to being either the gennie running or the battery on......thinking maybe running 2 of 6hr max periods with the gen and the battery for the rest

Any good 3 stage charger between 5 & 15A will do just fine..

Hi Kev

As mentioned a small is charger is fine. Check your battery specs but rule of thumb is 10% of the battery capacity so 12 or 15 amp will do.

Try get one with power supply mode so you don't over charge the battery when the fridge is running for extended periods in summer.

The 15A Ctek or 15A ABR unit will be fine.

Regards

Derek from ABR

Hello kevmac,

...maybe running 2 of 6hr max periods with the gen....

So you're planning on running the gen for 1/3 of the time while the fridge draws 2.7A for 3/3 of the time, or around 64Ah per day.

At first sight it looks like the gen/charger needs to supply at least 3 times 2.7A equals 8.1A during its daily run time of 8 hours.

But there's more to it:
because the battery will allow this current only for about 80% percent of the time the remainder needs to be supplied during the following absorption and float charging stages.
Let's look at the numbers:

The 80% state of charge will be reached after 64Ah*0.8/8.1A equals 6.3 hours of charging, leaving only 1.7 hours for absorption and float stages. This isn't quite enough to fully recharge the battery.

To overcome this problem, select a charger which offers 25~30A during the bulk charging stage.

Now, the 80% state of charge will be reached after 64Ah*0.8/25A equals 2 hours of charging, leaving 6 hours for the absorption and float stages.
This outcome is a lot better for your battery's health because it'll get almost fully charged on a daily basis.

Hope this explains it?

More information about 25A high quality chargers can be found in my profile.


cheers, Peter

After much ado about nothing, finally decided upon a Calibre 20amp multi stage charger(currently have Calibre 6 amp) was normally priced at $199, but went in at right time and have on order at a special price of $159. At least if something goes wrong with it, i will be able to go to local store and slam it on counter and abuse them face to face(hahaha).
Oncee I have it installed and trialled , I will let you all know how it goes. Thanks again for your advice and help.