Charging AUX Battery

[Megsy!]

Hi all,
Just wondering how yas get on with keeping your second battery charged to run your fridge/winch & so on?.

I have a second Batt in my cruiser & it runs my 40lt Engel, Now from what I have been told by the battery joint is, that even tho I have it hooked up to charge off my main, after I run the fridge for about 2 days, even with driving somewhere in there, that I am still goiong to have to stop somewhere overnite & get my second batt charged up from a batt charger or some other source, as the fridge will draw more then what the car will charge will put back into it.

So I say's to him that it kinda defeats the purpose of having it charging off the main if I am still going to have to stop every 48hrs and recharge it.

So as to the above question, is this the way that most do it or is there a trick of the trade I am missing.

Cheers....

[drivesafe]

Hi Megsy, you don’t say how you connect your second battery to the “mainâ€

[-Richo-]

I wouldnt advise using a winch or anything that draws lots of current on the second battery unless of course the dual battery manager you have is rated for higher currents, otherwise youll fry it. Probably better off hooking up the winch to the main battery and then if you drain that you can charge the main off the aux if you need to start. But i would have the engine running anyway when the winch is going.

For the charging issue, it depends on a lot of things. How many amp hours is your battery rated at? how hot is it outside when the fridge is running? My old mans engel draws about 3.5 amps when its running, but it doesnt run all the time only when its needed to maintain the desired temp. You could work out roughly by doing the math with the amps and the amp hour rating of your battery or what would probably be better is to run the fridge off your aux battery at home and see how long it lasts. I am currently installing a 100ah battery as my secondary and the engel should run for almost a week without charge in optimal conditions.

[Utemad]

I have an 80L Waeco I use as a fridge and freezer on 5 lights. I have two batteries (both starting type 600CCA) and never need to charge from another source. Sounds like your auto lec is a bit odd. I only use a standard relay to isolate so they charge at the same time not seperately like a normal setup and it still works fine. I put in a third battery to go to Tassie and it still charged up fine when doing 3 together. Takes longer to fully charge but lasts longer between charges. I wouldn't worry about it if I were you.

As for winching I would connect the winch to main battery and keep engine running. Perhaps have a big arse switch which allows you to connect both batts together when engine is stalled and you need to winch.

[benjamin78au]

hey that fridge find out what the current draw is per hour on it, and r u using just a relay or smart charger in that old cruiser. um what rating is the batteries you have in there. If ya want i can drop in on weekend for ya.

bj