Comment: Electricity for Camping

Submitted: Monday, Jul 08, 2013 at 14:38

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Electricity for Camping

Revised March 2013 On an extended trip it's good to have some of the comforts of home. Electricity is obviously one of them and a good system can make all the difference to how comfortably

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Hi John and Val,

This thread is just what i was looking for I have spent a fair amount of time reading about a battery setup for my camper with provisions for expansion down the track (ie; More power drawn from fridge/freezer later on) and have found it the easiest to understand so far thanks.

I have a question in re guards to the 20% charge rule. If I run 2x 100 ah battery's in parallel does that mean i can put in a charge of 40amps from ether 240v charger, dc-dc charger or solar energy? If so will this reduce charging time without hurting the battery's?

Any feed back would be greatly appreciated as i am trying to make my final decisions on components for the fit out.

Thanks Matty.

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Reply By: Member - John and Val - Wednesday, Mar 04, 2015 at 00:52

Wednesday, Mar 04, 2015 at 00:52

Hi Matty,

Thank you for your kind remarks. I'm pleased you find the blog useful.

The 20% rule is really a guide rather than a rule, and the manufacturers of some of the more expensive batteries suggest they are ok at 50%. I reckon 20% is good for virtually any deep cycle battery.

If you run two 100 Ah batteries in parallel then they can be regarded as simply one 200 Ah battery, and yes, at 20% you could feed them up to 40A quite safely. In practice, although the charging source may be capable of delivering up to 40A, that rate usually isn't maintained for a long period due to the battery voltage rising to a level where the charger decides the battery is approaching full and the charger will then sit at its top threshold voltage.
You will charge faster with a 40A charger than with a lower capacity charger. This may be an advantage especially if you are charging from a generator.

You need to consider the capacity of your alternator if you are thinking of a 40A dc-dc charger, as the charger will draw considerably more than 40A from the alternator. (I use a 30A dc-dc charger for my two 100Ah batteries. Failing to check that the alternator could cope proved expensive!)

Cheers

John