Simple power workaround....

Yes that will work,how about rotating the batteries while travelling to put charge in the camper battery,once charged it should power lights and gamesfor several days at least,you really dont have a problem.

The short answer Rod, is no.

To charge a lead acid battery requires a voltage significantly higher than the resting voltage of a charged lead acid across it's terminals. Secondly, your batteries in the vehicle are going to be charged but "fully charged" is unlikely.

The current flow would be minimal and the charging effect negligable.

Hooking the jumper leads up to the battery in the trailer and leaving the engine running while in camp with the hand throttle knocked up a bit is about your only option without going to the trouble of generators or solar.

The other option would be to run an inverter off your aux and a decent battery charger (read quality not quantity (ie. smart not powerfull) to charge the camper.

Which ever of the two methods above you are running down the auxilliary in the vehicle and reducing the time you can run your fridge & lights etc off it.
What size battery is in your camper trailer?
What is the current draw of the devices according to their specs, and how many hours per day are you planning on using them?

Dave

Hi Rokkitt,

Have you considered a solar panel to charge your battery? A 10W panel and regulator will cost you about $150 and will trickle charge your battery.

If you know how much power your appliances/lights use you could use this solar calculator and battery sizer to determine what kind of solar system would suit your needs:

DC solar calculator

DC wire sizing

Regards,

Max

Hi,

Thanks for the responses, I was not sure if there would be a current/voltage transfer....say I have run the trailer lights for the evening, 4 or 5 hours - could I then go out driving the next day and return...hook up the leads and go have a beer and let the trailer recharge by means of a voltage transfer - not running with the jumpers still connected.

For instance would a 12.7v battery charge a 12.3, not a fully discharged battery. I was thinking they both may equalise to 12.5v relatively quickly.

Will go down the solar path in the future but I really want that front diff lock first - its far more important....:)

The problem of charging a battery from another is that you have to apply a voltage in excess of 2.2 V/cell (13.2 V for a 12V battery) for a battery that has a fairly good charge. This is the level considered to be necessary to prevent self discharge and anything above that will be a float or charge voltage depending on how high it is above 13.2V. You will get some charge into a discharged battery but you will be operating your camper battery at too low levels for good life.

Max's idea of a 10W solar pannel would be insufficient for your application you would need more like a 4-50W panel.

Dave (in reply 2) mentioned an inverter to drive a good battery charger. This is a good a good idea. A better way to go would be a recharger or booster like Arrid's Twin Charge, BCA's Leab battery booster or Engel's 12 Volt in car Battery Charger (cheapest @ $140.) All three boost the battery or alternator voltage to around 14.4V to fully charge a deep cycle battery. If you mount one of these in your camper trailer and have it permanently connected to the battery charge line you will get a better battery charge as you are travelling.

If you do not wish to purchase equipment at this time then swap your batteries daily or run your lights directly from your vehicles auxiliary battery. Paralleling the two batteries will do neither much good in the long run and not really achieve what you desire..

PeterD