Running Batteries in Parallel

[jarrah7rally Member Find all posts View Profile Close jarrah7rally]

Look forward to seeing how this setup works out thinking fo doing a similar setup to allow for extra load whilst doing comms support at rallies etc. Just a pity I can't fit two abtteries side by side liek the troopies can (or did) with the newer model.

At work we been setting up a few trailers as remote repeaters for radio comms, been impressive to watch the build and giving me lots of sneaky ideas - just wish I coudl get my hand on one of those decent looking trailers

[drivesafe Senior Member Find all posts View Profile Close drivesafe]

It charges from the alternator no problems.. and being 2 batteries, will take twice as long as charging one, and twice as long as draining one... all your doing is making a bigger battery really.

Jeff.

Hi Jeff and while you are correct about taking twice as long to discharge, and there are a number of other major advantages to have two auxiliary batteries over a single auxiliary battery set up.

If you were using a DC-DC device then yes, you would take around 90% longer to charge two batteries and this is one of the untold disadvantages of using a DC-DC device, If you need to add more auxiliary battery capacity, you also have to add hours more driving time to allow the DC-DC device long enough to charge two batteries.

BUT, when using an alternator, the alternator actually caters for the extra charging power required and increases it’s current output.

So at worst, if the two batteries are low it might take up to 20% longer to fully charge both batteries but in many cases, it will not take any longer to recharge two batteries as compered with charging one. Again, this is the biggest advantage of use an alternator as the primary charging device.

There is also a quirky advantage to using two batteries and actually being able to charge them hours quicker than when using a single battery, when using an alternator.