Batteries in parallel. What'sthe go......?
Submitted: Thursday, Jun 23, 2005 at 20:42
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Willem
Out in the
Gibson Desert my auxilliary battery started faltering. I ascertained that my Rotronics Battery Isolator had failed.
So after a lively discussion with my travelling mate I hooked up the two batteries in parallel. My mate was of the opinion that I would now have 24volt. I disagreed.
Have done around 10,000km since then and have had no ill effects to the electronics, though I have been turning the fridge off at night(it has been cold outside anyway).
Both batteries are newish Century 17plate 4WD Overlanders 700cca.
I do intend to get another battery isolator.
The question is: Will there be any detrimental effects to the vehicle electronics when running two batteries in parallel?
Reply By: Crackles - Thursday, Jun 23, 2005 at 21:46
Thursday, Jun 23, 2005 at 21:46
Have had my 2 batteries in parallel for a couple of years now & it can't hurt the cars electronics. It's really the same as having one big battery.
It doesn't seem to matter which brand of isolator people choose they all seem to have common failures when taken out in the outback heat and vibration. Why is it they always seem to let you down when you need them most?
I've seem so many go over the years that I now just have a 200 amp key switch to keep it simple & reliable. What brand will you go for next Willem?
Cheers Craig.........
PS. With 2 x 700 cca batteries in parallel you would have no problem starting your car in the morning even if you left the fridge & camping light on all night.
AnswerID:
117139
Reply By: Vinnie - Thursday, Jun 23, 2005 at 22:05
Thursday, Jun 23, 2005 at 22:05
G`day Willem
I have my auxillary managed by a Rotronics and all is still going good (cross fingers)
I wired a connection to the back of the truck to store & charge a battery on my
camp trailer - this works as a parrallel connection with a fusable link on the positive wire only. It is charging while on the move and if stopping for any length of time I just disconnect the plug.
I am using 50amp anderson plugs and 6mm wire, so far this is working all good too.
I can get three days using the Engel on the
camp trailer battery. To top it up I plug it into the Genny at night while running lights etc and get three more days...... and so on.
You will do no damage to electrics running parrallel batteries, but you will drain both if left running stuff. Be sure you can disconnect when not required
Vinnie
AnswerID:
117145
Reply By: Outnabout David (SA) - Friday, Jun 24, 2005 at 09:18
Friday, Jun 24, 2005 at 09:18
Willem,
See post 22973. Asked the same question after reading about your problem on your trip and have wired the 80 series up in paralell. No problems in going through the night and into the next day without switching the very simple high amp switch over.
Plenty of people will knock the system but after originally having one a few years ago and then every brand of "smart" type solenoids I will stick with the Kiss principle of the parralell wiring as I have less problems with that. My batteries are both new and of the same type so I am starting off with everything matched fore my own piece of mind.
To all the knockers who bring up the crook cell battery scenario I ask. What happens when the fridge battery has run down and the start battery is crook? This happened to me once and the answer is you need a jump start because the way those systems work is that the aux battery is isolated until the engine is running.
So you see there CAN be problems with both systems but I like the paralell system as when stopped you are just taking a little bit off the top of both batteries rather than a lot out of one.
David
AnswerID:
117207
Follow Up By: Mad Dog (Australia) - Friday, Jun 24, 2005 at 12:33
Friday, Jun 24, 2005 at 12:33
David, yes correct but it's important to present Willem with the facts so he can make an informed decision on what suits HIS circumstances armed with the facts. It's no getting caught short in the bush and then saying "nobody told me that could happen"
Personally I would never operate without an isolator because I make extensive use of a
HF radio not only for voice but data that is controlled by a computer and transmits periodically unattended drawing over 20 amps....just
too easy to flatten batteries if not very careful. My point here being we have different circumstances and expectations.
By the way, with the redarc it is simply a matter of grounding one little wire to parallel the batts, can be done from inside the cab with a switch. With some simple electronics both batts can be left paralled until the main drops to a preset level and then isolate automatically.
No matter what the system there are positives and negatives (pun intended) if we are aware of the negatives we are forearmed
FollowupID:
372670
Follow Up By: Outnabout David (SA) - Friday, Jun 24, 2005 at 13:04
Friday, Jun 24, 2005 at 13:04
Mad Dog,
You are correct. Go for what suits the owner. Yeh I know about the bridging on the redac etc but the installer forgot to tell me that and I had to wait ages for a jump start when all the time I had a good battery.
I just assumed that they would both come in to play for sarting.
FollowupID:
372672
Reply By: Member - Duncs - Friday, Jun 24, 2005 at 10:53
Friday, Jun 24, 2005 at 10:53
Willem,
My GQ ran like that for years with no ill effects.]
For about $20.00 I bought a terminal to attach to the second battery which had a screw on top of it I attached the standard car stuff to the OE battery and the aftermnarket gear to the aux. When i screwed up the terminal it seperated the batteries when I screwed it down it connected them.
Screw it up when you make
camp and screw it down when you break
camp. Make it part of the routine and it is never a problem.
Duncs
AnswerID:
117228
Reply By: Alloy c/t - Sunday, Jun 26, 2005 at 20:49
Sunday, Jun 26, 2005 at 20:49
Willem , would be very interesting to find out how/why your rotronics 'failed' ,,have you contacted the makers? , my cheapy rotronics , [classed as a w/ender] is fully charging my start...aux ... and 3x c/trailer batts ,,all batts same age + type = 5x fullriver 80amp AGM ,,
AnswerID:
117593
Follow Up By: Willem - Sunday, Jun 26, 2005 at 21:08
Sunday, Jun 26, 2005 at 21:08
Alloy
My Rotronics MH10 was bought mid 2002 and fitted to the G60. Then it found a
home in the GQ. So it worked for about three years.
I am still on the road and will send the unit back to Rotronics so that they may have a look at it. I only discovered that the Isolator wasnt working as my new battery started failing and output dropped below 10 volt. The battery came good when I hooked it up in parallel to the other one.
Will post result of finding sometime in the future.
FollowupID:
372947