Dual battery setup
Submitted: Sunday, Jan 12, 2003 at 18:58
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SteveA
G'day everyone,
I've got the The Piranha DBE 150S MKII Electronic Isolator fitted to my 80 series, went to Fraser for a week expecting to drive at least a half to an hour each day (which I did)Third day for 2 hrs but next morning aux battery almost flat.
Got batteries checked out before leaving by auto-electrian and he said they were in excellent working order. Great!!!!
Ok me thinking 80 amp alternator would charge the aux battery up fairly quickly after topping up the main after initial start up but Oh no!!!!! come on banter me up and tell me WHY the aux batteryalmost went flat.
Reply By: OziExplorer - Sunday, Jan 12, 2003 at 19:58
Sunday, Jan 12, 2003 at 19:58
Steve, just as a matter of interest, for 30 minutes running for two days, and two hours the third day, you would have at best put back 20 amp hours. With the battery being close to flat by the third day, I would estimage the figure of 20 amp hours to be reasonably accurate. At most it would probably be 26 amp hours.
Your alternator does not charge 80 amps into the auxillary battery. On the first day of driving around for 30 mins as the battery was not to flat you probably got in the 30 minutes driving 8 amp hours, on the second day, 4 amp hours and on the third day due to the battery now being close to flat 8 amp hours, and at best 14 amp hours.
To charge a second battery at full alternator capability requires a totally different system.
AnswerID:
11137
Follow Up By: Stevea - Sunday, Jan 12, 2003 at 21:14
Sunday, Jan 12, 2003 at 21:14
Ozi can you describe the other system because after paying reasonably big bucks for the dual battery system I'm interested in this other system you have written about or can I add some thing to my system to achieve a better result than what I'm getting now. Don't wan to get into the solar debate thanks
Steve
FollowupID:
6100
Follow Up By: Oziexplorer - Sunday, Jan 12, 2003 at 22:11
Sunday, Jan 12, 2003 at 22:11
Steve what brand of vehicle, model, year and engine type do you have?
If you can give the the numbers off your alternator I will be able to give you better information.
FollowupID:
6104
Follow Up By: Stevea - Monday, Jan 13, 2003 at 21:12
Monday, Jan 13, 2003 at 21:12
91 80 series turbo diesel I'll get the other info in the daylight tomorrow. Scared of the dark!!
FollowupID:
6173
Reply By: Member - Nigel - Monday, Jan 13, 2003 at 01:24
Monday, Jan 13, 2003 at 01:24
An independant charge isolator (like the Rotronics RFC12 or better) would cope with your situation better, but even so, if you've nearly flattened a battery then the alternator won't do much to bring it back. If your only using an alternator to recharge then try to avoid going below 11.5 volts (measured with load off).
A flattened battery needs a mains charger and many hours to bring it back to full charge.
An alternator will only charge a battery to about 80% in any case.
A good investment is a decent charger (eg 8 amps DC - 12 amps RMS) that at least has an auto cutout - but don't leave it on for days.
AnswerID:
11162
Reply By: Topcat - Monday, Jan 13, 2003 at 01:31
Monday, Jan 13, 2003 at 01:31
Hi Steve, I can't fully answer your question without having more info as OzExplorer has explained, however here are some useful web sites on batteries, charging cycles & isolators you might find of interest to give a better insight to your problem.
www.batterytender.com
www.uuhome.de/william.darden
www.surepower.com/ebrochures.html
I myself run a 40amp Rotronics charge unit to my deepcycle battery bank & a 600amp rotary isolating switch between start & aux batteries. It is a fail safe method of making sure the start battery is isolated when engine is not running. (i.e provided you don't forget to switch it over!!!)
Cheers.
AnswerID:
11163
Follow Up By: Stevea - Monday, Jan 13, 2003 at 21:13
Monday, Jan 13, 2003 at 21:13
thanks Topcat, a bit of reading to do.
FollowupID:
6175
Reply By: Raymond Charlton - Monday, Jan 13, 2003 at 19:54
Monday, Jan 13, 2003 at 19:54
Hi Stev
One of the problems is the type of battery you are using. From experience it takes 5-6 hours to totally recharge a deepcycle battery. The two solutions that I have come across are:
(1) I use a 32 watt solar panel (flexible type,easier to sore) to help keep the battery up.
(2) Seriously considering going over to a exide coil battery which only requires 2-3 hours of running. One problem they are only 55 amp hours and are about $350
So far the solar panel is working
well
Ray
AnswerID:
11213
Reply By: Raymond Charlton - Monday, Jan 13, 2003 at 19:54
Monday, Jan 13, 2003 at 19:54
Hi Stev
One of the problems is the type of battery you are using. From experience it takes 5-6 hours to totally recharge a deepcycle battery. The two solutions that I have come across are:
(1) I use a 32 watt solar panel (flexible type,easier to sore) to help keep the battery up.
(2) Seriously considering going over to a exide coil battery which only requires 2-3 hours of running. One problem they are only 55 amp hours and are about $350
So far the solar panel is working
well
Ray
AnswerID:
11214
Reply By: nissan4x4 - Monday, Jan 13, 2003 at 22:36
Monday, Jan 13, 2003 at 22:36
hi stevea,
I have the same one fitted to my GQ and I had the same problem,
mine got replaced under warranty.
I pulled apart the second one to look inside, I was quite alarmed at what I found. The unit is just a box with wires sticking out and some smart electronics inside. There were two issues I saw. Firstly from the outside, the main power cables, as they enter, do not have any sort of weather protection. You have a gap around the cables thru which dust/water can pass thru. Secondly, they use open relays in the electronics. Coupled with
the gap around the cables, dust/grime/moisture fowl the contacts. End result is your aux battery is not being charged.
Quick and simple fix, seal
the gap with silicon sealant.
If your unit is out of warranty, try this. Pull the unit apart. You will notice several relays, use a sensitive brush and clean the contacts with metho (don't use turps or anything that leaves a residue) and alow to dry.
This may not be the cause of your problem, but its a start.
Good luck.
AnswerID:
11240