
Originally Posted by
drivesafe
Hi wboner and I hope you don’t mind if I answer a few questions, yours and for others.
To your use first.
Unfortunately a single good charge, just before you leave a vehicle unused for a long period, will fully charge the battery but is not going to do give you the long term charge holding condition you need.
A single long charge or the occasional long drive will not condition a battery and in the case of the occasional long drive, it has nothing to do with the alternator not being able to charge batteries properly.
Continuos short drives means the battery will loose charging capacity, but just a couple of short drives will have the same effect because all lead acid batteries, once discharged below about 75%, all lead acid batteries need to first be fully charged and then need a long conditioning or “SOAK” charge, to allow the battery to regain some of their lost capacity.
Note, SOAK charging only regains a small percentage of the lost capacity each time you carry out a SOAK charge cycle, and leaving the battery on a charger all the time does not help to regain lost capacity, it will just keep the battery at what ever level of capacity it was at when you connected the charger.
Each time you do a short drive, you fail to fully RECHARGE the cranking battery, and this leads to a small percentage of the battery not being charged at all, and over a period of time, this percentage of unchangeable battery capacity just increases.
While my dual battery setups can either stop this from occurring in the first place, or reduce the effect in many cases, my systems still can not totally makeup for not driving either long enough to fully charge the battery or for not driving frequently enough.
So wboner, if you are planning to leave a vehicle in an unused situation for a long period of time, for a week or so be for leaving the vehicle unused, give all the batteries a good long charge every night, if convenient.
Then, if you are only going to do this once every blue moon, disconnect each battery’s negative terminal.
If you are likely to be doing this on a regular basis, fit a small switch into the thin earth wire coming from my SC80 or pre 2014 USI-160 isolators and this will stop unnecessary energy wastage.
NOTE, all USI-160 isolator supplied since December last year, now have the new Time-Out feature, where the isolator automatically shuts down 72 hours after the motor was last run.
Hi GD-4 and if the batteries have not discharged down to 12.0v, you can use the Anderson plug at the rear bumper to recharge all your batteries.
But as other have posted above, if your cranking battery is flat, you need to charge via BATTERY circuit in the 12S socket ( white ).
I’m not a fan of leaving battery chargers permanently connected to batteries for long periods of time and the is a better alternative, where practical. This is to use a solar panel ( and reg ) charge and maintain the batteries. The very nature of how solar panels work means they turn on every morning and turn off every night.
This is a much better charging algorithm for lead acid batteries and over a period of time, will also keep the battery’s condition at maximum state of charge.
Hi Andrew and leaving lead acid batteries in an unused state any time longer than one month should not be considered as these batteries self discharge, some fairly quickly, like wet cell batteries and some take much longer, AGMs.
As above, a good fix is to use a solar panel to maintain the batteries over such a long period of time.
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