Tip #25? EXAMINATION OF SELECTIVE BATTERY CHARGING SYSTEMS IN TOW VEHICLES.

Submitted: Tuesday, Mar 15, 2005 at 21:39
ThreadID: 121845 Views:2453 Replies:1 FollowUps:1
This Thread has been Archived
There are Dual Battery Systems and battery isolators on almost all tow vehicles these days, that venture out into the Outback. In the “Good Ole Days” the two batteries had a Ford type starter Solenoid, for an isolator switch. Ignition on, batteries connected together on the positive side through the Solenoid, ignition off and the second battery was disconnected. This was an extremely robust system, with little failure rate. Cost for D.I.Y. was about $30 in bits…. And a kit was about $125 with the spare battery tray and such…. Simple, that is “in those days” in the 70’s and 80’s…

Now, the original purpose was to isolate a spare battery, in case you left the lights on or something, so you were never caught in the Outback with a dead horse. This quickly progressed in the 1980’s with the invention of popular compressor drive fridges, to include another use for the second battery, that of running a fridge or whatever, without deadening the starting battery. Soooo, when the ignition was off, the two batteries were isolated, and one of them could always start the vehicle in a pinch if you made a Blue… Ok so far?…. So then, this trend naturally progressed to having a “Deep Cycle” battery as the second battery, to enable you to run it down further with refrigeration and such, without damaging it… Then came the complications of more electronic gizmos we were convinced that we could not live without…..

With a Public hungry for more toys, and technology, that would buy anything that made sense in toys for their 4x4, some enterprising individuals invented the need for “selective charging” because in Theory the charging rates of a “Deep Cycle” battery were different to the charging rates in time and capacity for the “Engine Starting Battery”…. The Deep Cycle one had heavier plates and took a much slower and deeper discharge, than the Engine Starting Battery with thinner plates that made for a rapid and shallow discharge and quick recharge when the engine started… And a standard Alternator and Regulator on the tow vehicle would just read them as one unit at an average, and charge them up together… This meant that one battery was still being charged when it was full, because the Regulator on the Alternator was averaging the two and sensing that the average was drug down by the other battery that was lower… Hence the full battery was still being charged and forced to dissipate that energy in heat, and this overcharging of the fuller of the two, to bring up the lower of the two, would result in a shortened battery life… In practice this shortened battery life proved to be something around 10%…

Is this general principle correct? Yes…. Ahhhhh, but yes, there is a problem! The problem is that the invention is an electronic selective charging system that senses the lower of the two batteries and directs the charge to it to bring it up first, and then equalizes the two of them together…. Great! The problem is that the toy costs $400 and up, and in the heat of the engine compartment and dust and vibration of the Outback travel, they do not seem to last more than a few years, and this makes it so that it never really pays for itself in extended battery life. It also adds another electronic gizmo in the charging system to go wrong and affect other things…. More to go wrong, that costs too much, and not necessarily cost effective in that it does not last long enough to pay for itself….??? Good idea??

So what is the final analysis from the “Lone Ranger”? Well, there are those that will argue, particularly the techno people and the those selling the electronics….. But, I say K.I.S.S. (Keep It Simple Stupid)…KISS Engineering is the best for the Outback…. These days we tend to electronically overcomplicate everything. In the remote parts of the Outback, we are reduced to basics and fixing things ourselves. I can fix the original solenoid system in the dark, rain, mud, with near nothing at hand, in a pinch. All of this trend to electronic black boxes to run our injectors and diesel injection pumps and accelerators, and charging system, and the rest? They are great as long as they work, but are disposable in the Bush, when they do not work… For myself, I would rather keep things simple as long as much as possible. Then the Bush Mechanic on the Station, can always give you a hand, and with a piece off a wreck, or tractor, or out of the junk pile, and a little healthy Bush Engineering, you can fix it yourself. And, the sad truth is that most of that older simple style of engineering has a very low failure rate… KISS Engineering…. And it is predictable…

The trend is to put these non-repairable electronics into everything so we are hooked on the Dealers and can keep coming back for more… The Trend seems to be to get the Dealers to make more money on the maintenance of these electronics… Which cannot be fixed by anyone else… Fine in the city, but not so fine when way out of back of Beyond in the Bush… Now, am I am probably just being “Cynical” and “Old Fashioned”, a Dinosaur, not up with the modern times……. Let me think about it for a minute……

Naaaaaawwwwww! I am right! Better to keep it simple, robust, and fixable in the Bush. The old fashioned engineering gave you plenty of warning before it failed, and when it did, it was fixable with just a little elbow grease… I will stay there as much as possible..

Happy Trails from the “Lone Ranger”………..
Back Expand Un-Read 0 Moderator

Reply By: Grumblebum & Dragon - Wednesday, Mar 16, 2005 at 07:57

Wednesday, Mar 16, 2005 at 07:57
You are pretty spot-on Steve. I can remember in the 1960/70's in Africe with a Series 11 petrol Landrover in the bush. A reasonable set of tools and a few basic spares and you were just about unstoppable.

These day's there is not much in the engine compartment I even recognise, never mind know how to fix. Dread the day the little orange engine warning light comes on.... "Hello Huston - we have a problem" ..... 'Oh F#ck It'

The only compensation is that of lot of todays vehicles are pretty reliable - until 'Muphy' steps in...... usually in the worst possible situation.

Regards

John and Jean.
AnswerID: 566018

Follow Up By: Bushtracker - Wednesday, Mar 16, 2005 at 22:06

Wednesday, Mar 16, 2005 at 22:06
My Mack Dualcab 4x4 horse truck has two black boxes running it. One the VECU (Vehicle Electronic Control Unit) runs all the computerized digital readout and such on the Dash... The other the EECU (Engine) runs the engine itself....

Now, I wanted new, not because it was new, but because it was nice and had no Peer. The older ones just did not have the horsepower or creature comforts.. The second best was the Isuzu, and it just did not compare... Sooooo, the Mack, with all of its Euro niceties of a luxury car, power heated mirrors, cruise control, blah blah blah, was the only choice..... In my new Landcruiser, I could still buy an older one from 2000 that had all the same feature but with no computers on board... But with the Mack there was no choice... So, what did I do????

Being defensive, or self reliant, or self sufficient, or protective...
(Paranoid) Ha! What I did was order a spare VECU and a spare EECU with the truck. Complete plug in units ready to go for about $3700.... Now I figure that is money in the bank, if I don't use them someone will always want them and "they ain't gettin any cheaper"... So, before you write me off as crazy (I am) think about being stranded 150km off the bitumen in a dark stormy night with five horses on board and my family in the truck.... I will cuddle my spare EECU and VECU, thank you...

Cheers...
0
FollowupID: 844413

Our Sponsors