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Electrical: Engine Starting, Charging
[BatteryTips from Tim Curry:] I talked to Exide here in Tucson a while ago and
found out a bunch about batteries. Basically, here in the heat, they last an average
of 28 months. If you buy a lifetime battery for $100 and it lasts 3 years (heat is
bad for batteries) you spent $33.00 per year. Pro-rated? Oh yes, that saves you
(you pay some every three years). If you need cold cranking amps, the plates are
thinner and there are more of them to make more juice in a limited container. They
also heat faster under a load. Heat them once without enough electrolyte (low on
water) and you get the dreaded China Syndrome, cooked plates. They distort, shed
some of the lead and it settles to the bottom of the container of the low cells. Get
enough and the plates ground out internally to each other if the level reaches the
bottom of the plates. Hot weather batteries? They use smaller plates and more
electrolyte (it acts as a coolant inside) to cover them so a low water condition isn't
as bad. Trade off is cold cranking amps (who needs it at 115 degrees, the car is
always warmed up). Best buy? A commercial battery (truck fleet types) that you
keep charged and full of electrolyte. 5 or 6 years at $65. How long do most people
keep their cars? $33 / year or $10 / year? Next bet is a 4 or 5 year wonder from
Wally's World for $29.95. It will last for as many years as stated and you will buy
another, so its cheap. Oh yes, the battery, alternator and starter are a SYSTEM!
Don't buy an 18 wheeler battery to start your VW or the alternator may be
unhappy. Don't buy a motorcycle battery to start your Volvo, the starter pulls too
many amps, the alternator will cook it from charging too fast and the starter will
poop out from not enough current to get the job done because of heat $$$$$. Now
you need one of each.
Battery Explosion; Wiring Chafing. Received panic call from wife that '88 740
Volvo just went completely dead on road and smoke was pouring out from under
hood. When I arrived, all electrolyte boiled out of battery and battery cable
insulation melted. Turns out was a direct short where cables pass under engine.
Volvo neatly bundles both cables in a plastic sheath. Unfortunately too tight against
bottom of engine and cut through, often at the clamp securing them. This is all too
frequent in pre-1990 cars. A new battery and cables cured the problem. Volvo later
issued a recall for battery cable chafing.
[Technical Note from UK Volvo Club, 700 Section] On 700's the front suspension
crossmember has the heavy battery-to-starter cable running over its nearside front
edge. These were the subject of a recall some years ago as they chafed, leading to
a big electrical short (and under-bonnet fires in some cases). Apparently, most cars
were caught, but the odd unmodified one must still be about. The recall
modification involved fitting a sheathed clip, which lifted the lead away from the
cross-member. It's screwed to the nearside front cross-member inside the fixing
point of the lower suspension arm.
Volvo Maintenance FAQ for 7xx/9xx/90 Cars
file:///C|/Users/Steve/Documents/Volvo%20FAQ%20Updated/ElectricalStarting.html[01/13/14 10:02:47 PM]
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