Unless I missed something, he STILL doesn't say whether a car starter battery or a leisure battery is best. Its as though he lumps them all together as thin plate lead/acid batteries.
To put it simply, the only difference between a starter battery and a leisure battery is the
thickness of the plates. A starter battery requires very thin plates to provide sufficient
surface area to give a high cold cranking current for a short period. A leisure battery has
much thicker plates which reduces the maximum instantaneous current available but allows
the battery to discharge to a much lower level without damaging the plates due to buckling.
A starter battery should not be discharged below about 65% to 7o% of it's total capacity
otherwise it's life will decrease due to stresses on the plates which cause buckling and
eventual short circuit. A leisure battery can be discharged to about 35% of it's capacity
without much damage to the plates.
As an example, a 100 Amp hour starter battery can deliver approximately 35 A/hours and
remain within it's expected service life. A 100 A/hour leisure battery can deliver about
65 A/hrs without charging and still remain within it's expected service life.
So the choice is, buy a reputable split charge system with a leisure type battery, or use
2 starter batteries simply connected in parallel with high current cable. For the split
charge system you have about 65 A/hrs usage before charging, whereas with 2 starter
batteries in parallel you would have ( 2 x 35 ) 70 A/hours use before recharging and the
Bongo would still start more reliably than a single starter battery. The problem is that it
requires some common sense to ensure that you don't blindly use all the power available
for leisure use. The advantage is when you use the Bongo for domestic use the Bongo
will always start virtually instantaneously in the most severe conditions. I have done
this for years without any problems, but then I always use a mains hookup when camping.
If you have a Bongo with the factory fitted winter pack, then you could use it as it is but
I would advise you buy a cheap battery charger and pay for EHU until you get used to it.
The trouble with using a split charge system is that if you completely discharge the leisure
battery and the VSR cuts in when the engine is running, the alternator could deliver up to
80 Amps to the leisure battery if the starter battery was fully charged. You must fit adequately
rated VSR relays and fuses to cope with these extreme conditions. If you regularly go wild
camping without EHU you may be safer to use a split charge system to avoid discharging
both starter batteries to the extent that you cannot start the Bongo.
Apologies for the long ramble and probably useless information, but at my age I don't sleep
much and have little else to do.
) but are you saying that (most/all?) split chargers simply isolate the leisure battery, and, when charging, give the full alternator output to the LB?