I used to think a starting battery was a great idea but my thinking has changed.
The biggest impetus has been the increasing economy of solar
, even if I completely run down the house bank, if I wait awhile solar
will bring it back enough to start the engine.
Secondly if I add a battery to the house bank I'm helping to extend the life of the house bank as long as I don't up my consumption
to compensate. If I still draw the same amount out daily on average then with a bigger bank 3 things happen:
1. Each battery experiences a slower draw rate and consequently provides more capacity, literally something for nothing.
2. With a bigger bank the daily depth
of discharge is less so you increase the number cycles the batteries will survive.
3. I'm less likely to run the batteries down too far to start the engine.
Additionally I am avoiding the secondary costs of charging
the starting battery. Doing so requires a second alternator
, a battery combiner, an echo charger
or a separate solar panel and regulator
If I were going to go with a starting battery I'd get a small 1-5w solar panel with a very low capacity regulator
. Starting an engine uses a bit less than 0.1a-hr. Even if it is hard starting it will only use 1a-hr. The small panel can recharge that in an hour or so. How many time per day do you start the motor
? The small panel method has the advantage of completely isolating the starting battery from the house bank, keeps the starting battery topped up even thru extended periods of disuse and is pretty cheap
If you are prone running the house bank down too far to start the engine then yeah starting battery is a good idea.
Otherwise add a battery to the house bank and reap a bunch of secondary benefits.
I only know the layout of the original Cat30 so I can't advise you on where to put an additional battery.
If you get a starting battery get a real starting battery. FLAs are the best bang for the buck. If you add to the house bank then match the existing batteries for maker and chemistry.
A house is but a boat so poorly built and so firmly run aground you would never try to refloat it