Limit to battery starts on a C208B?

[SpeedyG]

We are having some internal discussions in our unit that I would like an external opinion on.. Namely is there any truth in the theory that the more battery starts the Caravan does in a day 'degrades' the battery anhd could lead to a Hot Start?

Or is it as simple as, watch you temps on the initial start and as long as your alternator is working fine you should be OK for another 'fresh' start after a 30min flights and a 30min cool down?

Appreciate the feedback:8

[welliewanger]

Hi SpeedyG,
Take a look at the battery university:
What causes car batteries to fail? (http://www.batteryuniversity.com/parttwo-42B.htm)
Testing deep cycle lead acid batterie (http://www.batteryuniversity.com/parttwo-42D.htm)
Do and don't battery table (http://www.batteryuniversity.com/partone-21.htm)

In short - yes, there is truth in the theory.

I bet you wish you didn't ask now!

[Bla Bla Bla]

Used to operate in an extremely hot climate and the Ground power unit starts were much better than off the battery.

[Brian Abraham]

Proper battery maintenance by some one who knows what he is doing and you will never have troubles, or extremely rarely. One cue we used on one particular type was when you initially hit the start button if the voltage didn't drop below 14 (28 volt system) you would have no trouble. Anything less, watch out. On one operation we were doing, flights only lasted 15 minutes (not good use for the cycle count and not a Caravan) and the last start of the day was always as good as the first. Again we had exceptional maintenance.

[PC-6]

Your 30 minutes flight time plus taxi time should be enough to recharge what you have used during the start. So, I personally dont see any problem with that. The Caravan was built with battery starts in mind.

Like Brian said, when you flick the start switch, have a look at what voltage you see indicated. A good battery will give you around 18 Volts initially (PT6 small series and 40Ah lead acid battery in warm climate), gradually increasing as Ng builds up.
If you get at least 16% Ng before introducing fuel, the electrical side is fine.

In the operation I am in at the moment, we only do battery starts and the company gives us a new battery every 18 months. They found it is cheaper than mess with ageing batteries.

[SpeedyG]

Thanks Guys - that new battery every 18months sounds like a winner.. you are right the cost is certainly worth the exchange:ok:

[Heliarctic]

Hello SpeedyG
My company operates more than a handful of Bell 212 helicopters which also run on PT6 engines (-3B twinpack)
And work up between 5 and 15 starts a day on batteries, and this in temperatures ranging from 20+ in the summer to -35 in the winter (it´s in the arctic) And they never give us any grief. We run on Ni.Cad "Marathon" batteries. It´s only good that they work and are exercised. And if you have a good Batt.overhaul facility which check the individual cells on overhauls you should be fine.
Regards