:wink
Yes, you do need a starter battery for the engine. And yes, using a deep cycle battery as a starter battery may have contributed to early failure.
This is simply not true for the situation being discussed here.
Deep cycle batteries are designed to do exactly what the name says. Starter batteries will give more amps (cold cranking amps) in a short burst, then be recharged by the running engine.
Trojan Battery disagrees with this premise, as does Lifeline, the maker of the battery in question.
I will mention this once again....
There is;
NO NEED FOR USING A STARTING BATTERY ON SMALL AUX SAILBOAT DIESELS.
Why?
**Flooded starting batteries are lower quality batteries, cheaply produced with lesser quality components. The exceptions would be AGM or GEL batteries.
**They are 1000% not necessary for this application
**Because they are starting batteries they do very, very poor service when called upon as a reserve or emergency battery where you may need to cycle them.
I would not advise anyone wasting money on a
starting type battery, or even a dual purpose battery, for a sailboat AUX engine. In nearly every installation I have come across deep cycle batteries, on small aux engines, outlast starting batteries consistently.
Any good quality deep cycle battery will start a small diesel without so much as breathing heavy. It will last longer and can be used as an emergency back up battery without damaging it.
But hey don't take my word for it....
"Trojan Battery:
Q: Can I use my deep-cycle battery as a starting battery?
A: Deep-cycle batteries can be used for engine starting but starting batteries should not be used for deep-cycle applications. A deep-cycle battery may have less cranking amps per pound than a starting battery, but in most cases a deep-cycle battery is still more than adequate for the purpose of starting an engine."
Why waste your hard earned money on a cheap starting battery when you can get ample
double duty out of a deep cycle product?
I have deep cycle batteries starting 300HP + engines and they do so with ease. Heck I used to start my 6 cylinder Cummins, in February, with a pair of golf cart batteries. Many of my commercial lobstermen have switched to deep cycle golf cart batteries and they are getting, on average, double the life compared to the 4D or 8D starting batteries they used to use.
You can always buy a dual purpose or starting battery but you are really buying a fairly low quality product.
Once again the Lifeline battery in question is designed as both a starting and deep cycle battery.