Starter battery to go with firefly house bank?

[sailingunity]

I'm switching my house bank over from FLA to firefly. My starter/windlass battery (also shot and needs replacing) is an 8D FLA and is currently connected to the house bank via an ACR. I see no need to switch the starter battery to firefly, since it will be fully charged most of the time, but considering the slightly different charge profile would it be prudent to replace that with an AGM battery?

[smac999]

The fireflys don’t have high Caa compared to other group 31s. And way less then An 8d.

You can but 8d agms.

Or northstar makes an 8d kit out of smaller batts. So easier to carry. North Star are good cranking agms.

[Pete7]

Why do you need a 8D battery to start an engine? or are lots of other things running off this battery too?

A smaller AGM battery that matched the FF charging profile would be good as it will better supply the power for the windlass in conjunction with the engine which is presumably running when you lift the anchor.

Pete

[s/v Jedi]

I recommend the Odyssey 2150 group 31 battery. It is the same dimensions and designed for high power applications like starting, windlass etc.

[john61ct]

Yes PC-2150 are true dual-use, will withstand deep cycling well, but also fine with short bursts at high discharge rates.

[sailingunity]

Originally Posted by Pete7

Why do you need a 8D battery to start an engine? or are lots of other things running off this battery too?

A smaller AGM battery that matched the FF charging profile would be good as it will better supply the power for the windlass in conjunction with the engine which is presumably running when you lift the anchor.

Pete

Just the windlass and the starter. I think you're right, its probably bigger than we really need. If the house bank were ever to need servicing, I suppose a bigger battery would be better, but would be rare?

[s/v Jedi]

Originally Posted by sailingunity

Just the windlass and the starter. I think you're right, its probably bigger than we really need. If the house bank were ever to need servicing, I suppose a bigger battery would be better, but would be rare?

The Odyssey PC2150 will do great in that role Nice to have same physical size as the Fireflies as well

[roland stockham]

Generally the issue with a windlass is the length of run if it is rigged to the start batt. A simplr alternative is a small start type batt at the windlass with a charger or VCR so you have a very short high power run.

[ranger58sb]

Originally Posted by sailingunity

I'm switching my house bank over from FLA to firefly. My starter/windlass battery (also shot and needs replacing) is an 8D FLA and is currently connected to the house bank via an ACR. I see no need to switch the starter battery to firefly, since it will be fully charged most of the time, but considering the slightly different charge profile would it be prudent to replace that with an AGM battery?

A pair of Odyssey PC-2150 (Group 31) batteries is common in after-market thruster installations. Probably a single would be sufficient for starting/windlass.

These aren't inexpensive, but they offer more cranking amps than many other AGMs, and our two dual-purpose banks of 3x have given great longevity (12 seasons one bank, 11 and counting on the other).

-Chris

[RickG]

We decided to use a Firefly G31 as our start battery. Works fine, no issues after two years.

Cheers, RickG

[zboss]

We have a firefly house bank and a regular East Penn AGM battery for our starter that is connected with a Victron Energy Cyrix battery combiner. It works great since the voltages are the same.

[john61ct]

Yes all that really matters is Starter and House have spec'd voltage ranges that overlap, so no B2B charger / DC-DC converter is required, a less expensive voltage-following combiner works fine.

Using Firefly as a dedicated Starter is fine too but IMO a waste of money.

[FlyingScot]

Buy a cheap reliable starter battery and don't worry about the charge profile for the starter battery. Focus all the attention on the FF Oasis house bank. We keep on spare starter battery on board, but it is backup for two engines.

Starter batteries are available virtually everywhere for a decent price, or at least this is my understanding.

[RickG]

Originally Posted by john61ct

Yes all that really matters is Starter and House have spec'd voltage ranges that overlap, so no B2B charger / DC-DC converter is required, a less expensive voltage-following combiner works fine.

Using Firefly as a dedicated Starter is fine too but IMO a waste of money.

We liveaboard and combine our start battery with our house bank at anchor. That way we don't drag around a battery that is a different chemistry, heavy, and only occasionally used. It's unusual for our 800ah house bank to get below 12.5V with solar charging. If the bank voltage ever goes below 12.5V is isolate the house bank until the sun is out or I decide to run the generator.

Cheers, RickG

[john61ct]

Yes that sort of setup can be very efficient, eliminate carrying lots of "dead lead" inherent in dedicating Starters to nothing but cranking.

http://www.cruisersforum.com/forums/....php?p=2753564

For belt & suspenders, could have one of those small "personal power" jumper packs kept charged up for emergencies as well.