Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 04-08-2019, 21:04   #1
Registered User

Join Date: Jun 2016
Posts: 387
Starter battery to go with firefly house bank?

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?
__________________

sailingunity is offline   Reply With Quote
Old 05-08-2019, 00:51   #2
Registered User

Join Date: Jun 2013
Location: canada
Posts: 2,556
Re: Starter battery to go with firefly house bank?

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.
__________________

smac999 is online now   Reply With Quote
Old 05-08-2019, 02:11   #3
Moderator
 
Pete7's Avatar

Cruisers Forum Supporter

Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 11,770
Images: 14
Re: Starter battery to go with firefly house bank?

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
Pete7 is offline   Reply With Quote
Old 05-08-2019, 02:38   #4
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,599
Re: Starter battery to go with firefly house bank?

I recommend the Odyssey 2150 group 31 battery. It is the same dimensions and designed for high power applications like starting, windlass etc.
s/v Jedi is offline   Reply With Quote
Old 05-08-2019, 09:34   #5
Registered User

Join Date: Jan 2017
Posts: 11,654
Re: Starter battery to go with firefly house bank?

Yes PC-2150 are true dual-use, will withstand deep cycling well, but also fine with short bursts at high discharge rates.
john61ct is online now   Reply With Quote
Old 05-08-2019, 09:46   #6
Registered User

Join Date: Jun 2016
Posts: 387
Re: Starter battery to go with firefly house bank?

Quote:
Originally Posted by Pete7 View Post
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?
sailingunity is offline   Reply With Quote
Old 05-08-2019, 11:34   #7
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,599
Re: Starter battery to go with firefly house bank?

Quote:
Originally Posted by sailingunity View Post
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
s/v Jedi is offline   Reply With Quote
Old 05-08-2019, 19:52   #8
Registered User

Join Date: Sep 2013
Location: Alert Bay, Vancouver Island
Boat: 35ft classic ketch/yawl.
Posts: 1,550
Images: 4
Send a message via Skype™ to roland stockham
Re: Starter battery to go with firefly house bank?

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.
roland stockham is online now   Reply With Quote
Old 06-08-2019, 05:00   #9
Registered User
 
ranger42c's Avatar

Join Date: Aug 2012
Location: Maryland, USA
Boat: 42' Sportfish
Posts: 3,931
Re: Starter battery to go with firefly house bank?

Quote:
Originally Posted by sailingunity View Post
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
__________________
Selby Bay, South River, Chesapeake Bay, USA.
ranger42c is offline   Reply With Quote
Old 06-08-2019, 05:47   #10
Registered User

Join Date: May 2013
Location: St. John, USVI
Boat: 2003 Beneteau 423
Posts: 260
Re: Starter battery to go with firefly house bank?

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

Cheers, RickG
__________________
RickG & Sweet Christine
S/V Echoes - 2003 Beneteau 423
St. John, USVI - hauling out Fajardo, Puerto Rico for hurricane season July 1
RickG is offline   Reply With Quote
Old 06-08-2019, 05:54   #11
Registered User
 
zboss's Avatar

Join Date: Sep 2011
Location: On a boat
Boat: 1987 Cabo Rico 38 #117
Posts: 3,918
Re: Starter battery to go with firefly house bank?

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.
zboss is offline   Reply With Quote
Old 06-08-2019, 11:26   #12
Registered User

Join Date: Jan 2017
Posts: 11,654
Re: Starter battery to go with firefly house bank?

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.
john61ct is online now   Reply With Quote
Old 06-08-2019, 11:53   #13
Registered User

Join Date: Nov 2015
Boat: R&C Leopard 40
Posts: 422
Re: Starter battery to go with firefly house bank?

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.
__________________
-Chris
FlyingScot is online now   Reply With Quote
Old 06-08-2019, 12:17   #14
Registered User

Join Date: May 2013
Location: St. John, USVI
Boat: 2003 Beneteau 423
Posts: 260
Re: Starter battery to go with firefly house bank?

Quote:
Originally Posted by john61ct View Post
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
__________________
RickG & Sweet Christine
S/V Echoes - 2003 Beneteau 423
St. John, USVI - hauling out Fajardo, Puerto Rico for hurricane season July 1
RickG is offline   Reply With Quote
Old 06-08-2019, 13:23   #15
Registered User

Join Date: Jan 2017
Posts: 11,654
Re: Starter battery to go with firefly house bank?

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.
__________________

john61ct is online now   Reply With Quote
Reply

Tags
battery

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
House Bank or Genset-Engine Bank? BlueSovereign Electrical: Batteries, Generators & Solar 12 02-04-2019 08:45
could inverter be only using starter battery and not my house bank? EvilRabbit Electrical: Batteries, Generators & Solar 8 03-01-2017 13:56
How would you wire a starter battery-house bank connection earthbm Electrical: Batteries, Generators & Solar 21 26-08-2013 23:29
Charging a Dedicated Starter Battery and House Bank Ericsn25Chespk Electrical: Batteries, Generators & Solar 8 02-09-2010 07:44
36vdc Motor Bank and 12vdc House Bank bobola Electrical: Batteries, Generators & Solar 24 22-12-2009 20:30



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 22:01.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.