Thruster Battery

[dbsea]

Does anyone know the spec of the "from the factory" battery for the thrusters on a C-30 CB? The previous owner of my boat replaced ALL the batteries with 550CCA Universal Battery Group 31 Deep Cycle AGMs (not sure if this was purposeful or accidental). This was definitely NOT powerful enough to crank my engine, which I almost learned the hard way. I replaced the engine battery with a 900CCA Optima Group 31 dual purpose last week, and it made a huge difference. Based on my reading, Side-Power calls for 570CCA on each thruster, and my thruster battery is only 550CCA! I learned first-hand what happens here, I was trying to dock in a lot of wind, and ran my thruster battery down to the point where they wouldn't operate anymore, which was really unpleasant...

The net of this is that i'm wondering if I should take the extra Group 31 Universal Battery that I have now that I replaced the engine battery and daisy chain it to the existing thruster battery (adding 65lbs of weight to the boat), or just yank the existing thruster battery and replace it with the same 1150CCA Optima that i put in for the engine battery.

 

[Submariner]

I like your idea of going with a single 1150 CCA Optima engine starter battery for the thrusters.

I only have the bow thruster and I suspect it's smaller than what's on the C30. When my deep cycle 110ah factory battery dies, I plan on replacing it with an engine starter battery. I moved the T9.9 kicker over to my thruster battery, so between that and the thruster, an engine starter battery makes more sense.

 

[Chimo]

I changed all our 4 batteries last year and went with the Optima D31M 900 CCA for the engine (didn't see an 1150 CCA option) and 3 x Lifeline GPL-31T deep cycle for thruster and house. These Lifeline batteries have a CCA rating of 880 @ 20 deg. C (68 F) and 750 @ 0 deg. C (32 F). I have found the thruster battery stands up well. I did think about another Optima but decided against, I can switch the thruster battery in parallel with the house batteries when I'm on the hook, adding another 105 Ah to the bank, and I prefer to have all three batteries identical at that point. I may be wrong in my thinking and welcome comment.

 

[dbsea]

I changed all our 4 batteries last year and went with the Optima D31M 900 CCA for the engine (didn't see an 1150 CCA option) and 3 x Lifeline GPL-31T deep cycle for thruster and house. These Lifeline batteries have a CCA rating of 880 @ 20 deg. C (68 F) and 750 @ 0 deg. C (32 F). I have found the thruster battery stands up well. I did think about another Optima but decided against, I can switch the thruster battery in parallel with the house batteries when I'm on the hook, adding another 105 Ah to the bank, and I prefer to have all three batteries identical at that point. I may be wrong in my thinking and welcome comment.

Whoops, data entry error on my part. The optima is 900CCA, 1150MCA. Your reasoning for keeping things the same makes sense. My house is only paralleled to my engine for emergency start purposes, so I’m not as worried about them being the same.

 

[tranmkp]

Im about to replace the batteries on my 2015 27 classic - Im seriously thing about replacing the 2 houses with some Northstar 31's and combining the starter and thrusters on two Odyssey 31's. My reasoning is that the thrusters and starter need the extra beef the starter type battery provides. using two thrusters to spin the boat is a lot of loa and juice. Remember the save for the starter - the thrusters and being juiced by the alternator when being used

Make sense?

 

[knotflying]

Group 31 will give you more amps definitely. I joined my thruster battery on my group 27 batteries to the house with a switch in between so while on the hook I had more amperage. I never had an issue not having enough power when there was only one battery powering the thruster. The thrusters with enough wind and current can be ineffective at best. Don't take this wrong, but I think you are using them too long to have the issues you are having or perhaps the thruster battery has been compromised. I would do a load test to ensure the battery is healthy then I would connect the thruster to the house. You will have more amperage available when anchored and if you feel you need it you will have plenty of power to use your thrusters.

 

[GaylesFaerie]

I don't quite understand the need/desire to combine the Start and Thruster batteries. I assume you will make them both "starter" batteries designed to provide max CCAs to start an engine and not be used for longer time deep cycle applications (I would put thrusters into this category since they can draw alot of amps for much longer times than it takes to start an engine). Why would the engine need that much power to start? OTH, it seems the thrusters which draw lots of amps could deplete those start batteries if used under difficult docking circumstances. The battery configuration change that many Tuggers seem to go with is combining the 2 house and thruster batteriess into 1 deep cycle bank (as did the original owner of my 27). Isolate the engine battery so it will always be fresh, but if there are ever starting problems or emergency house needs, you can flip the parallel switch and draw off the large house bank. Knotflying is correct, about the futility of thrusters sometimes but that doesn't always stop one (i.e. me) from trying, so I really appreciate the 3 unit house bank. Gary

 

[dbsea]

I don't quite understand the need/desire to combine the Start and Thruster batteries. I assume you will make them both "starter" batteries designed to provide max CCAs to start an engine and not be used for longer time deep cycle applications (I would put thrusters into this category since they can draw alot of amps for much longer times than it takes to start an engine). Why would the engine need that much power to start? OTH, it seems the thrusters which draw lots of amps could deplete those start batteries if used under difficult docking circumstances. The battery configuration change that many Tuggers seem to go with is combining the 2 house and thruster batteriess into 1 deep cycle bank (as did the original owner of my 27). Isolate the engine battery so it will always be fresh, but if there are ever starting problems or emergency house needs, you can flip the parallel switch and draw off the large house bank. Knotflying is correct, about the futility of thrusters sometimes but that doesn't always stop one (i.e. me) from trying, so I really appreciate the 3 unit house bank. Gary

Hi Gary, not trying to combine the start and thruster. You're correct that I was trying to get more CCA out of the thrusters, since by their specs they require 570 CCA and the single battery I have is only 550CCA for two thrusters. Regarding my engine battery requirements, I have the volvo D6-435hp, and the guidelines are 900+CCA, it's a fairly large 5.5L 6cyl. I already have 4 110ah AGM Grp 31's for my house battery bank, so have quite a bit of juice there. My house bank is paralleled to my engine, but I can certainly see the value of having it to the thrusters so you have extra juice on the hook. I am definitely over-dependent on my thrusters still. The boat is 6 months new to me, and i'm coming from a twin engine express cruiser with out drives to a single diesel direct drive... still figuring out to how properly maneuver it. 🙂

 

[dbsea]

Group 31 will give you more amps definitely. I joined my thruster battery on my group 27 batteries to the house with a switch in between so while on the hook I had more amperage. I never had an issue not having enough power when there was only one battery powering the thruster. The thrusters with enough wind and current can be ineffective at best. Don't take this wrong, but I think you are using them too long to have the issues you are having or perhaps the thruster battery has been compromised. I would do a load test to ensure the battery is healthy then I would connect the thruster to the house. You will have more amperage available when anchored and if you feel you need it you will have plenty of power to use your thrusters.

you're 100% right on the overuse! Still learning after coming from a twin engine out-drive boat to a single diesel direct drive :lol:

 

[GaylesFaerie]

Gotcha. Looks like a possible underspecing by the previous owner. WRT "thruster overuse"... well... yea you definitely want to improve your single screw handling but... the way I see it... if you got em use em. Good luck. G

 

[tranmkp]

I just realized that I failed to mention the windless as a power sucker. So in my convoluted way the thought would be to combine the start, windless an thrusters on the same 2 group 31 starters.
On keeping the thrusters on too long - it’s always no more than 5seconds - seriously


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[knotflying]

I just realized that I failed to mention the windless as a power sucker. So in my convoluted way the thought would be to combine the start, windless an thrusters on the same 2 group 31 starters.
On keeping the thrusters on too long - it’s always no more than 5seconds - seriously


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I would be reluctant to join the engine battery to the thrusters. The ECU's are very sensitive to voltage drops etc. The engine battery, in my opinion, is sacrosanct. For added power It works both ways joining the thruster battery and the house. Even if one were to make the connection without the isolation switch, think about it. You will not be using your thrusters while at anchor or retrieving your anchor. You will most likely have your engine on while using thrusters or windless. Hence the Alternator will help with the draw on the batteries and bring them to full charge while underway. To join the thruster battery to the others you only have to make up one positive cable to the house since they are all connected by the negative already.
As far as overuse goes, practice often docking etc. without them and they are in working condition. The day will come when you go to use them and you will hear nothing.

 

[tranmkp]

Thank again for all the wisdom -!I’ll practice more - what a diff this boat feels from my Albin 27 - it’s big barn door rudder made a huge diff - the ranger needs a quick goose from the throttle for sure - it makes interesting entertainment for the other boats in the slips


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