New start batteries

[SeaDogAK]

It looks like I’m going to need to replace my start battery bank. These were replaced by the previous owner as part of a major electrical upgrade (new alternators, Balmar regulators and centerfielder and all new batteries) in 2016, which makes them 8 years old.

The engines have always started just fine, but lately I’ve started getting low voltage alerts on starting, and the windlass, which is also powered off the start bank (?) recently overheated and popped the breaker after drawing the voltage down to 11.4 while raising the anchor.

The existing start bank is two Lifeline GPL-8DL deep cycle batteries. I would just replace them with the same batteries but I have always understood deep cycle batteries are not best for start batteries, PO had a marine electrician do all the upgrades, so I would think there is a reason an “expert” picked these batteries.

Does anyone have suggestions about whether to just replace these with the same batteries or switch to something other than a deep cycle battery?

 

[tiltrider1]

You are correct, deep cycle is not appropriate for your situation. I am fine with the windlass being on the start bank. Start engines, bring up anchor, so no problem there, both want CCA not constant voltage low amp use.

My only recommendation would be to replace each 8d with either two group 27 or two group 31 depending on which fits your space best.

 

[SteveK]

I remember changing a lot of house deep cycle batteries, only remember changing current start from very old 8D,, and not with deep cycle. They each have their purpose even if they work for both uses.

 

[Bacchus]

Lifeline are certainly a well respected AGM. I would be inclined to replace them but with 8Ds rated for starting or a pair of GP31s replacing each 8D.

 

[guy with a boat]

The Lifeline deep cycle 8Ds served you well for 8 years; I would say that is pretty good evidence that they were the correct choice. Our start batts are all Lifeline deep cycles, and I did consider the options when I replaced them (also after 8 years).

Two 8Ds is a lot of battery to start a diesel engine, and I mean that in a good way. If the batt size were little 27s or 31s I think you might need the start type batteries to meet CCA requirements. With the big 8Ds, you should exceed all the specs including CCAs. Plus you have the right batteries for the windlass also.

IMO you have the right setup and should stick with it.

 

[Nick F]

11.4 volts when running the windlass does not seem low to me. (I assume that was without the main engines running - although it does seem strange to run the windlass this way)

Do make sure that you do not have a wiring problem.

 

[Iggy]

Yes, you can use deep cycle to start. As long as the CCA of the battery or batteries are greater than what is needed to start the engine.

 

[BruceK]

Yes, you can use deep cycle to start. As long as the CCA of the battery or batteries are greater than what is needed to start the engine.

If a "deep cycle" comes with a CCA rating it may be a "dual purpose" battery intended to be use for house and start purposes. If it`s purely intended as storage for house use, it`s more likely to be pure "deep cycle" .
I can buy AGMs here both with, and without, a CCA rating.

 

[luna]

I would think that the choice of battery chemistry should be made once you understand what your charging systems (alternators, chargers, and/or solar) can do.
It is likely simpler to select the chemistry of your start/windlass bank to be the same as your house bank, provided all of the charging systems treat (or can be reprogrammed to treat) your house bank correctly.
My start and my windlass banks are constructed from start batteries, not deep cycle.
All banks are wet lead acid currently.

 

[SeaDogAK]

11.4 volts when running the windlass does not seem low to me. (I assume that was without the main engines running - although it does seem strange to run the windlass this way)

Do make sure that you do not have a wiring problem.

This was with the engines running. But my system charges the start bank from the house bank, so it wouldn’t be putting all of the alternator output into the start bank, only whatever the output of that charger is.

I can say that the windlass was noticeable slowing and overheating from the low voltage, and eventually the breaker tripped — and failed.

 

[SeaDogAK]

If a "deep cycle" comes with a CCA rating it may be a "dual purpose" battery intended to be use for house and start purposes. If it`s purely intended as storage for house use, it`s more likely to be pure "deep cycle" .
I can buy AGMs here both with, and without, a CCA rating.

Those Lifeline “deep cycle” batteries are rated at 1350 CCA (times two batteries). That’s more than twice some Group 31 starting batteries.

 

[fgarriso]

We replaced our starting battery bank with two 8D AGM in parallel.
One 8D AGM directly below the windlass.
Ten 8D AGM on the house bank. We didn't worry about the weight of the 8Ds as we run with lead ballast in the bottom of the hull.

 

[tiltrider1]

Those Lifeline “deep cycle” batteries are rated at 1350 CCA (times two batteries). That’s more than twice some Group 31 starting batteries.

A good quality group 31 should put out 1000 CCA. So, 4 group 31 batteries in place of 2 8d batteries would give you 48% more CCA.

 

[ranger58sb]

It looks like I’m going to need to replace my start battery bank. These were replaced by the previous owner as part of a major electrical upgrade (new alternators, Balmar regulators and centerfielder and all new batteries) in 2016, which makes them 8 years old.

The engines have always started just fine, but lately I’ve started getting low voltage alerts on starting, and the windlass, which is also powered off the start bank (?) recently overheated and popped the breaker after drawing the voltage down to 11.4 while raising the anchor.

The existing start bank is two Lifeline GPL-8DL deep cycle batteries. I would just replace them with the same batteries but I have always understood deep cycle batteries are not best for start batteries, PO had a marine electrician do all the upgrades, so I would think there is a reason an “expert” picked these batteries.

Does anyone have suggestions about whether to just replace these with the same batteries or switch to something other than a deep cycle battery?

You got 8 years from your batteries, seems like a good idea to replace in kind.

Those 8DLs are rated at 1350 CCA each, so you have 2700 CCA @ 12VDC... probably enough to start a rocket. Way more than you need for most single diesels like what you probably have. Perhaps the design was specifically to support the windlass for anticipated (?) longer run times.

Otherwise a pair of G31s could be decent enough, and might let you put more battery money into the house bank. In that case and were it me, I might consider a pair of Odyssey Extreme G31s for starting; even higher cranking amps, and we've gotten good service from those in the past.

Our current combined starting/house and thruster batteries are pairs of Lifeline 8DLs @ 24VDC, in our case specifically selected because our main banks are dual purpose, our engines actually do need 1350 CCA, our thruster bank needs to supply high current, and the physical layout doesn't lend itself easily to other options.

I wonder if your windlass overheat really had anything to do with your battery voltage. Reading suggests long run times can reach an overheat status, without regard to available battery voltage. (I don't know any of that first hand.). Low voltage alerts on starting do suggest it's time to replace your batteries anyway, though.

-Chris

 

[Iggy]

I have used Odyssey Extreme for years and had very good luck with them. My 4D starting battery died and went with 2 G24 Odyssey batteries. About 200 CCA more than the one 4D. The wight to lift the 4D out was a factor in this.

At the same time I replaced the battery for my NL 5.5 genset. I can't remember the size. But it was a little smaller that the G24s. Works just fine.

For some this maybe common seance. Just remember in connecting more than one battery as a bank. Is to balance them so they all see the same load.

 

[dhays]

I agree that what you have had seems to have worked well for a number of years. I would not replace with 8Ds but maybe two sets of two Group 31s.

I have an old 8D lifeline in the ER to start my 5.9L QSB. Hugely overkill. When I finally need to replace it, (unless I go LiPo or something) I'll replace with a single Group 31.

 

[guy with a boat]

Just for shop talk purposes, I’ll bring up that the choice of start batts is affected by the intended use of the boat. If you use it near civilization and on relatively short trips, just meet the CCA spec and you are probably fine.
As a counterpoint, imagine you are in year 4 of your start batts and you have engine trouble in the middle of nowhere or possible in the middle of an ocean crossing. You work through the problem and have to crank and restart multiple times while you deal with contaminated fuel or whatever. In that instance you might want lots of reserve capacity.
That’s why Nordhavn (among other) puts in two 8Ds to start a single diesel engine. Certainly not necessary for all boats, so do what suits your situation.

 

[tiltrider1]

I have two 8D’s in Parallel to start my two CAT motors. I do not find this overkill for various reasons. I cruise in remote locations on occasion. If a cell shorts I can isolate the bad battery.

I don’t see any reason why two 8D would have an advantage over 4 Group 31’s.

 

[Nick F]

This was with the engines running. But my system charges the start bank from the house bank, so it wouldn’t be putting all of the alternator output into the start bank, only whatever the output of that charger is.

I can say that the windlass was noticeable slowing and overheating from the low voltage, and eventually the breaker tripped — and failed.

Once again, I don't think that this (11.4V) is low voltage. Perhaps your windlass motor is developing a problem (brushes? bearings? - could show the observed symptoms).

Personally, I would not supply the windlass from the start battery. I would run it from the house battery - especially since you say that the major charge from engines is going to the house.

 

[SteveK]

@Nick F
When you haul anchor, are your engines running. I would like to understand your logic why you would not connect windlass to run from start batteries which are being charged and are designed for high CCA for start and similar windlass.