Replacing the starting battery

Alpina

Well-known member
Joined
Sep 11, 2020
Messages
188
Fluid Motion Model
C-30 CB
Vessel Name
Alpina
Not having issues but was looking for a little extra battery capacity. Was thinking of adding the starting battery to the house bank and buying a true starting battery. My understanding is that the starting battery that comes from the factory is not a true starting battery. I would test the battery with a load meter to ensure it is equal to the others. Anything else that I should be thinking about?

Franco


Sent from my iPhone using Tapatalk
 
Deep cycles are excellent starting batteries, just heavier and more expensive. I recommend all be the same.
 
First, check the engine manual. The engine manufacturers specify the minimum CCA or MCA (these are amps) that the engine needs from its starting battery.

Second, all the batteries need to be the same type: flooded, AGM, etc. Do not mix battery types because the chargers do not like it.
 
Here is a previous thread about replacing the engine battery on your model boat:
viewtopic.php?f=6&t=16513&p=110173&hilit=Battery+yellow+top#p110173

I found that the standard AGM Universals were marginal at best for starting the engine on our R-31. As recommended by Kevin Lamont in this thread, I replaced the standard AGM with an Optima Yellow Top. The corresponding Optima Blue Top is equivalent in properties and may be more convenient because of extra terminals for connections.

The charging recommendations for the Optima are within 0.1 amp of the AGM profile so it is happy alongside the OEM AGMs. Most importantly, after replacing the engine battery with the Optima about 2-1/2 years ago, I have had no more problems with cranking the engine.

John
 
Thanks all.


Sent from my iPhone using Tapatalk
 
Alpina":2t5zef2g said:
Not having issues but was looking for a little extra battery capacity. Was thinking of adding the starting battery to the house bank and buying a true starting battery. My understanding is that the starting battery that comes from the factory is not a true starting battery. I would test the battery with a load meter to ensure it is equal to the others. Anything else that I should be thinking about?

If you were to use your starter battery in a deep cycle application, I've heard Jeff Cote at Pacific Yacht Systems repeatedly talk about them exploding (not immediately, but eventually). He says it's the kind of explosion that may have your significant other wanting to trade in the boat for an RV.

The thruster battery, being a deep cycle battery, same as the house, is a better candidate to join to the house battery bank for additional capacity. The engine battery, as a starter battery, should remain isolated in its own bank.
 
Submariner":3fn8qoba said:
Alpina":3fn8qoba said:
If you were to use your starter battery in a deep cycle application, I've heard Jeff Cote at Pacific Yacht Systems repeatedly talk about them exploding (not immediately, but eventually).

My understanding is that FM doesn’t use a true starting battery which is why I was thinking of the change. I will pull out the battery sled and take a look. If it’s a starting battery I won’t make the change.

My last boat used deep cycle for starting and when I replaced with a true starting battery I noticed the difference immediately. My understanding is that starting batteries are design for short high amperage draws while deep cycle are not.


Sent from my iPhone using Tapatalk
 
Alpina":2oysxdt9 said:
Submariner":2oysxdt9 said:
Alpina":2oysxdt9 said:
If you were to use your starter battery in a deep cycle application, I've heard Jeff Cote at Pacific Yacht Systems repeatedly talk about them exploding (not immediately, but eventually).

My understanding is that FM doesn’t use a true starting battery which is why I was thinking of the change. I will pull out the battery sled and take a look. If it’s a starting battery I won’t make the change.

My last boat used deep cycle for starting and when I replaced with a true starting battery I noticed the difference immediately. My understanding is that starting batteries are design for short high amperage draws while deep cycle are not.

We have the R27-OB. The F300 outboard requires a minimum of 680 CCA per Yamaha. The diesel inboards have much higher requirements. The Universal Power AGM batteries that our boat came with were 110Ah deep cycle and have 535 CCA.

The engine/starter battery that our boat came with is an AGM starter battery. It's different than the others. It's a Centennial Battery Systems G31 starter battery with 950 CCA.

The two house batteries and thruster battery were all the same AGM deep cycle from the factory, 110Ah.
 
What happens if you parallel a starter battery with a deep cycle house bank?


Sent from my iPhone using Tapatalk
 
CruisingElvinRay":ieyx0t0m said:
What happens if you parallel a starter battery with a deep cycle house bank?

That joins the engine and house bank into one bank. It's 'ok' to do this when your engine battery is dead and won't start the engine (obviously). It's also 'ok' to do this when the engine is running as it's putting in between 20 and 45 amps. What you don't want to do is parallel the house and engine battery, turn off the engine and use that starter/engine battery for deep cycle loads.

The big difference is the starter battery is meant to give off a lot of amps in a short period of time and then be recharged immediately by the engine. A deep cycle battery is meant to give off a few amps over a longer period of time and remain in a partial state of discharge for longer periods of time.
 
I understand the difference between the batteries. I was wondering which gets damaged in that scenario.


Sent from my iPhone using Tapatalk
 
The first thing to do is look at the specs on the battery installed. Does it meet or exceed minimum Volvo Penta requirements ? (750CCA ,75AH @ 41F or 800 CCA, 75AH @ 23F) CCA is calculated at 0 degrees. When reading the cranking capacity on marine batteries it may be rated MCA (Marine Cranking Amps) This is a higher number because it is calculated at 32 degrees. If your cranking battery specs is less than 950MCA, 75AH it does not meet specification. The next rating is what type of battery is installed? Cranking battery ,Dual Purpose, Deep cycle. The DP is the most common used battery by manufacturers because they do not have to stock as many different batteries. A R29 Could have all the batteries the same as long as they meet the engine specification.


If your batteries are all in good condition and meet the recommended requirement there is no need to replace the engine battery with a higher capacity. If your goal is to add a extra battery to the house bank and the engine battery is a DP with the same rating and as the same date code as the batteries now in use. That would be a good solution.

Installing a larger capacity CCA cranking battery for the engine would be a good idea.

If the now installed engine cranking battery meets the Volvo Penta requirements and you want to add another battery to your house bank for more battery capacity while on the hook. A solution may be to just add a parallel switch between the Thruster battery and the house bank. When your at anchor you do not need the thruster battery it is just sitting there taking up space and doing nothing. Use it for additional house bank capacity. This is a good way to add capacity and add no extra weight to the boat.

CruisingElvinRay":2w8qtf47 said:
I understand the difference between the batteries. I was wondering which gets damaged in that scenario.


Sent from my iPhone using Tapatalk

If it is a DP nothing gets damaged DP Dual purpose can be used for cranking and deepcyle. The dual purpose is not as good as a true cranking battery but it is designed to be used in that application. A DP is not as good as a Deep cycle for a house bank but it is also designed to be used for that application. A deep cycle battery used to start an engine in an emergency will not damage it. Using a true deep cycle continuously as a stating battery will decease the longevity. The same goes for using a Cranking Battery as a Deep cycle for extended uses the cracking battery's longevity will be compromised.

bill46":2w8qtf47 said:
Deep cycles are excellent starting batteries, just heavier and more expensive. I recommend all be the same.
This is not true!

Submariner":2w8qtf47 said:
If you were to use your starter battery in a deep cycle application, I've heard Jeff Cote at Systems repeatedly talk about them exploding (not immediately, but eventually). He says it's the kind of explosion that may have your significant other wanting to trade in the boat for an RV.

I have never heard this before. I have witnessed a battery explosion a few times in my life of being around equipment. I did not associate the explosion to the way it was used. I have always thought that the explosion was from the battery being over charged generating heat and causing gases to build up, bulging the case to the point that it explodes. I have also seen a battery bulge when a high amp charge was applied to it. I'm not disregarding his statement.
 
Hi all,

There are various reasons for a battery to explode, but using a starting battery as an ersatz house battery, or vice versa, should not be one of them. Battery explosions are usually caused by internal failures and other issues. As Brian said, simply check to make sure that the battery you intend to use for the engine meets the Volvo Penta requirements. Hope this helps.

Cheers,

Ralf
 
If you want more house capacity join your thruster to the house bank. You can run a positive cable from the thruster battery to the house bank and also put a switch in between so you can also isolate if you want to. You already have a parallel switch between the house bank and engine. This switch should always be in the off position. In the event the engine battery gets weak you then turn the parallel switch on.
 
BB marine":2apf8vgd said:
Submariner":2apf8vgd said:
If you were to use your starter battery in a deep cycle application, I've heard Jeff Cote at Systems repeatedly talk about them exploding (not immediately, but eventually). He says it's the kind of explosion that may have your significant other wanting to trade in the boat for an RV.

I have never heard this before. I have witnessed a battery explosion a few times in my life of being around equipment. I did not associate the explosion to the way it was used. I have always thought that the explosion was from the battery being over charged generating heat and causing gases to build up, bulging the case to the point that it explodes. I have also seen a battery bulge when a high amp charge was applied to it. I'm not disregarding his statement.

I've also never seen it, but Jeff Cote has mentioned it enough in his presentations and videos. I believe him. He's also mentioned that this is possible through overcharging of a battery.

Jeff Cote talked about this situation which can lead to an explosion:
Boat owner wants to sell their boat. There's several house batteries and all are in need of replacement. So the unsuspecting seller purchases the least expensive batteries they can find which are usually starter batteries. Things work great for the walk-thru and sea trial on the boat and the boat is sold to the buyer who now has a house bank comprised entirely of starter batteries.
 
CruisingElvinRay":37de20ml said:
What happens if you parallel a starter battery with a deep cycle house bank?

BB marine":37de20ml said:
Submariner":37de20ml said:
If you were to use your starter battery in a deep cycle application, I've heard Jeff Cote at Systems repeatedly talk about them exploding (not immediately, but eventually). He says it's the kind of explosion that may have your significant other wanting to trade in the boat for an RV.

I have never heard this before. I have witnessed a battery explosion a few times in my life of being around equipment. I did not associate the explosion to the way it was used. I'm not disregarding his statement.

Jeff Cote talking about using a starter battery for deep cycle applications. Starts at minute 26:00.
https://youtu.be/OgsMBe-DFJo?t=1558
 
knotflying":2btfexbe said:
If you want more house capacity join your thruster to the house bank. You can run a positive cable from the thruster battery to the house bank and also put a switch in between so you can also isolate if you want to. You already have a parallel switch between the house bank and engine. This switch should always be in the off position. In the event the engine battery gets weak you then turn the parallel switch on.
Thanks for the input. I’m going to be a little paranoid on this one and keep them separate because I have a generator and the thruster battery also serves as the generator start battery. The generator would be my ultimate fall back. I’m going to pull the sled out (apparently not so easy) and see what I have for house and engine starting and go from there.


Sent from my iPhone using Tapatalk
 
BB marine":31z7a0ns said:
Submariner":31z7a0ns said:
If you were to use your starter battery in a deep cycle application, I've heard Jeff Cote at Systems repeatedly talk about them exploding (not immediately, but eventually). He says it's the kind of explosion that may have your significant other wanting to trade in the boat for an RV.

I have never heard this before. I have witnessed a battery explosion a few times in my life of being around equipment. I did not associate the explosion to the way it was used. I have always thought that the explosion was from the battery being over charged generating heat and causing gases to build up, bulging the case to the point that it explodes. I have also seen a battery bulge when a high amp charge was applied to it. I'm not disregarding his statement.

Jeff Cote recently released this video with the "why" a starter battery will actually explode when used as a deep cycle application. He explains in detail what happens.

https://www.youtube.com/watch?v=-_tNOzVPuKs
 
I have “starter” batteries for the engine and the thruster+windlass banks. If the engine battery ever failed I would connect the engine battery to the thruster battery in parallel to get the engine started. I have a pair of properly sized 1/0 gauge + jumper in my spares locker for this purpose. If that failed to provide the power to start the engine only then I would use the emergency switch to link to the deep cycle house batteries.
Just a different way to tackle the problem of a dead engine starter battery.
.
 
Back
Top