Battery

Steeldieman

Well-known member
Joined
Feb 3, 2016
Messages
102
Fluid Motion Model
C-24 C
Non-Fluid Motion Model
Cutwater 28
Vessel Name
Katy A
Brian, I have an issue I am hoping you can help me with. Over the winter I didn’t have my batteries hooked up to power very much. The yard where I keep my boat had the power cord hooked up to a generator for a couple hours this morning before I arrived to take the boat to burnham harbor. Of course it wouldn’t turn over , we used a jumper hooked up to the stater to get it running. I thought the trip down the river would bring the engine battery back from the dead but once I had tied up in my slip and shut down the engine I immediately tried to restart it without success. I have now had it charging on shore power for approximately 2 hours and still no joy . I’m not very battery savvy , is it dead ? is it salvageable? I’m also going to post this on the forum.
 
After a two hour low speed chug down the Chicago river and about 3 hours on shore power it cranked over. I’m just curious about that charging duration, anyone got a idea ?
 
A fully charged battery should hold its charge over winter. I have 4 batteries and each May they register 12.7 volts. They are not connected to a charger over winter. I do disconnect all the yellow negative cables from each battery. So there is no drain on any battery.
 
Steeldieman":3k2kdvq5 said:
...I’m just curious about that charging duration, anyone got a idea ?
There's no simple answer to the question about charging time. Much depends on battery condition, state of charge, alternator/charger output, load during charging, etc. Learning some basic information about batteries can save you several hundred dollars per year in new batteries, towing/mechanic charges, etc. A couple of good sources are battery university on-line or the 12 volt doctor's handbook.
 
I just want to mention that I am running Factory Agm batteries in their forth season
 
Charging time is a question I too wonder about. My two house batteries, also AGM, are two and a half years old and will not hold a charge over night with only the anchor light on. Two weekends in a row, anchored out, I wake up to batteries showing only 10.6 volts. They have been acting up for several months.

I would think 3 hours on the charger would be enough to bring your batteries to proper voltage. It's how well they hold a charge that seems problematic.

I keep my batteries on charge 24/7. Now I wonder if that practice may have contributed to them now not holding a charge being less than 3 years old?
 
Despite the claim that they are sealed, you can open the AGM batteries and add water after a few years of use. They use a 19 mm thin wall socket, safety glasses, and a period of time we have not been collected the loan for the gas to dissipate.

Open them up and there’s a triangle in the fill cap. Add to Stillwater the triangle wait an hour and add water again.

Put the cap back on charge the batteries and you baby good to go
 
Batteries are a complex topic and then add the wiring set up and ACR's and it gets more complex. Starting from the beginning, as a safety (battery life) precaution, if I have a long layover I disconnect the batteries. This is the opportunity to clean all terminals after the layover. Disconnecting them ensures that you have decommissioned all items that continue to have a slight draw even when off.
As far as starting the engine when the battery is dead. The battery may not charge through the system if the voltage is less than 9.5 volts. The ACR will not close to allow charging if a battery bank is below 9.5 volts. If the battery was charging, a short charge will only result in a surface charge and may not be enough to start your engine. A good charge would probably require 3 to four hours of cruising time on a battery that is fully discharged. The same would hold true if using a charger. AGM batteries can take more abuse than flooded, but they do degrade each time they get over discharged. How long a battery lasts is a function of how it has been treated and there is no set answer as to how long they will last. I have seen an AGM last over seven years and I have seen it go in a year.
I suggest you fully charge your batteries, let them rest and then do a load test. This will give you an understanding as to their condition.
 
Agm batteries are great but they dont take abuse as well as flooded batteries. They don't sulfate as quickly and dont require regular maintenance . They are more resistent to vibration, charge faster and can provide more current than flooded cells. They are very prone to heat damage thus ideally would not be installed in a hot engine compartment. They can also be damaged with improper charging. Ideally you would have a temperature sensor installed on the battery to adjust the charge voltage.

With the battery switches off, what voltage do you have? Let them charge for 12 hrs (you should measure 14 to 14.6V at the battery during charge) , remove the charger and check again 1 hr later with no load applied. If you dont have 12.6 to 12.7V at the battery ( use a multimeter ), replace them. Did you try to parallel the house to the starting battery?

Did you check gor loose or corroded terminals?

Sent from my SM-T590 using Tapatalk
 
If you go below 50% charge and your batteries are a few years old that will often kill them. Charge them overnight then see if they work as normal. If not, they are gone and will need to be replaced.
 
I need to replace the engine battery in a 2015 Cutwater 30CB. Does anyone know if the engine battery is the same as all the other AGM batteries onboard? Are they dual purpose batteries?
 
It is the same type and size as the other batteries.
 
Thanks Kip. I think I actually need to replace all 6, so it's good to know they are all the same.
 
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