A few newb questions about batteries...

[Mustang65fbk]

It is odd that both batteries seem to be bad at once. No? For sure they are likely due for replacement but you may have a charging system problem. in my (automotive, not marine), a low voltage indicator with a running engine is a charging system issue. Not sure what gauge package you had but did the engine gauge (not the GPS) indicate low voltage while running?

When you went to start with the jump pack, I presume it was completely charged. Did you let the jump pack connect to the battery for a bit, like 10 minutes?

I don’t know how far you go to haul the boat out, it should start and run on new batteries but will discharge them. Would hate for you to smoke a new battery. Perhaps if close by you can get a tow to haul out and do some additional diagnosis and battery replacement in a more convenient location?

I'm not 100% sure that both batteries have gone bad at the same time, but I figured that if I'm going to replace one and I'm uncertain of the age of the other, that for an extra $80 it's a bit more peace of mind. The jump pack was charged up all the way but the motor went from starting up on Saturday to not being able to start on Sunday, which to me makes it sound like the battery gave up its ghost over those two days. My thought process would be that if it was a charging system issue and not an issue with the battery or batteries, would be that they in theory shouldn't be completely drained in a day and then having them powered off overnight. I suppose it's true that there could be more than one issue and that the batteries could be on their way out as well as having a charging system issue. That being said, with buying the boat used and not having any confirmed dates as to when the batteries were last purchased or replaced, that would be my first train of thought since it was a drastic thing and essentially happened overnight. If it was something where it took a few weekends or whatnot, then yeah maybe more of an alternator or charging system culprit. Lastly, if the batteries were still decent, I'd think the fully charged jump pack should start them right up even if they were a bit on the lower side. I had something very similar with my daily driver vehicle a few months back where I went out to start it one morning and it didn't want to start at all. Hooked up the fully charged jump pack to it, still nothing, and to where I had to use the jump pack as well as add a charger to it to finally get it to turn over and start. I ended up replacing that battery, which was 7 years old, and I'm thinking it sounds like a pretty similar story with my Grady to what happened there.

 

[Mustang65fbk]

The best $20 you will ever spend if you maintain your own batteries:

Load Tester

Unless there is severe battery damage, a freshly charged battery will always show 12.6 or so volts. But what happens when you put it under a load like starting your engine? I've used this Harbor Freight piece of junk for 5 years now and it has revealed weak batteries before they failed several times.

You did not specify what engine you have on your boat. Many engines, especially Yamahas, will draw more power to run their pumps and computers than the alternator can put out at low rpm. A big Yamaha 4-stroke can draw almost 20 amps. So they are drawing off the battery at low rpm and won't run without a battery connected. That's why they specify using a battery with a high reserve capacity. Group 24 batteries can't come close to meeting these specs. In fact, most group 27 are not sufficient. You need to check the specifications of the battery you are interested in buying.

Since you live in the Seattle area you most likely do a lot of slow trolling at low rpm or using a kicker. You probably have your chart plotter on all the time and intermittently draw a lot of current with your downriggers. Be safe and use dual-purpose group 27s with the proper reserve capacity. That's what Grady started putting in their boats as 4-stroke outboards became standard.

Thanks for the link on the load tester, I agree that for $20, you can't really go wrong with one and I'll have to get one the next chance I get. Maybe it's just me, but it seems like if it was the outboard that I would've experienced this issue before? This is the second season of running the boat and I've yet to have any starting issues, with the exception of at the beginning of the season where it was a little slow to start for the very first time after the winter. But last year and this year both were a quick start of the motor every time. I guess my thought process again would be that if it was the outboard that was causing the draw, then this should've happened at least once before? I've pretty much used the boat every weekend for a couple of hours trolling and then religiously make sure that the battery switch is turned off at the end of the day. The Costco Group 24 batteries have a 140 minute reserve capacity whereas the Group 27's have a 160 minute capacity. I think I'll try a couple of Group 24's and see what happens, as I'm not near the boat but am also not 100% positive I can fit Group 27's in there. I suppose in theory they should fit if you got them in your 226 Seafarer? I've got both on the passenger side facing "front to back" on my boat.

 

[Doc Stressor]

Yamaha actually specs 182 minutes of reserve capacity. That is probably overkill, but it will allow you to run the engine for about 3 hr after an alternator failure. It also provides plenty of power for a powerful amplifier system that uses a lot of juice to play music at anchor. If you just fish you are probably OK with smaller batteries, but I'm pretty sure that your 2004 came with Deka group 27 M6s just like my 2008 did. It is a bit tricky tilting in the inside battery but I can do it even with arthritis.

You don't want to use true deep cycle batteries for starting batteries. They don't provide enough cold cranking amps during cold weather. It takes a lot of juice to turn over an engine below 40 degrees. And deep cycles have fewer, heavier-built plates than starting and DP batteries. They are not designed to be constantly topped up from a big alternator so they don't hold up as long. People use them in Florida where low temperatures are not a problem. But they don't last long when rigged in parallel with a starting battery. Ideally, you want to use the same type of battery when rigging a pair, particularly if using an ACR to keep them both topped off.

 

[Peter A]

I'm not 100% sure that both batteries have gone bad at the same time, but I figured that if I'm going to replace one and I'm uncertain of the age of the other, that for an extra $80 it's a bit more peace of mind. The jump pack was charged up all the way but the motor went from starting up on Saturday to not being able to start on Sunday, which to me makes it sound like the battery gave up its ghost over those two days. My thought process would be that if it was a charging system issue and not an issue with the battery or batteries, would be that they in theory shouldn't be completely drained in a day and then having them powered off overnight. I suppose it's true that there could be more than one issue and that the batteries could be on their way out as well as having a charging system issue. That being said, with buying the boat used and not having any confirmed dates as to when the batteries were last purchased or replaced, that would be my first train of thought since it was a drastic thing and essentially happened overnight. If it was something where it took a few weekends or whatnot, then yeah maybe more of an alternator or charging system culprit. Lastly, if the batteries were still decent, I'd think the fully charged jump pack should start them right up even if they were a bit on the lower side. I had something very similar with my daily driver vehicle a few months back where I went out to start it one morning and it didn't want to start at all. Hooked up the fully charged jump pack to it, still nothing, and to where I had to use the jump pack as well as add a charger to it to finally get it to turn over and start. I ended up replacing that battery, which was 7 years old, and I'm thinking it sounds like a pretty similar story with my Grady to what happened there.

Ok. As I think about it, if they are wired in parallel when running on both, then when one starts going bad, it will be “supported” by the other and likely accelerating its demise. I was examining the config on my 208 recently which is a 2021 but similar battery layout and electronics loads. The later 2.8L 4cylinders have higher output alternators. Good idea to do both batteries regardless. Hope she starts right up! Then check the charging system to ensure all is well. Also, “new batteries” often do not have a full charge. Make sure you fully charge them before you put her away.

 

[Mustang65fbk]

Yamaha actually specs 182 minutes of reserve capacity. That is probably overkill, but it will allow you to run the engine for about 3 hr after an alternator failure. It also provides plenty of power for a powerful amplifier system that uses a lot of juice to play music at anchor. If you just fish you are probably OK with smaller batteries, but I'm pretty sure that your 2004 came with Deka group 27 M6s just like my 2008 did. It is a bit tricky tilting in the inside battery but I can do it even with arthritis.

You don't want to use true deep cycle batteries for starting batteries. They don't provide enough cold cranking amps during cold weather. It takes a lot of juice to turn over an engine below 40 degrees. And deep cycles have fewer, heavier-built plates than starting and DP batteries. They are not designed to be constantly topped up from a big alternator so they don't hold up as long. People use them in Florida where low temperatures are not a problem. But they don't last long when rigged in parallel with a starting battery. Ideally, you want to use the same type of battery when rigging a pair, particularly if using an ACR to keep them both topped off.

Agreed, I use few electronics and rarely ever anchor up other than perhaps once or twice a year to take the boat halibut fishing. Also, I'm typically a bit more of a fair-weather fisherman in that I don't use the boat over the winter hardly at all. Probably 95% of what I do is just fishing during the summer when the temperatures are in the 60's at the minimum. As stated above, I might go out halibut fishing once or twice a season in the spring when the temperatures are likely a little bit cooler, but probably nothing less than 40 degrees. I've only done that once in my previous 21' Arima where it snowed the night before we did a fishing derby and it was a little chilly to say the least. Nothing that wasn't doable or anything, but between the weather and the slow fishing, it's definitely made me think at least a time or two about going out again during that time of year. Especially since I have to "de-winterize" the boat, take it out and then "re-winterize" it again, which is oftentimes more effort than it's worth. Thanks for the information, I'll make a phone call to my local GW dealer and see what they have to say. I think the difference in price between a Group 24 and a Group 27 battery at Costco is less than $10 a piece. So if it makes any difference and will fit, then it's definitely a consideration at this point.

 

[pnw208]

A small solar panel like this one is a nice addition for a boat on a mooring to keep the batteries topped up. No regulator needed. https://www.amazon.com/DuraVolt-Mar...ocphy=9033307&hvtargid=pla-318232540466&psc=1

 

[Mustang65fbk]

A small solar panel like this one is a nice addition for a boat on a mooring to keep the batteries topped up. No regulator needed. https://www.amazon.com/DuraVolt-Mar...ocphy=9033307&hvtargid=pla-318232540466&psc=1

Definitely a good idea in theory, and something that I've very much considered in the past multiple times. The only issue that I can think of would be since I have the boat on a mooring buoy for months at a time during the summer, the seagulls and everything else crap all over the boat and especially the hardtop. Unfortunately, I'm not at my beach cabin constantly during the summer and sometimes go for a week or more without being there. Of which I'd have to assume those solar panels would get destroyed very quickly.

 

[Mustang65fbk]

I made a quick phone call to the Grady White dealership I purchased the boat from, explained what was going on and they recommended going with new batteries of the exact same size and Group as to what is currently on the boat. I ended up getting two Group 24 starting batteries from Interstate, went up to my beach cabin, installed them on the boat, took the boat out of the water and got her all cleaned up for the winter. Thanks all again for the advice!