Upsize Battery?
 

I'm wondering if I should upsize the battery in my 20' Harris tritoon with 150 Mercury. Factory came with an Interstate 24M-XHD (800CCA/1000MCA/135 reserve@25A) that lasted at least 5 summers. This would be the 6th, but as some of you know, I'm replacing it proactively even though it continues to start the motor because I've had a stalling issue when trimming down that *may be* battery related.

We only use four electronics onboard (in addition to the starting/monitoring system): radio, GPS, inflator (rarely), cell phone charger.

Should I consider upgrading to a 27/31 group battery or, because I got 5 easy years, just assume my usage is fine and that that's a reasonable time to expect a battery to last?

I know there are dual battery options, but I just don't think it's worth the investment/room/retrofit given that we've always carried a jump pack that's literally never been used even after whole days at the sandbar (and, frankly, we wouldn't be bothering with the battery right now if not for that once-in-a-while trim down issue).

One note: I've found in places that the *minimum recommended* for the 150 is 950MCA and that it should be higher if used with fishing/high-power-use applications.

One other note: I've got an Everstart 24 (same specs as previous Interstate) in my garage that I bought last night but can swap this afternoon before heading north tomorrow.

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The everstart will be fine for your rig. After a day of sandbar use do not assume the outboard will fully charge it. When at your dock putting a battery charger on it after a day of heavy use will help the battery last along time.

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I've thought about the charging aspect, especially given the comments on the other battery thread about charging rates at idle vs. high RPM. Though we typically cruise home at a decent pace, I'm thinking since the battery sits (connected) for a week or so in-between use, a charging apparatus might be useful.

There's no power where I beach the boat, so I'd be looking to do solar. I'm guessing I can rig up an easy clamp for the bimini pole and run the wires under the playpen cover to the battery.

What would I be looking for on a solar charger for amperage?

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Below is a link to the solar charger I use in FL and NH.

It yields 3 watts.

I put a carabiner in one corner grommet and clip it on to the boat.

The other grommets on the one in FL started rusting so I sandwiched some plastic canvas cover bungee stay attachments on them.

I did so on the NH boat but it may have been unnecessary at the lake.

That sounds complicated but it is not. See link below for those.

While 3 watts may not seem to need a fuse, everything connected to the battery does.

I installed a fuse on the positive lead for protection.

The cable has a 12V receptacle plug and an alligator clip option.

https://www.westmarine.com/buy/natur...84?recordNum=5

Bungee strays. See photo on site. The white parts will lock around the grommets to keep them off the wet deck or carpet of your boat.

https://www.sailrite.com/Stayput-Sho...SABEgIFP_D_BwE

I Have wanted to set up my boat with a dual switch for a long time, but just have not done it. I have been very successful with an Everstart group 29 deep cycle, and a 2.5 or 3 watt solar charger that stays on the battery whenever not under way. while underway it stays connected and i just stow it for safety. Then it comes back out. on very long days I do carry my jump pack, but I have never had to use it. I have however lent its use to some with one battery or a dual batter system. 2.5-3watts over a span of 4-8 hours at a sandbar should have no problem keeping your battery ready to turn the engine over

Even have the same charger on my little fishing boat, with a trolling motor and two garmins on it. haven't had a problem and it has the same 29 group battery in it

I have had this set up for 5 plus years

I even purchased a new charger at 5 watts last year but have not had to introduce it yet. its standby

This might be a perfect solution, but I can't seem to find the length of the leads–any idea? I could clip it to the bottom of one bimini pole and run it through the opening, so I'm thinking 6' or so.

most solar charges are about 6-10 feet long, you can always extend the wiring by adding some in with water proof butt connectors or anything like that

Thanks. You ever get a price on installing a second battery system?

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Something else to consider if you stay with a single Battery setup, is to install a basic on / off switch.... I installed one several years ago on my speedboat.... it saves lots of headaches... the only thing left with power when I through the switch is the bilge pump....

Did you put that right at the battery? Whatever I choose, I'd have to get in a new habit.

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I must be missing something, you guys keep saying Watts, not Amps.

My old school math tells me that 3 Watts is less than 1/2 an amp, which is maybe a reasonable trickle charge for a snowmobile/motorcycle battery if it has ZERO draw on it, but seems to me to amount to almost nothing for a boat charge.

I would guess that most boats suffer greater than 3 Watts to parasitic loss from the various marine electronics that have functions always running in the background, let alone if you were running any device which would put you at a significant net loss.

I personally have never had a trickle charger that was smaller than 1 full Amp and many are variable power up to several Amps as required due to the constant drain by some devices.

I guess everyone's needs are different, but it doesn't seem reasonable that anything under 1 Amp capability is going to really do much for you.

Sometimes paying a few dollars more for a more robust capability is a far better long term investment.

So with that said, and getting back to the original question, I wholeheartedly endorse upgrading to the larger 27 series battery. I have done this in every boat I had with a 24 series battery and never regretted the extra expense as it bought me a lot of peace of mind knowing I had that extra capacity and I believe it also bought me additional longevity, so in the end I feel the cost balanced out.

ATB

You can mount the switch really any place, For speedboat it is under the sundeck, which comes up, every time I take the boat out for a quick sniff test....

If I where going to mount one on my toon, I would likely mount it right by the battery.... and actually make it part of the battery case......

Where would the larger capacity battery fall in terms of recharging, though? Specifically, would the charging system generate enough power to keep a larger battery topped off or would I still be in pursuit of a trickle charger, maybe moreso, as a result of the larger battery?

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Thinkxingu - I have been following this thread and am still confused as to why trimming down would have any impact on motor performance.

I once had a bad battery so removed it, borrowed someone else’s battery (no one had cables) to start the boat, ran it without a battery connected (ran off alternator) out to the island where I could put my battery on a charger. Granted, this was an I/O. Are outboards wired differently?


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It doesn't seem like you are pulling too much out of your Group 24... unless you have an amp or 2 on your stereo. So the battery should suffice. Going to larger battery just reduces the time between needing a charge.

The real issue is the charging capacity on your OB motor. Most likely, as others have said, it doesn't keep your battery "topped off". Its an easy fix with a trickle charger... yes, trickle chargers are low rate, but think of all the time they are charging the battery when the boat is not in use.

I am not a fan of deep cycle marine batteries... (unless is a trolling battery) I use car batteries in my boat. Better warranty and for me they seem to last longer. For the record, no "new" battery comes fully charged. I always charge them up full before putting them in the boat.

Woodsy

I believe the solar charger cord is 6'.

In FL, the battery switch is off, the boat is on a lift and the plug is out.

The bilge pump on that one is connected after the battery switch.

In NH the I have no battery switch.

So far, the lack of a battery switch on this boat has only bitten me when the shop had the battery in place for a few weeks but the solar panel was stowed.

I plan to install one this spring to protect against that.

The bilge pump will be connected before the switch thus allowing it to run on the mooring.

In both cases my 3 watt solar charger has kept the batteries working for 4-5 years.

Fyi...fwiw...
 

One day, about Noon, I discovered my car had a dead battery. (Left key "on" overnight). :o

A little $6 "HF" trickle charger recharged the battery overnight! :look: