Do I Really Need a Second Battery?

[Guitarjesus]

Ok, I'm going to Havasu next week, and I'm installing a Rockville Atom 8w amp, and the Opt 7 Aura Pro lights. Here's some links for particulars.

Rockville Atom 8w 3500W Amplifier

Opt 7 Aura Pro Led Lights

Adding these devices, and just driving the stock speakers, do I need a second battery? How fast will running these with the boat off drain the single starting battery?

Any advice is appreciated. Thanks!

 

[tdonoughue]

Too many variables to give you a straight answer (like it will depend on how loud you run the music...). However...

Consider a second battery just for peace of mind. I have my 2nd configured so the house is all on one battery and the other one is reserved for starting. I can play until the stereo dies. Then I just start the engines and the charging starts. Yes, there are some people who stack 1st and 2nd to get longer play time. But I like the 2nd for the security.

Also, for point of reference, my setup is in the sig block here. Never have run out of one battery staying all day on the water...

 

[LoWeLL216]

I've never run out of battery either - but I have 2 as well.

Run 4 speakers, 2 tower cans, 2 subwoofers, and 2 amps powering everything.

It's nice having peace of mind with the second and just not having to think about it.

 

[Beachbummer]

Need...you need air to breathe, and food to eat... a second battery..,you only need if you draw down the first battery down enough so you can't start the boat with the one battery But who is to know if this will happen to you??

My humble suggestion, it will save at least 1 trip in the next year or two. You left something on, one wore out, etc... you are ready to go, and click click click no boating today without a trip to the store, or setting the charger for an hour and a prayer...OR, Switch the switch from 1 to 2 and BAM, right back to were you where, ready to go. For this reason alone, I do suggest a second battery and a 1-2 switch (and if you want to splurge, you can install an ACR, Automatic Charging Relay, which will bridge the batteries automatically while underway to charge both batteries at the same time without any manual intervention on your part.- Otherwise you can switch from battery 1 to 2 and vice versa every other weekend or month or whenever you want, to make sure both batteries are topped off and happy. Even with an ACR you need to switch once in a while between the 2 to make sure both are really good and ready if they are needed.)

 

[knoxboatin]

Could always grab a jump starter pack for peace of mind since you are on a short planning horizon. Unless you are looking to justify a third boat project.

There are cheaper ones, but I like my Noco. Noco jump starter

 

[FSH 210 Sport]

I’ll start (see what I did there) by saying I would have two batteries on my boat, a dedicated start battery and a house battery. And I’d set it up with a BEP Marine Dual battery switch with built in DVSR and emergency parallel switches.

Do you have an onboard charger you can plug in at the end of the day? If not, this is a must as well. Get a NOCO 10A charger, I’d get a two bank charger and tape up the leads for the second battery in case you decide you want a second battery down the road.

You don’t know how much battery capacity you have used until you install one of these smart shunts, anything less is a guess.

SmartShunt - Victron Energy

The SmartShunt is an all-in-one battery monitor, only without a display. Your phone acts as the display. The SmartShunt connects via Bluetooth to the...

www.victronenergy.com

Once you have the smart shunt installed on your battery and the app installed on your phone / tablet / pad you can very quickly determine the state of charge on your battery, how many amp hours / amps / watts / watt hours have been pulled out of the battery, as well as seeing in real time what the draw is on your battery, and if the draw is relatively consistent the shunt will show how much time there is left before the discharge floor (you set this in the settings, a lead acid battery should be 50%). Also, as you run the engine in your boat you will be able to see how many amps are being pushed into your battery by the engine and the state of charge will update as you run the boat.

Since you are making the Havasu trip in a week I wouldn’t suggest trying to tie in a second battery in a weeks time. I would definitely get a NOCO or Antigravity jump pack, charge it and put it on your boat. The INTENSE heat at Havasu will be a bit hard on your lead acid battery as well.

In the long run of you want to stay with one battery you could drop in a 60 Ah Dakota Lithium group 24 equivalent dual purpose battery that will have roughly three times the storage of your (I’m assuming) group 24 battery; DL+ 12v 60Ah Dual Purpose 1000CCA Starter Battery Plus Deep Cycle Performance or you could drop in DL’s 135Ah group 24 equivalent 135 Ah batteries that will have about 7-8 times the storage of your group 24 lead acid battery. These batteries are very light and very powerful, but they’re a grip.

 

[drewkaree]

I know that this is just my take on this, but why is it always the secondary thought to question whether there's enough juice to run things, AFTER they're added?

What happens when the budget is now razor thin because of the cost of add-ons? The cheapest solution is taken, and likely left in there since it's sunken money at that point.

As @Beachbummer points out, you won't ever know until it happens, so plan from the jump to start with the batteries FIRST. Some things may not even work well, or properly, without enough battery power, so you fight it the whole time.

I have never once read of anyone here that was mad that they added an extra battery to their setup, but multiple stories abound where the day on the water ended in frustration due to running out of battery power.

Go buy the battery and take along an adjustable wrench for the simplest and fastest solution for a short time frame if you can't set it up. The jump pack is the 2nd best non-optimal solution that I do, but I am running a stock boat, and only upgraded the speakers, and don't run my stereo while at rest.

Cheapest solution is to let another boat run the music and kill THEIR batteries ?

 

[2kwik4u]

Cheapest solution is to let another boat run the music and kill THEIR batteries ?

Nailed it.

I'm never going to sink the cash into a stereo to fill the whole cove. Just not my thing. S0 I let someone else play funky DJ while we float in a group if available.

I put a soundbar on mine to get sound out behind the boat while at anchor and us floating off the rear deck. It works great, was $500 and draws very little power. I also run the stock head unit, and I bought some "take-out" speakers from someone upgrading their 24ft boat with better stuff. Our little 19ft makes plenty of sound for us, but we're not winning any audio competitions either. Nor do we want to.

With all that said, I've played DJ a couple weekends as, well, as simple as my setup is, it's been the best setup on the water a few times with fishing and pontoon boats around that aren't able to get the sound out to the water. SO.....I've run my setup for a full 8hrs and the boat still started just fine. These little 19ft boats without all the fancy new screens and electronics really have a very low amp draw; even with the music set at 11.

Keep in mind these are tiny little 4cyl engines with only medium compression. These aren't 8.1L V8's with high compression we're trying to start. So, for me I just run a simple single battery, and carry a charged jump box with me on the water. We're 1/2 way through season 8 now and still going strong setup this way.

 

[dan144k]

Best thing I
I ever did was add a 2nd battery.
My stereo is stock and I don't need a 2nd battery.
However.
.....Best thing I ever did was add a 2nd battery for back up.
...
Mine is super simple. 2 chargers. 1 switch (off, 1 , 2, both)
And
I hardwired a 2nd bilge with built in float to one battery. For week long boating trips.
...
Also my boat had a battery drain, (took about 1 month without use to effect battery) so when I park it on trailer in driveway. I just turn off both battery feeds.
...
Also I installed one of these to monitor battery voltages. I installed.mine next to the glove box area. And people can charge phones too..

 

[YoDaddy292]

Having a second battery makes me feel better. I don't dedicate house vs. starting I typically switch between 1 and two every other trip and if it is going to sit for more than a week it goes on the trickle charger/tender. We've listened to our stereo for hours and never killed either battery but in my youth it seemed to happen a lot and being stuck somewhere with a perfectly good running machine but going nowhere and waiting to flag someone down for a jump while you drift towards rocks, boats, or just far away really sucks.

 

[Guitarjesus]

Here's what my work for today looks like (gonna be 107 here).

Redodo 100ah lithium for a house battery. Blue Sea 7650 battery switch with ACR. Noco battery tray, Rockville Atom 8W amp install, new speaker cable, Stinger amp power cabling, Mofeez distribution blocks, Solas Twin Impeller. Let the fun begin!

P.S. Whoever came up with the idea of using your truck, rolled up on a 2x6, holding down thr 1 1/16" in wrench to bust free the impeller from the driveshaft, you are a god amongst men!

 

[Lurch]

These little 19ft boats without all the fancy new screens and electronics really have a very low amp draw; even with the music set at 11.

Why don't you just make ten louder and make ten be the top number and make that a little louder?

 

[Guitarjesus]

Why don't you just make ten louder and make ten be the top number and make that a little louder?

But it goes to 11...

 

[FSH 210 Sport]

Whats up with the twin screw impeller?

Unless something has changed, and I’m just taking this last post with the lfp battery and the blue sea acr at face value, if you put that LFP battery in with an ACR the ACR will always be active because the resting voltage of the LFP battery is above the pick up value of the ACR. If left in this state and it ties with your lead acid battery, the LFP battery will discharge into the lead acid battery, which will basically over charge your lead acid battery and discharge the LFP battery to basically 0.

 

[Guitarjesus]

Whats up with the twin screw impeller?

Unless something has changed, and I’m just taking this last post with the lfp battery and the blue sea acr at face value, if you put that LFP battery in with an ACR the ACR will always be active because the resting voltage of the LFP battery is above the pick up value of the ACR. If left in this state and it ties with your lead acid battery, the LFP battery will discharge into the lead acid battery, which will basically over charge your lead acid battery and discharge the LFP battery to basically 0.

The twin screw will help with bottom end, getting on plane quicker with a loaded boat. I've always got 5-7 people on board. I'm not worried about the 1-3mph I'll lose on top end.

Now the batteries. Should I have just gotten another lead acid? Or what method do I use to have both batteries wired up?

 

[FSH 210 Sport]

The twin screw will help with bottom end, getting on plane quicker with a loaded boat. I've always got 5-7 people on board. I'm not worried about the 1-3mph I'll lose on top end.

Now the batteries. Should I have just gotten another lead acid? Or what method do I use to have both batteries wired up?

Wire the ACR power into the fuel pump hot wire, that way the ACR is only active when the motor is running. Or, put it on a rocker switch which is how I have mine. A few folks I know of have gone the fuel pump hot wire with great success.. @WiskyDan

The twin screw impeller is an awesome investment.. but I’m guessing you will not have time to test it before you go, I’d be sure and take the tools and the old impeller so you can swap it just in case it doesn’t work out correctly… if you take the tools and oem impeller you won’t need them ?