Adding battery

I am looking into adding a battery to my pro guide. I have 2-12” helixs. On a full fishing day the graphs will kill my cranking battery. I now carry a jumper pack. Plus I get interference while side scanning and getting power from the cranker. I’m debating getting a lithium battery to just run the graphs and nothing else. Mostly to save weight. Problem I’m having is I’ve found 3 different charts that list power draw for the Helix units. They have a power draw listed ranging from 1.75 up to 3.5. Thats a big difference and would almost double the size battery needed for a 12-15hr fishing day.
Also looking for recommendations on battery brand and size needed. I seen Dakota Lithium has a sale going right now. Thanks for any help.

Red Eye, what brand and HP of motor are you running?
The reason I ask if it is an older one, say pre 2005 the stator type charging systems are not designed to nor will they charge a lithium battery.
They wont charge a maintenance free or AGM battery either.

It is a 2013 mercury 90. But this new battery will not be hooked to outboard at all. It will strictly be used to run the 2 Helixs. With it’s own on board charger.

I am interested in the answers you get.

I run 4 helix units on my boat. 2 – 10”, a 12” and a 9” along with 360 imagery.

They have their own battery it is a group 27 dual purpose flooded battery. I don’t think I have had a 12 to 15 hour day of fishing on the set up. However they have went 8 to 10 hours.

Eventually I would like to switch the 2 trolling motor batteries and the graph battery to lithiums.

Thats a great plan Red Eye, A lot of folks dont realize the load they are imposing even on modern outboard charging systems with an alternator.
All the charging systems are designed to do is maintain a battery, not bring it back from the dead.

Have you referenced this chart from Humminbird? Should have all your answers. I did the same thing last summer, but with a regular group 31 battery. No more battery issues and I feel it’s easier on the outboard alternator. I run a 4 bank charger and plug it in after every outing.
Humminbird Power Chart

Most lithium batteries cannot be used for a starting battery. If you go that route, make sure your battery can handle starting loads.

Helix head units love the higher working voltage of the lithium.

This what I did last year that would work in your situation. I added a 5th battery just for my electronics. it was a 100 amp Renogy lithium with a self heating function for charging in low temps. I connected it to my agm starting battery through a Renogy DC to DC charger. The Dc to DC charger can take the lower 12 volts and change it to a lithium charge rate of 14.6 volts. What shocked me was every time I got home a connected the lithium battery to my NOCO 10 amp charger the battery it showed fully charged in like 10 minutes. The system is keeping the lithium battery fully charged most the time.

I am running 3 Helix 12’s and 1 Helix 9 with Mega live and 360.

Joe Jarl wrote:

Have you referenced this chart from Humminbird? Should have all your answers. I did the same thing last summer, but with a regular group 31 battery. No more battery issues and I feel it’s easier on the outboard alternator. I run a 4 bank charger and plug it in after every outing.
Humminbird Power Chart

I did see that chart. But I also found a chart that says 1.75 amps and another that read 3.5. Not sure which to believe.
If I go by that chart which lists 3.2amp draw. How big of a battery would I need to run for 12 hours?

Running 2 of the 12’s would be 6.4 amps total x 12 hours = 76.8 amp hours if you’re not running anything else like 360 or mega live.

My group 31 Interstate is rated for 98ah. Actual capacity running electronics is likely significantly less than that due to voltage drop. Something you don’t get so much of with a lithium. I went that route because I couldn’t stomach the cost of a lithium that size.

Amp draw is easy to figure out with a multi-meter. Screen brightness plays a huge factor, with a big difference between 90-100%

Here’s a video I found testing a Helix 10. I’d say a 1.75 amp draw would be about right for a 12 with it at 100% brightness.

Iowaboy1 wrote:

Red Eye, what brand and HP of motor are you running?
The reason I ask if it is an older one, say pre 2005 the stator type charging systems are not designed to nor will they charge a lithium battery.
They wont charge a maintenance free or AGM battery either.

I don’t get it,I ran an AGM battery with my Yamaha 50 2-stroke for 14 years without an issue. Currently running a Lifepo4 battery with a Honda 50,now going on year 4.Using a battery qualified for cranking(LBP/Ionic).

milemark_714, the motors I am talking about are Johnson/Evinrude, and Mercury.
Their charging systems were designed to use an old school lead acid battery as the FINAL voltage regulator, they were very basic systems that would maintain a battery.
AGM, dry cell, maintenance free batteries didnt exist when these charging systems were being used and they have a different chemistry that those systems cannot over come to charge.
Symptoms are, burned out voltage rectifier/regulator, burned out stators and wiring most often accompanied by burnt ignition systems.
On those old systems when the rectifier/regulators diode goes out the charging system can charge as high as 330 volts AC and at up to 35 amps depending on the rated capacity of the system.

AC voltage instantly takes out the ignition system when this happens as it is a DC circuit.
Stator type charging systems are still used today without much of an upgrade from just a few years ago.
Honda, Yamaha, and Suzuki used a different design that wasnt nearly as touchy.
I hope that helps, you can always call me at the shop if you want to learn more, just shoot me a pm.

Iowaboy1 wrote:

milemark_714, the motors I am talking about are Johnson/Evinrude, and Mercury.
Their charging systems were designed to use an old school lead acid battery as the FINAL voltage regulator, they were very basic systems that would maintain a battery.
AGM, dry cell, maintenance free batteries didnt exist when these charging systems were being used and they have a different chemistry that those systems cannot over come to charge.
Symptoms are, burned out voltage rectifier/regulator, burned out stators and wiring most often accompanied by burnt ignition systems.
On those old systems when the rectifier/regulators diode goes out the charging system can charge as high as 330 volts AC and at up to 35 amps depending on the rated capacity of the system.

AC voltage instantly takes out the ignition system when this happens as it is a DC circuit.
Stator type charging systems are still used today without much of an upgrade from just a few years ago.
Honda, Yamaha, and Suzuki used a different design that wasnt nearly as touchy.
I hope that helps, you can always call me at the shop if you want to learn more, just shoot me a pm.

This used to be a major concern but with the new BMS ( battery management systems ) on SOME of the newer batterie’s the concern is fading. More and more companies are coming out with LifePo4 batteries that have starting capability.

I have a Lifepo4 in my 1996 Polaris 4 wheeler with stator charging system going on 4 years and not one hiccup. When it gets to zero F or below it will take about 3 times trying to start it until the battery warms up some before she finally starts.

Tom, the rectifier/regulator is where the difference is, as I said about the outboards I mentioned, the battery is the FINAL voltage regulator and they will not charge the battery type like you are using, nor any of the ones I mentioned.
They may attempt to but will not last very long at all, sometimes as little as ten seconds before they burn out.

Joe Jarl wrote:

Running 2 of the 12’s would be 6.4 amps total x 12 hours = 76.8 amp hours if you’re not running anything else like 360 or mega live.

That’s what I’d go by too. They state in their specs that a Helix 12 uses 3.2 amps/hour and Humminbird didn’t just pull the numbers out of the air. I like to go with a battery that’s 10% or so larger than I calculate if I can when I buy batteries, just for piece of mind if nothing else.
I did something similar last summer and bought a dedicated 80Ah AMPED lithium battery for some of my electronics that I calculated would use 67.5 amps if I used the electronics hooked to it 100% of the time in a 10 hour day which is more than I usually fish in a day.
I just charge it at the same time I charge my trolling motor batteries when I come in at night. It works pretty nice.

Thanks Iowaboy,I haven’t owned those brands in many years.The thing with lifepo4 batteries is how they handle charging current.A call to the seller would be in order,that’s what I did before plunking down the cash.The cheaper ones will cause problems when used for starting,they can’t handle charging voltage and will shut off.It’s how the BMS is programmed.

Also when using them in cold weather,it helps to cycle the trim/tilt before cranking for faster starts.Again,the better batteries handle cold charging better and will not shut off or get destroyed.Heated are best option for sub 32F temps.