Electronics Battery Usage

[nhxrunner]

Spring is coming and it need batteries. What is typical battery usage for a boat equipped with HDS electronics? I'm running a pair of HDS7 Gen 2 Touch and the Point 1. Side scan in the console and the HD transducer for downscan on the bow. My batteries have failed and want to be sure I'm running the proper number of batteries for my setup. I had the switchable 12v/24v trolling motor tied to a pair of interstate SRM-27s. The electronics were also tied to one of the SRM-27s. The SonicHub was the only accessory tied to the 3rd battery (Interstate Starting). Do I need a 4th battery for the electronics? I didn't think they used that much power but maybe I'm wrong. If I do what size would you recommend? I thought that I've read that guys run their electronics of the starter battery, but I've always been worried about draining the starter battery over a long day and getting stranded.

[akaslyguy]

Honestly, I would not run anything on the trolling motor batteries except for the trolling motor. I have been running HDS electronics (2x hds 9 touch units, lss2 and regular skimmer transducers on transom, hdi transducer on bow, NMEA network, point 1) on a group 27 everstart battery that is used for starting my 200 efi, running livewell, occasional radio, and everything else that is wired to the boat. I recently upgraded my battery to the Sams Club Duracell AGM 31 though. My everstart was almost 5 years old and I decided to replace and upgrade.

I use 3 batteries in my boat. 2 for trolling motor and one for starting. My trolling motor batteries are the same everstart group 27's, but soon to be either the group 29 everstart maxx or the Sams Duracell group 31 wet cell.

[Fishysam]

Shouldn't need a fourth battery and I wouldn't run hds off trolling batteries. Run everything off the starting I'm thinking your hds's use 1ah each =1 amp per hour each =2ah a high quality starting battery will have 1000 cold cranking amps, and a reserve of over 200ah, I can't imagine a new health battery having an issue. I ran 2 blades 2 hds9' and two bird 999's and other accessories for a season long hours and dint have an issue

i did put my 2 blades on trolling batteries tho. Reason you don't want sonars on tm bats is it makes it very likely to get rf interferance

[catdude28]

If your 27 series have been adequate for the troller, then simply replace those with the same, or go 31's if you want larger capacity. A group 31 series will do the job for the cranker, and, as mentioned, all electronics should be hooked to it. Probably best to stick with a wet battery for cranking with your EFI. With a quality crank battery and healthy charging habits, you should be fine.

[nhxrunner]

Thanks for all the responses guys. I'll look into a larger starting battery and 2 trolling batts. Anyone have a brand preference?

[nhxrunner]

Bumpity bump

[PECo]

Lots of people have a battery preference.

While I like the idea of AGMs and have used them in the past, there are plenty of good, much less expensively replaced, flooded lead acid batteries on the market. A fresh flooded lead acid battery is at least as good as an old AGM battery.

[nhxrunner]

I've done a little research and contrary to what the picture shows, this batt is a dual purpose. Can anyone else confirm? I'd be using this as the starting/electronics batt.

https://www.samsclub.com/sams/durace...to:product:1:1

[catdude28]

Pretty sure that with that EFI engine that it is suggested to stay away from an AGM and stick with wet battery for cranking.

[bgibson]

For the EFI get a Maxx Marine 29 series battery from Walmart. The 27 series for the trolling motor. Good to Go!

[nhxrunner]

What's the reasoning behind not using an AGM for starting on an EFI? Everything in EFi these days, and AGM are widely used.....

[DrewFlu33]

What's the reasoning behind not using an AGM for starting on an EFI? Everything in EFi these days, and AGM are widely used.....

Don Weed on the Mercury forums recommends not using AGMs for EFIs. I believe I recall his reasoning being that the stator-type charging system on the EFIs can't correctly charge AGM batteries. This makes a lot of sense to me, as we all know that our on-board chargers sometimes aren't compatible with AGMs or at least must have a different charging mode to charge them.

The Optimaxes are a different story (DFI instead of EFI as well). I don't think it has anything to do with the fuel system, but more to do with the other parts on the motor.

The good thing here is that AGMs (the economical ones, at least) really don't have any additional capacity over similarly sized lead acids and generally weigh more. While they have better longevity in terms of charging cycles and are maintenance free, you can buy two lead acids for the price of even a cheap AGM. Do you expect the AGM to last more than twice as long as a lead acid? Maybe...but the difference is pretty minor in my opinion.

As long as your charger is okay with it, AGMs should be fine for your trolling motor batteries.

[DrewFlu33]

A battery I've been eyeing for a cranking battery lately is the Duracell Commercial available at Sam's Club. Not technically a marine battery per se, but I'm personally not all that concerned with my boat being harder on my battery than a fork truck or big rig that bounces all over God's creation.

The 31-P model seems to have the same terminals as most of our marine crankers, checks in at $100, and offers 950 cca and 1170 ca. Pretty stout, in my mind! LINK

[catdude28]

A battery I've been eyeing for a cranking battery lately is the Duracell Commercial available at Sam's Club. Not technically a marine battery per se, but I'm personally not all that concerned with my boat being harder on my battery than a fork truck or big rig that bounces all over God's creation. LINK

I have a Deka/East Penn commercial/fleet 31 truck battery in my P2, going on 3rd year, still as strong as ever. Specs are 1060 cca's, 1300 mca's, 190 reserve. Had a fleet battery in my previous rig also. They work great. Great bang for the buck. Rebadged for NAPA Canada.

[DrewFlu33]

I have a Deka/East Penn commercial/fleet 31 truck battery in my P2, going on 3rd year, still as strong as ever. Specs are 1060 cca's, 1300 mca's, 190 reserve. Had a fleet battery in my previous rig also. They work great. Great bang for the buck. Rebadged for NAPA Canada.

Maybe you know the answer to this because I've certainly been wondering: how in the world do NAPA's group 31 commercials have more "juice" than the Duracells? Same thing in the US, though I don't think they're as high as what you list for yours. They're both made by East Penn, right? Does East Penn just build that one to better specs? Or is there something screwy going on with the posted ratings on these? I've often read about people "home-testing" East Penn batteries and coming up with higher-than-advertised figures....

[nhxrunner]

So to follow up on the AGM charging off the EFI issue. All 3 of my batteries will be connected to a 3 bank on-board smart charger that will be plugged in after every use. Does that change things? Or would the run time charging off the EFI damage the AGM?

[catdude28]

how in the world do NAPA's group 31 commercials have more "juice" than the Duracells? Does East Penn just build that one to better specs?

I suspect that would be why. They likely sell a great deal of these fleet batteries, so they have a specific line and build them to better specs. Napa Canada has a whole line of them. The three with cca's all over 800 have 950 cca's and 1170 mca's (same as your 31-P), 1060 cca's and 1300 mca's, and 1000 cca's and 1230 mca's. It was one of the bass cat dealers who introduced me to the idea of using these truck batteries a few years ago. I likely will never use anything else for cranking. I take good care of my batteries, these truck batteries are very reasonable in price, and have great specs. I don't need AGM.

One of these would also be a very safe choice for the OP. From what I have read, that EFI still likes a lot of cca's, but needs a flooded battery.

[Lou r Pitcher]

recommends not using AGMs for EFIs. I believe I recall his reasoning being that the stator-type charging system on the EFIs can't correctly charge AGM batteries. This makes a lot of sense to me, as we all know that our on-board chargers sometimes aren't compatible with AGMs or at least must have a different charging mode to charge them.

The AGMs are very compatible with automobile charging circuits. All AGMs do have a maximum allowed charging voltage that if exceeded could convert the electrolyte to gas (bubble) leading to increased pressures within the normally sealed battery cases. If the AGM's valve were to release, the release of gasses results in permanent loss of electrolyte and reduces the capacity of the AGM .

Don't have an EFI, but would not expect to find that its regulated charging voltages could exceed the voltage limit of an AGM.

Instead of voltage, could see that the low typical internal resistances of large capacity heavily discharged AGMs might result in a outboard's such as the EFI or an E-TEC having a water cooled charging circuit might overheat and possibly fail. In fact, such charging circuit failures have been reported quickly following owners choosing to place two AGMs in parallel on an outboard engine to allow them longer times before a need for recharging.

[DrewFlu33]

I suspect that would be why. They likely sell a great deal of these fleet batteries, so they have a specific line and build them to better specs. Napa Canada has a whole line of them. The three with cca's all over 800 have 950 cca's and 1170 mca's (same as your 31-P), 1060 cca's and 1300 mca's, and 1000 cca's and 1230 mca's. It was one of the bass cat dealers who introduced me to the idea of using these truck batteries a few years ago. I likely will never use anything else for cranking. I take good care of my batteries, these truck batteries are very reasonable in price, and have great specs. I don't need AGM.

One of these would also be a very safe choice for the OP. From what I have read, that EFI still likes a lot of cca's, but needs a flooded battery.

That's a really good point. I didn't even really consider the sheer volume of commercial and fleet customers that NAPA serves. Thanks for the info, and hopefully it was useful for the OP such that I didn't hijack the post with my little tangent!

So to follow up on the AGM charging off the EFI issue. All 3 of my batteries will be connected to a 3 bank on-board smart charger that will be plugged in after every use. Does that change things? Or would the run time charging off the EFI damage the AGM?

I'd have to defer to the experts on that one. You could drop into the Mercury forums and ask the question and I'm confident you'll have a great answer in short order. Otherwise, it sounds to me like Lou r has a good explanation!

One thing I'll add that completely jives with his explanation is that I've found that my on-board charger charges at a significantly lower voltage when in AGM mode versus "regular" mode. With that line of thinking, given that the stators on older EFIs charge lead acids well, it seems like it's pretty likely that the stators charge at a voltage that's high enough to damage an AGM, no? IF that's the case, maybe installing a voltage regulator of some sort could remedy the issue. That's above my pay grade and definitely not something I'd be willing to risk with such an expensive test subject....

[RANGER487]

For the EFI get a Maxx Marine 29 series battery from Walmart. The 27 series for the trolling motor. Good to Go!

This is what I have and they are going on there 4th year with no problems