Are Dual Batteries Really Necessary in All Cases?

[Saxe Point]

I finally sprung for an electric downrigger and am wondering whether a second battery in my boat is really necessary. I know this has been covered a bit before, but I would be grateful for the wisdom and experience of the forum members. Here are the details.

16 Double Eagle with 90 Johnson and T8 hp Yamaha High Thrust kicker (2008, pull start). Both motors have regulator/rectifiers connected to my battery. When trolling I run a Garmin GPSMAP 421 chartplotter and Lowrance X-4 Pro fishfinder, as well as a Standard Horizon VHF. According to the specification sheets, each of these draws minimal current and I have never even experienced a hint of a stutter when starting my main motor. The used electric rigger I just got is not an HP, but the regular Depth Power. I plan on getting a second one down the road.

I'll say first off that there is no question that a second battery offers peace of mind. But I wonder if it is necessary as my current electrical load is inconsequential and although I have no experience with electric riggers, I suspect that even with a fair bit of "up & down" on 2 riggers, my kicker will be able to keep the battery charged. I also keep a portable jump starter/power pack in my boat anyway, to get my main motor started if the battery dies.

Does anyone else in a situation like mine just go with a single battery and a back up power pack? For bigger boats with lots more electrical accessories and HP riggers, 2 batteries for sure, but my situation seems different.

Again, experience and advice of members would be most appreciated.

 

[profisher]

I would say that as long as your main engine is a reliable and consistent easy starter you are ok with a single. Having the power pcak is back up enough.

 

[Sharphooks]

I think it's a bit like saying: are four brakes necessary on a dual axle trailer?

Two brakes on one axle will probably work in most conditions (flat highway driving, towing vehicle with a fairly significant footprint and GVW, reasonable size boat etc) but towing your trailer from let's say, Campbell River to Port Hardy, or Nanaimo to Ucluelet? Different story (also, I think you're probably not legal having two brakes on a dual axle but that's a different story...).

I'm a dual battery guy...."just in case"...

My Honda 9.9 has a 12 Amp alternator, but when I run my Depthpower Scotties, there's a noticeable drop in RPM's. That tells me those Scottys draw some juice, especially when fishing deeper water like I had to do this summer

I want my main engine battery (as opposed to house battery) to be fully charged and ready to turn over my main engine at all times.

Just my .02. Results will vary (as much as opinions)

 

[Wooly]

Your good to go!

As long as you have a backup and keep you batt maintained and in good shape you wont have issues. I had a 19 ft harbercraft with 1 battery I kept it on good shape for 6 years and put over 1000 hours on the engine and never had an issue. Ran 2 electric d riggers, all electronics and charged stuff off the battery. As long as you have a way of charging it if it dies or a way to start the kicker to charge your battery you will be fine. Having said that dual batteries is a great idea. I have a new wooldridge getting built for me right now. 24 ft, and I have 3 batteries in it. But I also have lots of electronics and a fridge. Anyway Just letting you know I ran of 1 battery with a similar setup as you for 6 years and never had an issue.

Cheers,

 

[CCB]

I have a 23.5 Trophy full Alaskan package with fridge and all that lots of lights and what not but when I was running my down riggers for long stretches of time radio and all electronics my batteries died even when only on one I had to start the boat numerous times . Lucky it had enough juice to turn over on 2.That being said I only had a 9.9 Merc pull start.Without even selling that I up grated to 9.9 bigfoot added another GPS Unit and now I run 3 units my radio/Cd player for hours and it fires up all the time.I don't have to worry about the batteries going dead my kicker like your kicker keeps them juiced up.I have had this for 3 years and not once had to worry about it.The main motor has nothing to do with the battery while your trolling unless your trolling with the main motor.Another benefit of 2 batteries is if one goes completely dead you have a spare.The electronics will all be hooked up to one but the cranking too both .The down riggers suck a lot of juice kicker that charges is a must.There so many electronics on the boat like everything even plugging in a ipod or iphone or whatever else it all sucks juice.If your battery goes dead dead like not chargeable then a power pack is useless.its rare both batteries do this on the water at the same time in storage yes but not on the water.Just my experience .

 

[tubber]

Where's Charlie? Pretty sure having 2 charging outboard motors connected to one battery can lead to problems with things like stators and possibly the battery itself(overcharged) if both motors are ever run at the same time. If your boat has room for the space/weight of a booster pack, why not get rid of that and add a battery for the kicker and riggers and throw in a set of booster cables for just in case. Or keep the booster pack if you have room. No need for Perko switch in a small boat is what I've been reading on various forums. As always, I stand to be corrected by the more experienced.

 

[Lipripper]

You're good.....

 

[MRACER]

i THINK YOU ARE GOOD WITH THE POWER PACK BACK UP--i HAVE 2 HOUSE FOR MY ELECTRONICS AND 2 FOR STARTING--OBVIOUSLY i AM PARANOID! (sorry about the caps!) Going to install a small solar charger for the house units...I like 4 engine airplanes too, but as soon as they offer 6 engine ones-they will be my choice-LOL

 

[wstcoaster]

i have run a 16 ft armstrong boat for 12 yrs about the same electronics as you never had a problem as long as the battery was charged every month or so two downriggers also

 

[Rockfish]

Lots of guys run one battery in a boat your size with minimal amp draws but if space or weight is not an issue, two offers a safety factor. I think you are good with one and your back up starting pack but there is a better alternative. For close to the same weight and space as your starter pack, why not keep a fully charged not hooked up starting battery on your boat with some jumper cables. You would have much more reserve and higher cranking amps for an emergency.

With one battery or two for that matter, battery condition is critical for you. I use maintenance free batteries but that still means removing and cleaning and checking your connections every year and coating with appropriate corrosion protection. In addition it is a good Idea to swap out you batteries every few years before they get weak or at the first sign of problems. Buy the best batteries available with max reserve.

When I replace my batteries I keep the best of the two being replaced as a spare completely independent from my two main batteries and not connected . There are also long jumper cables on the boat and I use the weight of the third battery to help counter balance the weight of my kicker which is on an outside corner of the Pod. Those starter packs don’t have sufficient cranking amps on their own to start my big Opti.

Volt meters or smart meters systems with alarms on your helm station are useful. Better to know your batteries are not charging before they are drained. With three charged batteries I know that even if my charging system on my main failed I could turn off everything and have sufficient reserve power in the two connected batteries to run my main motor for a good long distance. I could then start my kicker with the independent battery and slow go home the rest of the way while recharging my connected batteries if I needed to go back on the main. Also if I were to suspect that for some reason my main batteries were low on charge I would leave my kicker with its 11 amp charging system running to assist the main in starting up but would not do this otherwise because of the risk of damage to motor electronics.

I recently had a problem with the duel batteries in my big pickup with a 10,000 lb Warn. Both were less than a year old and one developed a bad cell and drained the other battery and kept it from charging, even with some fancy separator system. When the truck was jump started it would run but would not charge the one good battery, possibly because the other had a bad cell. This convinced me that duel batteries are not completely failure free even with isolator systems.

If necessary I can disconnect my main batteries on the boat and swap out one and isolate the replacement with the Perko for getting home. If in a time sensitive emergency I can hook up the jumper cables.

Battery/power failure is a common problem on the water just as with vehicles and if it came down to it and I had to help a fellow boater with a dead battery, I would rather use my independent non connected battery and jumpers to start him or even lend him the battery and starter cables and tools to install it rather than have to go through all the risks and problems associated with towing him. Jumping someone off your connected batteries can sometimes cause damage, what with all the sensitive electronics built into modern motors and then you both have problems. Hope this is useful.

 

[Seafever]

I run off one battery with two depthpower electric riggers. Battery is a Nautilus spiral cell.

It's now about 4 years old.

My kicker does not have charger....main engine does.

if I'm fishing Springs I'll use the kicker......if I'm fishing Coho I use the main.

last few times out....fishing for Coho....and tons of shakers around....so the lines are coming up and down all day long steady.

No problem with the batt.....no power loss, no dead battery......but the main engine is running all the time charging on days like that.

Fried a battery in the past with an aftermarket charger on my old engine that had no "charge-limiter" on it. The newer engine chargers have this feature. (Mine will not charge over 15 volts).

For small boats the Nautilus Spiral Cell is good (Can Tire). No plate deterioration, no acid spillage. They cost about 200 bucks.
But before that the normal "marine" wet batteries were letting me down. Plates in the battery would fall apart from normal vibration and pounding chop.

If I think the battery might be too charged up from long trolling session, I turn the lights on to burn off some juice.

My kicker is pull start so if batt failure, it will start anyway.

My main is combo electric start/pull start....so if batt failure I can pull start it as long as key is "on"........the charger on main would be running then , but it is o.k. if charger is running into a "defunct' battery (one that is dead and won't charge). It doesn't hurt charger.
What hurts charger is if you unhook the battery leads and run engine with nothing hooked up or if you touch the wires together while it is running but not hooked up to battery.

 

[Rockfish]

I run off one battery with two depthpower electric riggers. Battery is a Nautilus spiral cell.

It's now about 4 years old.

My kicker does not have charger....main engine does.


For small boats the Nautilus Spiral Cell is good (Can Tire). No plate deterioration, no acid spillage. They cost about 200 bucks.
But before that the normal "marine" wet batteries were letting me down. Plates in the battery would fall apart from normal vibration and pounding chop.


.

In my younger days I did a lot of 4x4 off road stuff. I bought a special off road battery that had heavy duty plates and vibration protection designed to take a pounding. One would like to think special purpose marine batteries would be built to a similar standard. So far no problems of this nature with my marine batteries.

 

[Seafever]

I think any battery that is the "wet" type with separated plates in it is subject to pieces of the plating flaking off under vibratorial duress and pounding.

My wet batteries I used to use were marine-type deep cycle.They would usually die after about a year. They weren't cheapos but they weren't the most expensive either.....I heard Surette batteries were pretty good but you pay for 'em.

The Nautilus is a marine deep-cycle...but it doesn't have wet acid in it and it's built internally different than a wet battery. The coils are spiral inside a thick gel substance. You can turn it upside down and it won't spill.

 

[Foxsea]

I finally sprung for an electric downrigger and am wondering whether a second battery in my boat is really necessary. I know this has been covered a bit before, but I would be grateful for the wisdom and experience of the forum members.

We rely so much on our batteries for everything safety-related, from pumps to nav lights to VHF, I'll always go with 2.
However, I'd suggest that if you head out with only one battery, make it a good one - and well maintained. Here's a couple of interesting battery threads from the past:

http://www.sportfishingbc.com/forum/showthread.php?18567-need-new-battery&highlight=batteries

Charlie has some good info here:
http://www.sportfishingbc.com/forum/showthread.php?19173-Battery-help&highlight=back-up+battery

 

[searun]

Just recognizing the need to ask the question should be reason enough for 2 batteries. The sea is unforgiving and so much depends on good batteries. More is better.

 

[AlK]

I run 2 batteries. One battery is dedicated for starting the main engine the other is the house battery and it handles everything else. The batteries are connected to a Blue Sea ACR and a switch.

 

[Saxe Point]

Thanks very much to each of you for all your viewpoints. You've given me a lot to think about.

 

[Charlie]

I run 2 batteries. One battery is dedicated for starting the main engine the other is the house battery and it handles everything else. The batteries are connected to a Blue Sea ACR and a switch.

Not sure what you mean by "switch" and wondering if that refers to the "Dual Circuit Plus Battery Switch"?

Everyone's situation is different and an “Automatic Charging Relay” (ACR) is fine; but without that Dual Circuit Plus Battery Switch I really would NOT suggest using the ACR alone as the ACR is only disigned to combine the different battery banks during charging and isolate them while not charging. That is fine if that is really what you want to accomplish - charging two separate battery banks from one charging source. Keep in mind while those batteries are connected in parallel sending the charge to those two batteries from a kicker producing a MAXIMUM of 6 amps the most each battery is going to get is 3 amps. If you are using 10 amps, and that done long enough that battery discharging and is going to be discharged to the point the ACR safety feature (“Undervoltage Lockout”) is going to reach its level and lock that battery out of the charging system and you will end up with one each battery - DEAD. Hopefully, that lockout level will be reached and the lockout occur before both batteries EQUALIZES to the lower battery’s level during the period the ACR has them combined? If not, you very well could still have result of TWO batteries discharged (and/or - DEAD) to the point neither will start your main. I would highly suggest "IF" you have installed an ACR, you also install the “Dual Circuit Plus Battery Switch” to properly manage your batteries, especially to have the ability to ONLY charge the battery needing the charge. I do quote:

"An ACR does not direct the charge to the battery that “needs it the most” or has the lowest terminal voltage. If there is a charge present on either battery, indicated by a high enough voltage, the ACR will combine the batteries. To read more about this subject click here to download the ADD-A-BATTERY Sales Sheet (1000kb - PDF file).

“As a safety feature, some ACRs prevent combining into a severely discharged battery. A dual-sensing ACR will monitor the voltage on both batteries and will not connect if either battery is below the undervoltage lockout level. Use caution when combining into a battery with extremely low voltage, because this might represent a faulty battery or a problem elsewhere in the system.

"Before replacing your charger or inverter/charger, consider the benefits of an ACR; and for a fully automatic system, add a Dual Circuit Plus™ Battery Switch.

Just something to keep in mind!

 

[2xeagle16]

I have a 16 Double Eagle also with a 90 and a T8. I run 3 Scotty electric downriggers, Gps/Sounder, Trollmaster and sometimes a window defogger - with one battery that has lasted 5 1/2 years and still going strong. My concern with two batteries would be the extra dead weight in the back of you're boat.

 

[Saxe Point]

Thanks again guys. If I decide to go with just one battery, what are the good choices in terms of brands? I know that this has also been covered to some extent before, but what are the better batteries that aren't ridiculously expensive? I know that the WalMart/Canadian Tire/Costco brands are all made by one of two or three main manufacturers. Is one of those as good as any of the higher end batteries?