P1000 Pro's and Con's of isolated 2nd battery for accessories vs 2 batteries in parallel

[Jason312]

Hi folks.

I've done some searching but can't find any info on running 2 regular batteries in parallel.
Looks like everyone is adding a second deep cycle battery with an isolator to run all their accessories.

However, I don't have a lot of accessories. I have a winch which is a biggie when it's being used but is only used a few times a year plus lifting my plow which should't tax a 5k lb winch much to lift a couple huntred pound plow a few inches with block and tackle set up.

I am thinking 2 batteries in parallel like diesel trucks use would be a better way to go and a lot cheaper and simpler to install. This would give my starting system more umph in the cold and should be better for the tranny etc.....
I will be running Camso tracks and plowing so a lot of cold winter operations where I want extra starting power.

What are the opinions of the electrical pro's out there???

 

[Admin]

 

[Scoop]

I'm no electrical genius, but IMHO the disadvantage of running in parallel vs running an isolator is you get zero protection from running both batteries down at the same time. I'd rather have one dead battery and some accessories not work but still be able to start and get home because the starter and DTC had adequate power from a full battery. The cost of an isolator is dirt cheap compared to both what we put into all other accessories (and the unit itself) versus the cost of being stranded. At least for me this is a deciding factor.

 

[Jason312]

Thanks Scoop!

I agree that the isolator gives you protection from running your main battery dead from over use of accessories. That way you always have the main battery for starting and DCT.

My delema is that I don't run a lot of accessories so I don't think an accessory only battery is justified.
All I run is a winch at times and always with the engine running so I'm thinking 2 regular batteries in parallel always supplying the starting and DCT functions would be better.

Any other thoughts?

 

[Scoop]

If you're not planning on running (m)any accessories, then I'd also say that installing a dual battery setup (either way) could be overkill - unless you live in a (very) cold weather climate.

I've been running a (heavy) Warn ProVantage plow setup (including the ProPivot (power side to side) and a Superwinch Terra 35SR) on a 2014 Yamaha Grizzly 700 with its small single OEM sized battery and haven't had a single battery issue in nearly 8 years here in SE Michigan.

 

[bumperm]

Advantage in an isolated battery is redundancy. If you have to winch, you may not be in a situation that allows you to run the engine while winching (or wenching either, for that matter). That, and it provides a level of redundancy you don't get with two batteries in parallel. Say one cell shorts, you can end up with two batteries down wasted.

When batteries are connected in parallel, they should be the same brand, size, and age. With a isolator, such as the True, different is fine - they even have a version for adding a LiFePO4 battery.

 

[Jason312]

Ok, I see your point about possibly having a dead engine and needing to winch it.

I also see the advantage of being able to mix batteries versus buying 2 identical new ones to connect in parallel.

I didn't know they had to match that precisely and was thinking I could just add a similar 2nd battery at any time.

Thanks!

 

[trigger]

Been running two batteries in parallel for 5 yrs on my machine. An isolator is just another electrical component to take a crap IMO. If you're the type to sit around playing the stereo without the engine running then the isolator is the way to go. Even then I wouldn't go with the True one, consider a manual one instead. Another thing to consider is that the second battery will only see charge after the first. Multiple short runs means the second battery won't see any charge. Also if stuck in a mud hole and you drain the second battery dead, you have a fully charged primary that you can't use. Two in parallel work as one big battery.

 

[Scoop]

There are far more accessories than just a stereo that people can/will install and use that can take down a battery with extended use. Boats have used isolated start and "house" batteries for decades.

 

[StewB]

Jason312 - I'm pasting a slightly edited post I made re my decision. I've already plowed twice this year on the Wasatch Back; hope you're down south where it's warmer. (Was in the GSENM two weeks ago, beautiful.)


_________________________________________________

I had the same question a few months ago and after sifting through a lot of info. decided to add a second battery with an isolator for my 2021 P1K5 LE.

I have a winch and lights and use both for plowing quite a bit, which means lights, shifting and lifting. I also ride way, way out there alone and like the peace of mind of a second battery.

There is a key difference in set ups that others noted above. You can parallel two batteries, hook new accessories to the main battery, and that will work just fine. The batteries will, however, live together and die together because the lower-charge/failing battery will suck down the stronger battery. It still works and might be the solution for you.

If you use an isolator, put all of the new accessories on the second battery. That will save the main battery for starting and shifting, while putting the add-on load entirely on the second battery. If the second battery is low, you can still start and drive the machine and it will re-charge the second battery or at least get you home. And if your main battery dies, you can use the second battery to jumpstart.

Gratuitous thoughts: the winch should be tied straight to the battery because of the high load, but I really suggest using an automotive relay and car/marine fuse power block for the other accessories - about $20 for a relay and six tap fuse block. Using a fuse block makes adding new accessories super easy and you can get rid of the in-line fuses. Rather than hunting down scattered in-line fuses, they will all be in one place - just make sure to use the right amp fuse for the specific accessory.



This is my dual battery set up. The isolator is just out of the picture (mounted in the flat oval near the anti-freeze fill cap) and the winch relay and breaker are mounted out of view on the right. This shows off my super-engineered Gorilla tape battery lifter (we've come a long way from duct tape, baby!) and I also added a 30A circuit breaker (far left) primarily so I can cut the power to the system (about $20 for the circuit breaker). Don't tell my wife, but I didn't really need the circuit breaker, I just thought it'd be cool.

Negative is hard-wired from the battery to the negative bus on the new fuse box (out of view on bottom of the fuse box).
Positive runs from battery to top of the 30A circuit breaker to the relay to the new fuse box. The relay (next to the fuse box) is a standard 30A automotive relay that is key on power (KOP) switched from a PosiTap on the factory acc. fuse. You need to pick the right side of the acc. fuse to tap, so read about it; I forgot which one it is and don't know if it's different in other model years.

All of my accessories and their relay switches run through the new fuse box (winch relay, light relay, dual battery voltage meter, wireless winch remote).

Good luck!
___________________________________

End paste.

If you don't like your first choice, you can change your mind later.

 

[Jason312]

Great to hear of someone who is running 2 batteries in parallel. I searched but not found anything on it.

I never plan to install a stereo or any accessories that would be running when the engine is off so that's not an issue. I like the peace and quiet of the outdoors so I don't want to mess that up with a radio.

I could totally justify an isolator on a boat that has an electric trolling motor. You could be running the electric motor all day without the main engine running and charging the batteries.

I do like the idea of 1 big battery but I don't want to install an automotive under the seat since I use that for storage. That's what was leading me to 2 batteries in parallel. I just hadn't seen anyone who has done it and was wondering why.

I think for my situation 2 in parallel (like 1 BIG battery) is the way to go and a simpler setup. Simple is good!!!
It may be over-kill like Scoop stated but I guess I feel like it's better insurance for winter time.
I really think a battery dedicated just to accessories is over-kill for me! However, there are pros and cons to each way which is why I started this thread.

Thanks again for all the input!!

 

[Scoop]

That's what was leading me to 2 batteries in parallel. I just hadn't seen anyone who has done it and was wondering why.

Now think about that ...

Sounds like your particular requirements may benefit more from a parallel setup, so ...

 

[bumperm]

Another thing to consider is that the second battery will only see charge after the first. Multiple short runs means the second battery won't see any charge. Also if stuck in a mud hole and you drain the second battery dead, you have a fully charged primary that you can't use. Two in parallel work as one big battery.

I respectfully disagree (albeit strongly). As soon as you start the engine, the main battery is being charged and it's voltage will normally rise quickly above 13.4 volts. I see 14.2 volts almost immediately upon engine start. This is so as the internal resistance of a Pb battery is relatively high (compared to say a lithium battery), so a discharged Pb battery won't suck down the system voltage by drawing too much current. This also assumes you are not otherwise loading down the stator based charging system, which on a p1000 is capable of putting out 50 amps (600W at 12V) IIRC. The result is that charging voltage rises more quickly than charge rate in amps. You can check it with a voltmeter (or the dual voltmeter that's included with the True). The True's switching to charge the aux typically happens within a minute or two, though usually just seconds, so the aux battery will get charged even on the multiple short run example you used.

As to having a " . . . fully charged primary that you can't use", you might need to explain that one a bit further, please. If you have two batteries in parallel and draw them both down, absent a way of charging them, you are stuck and will need a jump. If you have isolated main and aux batteries, you can discharge either all the way and still jump one from the other. If it's the aux that's discharged, just start the engine, drive away and the aux get's charged. If it's the main that's DOA, probably a rare event in an isolated battery equipped rig, absent something wrong with the main battery, you can carry a short jumper cable to jump start the main from the aux, or carry one of the Lithium powered jump starters for a doubly redundant system. With that short jumper, you could even disconnect a defective main and jury rig to operate from the aux for the drive home, (another very unlikely scenario, I'd guess).

At least with the P1K, my understanding is it needs reasonable voltage to both start and then run properly due to the electrical needs of the computer, shift motor, DCT, and other running gear do-dads. So either a big or two parallel battery set up that's DOA isn't gonna be of much comfort or use. At least with an isolated setup, running the aux battery into the ground while winching, given a situation where you can't run the engine to help provide power for the winch, would still be a non-event. Winch out on the aux, start up on the main, then drive away while the aux is charging.

BTW, True suggests hooking up any external charger to the aux battery. Their logic is that if a battery is low, it'll most often be the aux. On trickle charge, once the aux climbs past 13.4, the main battery starts charging too, so nothing lost, even if you don't have time to top off the aux with the wall charger - it'll continue to charge while driving. That's the way I've connected my external trickle charger socket. That logic is based on the fact that with the True, either battery voltage, that rises over 13.4 will charge the other battery (a blue LED comes on to indicate this condition).

No matter which way you slice it, either parallel or isolated will work - advantages and disadvantages to both. That said, it's good to be informed on those advantages and disadvantages in making a decision. Erroneous information is of no help.

 

[Scoop]

Appreciate the in-depth explanation for those of us who aren't as electrically knowledgeable as you, @bumperm 👍

 

[Jason312]

What he said ^^^^^^^^^^^^ !!!!!!

It's always good to hear from someone knowlegeable in the subject.
I wish I was more electricly inclined.....Luck for me I've got a 50/50 chance of hooking the battery up correctly

So my takeaway is neither way is bad but it appears there are more pro's to having an isolated battery. As stated above, I don't have many accessories but the winch is a big one when being used.
I could view the isolated battery as a portable (perminently attatched) emergency jump starter.

Now I'm leaning to the isolated route.

Thanks!!!!!

 

[Jason312]

@StewB I'm in Cache valley. I don't mind the cold and snow but that's slowly changing as I get older :/
I've never been to GSENM. All I've been to is Arches. I need to spend more time in southern Utah.
I also end up way out especially with tracks in the winter and having a back up jump start battery is definitely a big plus for me.

Thanks for the pic. It's nice to see where others have mounted their accessories. If I go this route I will definitly use the relay and fuse/power block like you did.

 

[StewB]

Lived in Cache Valley for 15 years and consider it god's country. Still, it gets cold as hell.
The True isolator is easy to install, should last as long as your machine, and does give you a built-in jump starter.
Dig around this site. There are a lot of good ideas about where to mount fuse boxes and relays.
Best.

 

[trigger]

I respectfully disagree (albeit strongly). As soon as you start the engine, the main battery is being charged and it's voltage will normally rise quickly above 13.4 volts. I see 14.2 volts almost immediately upon engine start. This is so as the internal resistance of a Pb battery is relatively high (compared to say a lithium battery), so a discharged Pb battery won't suck down the system voltage by drawing too much current. This also assumes you are not otherwise loading down the stator based charging system, which on a p1000 is capable of putting out 50 amps (600W at 12V) IIRC. The result is that charging voltage rises more quickly than charge rate in amps. You can check it with a voltmeter (or the dual voltmeter that's included with the True). The True's switching to charge the aux typically happens within a minute or two, though usually just seconds, so the aux battery will get charged even on the multiple short run example you used.

As to having a " . . . fully charged primary that you can't use", you might need to explain that one a bit further, please. If you have two batteries in parallel and draw them both down, absent a way of charging them, you are stuck and will need a jump. If you have isolated main and aux batteries, you can discharge either all the way and still jump one from the other. If it's the aux that's discharged, just start the engine, drive away and the aux get's charged. If it's the main that's DOA, probably a rare event in an isolated battery equipped rig, absent something wrong with the main battery, you can carry a short jumper cable to jump start the main from the aux, or carry one of the Lithium powered jump starters for a doubly redundant system. With that short jumper, you could even disconnect a defective main and jury rig to operate from the aux for the drive home, (another very unlikely scenario, I'd guess).

At least with the P1K, my understanding is it needs reasonable voltage to both start and then run properly due to the electrical needs of the computer, shift motor, DCT, and other running gear do-dads. So either a big or two parallel battery set up that's DOA isn't gonna be of much comfort or use. At least with an isolated setup, running the aux battery into the ground while winching, given a situation where you can't run the engine to help provide power for the winch, would still be a non-event. Winch out on the aux, start up on the main, then drive away while the aux is charging.

BTW, True suggests hooking up any external charger to the aux battery. Their logic is that if a battery is low, it'll most often be the aux. On trickle charge, once the aux climbs past 13.4, the main battery starts charging too, so nothing lost, even if you don't have time to top off the aux with the wall charger - it'll continue to charge while driving. That's the way I've connected my external trickle charger socket. That logic is based on the fact that with the True, either battery voltage, that rises over 13.4 will charge the other battery (a blue LED comes on to indicate this condition).

No matter which way you slice it, either parallel or isolated will work - advantages and disadvantages to both. That said, it's good to be informed on those advantages and disadvantages in making a decision. Erroneous information is of no help.

Erroneous information? Lol! Multiple cold starts will drain a starting battery quite a bit and the aux won't see charge in seconds with a True. That's why I suggested a manual switch. The last thing I want to do stuck in a mud hole is have to jump one battery to another. As you stated, advantages and disadvantages to both but the information I gave wasn't erroneous, you just explained a way around it. Wired in parallel and carry a LI jump pack, problem solved.

 

[Jason312]

A couple questions if I needed to jump start from the isolated battery.

1-- Do I need to disconnect the isolator or anything else first?
2-- Do I just jumper the posative (assuming they both have a common ground) or do I need to jumper both posative and Negative?

Thanks!

 

[trigger]

So we've now graduated from a single battery to dual batteries in parallel to, now, just carry a THIRD battery? Doesn't sound like it's solved anything ... sounds like it's creating a big mess.

Still chiming in with nothing valid to offer and just to stir it up I see Scoop, you haven't graduated yet.
Carrying a jump pack, which is about the size of a cell phone, or carrying cables to jump one battery to the other. Taking into account the extra wiring connections and hardware associated with an isolator, that you're hoping doesn't malfunction, exactly which one is the big mess? There's no misinformation being given here or I wouldn't offer it. Again, advantages and disadvantages to both and seeing as the P1k is more sensitive to low voltage, that may be the way to go for that particular machine. It's definitely not the one and only answer to running dual batteries. I'll retract "problem solved" to good to go.

 

[StewB]

Not stirring. And not kidding.
I have an isolated dual battery setup.
I also have a Li jump pack tucked away overhead.
And this morning I saw I had jumper cables beneath the toolbag under the front seat.

I think I have enough gigamajoules to go back to the future.

Now I'm thinking about on-roof solar panels.