Read through some older posts on this subject which have been helpful as far as coming to the conclusion I'd like to go ahead and install a 2nd battery. One thing I'd like to put out there is suggestions for placement. The most common spot seems to be under the drivers seat but there are some concerns I have. First is the fact that it is not a waterproof compartment and seeing as it is a lot lower than the original battery placement I am concerned about water, etc compromising the whole system. Summer runs consist of a lot of mud and water and I also run in the winter although I can't see snow getting in there. Placing it there would make sense as far as wiring is concerned but I am also looking at putting the 2nd battery under the front hood. Can still get water/mud in there but it is much higher up so the concern is much less the con of putting it there is the longer distance to get to the original battery in order to hook them together.

That is my main question, where do people put the 2nd battery and the pros/cons they have noted.

follow ups would be recommendations on what else to include; battery separators? starter vs. deep cycle battery, etc

Any and all info is appreciated. Running a 2017 ZForce 800

If the battery chosen is an AGM type like the OEM then it doesn't matter if it gets wet, it's all sealed. Still I was wary of getting stalled and low on power somewere remote and I elected to carry one of those lithium jumper batteries. Tons of power (I started my Ram Hemi with it, with the vehicle battery disconnected!) and light weight, portable versatile and no permanent changes need be made to wiring. I just keep it in the cargo box but it will fit in the glove box.

[2015 Z Force 800 53/Trail EPS]

All I have is dust down here but like glenlivet says the AGMs aren't vented and with a water proof isolater there shouldn't be an issue. The compartment does drain but I'll bet it could be made to be a bit more water proof as well...not sure I would though. I guess the point is no one that has added a second battery to that second battery location has reported any issues so...not sure it's something to worry much about.   

glenlivet & NMKawierider Thanks.

I agree that compartment could be sealed up without too much trouble and I might do that as well. More of a peace of mind thing than anything else I think. The main goal for this was to run off all the extras I want to put on and not necessarily to make sure I had power while i'm in the middle of nowhere. Right now all i have are dreams and ambitions of installing light bar, back up lights and possibly radio.

I've put a second battery in ours in that location, we ride in some pretty wet trails a lot
and have never had a problem at all, it's been in for three years now.

[2015 Z Force 800 53/Trail EPS]

I think the biggest thing people forget is- no matter how may batteries you have, you only have one charging system that only puts out so much. Just can't take out more then you are putting back. Got about 12 extra amps as I recall. 

I think the biggest thing people forget is- no matter how may batteries you have, you only have one charging system that only puts out so much. Just can't take out more then you are putting back. Got about 12 extra amps as I recall.

Valid point and I've tried to weigh this install between a need or a want. I know it is more of a want since it the goal is to focus any add on gear towards the 2nd battery as well as to have an easier access to the battery. I don't have a problem with the original battery location but man oh man that cover they put on is pure evil in my eyes. No fun trying to get at it when you're nutts deep in snow with negative stupid temps lol

Again, thanks for the input from all.

[2015 Z Force 800 53/Trail EPS]

I think the biggest thing people forget is- no matter how may batteries you have, you only have one charging system that only puts out so much. Just can't take out more then you are putting back. Got about 12 extra amps as I recall.

Valid point and I've tried to weigh this install between a need or a want. I know it is more of a want since it the goal is to focus any add on gear towards the 2nd battery as well as to have an easier access to the battery. I don't have a problem with the original battery location but man oh man that cover they put on is pure evil in my eyes. No fun trying to get at it when you're nutts deep in snow with negative stupid temps lol

Again, thanks for the input from all.

I guess I just have to ask..why would you need to get at it in those conditions? For maintaining I have put  one of these on my battery:

https://www.amazon.com/Battery-Tender-081-0069-6-Terminal-Disconnect/dp/B000NCOKZQ/ref=sr_1_fkmr0_1?keywords=Battery+maintainer+pigtail&qid=1551969540&s=gateway&sr=8-1-fkmr0

If I ever need to jump it, the positive or line post on the starter solenoid is accessible and I can clamp to the frame or most any bolt for ground. And if it ever came to that I would need to ask myself. "what caused this?"...but for me with my battery going on 5-years old now I might need to think about a little preventive measure and just replace it...but that's hard to do when it acts like new still...lol 

A number of years ago I had a real problem with a battery in one of my quads when plowing. Constantly using the winch to raise and lower the blade would suck the battery down faster than it was charging and it would eventually kill the motor. The battery was too small for the task at hand but was fairly new. So I added a second battery with a quick disconnect in the quad box and wired it in parallel and that solved the problem. When those batteries finally gave up the ghost instead of putting two batteries back in, I put in just one Lithium Ion battery that had more reserve power than the other two combined. They are super light, charge up very fast and can be mounted in any position like an AGM battery. They are expensive but are a great bargain if found on sale. Also put one in my Goldwing GL1800 when the factory battery finally died as I run a lot of accessories and tow a trailer with it.

If you want a lot of reserve power in a small package they are worth considering.

[2015 Z Force 800 53/Trail EPS]

Yeah I went to a Shorai LI battery and special rectifier/regulator when I added power steering to my Brute Force. Great battery. Light as a feather. I remember thinking they forgot to pit anything in the case it was so light...lol.

I think the biggest thing people forget is- no matter how may batteries you have, you only have one charging system that only puts out so much. Just can't take out more then you are putting back. Got about 12 extra amps as I recall.

Valid point and I've tried to weigh this install between a need or a want. I know it is more of a want since it the goal is to focus any add on gear towards the 2nd battery as well as to have an easier access to the battery. I don't have a problem with the original battery location but man oh man that cover they put on is pure evil in my eyes. No fun trying to get at it when you're nutts deep in snow with negative stupid temps lol

Again, thanks for the input from all.

I guess I just have to ask..why would you need to get at it in those conditions? For maintaining I have put  one of these on my battery:

https://www.amazon.com/Battery-Tender-081-0069-6-Terminal-Disconnect/dp/B000NCOKZQ/ref=sr_1_fkmr0_1?keywords=Battery+maintainer+pigtail&qid=1551969540&s=gateway&sr=8-1-fkmr0

If I ever need to jump it, the positive or line post on the starter solenoid is accessible and I can clamp to the frame or most any bolt for ground. And if it ever came to that I would need to ask myself. "what caused this?"...but for me with my battery going on 5-years old now I might need to think about a little preventive measure and just replace it...but that's hard to do when it acts like new still...lol

I've had to jump in a couple times in extremely cold weather which was challenging at best and apparently i am not as mechanically inclined as you are because I pulled the cover to get at the +/- posts (no sarcasm there, i seriously did not know that lol). I also had a wire break off (the one that is for the voltage regulator) due to corrosion. As long as i kept applying gas she would go but it stalled out a few times while in the woods. Only way to restart was from a booster pack. Once I was out of the woods (physically and figuratively) I was able to see what the problem was.

 

I believe dual batteries can be a good idea and also agree the charging system can be compromised if too much load is applied. 12 VDC batteries like voltage above 14 VDC. Additional loads create a voltage drop and start to run the starting battery down since this is a function of run time. My plan is to use a "smart charging system". This incorporates a circuit that reads the voltage of the starting battery charging state. As long as that is about 12.8 VDC, the circuit closes and will charge the second battery. The second battery now can "catch up" if depleted. Once you turn the engine off, the batteries will drift back down to 12.6 VDC and the circuit opens preserving the second battery.

I will run any of the ancillary stuff off the second battery. Typically most of my runs will be during the day or starting during the day so the second battery will have a chance to be available to the extra stuff.

dbrakeman

Can you elaborate on how to implement the "smart" charging setup?

I'd be interested in that set up too.