Battery upgrade idea?

[ES_97Sport]

On my list forever is a battery upgrade. I don't mean upgrade what battery I already use, since I already run a Group 65 AGM DieHard which is just a relabeled Odyssey 65-PC1750T-A. Anything else 'bigger' has an unusable form factor or is even more outrageously expensive - or both.

So, for grins I started looking at other Odyssey batteries.

Odyssey® batteries (PDF)

I have probably 2" of extra room on top because the existing battery is shorter than stock. About 1" extra in width to work with, but that's pretty much it. I THINK I could eak out 2" more space in length. Right now the Group 65 is about 1" from the brake lines and master cylinder, but I have about 1.5" or so towards the windshield washer tank.

The point of this exercise is to get multiple batteries. I love my current battery and I've never had problems with any of my Platinum (Odyssey) batteries but relying on one battery in the middle of BFE nowhere makes me nervous. I've been religious about making sure that nothing is left on and disconnecting stuff but all it takes is one lapse in attention and getting stranded 100+ miles from anywhere is not my idea of entertainment.

Anyway, so I started looking and found the PC1200.

The Group 65 battery I use has the following dimensions: 11.83L x 7.20W x 7.43H in.

65-PC1750 Specs:
PHCC: 1750
CCA: 930
HCA: 1350
MCA: 1070
Reserve (Min): 135
Nom Capacity -
20Hr Rate-Ah: 74
10Hr Rate-Ah: 65
Weight: 58 lbs

The PC1200 has the following dimensions: 7.87L x 6.66W x 6.8H in.

PC1200 Specs:
PHCC: 1200
CCA: 550
HCA: 860
MCA: 725
Reserve (Min): 78
Nom Capacity -
20Hr Rate-Ah: 42
10Hr Rate-Ah: 40
Weight: 38.2 lbs


A cool thing about the PC1200 is that it comes in two post configurations - PC1200 and PC1200L. Negative left and Positive right and Positive right and Negative left. If I use one of each and sit them sideways next to each other, the positive and negative line up with the factory cable locations which means very little modification - which means this is easily reversible if necessary.

The PC1230 and the PC1400 seem to be the 'stock' replacements. I have one of each in my other two Sports and they've never failed to start either vehicle even after having sat outside in sub-zero temps for days. Even when they're more than half discharged, they still will start my 3.5L.

So, my theory is that in an emergency a single PC1200 shouldn't have any problems in the middle of the summer. I don't think my original factory battery was even rated to 550 CCA. IIRC, more like 450/500.

Weight difference is 18.5 lbs. I haven't put my Group 65 into my stock Sports so I can't speak to how that would affect driving, mechanical and such. Its not really a necessary consideration for my big Sport anyway because of the SAS. Weight distribution affects IFS more than it would with a solid axle. 18 lbs extra on the front of my big Sport would never be noticeable.

So, it comes down to finding an appropriate battery controller. Two 1200s is way more than enough in tandem to start a 3.0L or 3.5L in any weather down to probably -20 or -30 I would think and with the right controller it'd give battery redundancy. In tandem its about an extra 20 minutes on the 1750, but since I don't have a refrigerator (or anything else that I really run while the vehicle is off for more than a few minutes, and this is in my '97 so less built in OEM electronics) this isn't really interesting to me. And, since these are AGMs and I run a 175 amp alternator they'll charge faster than a stock alternator on a pair of wet cell batteries. Even in trail groups I don't do a lot of off/on starts, so ....

So, ... opinions? Ideas? I've never personally run dual batteries in anything. I've been around RV systems most of my life in campers, trucks and boats, but those were all old and now outdated systems.

Edward

[russiankid]

I don't really see the need for two batteries. When my roommate had my Montero before I bought it from him, we used it last winter with temps being in -20F. After sitting all night, it fired right up with a Pepboys special battery.

[ES_97Sport]

Jan 19, 2015 21:02:45 GMT -5 russiankid said:

I don't really see the need for two batteries. When my roommate had my Montero before I bought it from him, we used it last winter with temps being in -20F. After sitting all night, it fired right up with a Pepboys special battery.

Getting it started in the cold isn't the issue or I'd just stick with my Odyssey 1750 - plenty of capacity and plenty of CCAs.

The issue is having only one battery. How do you start your vehicle when you're 100 miles from nowhere and your battery is dead?

Excluding doing something stupid like leaving a light on for a week while backpacking, electrical problems happen. They're especially problematic on an off road vehicle because of the abuse the vehicle takes. It only takes one piece of brush to reach up and tear a wire loose that causes a short. What happens if a wire comes loose and wears through?

And since we've been on the topic, what happens if you're alternator goes bad and you don't realize it until your battery is almost dead? Would you trust an almost dead battery to get you out of some place that's 150 miles from the nearest gas station? Maybe don't see another human for a week?

Lots of places we wheel are very dangerous if you're not prepared. I'm not really willing to risk my passengers lives and/or watch a $100K+ vehicle destroyed because I'm stuck in a flooding wash, just because I can't start my vehicle.

This is about redundancy.

Will I ever need it? Who knows? It doesn't seem like a chance to take to save maybe $500.

Edward

[jkdv8]

Looks as if you have it figured out. If you are worried about being stranded something to think about is putting one on an isolator connected just for starting. Then the other battery run the electrical. Wiring would be a bit tricky but would practically eliminate any chance of a no start situation. Possibly put the isolator on the second battery and connect it to the starter. Probably wouldn't hurt to allow everything else to run off the main batt. Starter/starting seems to be what kills them. If that makes any sense. These trucks do go nom nom on batts

[russiankid]

Well in this case you may as well just carry a spare battery in the trunk. Like you said, what if something causes a short a ruins the battery. If you have both batteries interconnected, it would fry both of them.I am not knocking your idea, if you travel a lot especially far away from home out in the middle of no where, having additional items that can get you out of a pinch is great .

[jkdv8]

Yes this is true. However the chances of the battery failing are much higher than the chance of a cable shorting out/coming loose. When you make the cable needed then taking the steps to protect it, it becomes a non issue. It is possible to over engineer it to the point of it outlasting the truck. There would only be the need for 3 additional wires and only the one running to the starter would be of concern for the above mentioned reasons. Also, when properly fused shorting anything is highly unlikely. Possibly even use the existing starter cable and just splice it to the second battery. However I believe this would not be reversible cause iirc the starter cable is spliced into the main power/charge cable. Don't remember if it runs directly off the alt or the battery. Do remember the battery has 3-4 8ga wires running off it.

Or just take the manual wheeling. Then you can just push start or roll it down a hill if it dies.

Carrying an extra battery around isn't a bad idea except maintaining it is one more thing to add to the checklist. Even a healthy battery won't have a full charge if it isn't maintained. In a short amount of time it diminishes even more as the temperatures drop. Especially if the cca amp of the battery is the same as the truck needs. Those figures are based on a fully charged healthy battery.

Kinda funny about the mention of redundancy. I have noticed these trucks have quite a few redundant systems in place. Don't know if other car manufactures do the same but being that mitsu started by building aircraft, where redundancy is a must, it is not all that surprising. Don't see another redundant feature being an issue when done correctly.

[ES_97Sport]

Jan 20, 2015 19:05:27 GMT -5 russiankid said:

Well in this case you may as well just carry a spare battery in the trunk. Like you said, what if something causes a short a ruins the battery. If you have both batteries interconnected, it would fry both of them.I am not knocking your idea, if you travel a lot especially far away from home out in the middle of no where, having additional items that can get you out of a pinch is great .

You're right. I've thought of that, too. Not such a big deal if you have several vehicles but unless I'm in CO I'm usually on my own.

Yea, I've actually thought of that. The problem is that I'm running out of room inside the cab. Well, that and you really don't want a 60 lb battery wandering around in a roll-over. You really don't want one unanchored at all even off road. That thing starts moving and it'll break something.

In order to anchor it in the back I'd have to do some major re-engineering. I don't want to loose any underfloor storage. I already carry a 7 gal water cooler + a 5 gal jug. Taking those in and our is a PITA when the foor is 4' off the ground.

I also thought about doing what they did to a LC on Offroad. Have a holder welded up and attached under the rear where the spare tire normally sits. It doesn't necessarily have to be connected. Might just be a good place to carry a spare. Low down wouldn't hurt my feelings at all, either.

I think I'll still go with interconnected realizing that what you're saying is definitely a possibility. What I really hate is running cable ALL the way back to the front of the vehicle. My 'Bird has a rear mount battery and that long cable run is a pain. I dislike running things under the vehicle - just something else to snag potentially. Or, more likely, something else for some random idiot to melt with a torch.

Anyone have any ideas on a controller? I've been looking and there are a bunch. Some seem ok but some are junk.

Edward

[ES_97Sport]

Looking at the following controller:

Blue Sea Systems

ML-ACR Automatic Charging Relay with Manual Control - 12V DC 500A

'Choose the right ACR ..." Product Brochure

This is a marine grade solution. Fully sealed and waterproof. Continuous rating is 500A, which is very important for winching. It isn't unheard of for a winch under load to pull 400-450 amps and pull 250-300A+ for several minutes depending on the pull.

The big problem I've been having trying to find a box is that they're all rated for 100-150A continuous and maybe 200/250/300A peak. That doesn't work for two reasons. First, I have a 175A alternator which is theoretically capable of producing 175A - continuous. Second, for the above reason - winching. Sigh.

I also don't particularly want a diode solution. I've read too much of the downsides of using that kind of controller. One of which is increased battery wear. Not what I want on two $200+ AGM batteries. Also, I've read that the diode controllers don't treat AGM batteries well and some diode controllers have problems with our type of charging system.

So, anyway this is what I've come up with so far. I'm still trying to figure out whether I want to do dual "one in the engine bay and one in the spare tire well" setup or stick with the dual 1200s in the engine bay.

The pros for the remote location is I can run a group 25/35 in the bay and a 65 or larger in the well which is a nice setup should I ever need massive winch power or use a fridge and I get some engine bay room back. The cons are that its EXPENSIVE. Custom battery box and mount. Two 18'? runs of 2/0 at least from the rear to the engine bay. 400A slow blow fuse and holder. Bunch of lugs. At least I'd have both batteries if I choose to use my 65 and one of my spare 35s.

Actually I thought of another +. Two big batteries would allow for trail welding - which would NOT be a bad thing.

Hmmm. Have to keep thinking on this.

Edward