2'nd battery option for 100 with AHC (1 Viewer)

[rohitash]

Folks,

I have a 2003 LX 470 so the Slee tray cannot be used with the AHC being in the way. I used the space next to the AHC (by relocating the steering fluid bottle) for an on board air system. I'm considering using the space between the fuse/relay box and the brake system for mounting a second smaller battery. See picture below.

I can get a space about 8" by 7" by doing the following:
- relocate what looks like a vacuum relay or switch (see orange arrows). In the picture I've removed it and shoved it under the harness on the right. There is an M8X1.00 nut in there that can be used to mount it.
- re-locate the evaporator hose (red arrow). The hard line towards the bottom of this hose seems to be plastic. I'm thinking of cutting the plastic at the bend lower down (yellow arrow) and then getting a longer peice of hose to connect between the service port and the end of the cut plastic piece.
- remove and re-route the wire harness / plugs originally mounted on the Fuse/Relay box (green arrow). I think I can route this under the Fuse box. There was also a wire clip with two wires mounted next to the fule filter (purple arrow). I removed this and plan to mount it below the fule filter using the fuel filter mounting nut itself.

With this space I can mount an Odyssey P925 MJT battery sideways. The battery is 6 5/8" long, 7" wide, 5 7/8" tall. Mounting it sideways would give me space for two j hooks on the sides. Will need to figure out a way to bolt a flat steel or delrin plate on the bottom with some spacers to account for the uneven bottom. I'm hoping this battery will be enough for a couple of starts. Its only use will be as a back-up starting battery. I have a hellroaring isolator system from my previous car already installed.

Battery Spec:

• 925 cranking amps for 5 seconds
• 870 cranking amps for 10 seconds
• 765 cranking amps for 20 seconds
• 675 cranking amps for 30 seconds
• Short circuit current over 2400A
• 28Ah
• 52 minute reserve capacity with 25amp load
• CCA - 380

Please let me know what you think - both on the location/mounting and on the battery itself. I'd like to think this through before I actually cut that evaporator pipe .

 

[Skidoo]

Take a look at Proffitt's Cruisers webpage, he has 100 where he put a red top and yellow top where stock battery goes. Not sure how much fab work, but could be an option.

 

[hoser]

Rohitosh, I'm using the PC925 in my NSX as it's only battery and I think it would do fine as a jumper battery most of the time... Not sure about extremely cold temperatures though.

Another idea I had was to mod an 80 series cyclonic air box to fit our 100. It is a better design anyway. This would give you room in front near the headlamp to use the OEM battery tray and a full sized battery.

 

[1loudLX]

Take a look at Proffitt's Cruisers webpage, he has 100 where he put a red top and yellow top where stock battery goes. Not sure how much fab work, but could be an option.

or slee's...his white LX has had dual batteries there way longer.

 

[rohitash]

Thanks. I looked at the option for two batteries in the stock battery location but decided against it. Mostly because I already have an Odyssey 1700MJT battery in the stock location and am extremely happy with it. Also I think it involves almost the same level of 'fab' work to accomplish as the option I'm trying to explore + the expense of two batteries that will fit there (the 1700MJT will not fit longitudinally).

Les, modifying the 80 cyclonic air box might be an elegant option, but I don't have access to one to explore how it would work. Also not sure whether it'll work with the 100 series snorkel or with the space I've already occupied next to the stock airbox for my OBA system. I do remember seeing the battery in your NSX and wondering what it was!

Since I got the trailer I don't usually run the fridge in my truck so very rarely do I actually drain my main battery on purpose. The second battery is more for accidental draining. That is why I was thinking the 925MJT might be good enough. In very cold weather I could go back to the traditional way of jump starting!

Does anyone see any downsides to my current plan?

 

[spressomon]

I'm starting to warm up to the evap can being in the back on the newer LC/LXs. I'm tired of smelling that acrid smell on long slow steep climbs with the trailer in tow (figuring out how to replace the charcoal is a project on my "list") and having all that space in the engine bay that is taken up by the evap can on mine would serve me well!

I think you're on the right track Rohitash.

 

[1loudLX]

I'm starting to warm up to the evap can being in the back on the newer LC/LXs. I'm tired of smelling that acrid smell on long slow steep climbs with the trailer in tow (figuring out how to replace the charcoal is a project on my "list") and having all that space in the engine bay that is taken up by the evap can on mine would serve me well!

I think you're on the right track Rohitash.

zactly what i was thinking as well.

 

[rohitash]

Here's a teaser picture of my test fit. I got the battery today so was able to fab up a mount for it with marine plywood. I did not have to cut/relocate the evaporator tube assembly - so everything is reversible as of now. I basically have a 6" into 7.5" marine ply base shaped to accommodate some protrusions. At two places I' screwed in blocks of wood to the bottom and sanded them to follow the contour of the metal base. 1/4" threaded rod with fender washers and nyloc SS nuts on the bottom go through existing holes and I've used my old Slee battery hold down on top. I still need to make this more sturdy with some alum channels on the plywood to prevent lateral movement of the battery and also screw/bolt the play base to rigidly mount onto the metal base. I the long run I might make a delrin base. Also have to complete the wiring and bolt down all the relocated stuff.

 

[rohitash]

2nd battery install complete!

Ok - finally complete my install. I painted my plywood base plate black and put some alum channels on it to prevent lateral battery movement. Here's a photo of the underside with blocks of wood sanded to follow contours.


Here's the base plate installed.


And finally here's the battery installed and wired up to the Hellroaring isolator. Now my engine bay is looking quite full!

 

[hoser]

I think that turned out great! Bravo! I'll have to check out your on-board air set-up next time too.

 

[spressomon]

Great job Rohitash!

 

[hoser]

This battery hold down would be nice too.

 

[rohitash]

Thanks Guys! Here's the hold down I was considering:
Odyssey aluminum hold down

The key issue is in getting something that can be flat and stable on the curved and indented 'floor' and can be rigidly attached - so something does need to be fabbed up. The plywood base seems to be quite stable but I will keep a close watch on it for strength. Am not sure how it wold hold up in the long term.

In all it was a lot simpler than I had been expecting - once I got around to it that is.

 

[hoser]

With a battery tray like the one I posted above, it has a flat bottom already. You can take 4 delrin spacers (or washers) used as feet and only worry about adjusting the height at the four corners. However, the two corners towards the engine side look steep! So maybe not. Maybe a bracket on that side would be needed.

Of course, you can also just add a flat plate to the bottom of the Odyssey hold down you were thinking about getting too.

 

[gotmud]

rohitash,

I admire what you have accomplished in such a tight spot! My only concern would be the longevity of the plywood, due to its enviroment. Motorhome builders used to use marine plywood in the construction of RV's. However, the elements would eventually take their toll.

Keep us posted on how well that bracket holds up.

 

[rohitash]

I agree. For now I put some waterproofing compound + paint + polyurethane coating on it. However once I'm satisfied that the current location/config works well then I'll change it to a delrin or metal base or an aluminum box with spacers below as Hoser suggested. Will update this thread after a few runs.