Resto battery "conversion"

[Just 6T9 CHGR]

Recently my resto acid filled group 27 battery "gave up the ghost".   I cant say that I'm disappointed in its performance.  I got almost 7 years out of this battery.

The new style sealed "maintenance free" resto batteries sure are nice but the $255 price tag isn't

A few years ago I got the idea from 1_WILD_RT (Randy) on Moparts to gut my old acid filled battery & "hide" a smaller AGM (absorbed glass mat) inside the shell of the resto battery.

The battery I chose (as well as did he) was the Odyssey PC925 http://www.odysseyfactory.com/  The dimensions of this battery are small enough to fit inside the case yet provide adequate cranking power for my big block.   The design of this non-acid filled battery makes it possible to mount in any position.

I must warn you this conversion is EXTREMELY DANGEROUS & MESSY!  Do not attempt to do this without adequate personal protection as well as a well ventilated area & basic knowledge of electrical theory

First I started out by drilling holes in each of the cells on the bottom of the battery & drained out the acid.  I was able to do this at work where we have a "battery room"  that maintains bus batteries.   I ran fresh water as well as baking soda through the cells to neutralize the acid.
I then cut a square hole in the bottom of battery thinking that just the bottom of the case would come off.......wrong!  The case is molded and each cell is divided with plastic.  I had to cut 6 individual slots to be able to gut out all the lead & glass matting in each cell.

Once all of the junk was out, I was left with 12 individual lead contacts.  I only needed 2 of these (1 attached to the positive post & the other for the negative post)

To fit the new battery in properly I had to remove the center lead contacts as well as break away the fill ports for the cells to get the case to be "flush" (see pic 1 & then 2 for the removal)
I then drilled & tapped holes to connect my small internal battery cables needed to connect the new battery in the case.  (pic 2)

Picture 3 shows the comparison between the 2 batteries....

I then slid in the battery, connected my new cables I made up & then cut a piece of Plexiglas to hold the battery in place. (Pic 4)

[Just 6T9 CHGR]

All said & done I saved about $120 off the price of a new sealed resto battery.

This battery shipped to my door was $130.  I got the cables & ends from work.  Weight savings off the front end was about 30lbs

I must tell you though that the CCA on this new battery is only 380 amps @ 0º F  ( the resto battery is 700 CCA @ 0ºF)

In my application, I will never crank my car over in 0ºF weather.  This conversion is NOT for an all season car.  This is for a "show season" type of car like mine is.....



I dare you to tell that there is a small battery inside this case

[Charger-Bodie]

looks great!!! i was going to do that too but a buddy of mine that was going to donate the expired acid fiiled repop mistakinly let the interstate batterry guy take it as a core. so i had to buck up and get the new one and it was 250. by the time it was shipped

[resq302]

Looks good Chris.  Do I also detect the correct master cylinder back on your car?

[OttawaCharger]

Looking real good!   
One question though - what is stopping the battery from sliding back and forth on your plexiglass when you accelerate or slow down?

[Just 6T9 CHGR]

Aa

Looks good Chris. Do I also detect the correct master cylinder back on your car?

Nope.....still have the other one on there.  Batt conversion done before that pic....

Looking real good!
One question though - what is stopping the battery from sliding back and forth on your plexiglass when you accelerate or slow down?

Aaahhh good eye
I forgot to mention that I inserted a piece of wood in there to take up the space to prevent movement.  Thanks for the reminder

[OttawaCharger]

that'll work 

[Shakey]

Very cool stuff.  Well done.

I like the 30lb weight reduction.   

[41husk]

That looks great, i did not realize the sealed group 27 repro was that exspensive,  That is slick!

[dkn1997]

next question is where can we find group 27 cores?!!!!

[resq302]

next question is where can we find group 27 cores?!!!!

You basically have to buy one off of someone who had a lead acid one that went bad.  That is what I had to do only I found a sealed one from someone and it was hell to get all of it out.

[Just 6T9 CHGR]

next question is where can we find group 27 cores?!!!!

You basically have to buy one off of someone who had a lead acid one that went bad. That is what I had to do only I found a sealed one from someone and it was hell to get all of it out.

Woah Brian, you did this as well?  What battery did you use?

[CharlieCharger]

This thread is an example on why this site is so valuable to folks in the Do-It-Yourself market..I tell you as simple as some of the things thought up here ..I would have to admit I would have never thought of it...That is really cool Chris, nice job

[resq302]

Same as you Chris.  The Odyssey battery that I got from Batteries Plus in my town.  My PD gets all of their batteries there for their flash lights and such so I got a good deal.  I got the metal jacket version which is supposed to cut down on any vibration that will cause the battery to go bad sooner.  After I went through all of that, a friend of mine had the maintenance free one that he was selling the car and he gave me that still worked.  Good think I took it since my dads El camino battery started crapping out and the Odyssey battery fits in his shell also.  Supposedly, the Odyssey battery has AT LEAST an 8 year life span if not more.  Trick is to keep one of those Battery Tender Plus models on it when you are not using the car to keep it at top charge.  To prevent my battery from sliding around, I used thick pieces of styrofoam to take up the space and "wedge" the Odyssey battery in there.

If you remember last year, I had my battery already gutted but was just swapping the new Mopar battery in and out at shows and putting the shell of the OE one in place.  After almost dropping the new battery on the fender, I decided it would cost less to do the hidden battery thing but then I lucked out with the maintenance free one.

[Chatt69chgr]

Who makes the resto Group 27 battery that you guys modified.  The one that costs $255. 

[resq302]

Mine was an original lead acid from Antique Auto Battery.  I would stay away from them as lately I have heard their battery's dont last worth a damn.  Basically, once the warranty is out, so is the battery.  At least that is what I found out with the one we got for our el camino.  The one I had in my charger lasted 6 years so I can't complain about that but it has been recently that their quality has gone down.

[billssuperbird]

I got a old battery for 35.00 i am going to try to do that. 

[ODZKing]

 
I have a group red cap 27 that someone can have if they want to come get it.
It is the AAB one I mentioned in the other post.
Not dead, but close. Won't start the car anymore.
I live in Syracuse.

[resq302]

If anyone needs an Odyssey PC925 battery, I have a brand new one that I got for a conversion that my buddy changed his mind on after I got the battery for him.  If anyone is interested, please PM me.  Selling for less than I bought it to get it out of my garage.  Thing is still in the box that it was shipped to me in.