Has anyone ever converted to a top post battery in the stock location? Any tips or recommendations to share?
I'm approaching new battery time, and I'm really not happy with the battery cables on the car - they don't fit well, I suspect they are not stock so I have reason to replace both. Plus, jump starting the car - which admittedly has only happened once - is a real PITA with the side post setup. I have a high quality battery cable crimper, so making new cables is no issue. It seems there is plenty vertical clearance for a top post battery as well. I just wanna be sure I'm not overlooking something - hoping it's a BTDT for someone!
Other standard batteries have dual terminal setup too. I forget what group no. is same size as group 75 side terms.
Use only ACDelco cables w/ side terminals. They use same Delphi ends as GM. All others w/ lead ends often don't fit right and doesn't have plastic to insulate most of ends. Keep a "battery wrench" in the car. Very small racket type that can't short the battery.
Warnings:
Always pull negative terminal First on all battery in negative ground cars! Any tool can short battery to frame etc when you pull + side first.
Top terminals are very close to vents, more so them vents are taken off and put on. Vent "screen" can get loose too. worse w/ 85-86 hex hole screens. That can easily short out the battery dumping 300+ amps when that happens. You must use something on Plus terminal to prevent that.
Jumping: the last connection is to block on dead car. Is to prevent sparks at battery. Even then Jumping side terms is easy when only + cable goes to battery(ies) and Neg to block on both if both are side terms or good battery is.
"I have a high quality battery cable crimper, so making new cables is no issue." Many think that but not true. ACDelco and others use Hydraulic crimping w/ many Tons of force that is much stronger physical and electrical then Any DIY methods including most Solder methods.
Most cables w/ iffy ends have heated the cables and wreck the wire itself. May look ok to you but wire often has more resistance and make more voltage drop to start the car. So Just replace the entire thing.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Problem w/ any adapter... Size may matter. But main issue adapters add more resistance. Every joint etc add to circuit resistance and make more voltage drop when you start. Every 0.1v drop will cause starter to pull more amps. You can't measure this w/ normal Ω meters because of wire size. Can often see look at Vdrop w/ a good Volt meter but Start a car is often too fast to watch w/ many digital types because display updates are only ~1 per sec. Even Meters w/ Peak/hold often won't work right. Starter "in rush" current is why... Start a starter 2-3 times the amps for milliseconds vs running them. Vdrop change for amp load so Peak is invalid for this.
Originally posted by theogre: But main issue adapters add more resistance. Every joint etc add to circuit resistance and make more voltage drop when you start.
OP is in California... I don't think he needs to worry about getting the most cold cranking amps from his battery.
Edit: we don't know OP, rather than tell him he's incapable of making good crimps, maybe we can learn something regarding crimping from him instead.
[This message has been edited by pmbrunelle (edited 03-29-2018).]
Originally posted by pmbrunelle: OP is in California... I don't think he needs to worry about getting the most cold cranking amps from his battery.
Edit: we don't know OP, rather than tell him he's incapable of making good crimps, maybe we can learn something regarding crimping from him instead.
Starting in cold weather often doesn't mater. 1 example: Many time people stop a store for a few minutes and heat soak starter and/or cables won't start. Heat causes more calls to AAA for no start cars. Heat from weather and/or engine cause more resistance in cables and the starter motor and solenoid then add iffy connection and cables and you will get problems.
Yes you can make cable but Even if you do, make the whole cable w/ new wire. Not cut off the end you don't like for whatever reason because most times the wire is damage. Many places sell crimp tools but the tools most buy often doesn't make a good joint for electrical physical or both. Worse water and crap will wick into the voids in the joint and eat it inside out while outside look perfect. Hydro crimpers can safety use so much force can "cold flow" the copper to close voids in the cable itself.
When you often can get ACDelco for <$20 each, RA has them ~$15 or less United Motor Products seem to use same Delphi ends but cheaper wire and sell ~$10 or less there's very little point making them supplies and time will cost that much and likely more. Many people can have a hard time finding 4awg or bigger w/ high temp insulation.
It gets *fairly* cold here in Sacramento, down to the 20s, but it'd be unusual to be trying to start the car in anything under 30 degree weather... by the time I'm up in the winter, it's mid-30s usually. Still, like Ogre said, the temperature isn't much of an issue. My Saab started just fine with a teeny tiny Braille battery in it for many years.
Crimps are not a problem - I have this monstrosity:
Using marine grade (adhesive lined) shrink tube and proper terminal protectors keeps the crimps safe - I'm not worried about contamination. I have a good inventory of terminals and lugs from numerous battery projects, and I have dozens and dozens of feet of 2, 4, 6, and 8 gauge SGX cable. Supplies are not an issue - plenty of leftovers from recabling my motorhome, a battery relocation on my Saab & Falcon, and a dual battery conversion on my Cadillac Fleetwood. Honestly, I'd be happy to use some of it up.
However, I have only found one company that makes replacement/loose side post terminals, and they suck... I tried them on my '84 Suburban and they were garbage and I'm not doing that again. I don't want to buy generic parts store battery cables because a) I'm particular about the quality of my cable and b) I don't want to deal with too long or too short generic length cables. I have the capability to make perfect custom-length cables and that's what I wanna do.... but it would mean switching to a top post battery.
There are several top post batteries with similar dimensions to the factory battery, and as noted there are dual post batteries as well - but again my limitation is the terminals that are available to me.
It looks like there is plenty of clearance under the vent:
but I wanted to see if anyone else had done this and had ideas or pointers.
To be clear, my goal here is replace the shady battery cables on the car right now - they're 30% likely the original cables and in poor shape, or 70% generic parts store cables and in poor shape. Either way, they gotta go. Being able to easily jump start the car is just my push over the edge to try top post.
[This message has been edited by thesameguy (edited 03-30-2018).]
Many times clean the factory ends then coat w/ silicon and is good for many years. If you want to crimp then do it w/ new wires. Heating wires from iffy/bad battery starter and/or ends very often changes the metal in the wires and can bite later. Water etc causes "rust" anywhere and adds a lot of cable resistance.
Measure top clearance often doesn't matter when vents are taken off or put on w/ top post battery. W/o protection is very easy to short out the + term to neg term or frame. Not just vents either. Tools and everything else Metal have an easy target to short the top posts and cable ends. Things get thru or push into the vent too. Worse Many use spray cans while working on/near engine that falls and short the battery... most are oil based or have propane/butane as propellant and battery burns thru the can and instant fireball at best. This is very common but news only report it when people are hurt or cause a building fire.
This is why nearly all cars built in last 20+ years have some type of cover on plus side.
GM/Delphi side terms w/ plastic covers make a much harder target to short in the first place and all made to have a small cover over the bolt too. Examples: GM's cover w/ current ends
Think GM never used the cover on Fiero because plastic "head shield" also adds protection over/around plus term. I've seen different versions of cover that are Factory install. Your picture is missing that shield.
While I appreciate your response and knowledge, it would be really nice if you read my posts rather than just pontificating. I read what you're saying, it would be nice if you would reciprocate. I have addressed wire, terminals, my non OE cables, and protection twice now and you just keep restating what I have already said. It kinda sucks to go to the trouble of being specific about my situation and my intent and then just have you say it all over again rather than providing new information or helpful thoughts. It is not useful for two people to say the same things at each other.
There's absolutely nothing wrong with doing a top post conversion. You should have plenty of room. I would just add the protective red cover over the positive terminal in case the engine vent ever came loose for any reason. And while you're replacing cables, add another ground cable directly to the engine block in case those annoying mini ground straps break.
[This message has been edited by IMSA GT (edited 03-31-2018).]
Originally posted by thesameguy: There are several top post batteries with similar dimensions to the factory battery, and as noted there are dual post batteries as well - but again my limitation is the terminals that are available to me.
With the factory tray, you need not only similar, but damn near dimensionally identical at the bottom. The factory clamp which grips the battery by its two lips at the bottom is a real picky setup.
If the shape of the battery at the bottom is a little different, the factory clamping method won't work. Actually, the factory clamp even fails to secure the battery with variations within the BCI group 75 format.
Even if you want to use top-post terminals, the reason to use dual-post is that you need something that is group 75 compatible, for factory clamp compatibility. Something that has the shape of a 75 at the bottom will most likely also have side posts. Thus, the dual post suggestion.
I have decided to avoid these headaches; I am scrapping the factory clamp, and I will be using a more conventional setup of a hold-down bar over the battery held by two threaded rods. There will be a tray at the bottom to restrain sideways movement.
But have you not thought of getting "good used" cables from an unmodified Fiero?
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Originally posted by thesameguy: While I appreciate your response and knowledge, it would be really nice if you read my posts rather than just pontificating. I read what you're saying, it would be nice if you would reciprocate.
Ogre is a forum veteran... he is the way he is. I wouldn't expect that to change anytime soon!
[This message has been edited by pmbrunelle (edited 03-31-2018).]
Originally posted by pmbrunelle: With the factory tray, you need not only similar, but damn near dimensionally identical at the bottom. The factory clamp which grips the battery by its two lips at the bottom is a real picky setup.
If the shape of the battery at the bottom is a little different, the factory clamping method won't work. Actually, the factory clamp even fails to secure the battery with variations within the BCI group 75 format.
Is mainly Width at the bottom. Smaller Length and/or Height should be ok. Bigger Length won't fit. Bigger Height have limits depending on terminals.
Note: Publish Dimensions is Total L W H including the side/top/both terminals. Is why battery example I posted should fit and straight 86 and likely other top posts should fit Fiero mount area.
With the factory tray, you need not only similar, but damn near dimensionally identical at the bottom. The factory clamp which grips the battery by its two lips at the bottom is a real picky setup.
If the shape of the battery at the bottom is a little different, the factory clamping method won't work. Actually, the factory clamp even fails to secure the battery with variations within the BCI group 75 format.
I am not too worried about the retention method - lots of modern cars use the clamp so most batteries I think have the foot. The 36R battery in my '85 Saab is virtually identical to the 75 in the Fiero - if nothing else I'm 99% sure I can use it. I want to keep looking because I'd prefer to have the terminals in the opposite position, but it's an option. Uh, actually, maybe I could just turn the battery 180 degrees. Derp. I'll do a test fit and see how it looks.
I'm really not interested in 30 year old battery cables... regardless of how well they've been treated, there's just no way they're in good shape. Oxidation, insulation degradation, etc. I don't think I've ever seen an older car whose electrical system performance hasn't been improved with new battery cables. IME it kinda goes double with older GM cars - I really feel like GM "value engineered" the starting/charging system. :| It's actually why I bought the crimper in the first place - the cables on my '84 Suburban were not so good.
[This message has been edited by thesameguy (edited 04-02-2018).]
Had some time this afternoon, so I test fit the 36R battery... did not work. The base is about 1/2" too wide as the foot sticks out beyond the case, versus the 75 battery where the foot is recessed into the case. I ganked the group 34 battery from my Jeep and it appears it will fit just fine... which is not a surprise since "Group 34-75 dual terminal" is a thing. It's too dark now for a driveway test fit, but I've got fair confidence. It's a common battery - more common than a Group 36R - so it makes sense as a direction to go... definitely do not want to increase the difficulty of spare parts for no reason.
If it works I'll probably get to the retrofit immediately, as the Jeep is laid up for some major engine work. I'd be happy to get its battery off the charger and back to work.
So, the next question(s) is(are): Does anyone happen to know offhand the size and location of the OTHER sides of the battery? It's easier than taking it apart and measuring... I just like to be sure I have all the right parts to minimize downtime.
34 is a good size... probably what I'd pick if building a car from "scratch" and I had the freedom to choose the most common parts.
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Originally posted by thesameguy: So, the next question(s) is(are): Does anyone happen to know offhand the size and location of the OTHER sides of the battery? It's easier than taking it apart and measuring... I just like to be sure I have all the right parts to minimize downtime.
Are you asking for dimensions on a 75 or a 34?
Your request is unclear.
I will have access to a MotoMaster 75 battery this Friday (removed from my Fiero).
Be careful with measuring only one battery. For my battery tray project, I've also taken measurements of the AC Delco 75 battery from my dad's car, and it differs from the MotoMaster battery by 1/8" in some cases.
You wouldn't want a setup that works with one brand of battery, but then if you buy a replacement of a different brand, it doesn't fit anymore.
Sorry, that was indeed unclear. I meant "what's on the other side of the battery cables." Obviously the top terminals are standard, but I don't know anything about the routing of the positive cable between battery, starter, and alternator and I have no idea what the lugs are on those components. The ground cable is a bit more straightforward, I think. This is some pretty obscure data, but perhaps someone knows.
I do agree the Group 34 battery makes good sense - always better to use more universal components when possible. I can yank the starting battery from my motorhome - it's a 34-75 and that'd give me two common brands to check - Autozone/Duralast and NAPA/Legend. Your advice is definitely solid - the size difference between the Interstate Group 75 battery that came in my Fiero and the Duralast that's in it now is probably an inch... although it's an inch in an irrelevant direction... the "depth" dimension that's critical for mounting is the same.
I am planning on taking a closer look at the Fiero's positive distribution while I'm at it... maybe replace some old fusible links & distribution blocks with new mega/maxi/etc. fuses & such. I've got some good successes under my belt, I'm pretty good with this stuff at this point.
Upgraded alternator & battery relocation on my '85 Saab, using a megafuse to isolate the alternator and provide a better distribution point... probably saved 5lbs of wiring!
My XR4Ti came from the factory with a "universal terminal" style battery and it had been dealer-modified to use a GM-style side post battery that never worked right. I redid the entire charging/starting system a couple years ago.
Redid the entire electrical system on my '62 Falcon using Bussman & Littelfuse components, including a 130a alternator, distributorless ignition, and some other modern amenities:
Oddly, I never take pictures of the finished product... it's always just so I can remember what I did. The Fiero doesn't need that level of remediation, but if I'm going in, I'm gonna do it right the first time.
[This message has been edited by thesameguy (edited 04-03-2018).]
That's great information, thanks guys! I have a turbo to install in my XR4Ti and then I will get to work on new battery & cables for the Fiero. Thanks!
Waiting for some parts for the XR4Ti, so I got going on this battery swap project.
There is definitely plenty of room for a Group 34 battery in there:
I am not sure how the battery terminals are going to work yet - I have some straight and some angle ones, both have their merits:
Unfortunately, as usual, mission creep set in pretty quickly. I pulled apart all the corrugated wire shield because it was a disaster, plus it gave me the opportunity fully fish out the starter and alternator wire.
in doing so, I found the connector at the alternator to be 90% disintegrated, so I'm strongly considering a CS130 swap.... I need to research that a bit.
Plan is to replace the little positive junction by the battery with a megafuse and use that for the junction instead. I just need to make a little bracket to hold it. I'll do 2ga to the starter, 6ga to the megafuse, and 6ga between the megafuse and the alternator. Should be clean & compact. My dream of replacing all the fusible links the area is dead... I did not appreciate how many of them there are. But I'll get rid of the one in the alternator charge wire, and that's a positive (HA!) step.
Now, to research a CS swap!
[This message has been edited by thesameguy (edited 04-16-2018).]
Got a CS130 alternator en route... Amazon was about the cheapest option, with a new (not reman) AC Delco 100a for $85. I ordered a Dorman (ugh) 4-pin connector for $5 so I should be good to go on that.
I got a little side-tracked with the three fusible links that are right off the positive distribution point - I don't know much about the Fiero's electrical system and don't know where they go - a pair go off to the cabin, the other goes to the engine. Although they are not a problem - certainly in the scope of this project - they rather annoy me just being there, being old and ugly. It's a dumb thing to worry about. I'm probably going to let it go - admittedly mostly because my usual supplier is out of stock on the 4x maxi fuse holder.
In case I ever get back to it, this is sort of a useful page:
Although there is no direct translation between replaceable fuse and fusible link, there is some potentially useful (maybe anecdotal) information there.
Just about finished this work over the weekend - couple more minor things to do.
One Duralast Gold Group 34 battery installed:
Fits like a glove, no surprise.
The top terminals are double-hex-crimped which is mil-spec construction. Supported with adhesive-backed shrink tube to keep moisture out of the joint, covered with PVC boots. It's not *quite* as weather resistant as a side post battery, but it's a lot easier to jump start.
I replaced the little distribution point near the battery with a megafuse holder. It serves as a more robust distribution point but also eliminates the fusible link from the alternator.
It's 6 gauge cable straight from battery to alternator and a 150a megafuse in the middle. I probably could have used a 125a, but whatever... if the alternator shorts out it'll be a lot uglier than 150a anyway.
The alternator was swapped to a CS130 from an '88 Fiero, which wasn't necessary but I figured since I was rewiring I should do it once, right - especially since I had to replace the plug on the old alt anyway. Now it's all new. In this picture you can also see the new ground point for the battery - I had intended to use 2ga cable but didn't have any, so 1ga it is.
Obviously no fitment issues. I debated crimping the Sense wire from the alternator into the same lug as the charging cable, but I do prefer the option of removing cables separately whenever I can.
Doing this work required destructively modifying some of the wire conduit on the front of the motor... it was falling apart anyway, so no great loss. I replaced the conduit with new, and used some DEI heat shield to wrap the wiring. Although my updated heat shields do a tremendous job back there, retaining the factory heat protection seemed a good deal.
The starter is 2ga wire, which is plenty adequate - especially for such a short run.
The only thing I have left to do on this project is replace a small amount of wire conduit. I got tired and put it off to today. I decided to change the transmission fluid while I was down there and it's due for its annual oil change so I've got one more work afternoon then it's back on the road.
[This message has been edited by thesameguy (edited 04-23-2018).]
Got the transmission fluid changed (GM Synchromesh #88900333 / ACDelco 10-4006) and the oil changed yesterday and took the car out today.
It's a huge improvement. I've had zero complaints about the "driving quality" of the car to date, but replacing the battery cables tangibly woke the car up. It idles better and I'd bet money it freed up some power... whether it's less drain from the alternator or stuff just works better I don't know, but it's a dramatic improvement. Really happy I took the time to change the transmission fluid as well, because that's also much improved and nothing goes better with a more responsive engine than a more responsive transmission.
Hopefully that's my 2018 project on this car... seems like every year I do something other than get it painted, but it's great to drive and I'm not the one that has to look at the outside. Maybe next year it'll be paint.
It's a dumb thing to worry about. I'm probably going to let it go - admittedly mostly because my usual supplier is out of stock on the 4x maxi fuse holder. 
