Captain_Zeros

No battery was EVER at three volts during the process, when I say "dead battery" I mean not enough power to fire up any of the car electrical not to mention crank the starter (headlights etc) which in my case was around 5-6 volts. My bypass trick involved using a "dead" battery at around 5 or 6 volts, and a fully charged battery between 12 and 13 volts hooked up in parallel to give a bank with an average of 8 volts or so which is perfectly fine to charge. (Interestingly enough I watched the Optima resurrection tip video posted earlier in the thread and they actively suggest doing the same exact thing). Throughout and beforehand I measured voltages and temperature of all the components of the system and supervised it fairly closer. The unit is a maintainer/charger, says so in the manual, anyways I've only used it on a dead-ish battery maybe two or three times, it stays hooked up as maintenance generally. I'm comfortable with using it to charge, the documentation is fine with it and I only do it occasionally anyhow, it's not like I'm shorting it out and taking a vacation. It's had no issues so far nor has it displayed any behavior that would lead me to believe otherwise. I'm not saying other people have to charge with a Battery Tender brand battery charger, but I'm comfortable with it and telling me I'll burn down my garage by following the instructions.... feels a little extremist and like a personal attack.

The manual says you can use it to charge a battery, and what electrical knowledge I have tells me this is no big deal. It's not out of it's design specs to charge a battery, and as long as it's not pulling more than the .75 amps it's rated for it's not being overworked one bit (and considering it's a microcontroller based smart charger, it doesn't, it would go into an error shutdown mode if that occured.... which it hasn't). It doesn't get dangerously hot, and if a battery reads 13 volts it generally has the amps to crank a motor or anything else assuming the battery itself is damaged. Read the battery tender website yourself, as long as the battery isn't COMPLETELY flat, charging it with the .75 amp charger is no big deal, it just takes forever, as much as two days. Do your research on a product first before going off on a tirade about how it'll burn my workshop down. Edit: Here's the factory documents that describe how to charge a flat battery using a battery tender junior within spec. http://batterytender.com/includes/languages/english/resources/Product_Instructions_BT_Junior.pdf?osCAdminsID=340cf056b7e37f3662e001e495eac704&osCAdminsID=340cf056b7e37f3662e001e495eac704&osCAdminsID=340cf056b7e37f3662e001e495eac704&osCAdminsID=340cf056b7e37f3662e001e495eac704 Edit: The FAQ also says it's fine to charge similar batteries in parallel banks using the Battery Tender Plus which is basically the same brain + heat shutdown and an extra .5 amps of charging speed. It doesn't say whether it's okay or not to use the junior to charge banks, but I'm willing to take my chances while I supervise it for short periods of time.

I've charged a flat battery (under 7 volts) using my trick to fully charged green light in under 24 hours with my Battery Tender Junior.

I've got the "Junior" model myself and it's never done me wrong. It won't charge all the way up from a completely flat battery, it's not designed for that kind of amperage (It'll blink the red light at you for 'error'), however I found a little trick to jerry rig it into trying. If you throw a pair of jumper cables from a good battery to the dead one like you are gonna jump start it, then clip the battery tender to the dead battery, the microcontroller in the charger will see mean voltage between the two and start charging, then you can pull off the jumper cables and let it keep charging the dead battery. I wouldn't really suggest this on an extremely dead battery, but I did it anyways to no problems. I'd assume it's not that common of a problem to need to charge a battery when you have a good battery laying around and a pair of jumper cables... but... well.... my car doesn't run yet, not like I can start it up and let it charge off the alternator.

Mine has a side post battery installed as per previous owner

I haven't done it myself yet, but I was just reading up on the matter as I'm going to have to myself. It appears that it isn't too bad, removing a couple bolts for the tank straps and unhooking a bunch of rubber hoses. This guy has a pretty decent description on his log that I've been using for picture references: http://phreakmonkey.com/240Z/journal-2000-01.html

Gee.... maybe like this? :stupid: Thanks Arne, very helpful!

Previous owner believed them to be original to the car, but he was the third owner and since I've never seen something similar on a Z and they were made on the other side of the world, I'm sort of hesitant to believe that. Here are the wheels that are currently on the car as well, which I also haven't seen on a Z before. Not that I've seen too many.

These were in the back of my Z when I bought it, in basically unknown condition. I'm searching to see if I can find any information on them, but I don't recognize any of the manufacturer marks (which isn't saying much ) There is a very visible small mark saying XA494, and a second set of fainter larger marks which as best I can tell read: RSM 15 50 X14 CO ENGLAND D S

No starting issues so far yet.... but no starting either, seeing as I don't have a battery what fits in the car Thanks everybody for the suggestions! All the battery groupings are greek to me, knowing things like F for the mirrored terminal layout is a cool bit of knowledge. I'm not going for a spot-on restoration, but cheap and easy original things are fine in my book, I bought the car from a fellow who was considering pulling the fully working original engine to replace it with a small block chevy, not my cup of tea.

Okay, I'm working on a 1973 240Z which has been sitting for, oh, 10 years or so before I bought it. I am shopping for batteries, and low and behold I realized something rather odd. My car has side post battery cables (as best I can tell, I've never owned or worked on a car with side post battery cables before), and as best as I can tell, the Z came with more conventional battery cables. My questions on the matter boil down to -Is my conclusion correct? -What size battery do I really need? -Should I switch the battery cables and get a top-post battery, or just buy a side post battery? I don't know if there is any performance, durability, or monetary reason to go with either option. -Should I wish to replace the battery cables, what's the difficulty rating? It looks deceptively simple, which is usually when some tiny PITA part breaks and costs you an extra $100. I have the original battery hold down bracket (original as far as I can tell), and it has had some cutting on the side done to accommodate a side post battery, is my assumption.

I've had the car less than a week, just got the air-cleaner off yesterday (it was running into the brake master cylinder :stupid:) First thing I did when I found I had an extra set of carbs not on the car was google around for information, and ran across z-therapy.... looked around the site and went "WHOA, SALEM! COOL!" Nagging questions are gonna come after I try and get the car running, right now I'm still in learning and diagnosing mode

Any updates on your successes or lackthereof? I just bought a '73 240 with flat tops, and am basically planning on cleaning them up and trying to run them (it's been sitting for years, they're pretty scummy), however the last owner was given some Z parts by an acquaintance of his and threw 'em in with the car, including a pair of earlier carbs which seem to be remarkably cleaner (and better devices, if I can believe most of what I've read on the net). However, not sure if all the linkages and such line up enough to be able to do a swap, and if I'm not mistaken it'd require a new intake manifold as well, kind of expensive if I don't have to.

Thanks for the advice! Yeah, I haven't done anything but research so far, I was planning on draining all the fluids as soon as get a second set of jack stands to get the whole car off the ground. I turned over the engine just by putting the car in gear and pushing a few inches to see if it was all rusted solid and seized up or not, it doesn't even have a battery. Nobody around me seems to want to sell their cars with the batteries these days. However, as a bonus he threw in some spare parts, including a set of carburetors which I THINK are the more desirable bell shaped carbs as opposed to the flat tops of '73. One thing that has me a bit worried is the fact that the brakes don't seem to work at all, and the brake fluid reservoirs on the master cylinder are empty. Parking brake works just fine, the pedal just sort of mushes to the floor and does nothing. I'm hoping a brake purge and bleed will solve this, but if the lines are leaking somewhere, ugh.

Hi, new to the forum, so I'm posting here... to introduce myself.... in the introduction forum. My dad had a '79 810 when I was a little kid, and I learned to drive in my aunt's '81 720, and lo and behold, now I have my very own 1973 240Z! The catch is that it has been sitting for 10 years, so I have my work cut out for me, at least the engine isn't seized!