The Optima is a sealed lead acid battery. It is not vented and it is not a dry cell. Personally, I don’t think they are worth the cost for most applications, but my son uses two of them in his car, one under the hood and one in the trunk for his high powered amp. The are in parallel, connected with 2 ga copper wire, both pos and neq and the neg is grounded at both ends (which I do not recommend for his application). He uses two of the Optima’s so that both batteries are identical as far as the alternator is concerned. No mismatched impedances.
Twin, i’d like to see some of your work too. here’s my engine bay. i .too bent the tubing for the transfluid and although its not inside the frame it is well hidden
Not too shabby, but you still need to connect that alternator directly to the crank pulley.
.they are sealed lead acid…I must’ve confused the matrix with my motorcycle Gel cell technology type of battery. Any who…I’ve never seen an Optima leak as of yet… The product literature even states you can mount one upside down…lol. I find these to be top quality units…I have one that is over 8 years old and still going very strong…I have the worst luck in the universe with batteries I can tell you that. If its my battery its either dead or soon to be dead…but this Optima just keeps on cranking…and cranking strong I might add. Love them so far.
They seem to be HUGE in the Hot Rod scene…The no leak deal kinda works well with a nice Hot Rod.
Oh well…nice engine bay…lets hear you start her up! LOL Good luck! It will start, just do that test ground line…it will have no choice but to work…IF the starter is fully functional that is…
You don’t necessarily need an Optima. My current car has the battery in the trunk by design and a small vent hose runs out the bottom of the trunk. You could do similar. But if you have a battery in there that needs venting, by all means vent it properly. Hydrogen can build up and cause an explosion and the gases from a battery are very corrosive.
I don’t think you need an Optima or marine battery and 2 gauge wire is a bit of overkill in my book. Odds are this is a poor ground connection problem.
A project car I have has a rear mounted battery with 4 gauge wire and a cheapy 1 year, 550 amp Wal Mart battery. It’s fine no matter what.
You should definitely make sure the battery is contained in a box and vented to the outside. Gas buildup in the trunk, a microscopic stray spark from static electricity or a wobbly taillamp bulb in its socket, and the trunk lid could exit the car while bulging the rear quarters.
What is the point of running the alternator with an electric motor? The battery drives the motor that drives the alternator that charges the battery that drives the motor …? Unless you’re trying for a perpetual motion machine that’s kind of pointless. You’d need a motor and alternator that are more than 100% efficient for that to work. You’re probably better off NOT powering the alternator at all since the electric motor would use more battery power to drive the alternator than the alternator would generate, since it’s less than 100% efficient. Of course, that’s going to kill the battery too, just slightly less quickly.
As others have noted, you’re going to need to find another way to power the alternator, unless you’re planning on drag racing the car and not driving it on the street except for very short periods.
I also think 2 gauge wire is vast overkill…2 ga is like the diameter of your thumb is’nt it? Thats too big and too hard to hide… I am on board with 4ga
I too am a bit confused with this alternator setup… What exactly is going on there? If you have an electric motor spinning an alternator or a motor setup to be an alternator…This WILL NOT WORK… You need to drive ANY power generator directly off the engine… There is NO alternative. Sorry but there is’nt…youre going to have to go back to the drawing board on that one…otherwise the engine bay and engine look great…I’m sorry to spoil that clean look, but…you need to drive that off the engine pulleys
UPDATE: it turns out that it “was” a grounding issue. 2ga wire grounding the motor to the chassis up front and he fired on the first crank…and the second and the third…and every time. so, the biggest problem solved. also, i’ve known all along that efficiency from an electric driven alternator would eventually deplete the battery but the original intent was driving Frank for short periods and some “friendly performance comparisons” with fellow classic car owners. ive already ordered the crank pulley.
Amen man… Nice work.
I’m happy to hear that experience with 73 Comets works on 68 Mustangs. You have a very good display and performance / hobby car there. Nice Work.
Glad it’s working for you. Running an alternator from an electric motor is less than useless. It will actually drain your battery faster than not running an alternator at all. I’d suggest finding a way to drive an alternator from the engine, even if it detracts from the clean look you’re going for.
Looks great! My only access right now is my phone. Rearranging things so my 1 yr old has his own room. When PC is back up I’ll post some photos.
Keith, let me know why you believe the chassis must be an electrical path and I’ll respond. Have built a few without any chassis “ground” so curious why you think so. It’s especially easy to do on these vintage cars with few electronic gadgets…
Use a Group 27 battery and at least zero gauge welding cable for that positive lead to the fender-mounted solenoid. The short battery to car body lead can be #2 wire as can the car body to engine block cable…If you did not have a heavy ground cable from the block to the body, look for burned up “things” that might have been carrying the starter load, like the throttle linkage, clutch linkage and light gauge ground wires…
The short battery to car body and engine to car body ground cables must have perfect connections! bright, shiny steel with large washers to spread out the current flow quickly into the car-body…Otherwise, you will get high resistance, spot heating, and a failed connection…That positive cable going forward needs to be properly routed and supported to prevent ANY chance of snagging, dragging, rubbing, crushing, falling…Two cables, one for the engine ground, would be better…
Is the solenoid in the trunk too??? You should leave it in it’s original location…
It that an electric water pump?? No front crank pulley to steal power from? What is driving the alternator?? An electric motor? The entire electrical system will have to be re-done…Which is too bad because you have obviously spent a lot of time on that…If driving will be limited to a couple of hours during daylight hours you could use a “total loss” system where everything runs off the battery. But with an electric cooling fan and water-pump, the battery will be quickly depleted…
Frank, if you are just doing short runs and recharging the battery with an external battery charger, then just remove the alternator and its motor. Its doing more harm than good.
TwinTurbo, I did not say that the chassis had to be an electrical path, I said it has to be grounded. If you don’t ground it, then you have isolated grounds that can develop different potentials, known as floating grounds. Running one wire from the chassis to the electric ground, or negative terminal of the battery will ground the chassis but is not part of the electrical path. It only becomes part of the electrical path if the loads are attached to it and are using it exclusively for the return path.
attempted clarification of above
TwinTurbo, I did not say that the chassis had to be an electrical path, I said it has to be grounded. If you don’t ground it, then you have isolated grounds that can develop different potentials, known as floating grounds. Running one wire from the chassis to the electric ground, or negative terminal of the battery will ground the chassis but will not be a part of the electrical path. It only becomes part of the electrical path if the loads are attached to the chassis and are using the chassis exclusively for the return path.
i replaced the battery with a larger one, one with almost 1000 cranking amps. I have 2ga battery cables from the battery to solenoid (also in the trunk) and grounding to the chassis on bare metal. Ive got 2ga welding cable from the solenoid to the starter and 2ga welding cable grounding strap from the engine (3" above the starter) to the chassis on bare metal about 6" away. This setup seems to have solved the problems without over heating any other wires. all connections are brand new, bright, shiny. as far as the alternator goes, it can also be hidden on the rear axle with a bracket and powered by a pulley on the driveshaft. i think i’m going to go that route.
caddyman, thanks for the concern but the only electrical to be re-done is the alternator. electric fans, electric water pumps are typical race applications. electric motors have also been used to drive pulley-type water pumps and yes alternators too (for short periods). these types of builds arent new to resto-modders. neither is placement of the solenoid in the trunk. the car used to be a coupe, now a roadster/convertible- thereby eliminating the need for heating and A/C, wipers and alot of excess little electrical additives. in a previous post i mentioned that i have in fact ordered a pulley for the crank if i decide to keep the alternator up front. likely that i’ll move it to rear axle and pull from the driveshaft though
A lot of money is being spent on visual effect and impact…What is the heritage of your engine? Are we talking a Boss 302 or has the displacement been increased? What usually limits the performance of this type of car is traction, not accessory loads on the engine…Anyway, glad you got it running and good luck with that driveshaft driven alternator…
yes displacement has increased. was a 302, now overbored with highrise aluminum intake, holley 650 with 1" spacer for low-end torque, hei distributor, slightly more stout cam and long tube tri-y headers. traction is definitely there- now has a chrome 4link coil over rear end with QA1 adjustable shocks and brand new front end suspension with rack and pinion steering. the entire car has been lowered 2" and is sitting on 245/40-18 directional federal tires wrapped around 18" lenso wheels.stiffened the chassis big time to eliminate the all too famous body roll on these cars. so all the power in the 3.55 rear end should stay with the wheels. once back on the road the next step will be to slap a couple of 351C 4V heads worked and tuned for a classic Boss flare. 100% of the work and fabrication has been done by me which has kept cost way down. 16 months later though and im itching to roll