Commutacar
 

can someone tell me where on my Commmutacar car do I find the serial number ? It is a 1980, and I can't find the serial# which I need to know as there are modifications listed for cars below or after certain numbers. Can a Comutacar owner please help on this one...? thanks.
Also, can someone tell me how to measure the amount of charge/time/miles left in my batteries whilst driving? I'm using 4 X 12v batteries to get car running before I invest in the proper 6V ones. The original 'battery meter used 18v ( I can't figure out why?) I can't make 18v out of the 12's, so don't know how to measure how much range from the 12's?
They are C&D UPS 12v gell cells, and not intended to be deep cycled. Does anyone know if I can deep-cycle them? If so, how many cycles could I expect?
thanks again,
Electrique

vin number is on the dash and on the frame by the right rear wheel, on the square tubing.
I have a paktrakr gauge on my commuta-car and it will give me a state of charge in percentage, along with battery pack voltage and voltage of each battery on it's own because your mileage will vary and over discharging your batteries will shorten their life and that can only be figured by battery voltage.

Welcome to the site. Do you have any pictures of your car? :)

Where are you in Canada? I've only seen one CitiCar/ComutaCar before - maybe 20 years ago in Ottawa.

I'm not sure about gel cells, but the rule of thumb I follow for flooded lead acid batteries is you should never draw any individual battery down below 1.75 volts per cell (5.25 volts per 6 volt battery, or 10.5 volts per 12v battery).

Below that voltage you risk permanent battery damage (chance of cell reversal).

When voltage can't be held above this value under load (regular use), the battery is effectively at 100% depth of discharge. So you can estimate your range based on this info.

Ryland is right though: a battery pack monitor is best.

wow! you know your stuff...thanks very much, I'll bring you up to date once I get things going. the gel cells are just a stop gap power source, until I know everything works. The car now runs but won't stop! ( no brakes!) I hope they just need bleeding? Can the brake master reservoir be accessed through the L/H headlight hole?
Do you still recommend using the Trojan 6v cells...it's a $2000 investment for me, so I'd appreciate any comments on that? I have to go with batteries available locally, as any 'deals' are no longer deals when shipping and duty is paid, so unfortunately, nothing out of the US.
I'm in Victoria British Columbia, Canada

master cylinder is gotten to by the drivers side feet, but get to it from the passenger side with some twisting, if you have to replace it, they used a master cylinder from the AMC cars and jeeps before GM bought it out, cost should be around $45 for the part and take an hour to replace, wheel cylinders are industrial vehicle brakes from wear house trucks, kind of like golf cart brakes but heavier.