What should battery voltage be while cranking

But many of these meters are better at reading small voltages. YMMV, so the first commandment is "Know thy meter. SO if I am using the cheap meter I leave in my tool box and I suspect a wire has too much resistance due to size or age or damage what I do is to measure the voltage drop across the wire.

Specifically, measure from one end to the other when current is flowing. In this case, your meter should read zero volts when you have the leads on each end of the wire and current is flowing through the wire.

Somewhere you have a series of little voltage losses or one big loss that is robbing your coil of the energy it wants to make spark. Find those and you will solve your problem! Last edited by marthur; at AM. Originally Posted by marthur. Hanley is right that the R terminal can be a helpful thing, but Neil suspects that there is too much voltage being lost suggesting a repair is in order. I would consider the R terminal.

But I would not rest well until I tested the components the ignition and starting circuits. A corroded terminal or broken wire can fail unexpectedly or get hot due to the increased resistance and cause real trouble. Better safe than sorry. Battery bet. Jack, volts and power amps are not the same. As you increase the load the voltage will begin to drop and the worse off the batteries the more the voltage drop.

You added water and with the charger she'd spin well enough to start that's adding "POWER" or amps to start! Take the batteries out and get them load tested!!! I'll bet a liquid bread that is your problem. Weak batteries especially a load of them tied together not being able to spin the engine fast enough but with the charger all is bliss. That's batteries in a weak state. I have the need for new house batteries at the present. The house side in my set-up are a pair of 6v's for the house and an isolated grp27 for the engine.

I usually start on the both and when out I use only the house for starting and power at anchor, to save the start battery if needed. The 2 big 's will run the lights tv and stereo for days and all is well to start on them. At the present the "charged voltage" at rest is down a bit and they will barely start the engine when cold. The voltage drops considerably upon cranking and they will be replaced before the summer cruising starts!

The "R" terminal was a necessary part on the original wiring and ignition set-up on the A-4's equipped with the "old style ceramic ballast resistors". The ignition was reduced to 8v for the stock 8v coil and full voltage was tendered for the cranking circuit to boost the available spark! All times are GMT The time now is AM. Moyer Marine Inc. All Rights Reserved. User Name. Remember Me? Mark Forums Read. Page 1 of 3. Thread Tools. JackConnick Senior Member.

Find all posts by JackConnick. Posts: 4, Thanks: Thanked Times in Posts. Need more input Jack, that's not really that bad at the starter when starting I assume?

Find all posts by Dave Neptune. Find all posts by hanleyclifford. Argh the R Jack, the "R" wire hookup will do nothing for you unless you are using a resistor on the EI. No R If your not using an external resistor it will make no difference, but it may supply a bit more than your switch but only during cranking. Find all posts by roadnsky. This message has been deleted by ndutton. Back to it The 'R' terminal I'm so against this it's hard to find the words.

Find all posts by ndutton. Quote: Originally Posted by ndutton I'm so against this it's hard to find the words. Quote: As discussed it could be the batteries aren't cuttin' the mustard any more, maybe the ignition wire with splice has developed a high resistance for one reason or another, could be the battery cables or their terminations. Find all posts by marthur.

It can read a full voltage of However, when a battery with a bad cell is put under load, it will immediately fall well below its real voltage of Once the load is removed, it will only bounce back up to its maximum To answer your question, 10 volts under a load test shows a good battery, especially when it immediately bounces back up to over 12 volts once the load is removed.

EDIT : Starting a car is very different from a load test. The battery is under load for much less time. A battery that falls below 10 volts on startup but that consistently starts the vehicle is probably either a little under charged or is aging and has lost some of its cranking power as all batteries do over time.

Putting the battery on a charger will solve the under charged issue. If it is still falling below 10 volts after a good charge then the latter issue is the case.

An easy but hard lesson to learn when a car battery needs to be replaced would be either in summer or freezing cold temperatures with the battery unable to power the starter and a boost is needed. Most batteries last all the way to the end of their warranty and promptly die.

There are hints along the way. Good load testers places a load as if powering a starter drawing large amperage for a timed period seconds or more then reading voltage. Whether computerized or analog testing, good batteries will pass while marginal ones may just need charging. A battery nearing its end of life will not hold a charge and usually a candidate for replacing.

Honest auto parts stores will give accurate advice while the dishonest ones are to be avoided. Sign up to join this community. The best answers are voted up and rise to the top.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Is a battery healthy if drops under 10 volts with load? Ask Question. Asked 1 year ago. Paul Thomas. I have had intermitent start-up ignition problems lately. I thought it was gone but now the car wont start at all. And i could not drive it to Hershey. When i turn the key on, fuel pump runs, volts at the ignition hot lead.

Turn the key to start and the motor turns over great but the voltage at the ignition hot lead drops to around 2 volts. Not enough to power the crankfire. I talked to Richard Clewett great guy by the way , he is sending a relay he says i should have anyway and it might be the fix.

I am open to other possibilities. Could it be my alternator? Voltage regulator? Tim Walsh. Tim Walsh's Garage Porsche 2. Cranking a car takes LOTS of juice, but 2 volts is pretty low. I don't think it would be the alt since it just supplies maintence to your battery. You can run for an hour or more just on a fresh battery without an alternator. Fl Ted. If you've got volts with the ignition on and engine not running, you've got a voltmeter thats reading about 4 volts high!!

The battery will only read about Battery voltage will drop to volts while cranking, lower than 7 volts, your batt is bad. Something is loading down your ign circuit. When you're reading the 2v the ign hot wire, is the wire connected or dissconnected? If its connected, whatever it's connected to is the culprit. If it's dissconnected, it's something up-stream.

Get the wiring diagram and trace upstream. Checked both batteries and they are good. I pulled the alternator earlier to check all of the conections and the voltage regulator. The voltage regulator is available from Pelican. Wires going into and out of the regulator have some sort of brown goop on the wires. I may take a pic if anyone has any further insight. A good battery should maintain 11 volts while cranking at the batt terminals I'm not sure where terminal you are measuring this low voltage, please clarify.