One quick check that is relatively painless and easy is a voltage check on the system. For this you will need some sort of voltage readout; either connect a multimeter across the battery terminals (or somewhere else similar) to read voltage, or, perhaps enable a voltage reading on some instrument (my garmin 296 will show this) Check your voltage with the battery charged, master on, and engine off... you should see 11.8-12.4 or 5 try turning on some load (landing lights if u have them) and see how much drop you get...landing lights may drop you to the 8 V range, position lights or avionics to maybe the 10V range - this with the smaller 25 Ah battery in good shape, the 35 Ah should have slightly less drop....
ok this procedure assumes that a low amp DELCO generator is fitted (like the original) but the procdure does not vary much First, check your fuse... If that thing is blown, or even corroded internally (mine was) it will prevent the charging system from working... new ones are pretty cheap here... start engine and check voltage with all systems off and charging system operational you should see a pretty quick rise to 13.8 - 14 V if you DON't see this then you have a generator or regulator problem if you have a DELCO GENERATOR (NOT an ALTERNATOR) you can determine which one is the problem pretty easily... but you have to disconnect a wire from the generator this wire is the F for FIELD (the other is A for ARMATURE - leave this alone) (there should also be a ground wire on the generator case somewhere) so you ground the FIELD terminal on the generator with a wire and start the motor.... what is your voltage reading? if it hits 14 and starts climbing then the regulator or possibly the wiring is the problem... if there is no voltage rise then you either have a bad generator, or an unpolarized generator (was not flashed) or that fuse really is blown... as the voltage starts rising turn on some accessories... (landing lights) and see how much drop you get...if there is a drop to 12.5 or higher then the generator has sufficient amp output (13 amp gen here)... OK, so now you either have a good rise in voltage with a grounded FIELD terminal or you don't. If no rise in measured voltage then either you have an issue in your wiring or else you have an unpolarized generator, or you have a bad generator... try flashing it the procedure is simple but critical... unhook the A (ARMATURE) wire from the generator terminal find a HOT (+) connection and run a wire from this (NOT the A) and BRIEFLY (1 - 2 seconds or so) touch this hot wire to the A terminal on the generator, when you pull the wire off you should see a pretty good spark then reconnect the harness wire back to the A terminal and run your check again... (alternatively u can access the regulator under the starboard seat, disconnect the A lead from the regulator and touch it for about 1-2 seconds to the B+ (battery) lead going into the regulator, you should get the same spark run your voltage regulator connected (FIELD) and see if you get a rise in voltage, then try with the field terminal grounded if you get no rise with the regulator connected to the field if you are still getting no voltage rise then you need a generator if you get a rise with the field terminal grounded (I mean significant rise, up to like 14 V from a rest state of 11-12) but not with the regulator, then u need a regulator... (many people use delco tractor regulators here from the local auto parts (NAPA) store but to tell the truth, I really don't recommend this---in the US it is somewhat illegal (your chances of getting caught tho are about nil, the old regulators generally have no PMA markings at all to distinguish them and the regulator is a bit of a pain to access, as originally fitted) also the tractor regulator is about 80 and a solid state aircraft reg is about 130 (zeftronics) if your system passes the first voltage rise check but won't usually start then u either have a bad connection, bad cable, or bad battery... most likely it's the battery..... hope this helps... the voltage checks can be performed by any aircraft owner, the wiring disconnections probably shouldn't be, but as long as you hook things back up perfectly, and don't let loose wires touch anything, there is not much that can go wrong... I mention this as there are an awful lot of A & P mechanics out there who have no clue about how generator service really works... please note, these comments apply to the DELCO GENERATOR (13A) as originally fitted to an E model ercoupe... if you have an alternator conversion please DO NOT try this procedure as it does not apply to ALTERNATORS --- In [email protected], "Donald" <dongen...@...> wrote: > > > > A quick check to see how many amps your starter is actually drawing would be > in order as well. > > --- In [email protected], William R. Bayne <ercoguru@> wrote: > > > > > > Linda, > > > > Once again, I agree with Hartmut. A healthy 25amp battery will serve > > your needs just fine. > > > > WRB > > > > -- > > > > On Jun 18, 2010, at 02:23, Hartmut Beil wrote: > > > > > > > > > > > Linda. > > > > > > My experience with batteries is that a battery that is dying can > > > crank the starter fine for a few rotations, but is still source of > > > trouble. > > > > > > A Generator/regulator that is loading the battery properly can create > > > the same effect. > > > When all 3 parts of the system are in good working order, you won't > > > experience the problems you are describing. > > > > > > As a matter of fact, I was jump starting cars with my 12 Amp/h > > > Motorcycle Battery with no problems. > > > It is not the size of the battery that matters, it is the cranking > > > power that it can develop. > > > > > > Understandable a battery with a dying cell will develop little > > > cranking power, as are some batteries that are not designed for that > > > purpose. > > > A good 12 amp battery should be able to start your engine as well as > > > the 24 amp one or the 35 amp one. > > > > > > If you have these intermittent problems , I am hesitating to come to > > > fast conclusions that the battery is not big enough. > > > This is the logic of the inexperienced. > > > > > > It is usually either the starter itself or the charging system. Of > > > course one has to verify first that the battery itself is good. > > > I am afraid you mechanic wants to fix a problem from the wrong side > > > at your costs. > > > > > > Hartmut > > > > > > > > > To: [email protected] > > > From: lasprite@ > > > Date: Thu, 17 Jun 2010 16:09:08 -0700 > > > Subject: [ercoupe-tech] batteries > > > > > > What John wrote below helps a lot to understand the relationship of > > > battery & generator. The problem I've had recently has not related > > > to running enough electrical items in flight, rather, it has been > > > battery capacity for cold starts: e.g. when my local A&P ran a bunch > > > of "test starts," such as when he was adjusting the pull-starter he > > > tried it out a bunch of times, or when he cleaned the spark plugs and > > > was testing whether that smoothed-out how the engine was running. > > > Then when I went to fly next, there was not enough power to start > > > up. Yesterday, he had to give it a "jump start," but after I flew > > > 45 min. to my destination, did 3-4 starts & run-ups there for the > > > prop-balancing guy, and then it sat for 2-3 hrs. but still started > > > fine for me to fly home. > > > > > > John (et al.), can you please address battery capacity for cold > > > starts? Is it correct that a Concorde 35 will be better for this > > > purpose than a 25? The A&P wants me to get a 35 (and, Hartmut: he > > > says a field approval is no problem, and he'll measure the box for > > > fit, before buying it.) Is a 35 better for my purposes than a 25? > > > Other than the few lbs. extra weight, am I asking for any kind of > > > additional problems if I get the 35? My 414-C has a C-85 and a > > > generator, not an alternator. > > > > > > Linda > > > N3437H (Sky Sprite) > > > L.A. > > > > > > 1a. Re: batteries > > > Posted by: "John Cooper" john@ > > > Date: Wed Jun 16, 2010 6:16 am ((PDT)) > > > > > > On 6/14/2010 7:31 PM, Todd Fischer wrote: > > > > > > > Reading the Univair memo it sounded like the older generators just > > > > couldn't handle charging the larger batteries and only approved the > > > > RG25 batteries. > > > > > > > > > > > This is a misconception. The larger battery has more capacity, so it > > > will take longer to discharge, as well as longer to recharge, but, > > > unless you continually discharge it, which means your constant > > > electrical load exceeds the generator capacity, it will remain charged > > > the same as a smaller battery. OTOH, if you are exceeding the capacity > > > of the generator on a regular basis, the smaller battery will go flat > > > faster. > > > > > > If the RG-35 battery is in good shape, and you charge it up (once), and > > > you do not exceed the capacity of the generator with your electrical > > > load, then the battery will work fine. > > > > > > As an aside, the constant load on the electrical system should not > > > exceed 80% of the generator capacity. Constant load includes comm > > > recievers, nav radios, transponders, nav lights, etc.; everything that > > > is not intermittent, e.g. landing lights, flap motors, gear motors, > > > comm > > > transmitters, etc. > > > > > > -- John Cooper > > > Skyport East > > > www.skyportservices.net > > > > > > > > > > > > Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. Sign up > > > now. > > > > > > > > >
