After running on battery power for a while a few nights ago due to a blown GEN fuse, I took my battery out for a good slow MX charge as it would not even turn one blade upon arrival at Front Royal. The battery accepts a healthy charge, but the specific gravity on a few of the inboard cells will not come up to spec even after several days of charging I think it is about time for another battery and I was thinking of going with the new extra capacity valve regulated sealed lead acid battery from Concorde as opposed to the old technology flooded cell design. Has anybody had any experience with the SLA batteries in the 170 with the original generator circuit? My experience with the SLA batteries in electronic work dictates that they be charged rather carefully so as to not overcharge. I am somewhat worried that the generator on my 170 may overcharge an SLA battery, even with a modern electronic generator control unit
Yes I just install two of them in a Baron B55 at the owners request. Concorde has not followed through yet like Gill and has not gotten approval for installation in many aircraft. I had to go to the trouble of getting a field approval for their installation last week. Gill's should be approved for the Cessna 170 models and for the little more you pay has more cranking power and comes with approval installation paper work for the 170's.
John, I know of someone that has been running a Concorde SLA in a C170 in Arizona since 01/96 and he just replaced it. That is a pretty good for any battery here in Arizona. However at that time of installation he had to get a field approval. I do not know if they are STC'd now. Currently I am installing a 220 Franklin in my C170B and will seek a field approval for a 35 A/H SLA.
What's the advantage of these sealed batteries? My 3 year old Gill G-25 cranks 'er right over,never leaks,never needs water,doesn't seem to care how much ya charge it.......the expression "if it ain't broke,don't fix it" comes to mind.
The advantage to the SLA batteries over conventional flooded cell designs is that you have no MX tasks other that seeing that the battery is kept charged and the posts are kept clean. No worry of acid spilling in case the battery gets upset from the upright position. Downside is that the SLA batteries are more "finicky" when it comes to charging. The charging parameters must be controlled more precisely than with the flooded cell design. If you overcharge the SLA unit and vent out the gelled electrolyte you can throw it away vs. just adding some more distilled water to the flooded cell unit and then correcting the charging parameters.
I would not be thinking of replacing a good flooded cell battery with an SLA unit, but my flooded cell battery is at life's end. The SLA batteries from Concorde are available in an "extra capacity" model that gives 597 amps cranking vs. 235 amps for the flooded cell design. With cold WX coming on, I could sure use the extra power while grinding away on the starter the winter.
I have used the Concorde battery since 1994 and really like it. They do not have gelled electrolyte in them. The acid is in very fine glass fiber surounding each plate which is all sealed in a plastic sac. If the case breaks open there is no acid leak. One of the best features is I have not had to remove corrosion from the battery box since 1994 and before that it was a nasty job every year. I have an alternator and have had no problems with charging. It just worked fine for six years. When it finally died I got the one with extra power. A cell in it died in about 2 months which led to a whole bunch of work because I could not believe the battery was bad. I ended up with a new battery, new (rebuilt) alternator and new electronic voltage regulator. All I really needed was to replace the battery. The third battery seems to be holding up well like the first one. I would not get a wet battery again unless that was all that was available.
Since the sealed battery does not have free liquid acid in it, shipping is no problem. No extra charges apply. There is no problem getting it approved on a 337 but I think either Concorde or one of the major distributors has an STC for the 170. Try it. You will like it.
Hey Garry, you are correct. I did not read far enough into the catalog. I suppose the gelled type of SLA batteries are only found in the electronic sector. Another good point on the SLA batteries is that, in the case of the 25 series batteries, they are from 3 to 5 pounds lighter that the flooded cell units. As for FAA approval, the catalog says they are already fully FAA/PMA approved in aircraft from the C-150 to the Falcon 900. I take this to mean that I can just drop the battery in my 170 and go fly...or am I missing something here
Solomon said there's nothing new under the sun. That's how I feel about the claims made about the "new" battery types. SLA (sealed lead acid) has been around since before WW-2 but only recently has caught on with aircraft. So has gel-cell. And re-combinant gas batteries were used in submarines for 50 years before offered in aircraft. None of them have the longevity, charge-recovery, or capacity of lead acids when compared by price or weight. (And the gell cells are expecially sensitive to exact-voltage charging systems.)
If Gill (and other brands) lead acid batteries are not overserviced, they may be turned on their sides or even upside down and they will not spill acid in your battery box. When they are improperly or over-serviced, like anything else, they will fail. If you'll sprinkle some baking soda in the bottom of your battery box before you install your battery, and if you'll rinse your battery box out with the garden hose every so often when you inspect your battery (You do inspect your battery, don't you? Even the other type batteries must be regularly inspected/charged according to their STC's) any acid you spilled will be neutralised and corrosion will be eliminated. The advantage of traditional lead-acid batteries is that for the weight and price, they will deliver more amps per pound per dollar than any type presently offered. Unlike gell cells and "glas-pak" batteries they are especially suited to delivering their power in cold weather. If you buy from Aircraft Spruce and certain others, there is no "extra" shipping charges or hazardous materials charges because shipping is free.
Some of the same hype has crept into this thread as when SOMEONE talked about bronze plated cow-flop. If any 170 owner plans to fly upside down for extended periods of time, then maybe a "gel" battery is for him, other wise, dollar for dollar, the standard lead acid battery will usually give "over and above" service. George, you are correct in alerting servicemen (owners or others) about over watering the cells. Good maintenence practices and efficent battery terminal clamps are vital to long battery life.
Barry Jay, (TAP) has the best prices on batteries and shipping the acid in isolated little containers in the same big box, has eliminated the problem of having acid in the battery during shipping.
The next to the last Concorde I got from him failed in about three months. When I contacted him they shipped me a new Concorde that same day. He just asked me to send the bar code strip off the other one and a copy of the logbook entry that was made when installing the first battery. It was that simple! He has recently changed suppliers from Concorde to Aero. I just got one for "her" C150 last month. I guess time will tell abut the service life of the 'new' kid on the block. It looks like his warrenty is still the same.
P.S. GHORN DOANT BE A QWOTING THE BIBLE OR THE WISEST MAN IN THE WURLD. IT COULD GIT YOU INTO TROUBLE AGIN!!!
Winters nearly here, remember, one of the worst things we can do to our batteries is to have them face freezing temps without a good charge! If you are not able to fly often to keep the battery charged up, it will add greatly to the battery life to put it on a charger before the temp drops below freezing.
I think it is about time for another battery and I was thinking of going with the new extra capacity valve regulated sealed lead acid battery from Concorde as opposed to the old technology flooded cell design. Has anybody had any experience with the SLA batteries in the 170 with the original generator circuit? My experience with the SLA batteries in electronic work dictates that they be charged rather carefully so as to not overcharge. I am somewhat worried that the generator on my 170 may overcharge an SLA battery, even with a modern electronic generator control unit 
are vital to long battery life.