pk911 Posted June 18, 2017 Report Share Posted June 18, 2017 Good morning everybody! My Ovation 2DX 2004 has a problem with loading battery #2.Now I examined the surrounding a little bit and found the fuse near the diodes of battery #2 blown. It's a 15A 32V glas fuse. Does anybody know about the exact function of the fuse. By the way, fuse near battery #1 was also blown! But I had never problems loading this battery. Thanks, Peter Quote Link to comment Share on other sites More sharing options...
LANCECASPER Posted June 18, 2017 Report Share Posted June 18, 2017 If your battery is a Gill battery and it's been in there awhile, you probably need a new battery. Switch to Concorde 24-15M for much better service. Quote Link to comment Share on other sites More sharing options...
carusoam Posted June 18, 2017 Report Share Posted June 18, 2017 Could be a technical misunderstanding of the word 'loading'... Peter, are you installing new batteries? Could be something that has been added to the plane for charging the batteries, like a BatteryMinder. Peter, do you have a Battery minder that isn't working? I recently bought a pair of Concordes and a BatteryMinder for the O. The BatteryMinder has a pair of fuses to protect the batteries from various failures of the BM system or operators trying to mischarge something.... Am I close on this? Best regards, -a- Quote Link to comment Share on other sites More sharing options...
pk911 Posted June 18, 2017 Author Report Share Posted June 18, 2017 3 hours ago, LANCECASPER said: If your battery is a Gill battery and it's been in there awhile, you probably need a new battery. Switch to Concorde 24-15M for much better service. 21 minutes ago, carusoam said: Could be a technical misunderstanding of the word 'loading'... Peter, are you installing new batteries? Could be something that has been added to the plane for charging the batteries, like a BatteryMinder. Peter, do you have a Battery minder that isn't working? I recently bought a pair of Concordes and a BatteryMinder for the O. The BatteryMinder has a pair of fuses to protect the batteries from various failures of the BM system or operators trying to mischarge something.... Am I close on this? Best regards, -a- Thank you all, my batteries are both fine! Externally tested and found satisfactory. My question was for the function of the fuse near the diode. The fuse is blown. A cabling diagram would be fine. Thanks Peter Quote Link to comment Share on other sites More sharing options...
carusoam Posted June 18, 2017 Report Share Posted June 18, 2017 (edited) I have an O1, and I see a couple of differences there already... I have two relays mounted in that area where the picture shows a blue device and the offending fuse. Do you have access to your POH or the O's maintenance manual? The wiring diagrams can be found in both. PP thoughts only. Not a mechanic. Best regards, -a- upon reviewing the POH wiring diagram, no fuses were found in the drawing. Another difference that stands out is the 24V/12V converter mounted on the radio rack. The O1 didn't get that early on... is it possible that the fuses are there to protect the cigarette power socket? Or other devices that are live with the master off? -a- Edited June 18, 2017 by carusoam Quote Link to comment Share on other sites More sharing options...
pk911 Posted June 18, 2017 Author Report Share Posted June 18, 2017 Unfortunately there is no detailed wiring diagram in the POH with the fuses. I don't have the maintenance manual. Each battery / diode has its own fuse (no cigarette power!). Both blown! Other devices which are live without master are depicted in POH such as clock, interior light,... and I identified the fuses elsewhere. Quote Link to comment Share on other sites More sharing options...
pk911 Posted June 18, 2017 Author Report Share Posted June 18, 2017 2 hours ago, carusoam said: Could be a technical misunderstanding of the word 'loading'... Peter, are you installing new batteries? Could be something that has been added to the plane for charging the batteries, like a BatteryMinder. Peter, do you have a Battery minder that isn't working? I recently bought a pair of Concordes and a BatteryMinder for the O. The BatteryMinder has a pair of fuses to protect the batteries from various failures of the BM system or operators trying to mischarge something.... Am I close on this? Best regards, -a- Hi, thank you! I don't have BMs or anything not from factory. Bought the O2 DX in spring 2004 original and did no changes in that area. Quote Link to comment Share on other sites More sharing options...
carusoam Posted June 18, 2017 Report Share Posted June 18, 2017 (edited) One of the Midwest (?) MSCs had the MM on their site... I downloaded a copy from there. 1,000 plus pages... the Aux power plug has a relay and a diode as part of the system to protect from reverse polarity. I don't see any fuses related to it... Not sure how many diodes are used back there. It would help to narrow down the search... 1) reverse polarity protection... aux power port 2) AC/DC conversion... alternator, magnetos... 3) what else...? One thing for sure, connecting a battery backwards in the lawn mower burned up the magneto's diode... (Sears battery had reversed posts from standard identical looking battery) Best regards, -a- Edited June 18, 2017 by carusoam Quote Link to comment Share on other sites More sharing options...
pk911 Posted June 18, 2017 Author Report Share Posted June 18, 2017 5 minutes ago, carusoam said: One of the Midwest (?) MSCs had the MM on their site... I downloaded a copy from there. 1,000 plus pages... the Aux power plug has a relay and a diode as part of the system to protect from reverse polarity. I don't see any fuses related to it... Not sure how many diodes are used back there. It would help to narrow down the search... 1) reverse polarity protection... aux power port 2) AC/DC conversion... alternator, magnetos... 3) what else...? One thing for sure, connecting a battery backwards in the lawn mower burned up the magneto's diode... (Sears battery had reversed posts from standard identical looking battery) Best regards, -a- reverse polarity protection and aux port sounds good for the other end of the fuse box goes straight to a 3 pin connector above the aux port! Quote Link to comment Share on other sites More sharing options...
Guest Posted June 18, 2017 Report Share Posted June 18, 2017 The fuse is part of the battery charging system. Clarence Quote Link to comment Share on other sites More sharing options...
pk911 Posted June 18, 2017 Author Report Share Posted June 18, 2017 Thank you Clarence! That's it! I regulary switch the batteries before each flight. Due to bad weather in Jan + Feb I didnˋt fly lot. Battery quite low. After engine start high amps at ampere meter. Maybe 1st time blows #2 and next flight #1.Thus only charging the active battery. To avoid I try to keep the batteries up to avoid high recharge amps. Is there a possibility for more S&MM? Thank you. Peter Quote Link to comment Share on other sites More sharing options...
Guest Posted June 18, 2017 Report Share Posted June 18, 2017 5 minutes ago, pk911 said: Thank you Clarence! That's it! I regulary switch the batteries before each flight. Due to bad weather in Jan + Feb I didnˋt fly lot. Battery quite low. After engine start high amps at ampere meter. Maybe 1st time blows #2 and next flight #1.Thus only charging the active battery. To avoid I try to keep the batteries up to avoid high recharge amps. Is there a possibility for more S&MM? Thank you. Peter Not quite sure how to take your last sentence! Email me and I'll see what I can do for you. Clarence Quote Link to comment Share on other sites More sharing options...
Cruiser Posted June 18, 2017 Report Share Posted June 18, 2017 Please look at SB M20-275 there are fuses in line with the surge diodes to prevent discharging if the diode shorts. It appears from your picture that the fuse is one used for this purpose. IF they were blown, check the diodes. sbm20-275 Charging system.pdf Quote Link to comment Share on other sites More sharing options...
carusoam Posted June 19, 2017 Report Share Posted June 19, 2017 Thanks Tom & Clarence! Great drawings and photos... Other things I have learned about our batteries... it takes about two months to near fully drain a battery. They both appear to drain evenly no matter which one is selected... the document Clarence shared indicates a quick charge from a near dead state is going to be hazardous to those fuses. If the plane doesn't have those fuses, the diodes can be affected. The fuses appear to have been added after the O1. In Peter's case, the high rate of charge was enough to melt a fuse. This should have protected the diodes. This makes even more sense to use a BatteryMinder to keep the deep discharge from occurring during the unused months. Diode health is pretty easy to test using an ohm-meter. Getting access to them may be a challenge. Happy Father's Day gents (local holiday down here) Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
pk911 Posted June 19, 2017 Author Report Share Posted June 19, 2017 Thank you all for good advice! Took great steps the last 24 h! Checking the diodes is quite easy. Just remove all three fuses and you can check at least the depicted half of the rectifier which was o.k. Next question is the capacity of the fuses. Mine were all 15A. SB M20-275 shows 10A. I'm quite sure nobody changed the fuses. Which is right then? 10A or 15A? Battery voltage should be an important checklist entry. Everything below 23V could lead to blowing the fuses. AND there ist now indication to the pilot that the fuse is blown. I my case battery #2 was about 21V, I started with #1 guessing #2 will be charged during flight. Nothing happend. In case of emergency I would have only one battery! The only quick solution would be starting the engine with #1 and switch over to #2. This arises the question if the alternator should be switched of before switching over the battery with running engine because of voltage peaks during switching!? And you should ever have some 15 Amp fuses with you! Best regards and nice day! Peter Quote Link to comment Share on other sites More sharing options...
carusoam Posted June 19, 2017 Report Share Posted June 19, 2017 Peter, Nice details you have filled in. Interesting issue with what is the right fuse to have in there...vs what you did have in there. That may be something @M20Doc Clarence may be able to help with. A call to Mooney or your local MSC would be a good idea. we have had a conversation in the past regarding preflight checklist and selecting the stronger battery for start. But, I don't think people are seeing deeply discharged batteries. The O1 analog representation of voltage can be easy to miss how low the battery charge actually is... Another interesting conversation is the confidence people have with changing batteries in flight... the battery switch is supposed to be designed to have an overlap where both batteries are connected momentarily prior to the first battery going off line. Age or wear in the switch and relays has a tendency to kill the power momentarily instead. Don't be slow when pushing the battery selector switch... PP thoughts only. Stuff I learned reading MS. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
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