Solar Diode?

[ajriding]

I'm having dead battery problems and have not found the source. I suspect the diode could be bad from the solar trickle charger.
I still have current off the solar panel (although 19v seems high) measured off the wiring.

Can the diode still work (all current to pass) when shorted out (blown)?

notes: My batteries go dead quick, overnight only, and after 1 or 2 days are down to 1 volt. So, a short would probably have caused a fire, and I have unplugged everything else that I know of. The issue killed a pair of marine batteries in my RV. New batteries, and I thought the problem was solved and they were dead soon. I am unwilling to try different things for fear or damaging the new batteries further. I installed a small charge controller before all this, the solar ran through it, now have it unhooked and just have the charge controller hooked to battery, thus not controlling anything. I think the solar panel is similar to this one http://www.gumtree.com.au/s-ad/athelstone/other-home-garden/10w-10-watt-16v-solar-panel-rv-direct-battery-charger/1019816706 , though should be a 12v model...
Fridge was one thing not going through breaker box, but now is going through it - dosent seem to be issue and fridge has an on/off switch anyway. No CO2 monitors or anything either. The only drain on RV coach batteries is the radio memory, which has been the case for 10+ years (but not the radio main power). and The power drivers seat is also hooked up to the RV batteries. Both radio and seat work, so not suspect.

[MEXICOWANDERER]

Oh dumb me, and here I thought all along controllers were supposed to block reversed current. The post above mentions "panels" multiple?

[Almot]

ajriding wrote:

I had got bad advice that the solar panel was not big enough to drain a fully charged battery over a few days. Solar panels will do this. Forget science that someone tells you. The reality is in the facts. A man with experience is more than a man with an idea.

Glad you fixed it. Education still matters, but I'm not going to try and convince anybody on this one.

There could be several factors contributing to quick discharge of the batteries: bad battery, bad diode, and/or other loads. Could be bad diode AND loads running. After all your posts it was still not clear whether you disconnected all the loads. The "switch" that you were referring to tells me nothing. Disconnect means disconnect at the battery.

[MrWizard]

T this is real simple
Disconnect the solar panel
If batteries still drain down, you have a resistance short/load on the circuit
Possibly, the converter, maybe something else

Did you check the safety pin aka brake release on the tt tongue
If pin is pulled tt safely brakes engage draining battery

[ajriding]

Some users suggested that a solar panel cannot drain a battery very quick.
In fact, they did.
I installed a new diode and this fixed all issues. Apparently my old diode went bad and power was able to go back into the solar panel at night, so much that the batteries went dead fast.
Keep spare diodes on hand, they are easy to install.

I had got bad advice that the solar panel was not big enough to drain a fully charged battery over a few days. Solar panels will do this. Forget science that someone tells you. The reality is in the facts. A man with experience is more than a man with an idea.

[christopherglen]

OK, diodes can fail either open, or shorted. moving on.
Batteries with no load - disconnected - should last weeks between charges. If there is in fact no load, then you have nothing to loose installing them in storage. If there is a phantom load, a battery disconnect switch will deal with it without removing all the cables. If you put in a switch, the solar goes directly on the batteries. The radio memory in my truck goes weeks between starting it with no issues, so I think your problem is elseware.

[westend]

ajriding wrote:
thanks, I guess my main question was about the diode.
again, I got new batteries after the others ones got discharged and died. it's always humorous to read responses of those who did not understand the post.
disconnecting the panel was useless until I got the new battery bc dead battery would go dead again on it's own. oops, I had to park the vehicle at the storage place so could not run simple obvious test without endangering new batteries. My gosh, what a moron I must be. Oh, well, maybe next time I can dedicated all the hours in my day tending to the RV so I can do these easy test. well, thanks guys for the info, I can narrow my search when I get to visit the RV in it's parking place. I use a floor jack to load the batteries in, right now they are in my garage. To load them they go under the siding, up to clear the lip on the battery box that is attached to the frame under the floor, then down in a snug fitting cradle all while I lay sideways in an awkward position. I can't really see the terminals after this so connecting them is lots of fun. It's not something I want to do every 5-6 years, much less several times a day. I can't take the floor jack to the storage place though, so doing it by hand is a nightmare. To leave them in the RV means they will lose charge naturally until I get the system working again, to keep them here means it is impossible to track down the source of the drain. There is no outlet to plug in a charger at the storage place, and my covenant at home prevents me from storing an RV here. I wish I could do these simple test where u do this, then check back a few hours later, but checking back is sometimes a few days, in which time I would lose another set of batteries. So, there are the real details I guess...

I would put some effort into making the location where the batteries are mounted into a more favorable aspect. I would think that after mounting the new batteries in that location, there will be no way of servicing them. This maybe explains the death of your previous set of batteries. It may also explain a sudden discharge since you have no way to see where the terminations and associated wiring are situated after mounting them. I hope I'm understanding this right. I've never seen a battery mounting location where the batteries are lifted from underneath to mount. Around here, we call that going to Duluth by way of Mankato, it is an unneeded trek.

[BFL13]

"I still have current off the solar panel (although 19v seems high) measured off the wiring."

Yes, we need to explore this some more. You would not get that voltage if you had a working solar controller.

I have fond memories of Ga from taking a fighter direction course at Glynco in 1966. Strange place where magnetic = true so it was easier to teach us newbies. 🙂

[ajriding]

thanks, I guess my main question was about the diode.
again, I got new batteries after the others ones got discharged and died. it's always humorous to read responses of those who did not understand the post.
disconnecting the panel was useless until I got the new battery bc dead battery would go dead again on it's own. oops, I had to park the vehicle at the storage place so could not run simple obvious test without endangering new batteries. My gosh, what a moron I must be. Oh, well, maybe next time I can dedicated all the hours in my day tending to the RV so I can do these easy test. well, thanks guys for the info, I can narrow my search when I get to visit the RV in it's parking place. I use a floor jack to load the batteries in, right now they are in my garage. To load them they go under the siding, up to clear the lip on the battery box that is attached to the frame under the floor, then down in a snug fitting cradle all while I lay sideways in an awkward position. I can't really see the terminals after this so connecting them is lots of fun. It's not something I want to do every 5-6 years, much less several times a day. I can't take the floor jack to the storage place though, so doing it by hand is a nightmare. To leave them in the RV means they will lose charge naturally until I get the system working again, to keep them here means it is impossible to track down the source of the drain. There is no outlet to plug in a charger at the storage place, and my covenant at home prevents me from storing an RV here. I wish I could do these simple test where u do this, then check back a few hours later, but checking back is sometimes a few days, in which time I would lose another set of batteries. So, there are the real details I guess...

[christopherglen]

Step one, charge battery - fully.
step two, disconnect all cables from battery.
step three come back in 24 hours and see if it is dead.
step four, if dead replace, if live locate and fix drain when connected.
step five, come back and report outcome of step four.

[MEXICOWANDERER]

Let's see, you've repeatedly discharged the battery to less than one volt and insist the batteries are good...?

You have not tried the easiest test of all and disconnected the panel.

You are insisting that a shorted diode can miracle more current through a circuit than having no diode at all.

I think I am going to pass on this one...

[wa8yxm]

In a DC system Diodes have two failure modes

Shorted and open

Shorted current passes, both directions

Open no current passes (like a blown fuse)

So the answer is yes.

In some AC circuits there are more failure modes.. but we will forget those here since this is DC.

[ajriding]

Thanks Mexicow. I will go back and drudge through it. I did some testing with my meter, not a light bulb but same principal, and haven't found a draw.
Obviously the diode can conduct current when bad, otherwise a bad one would not let power go from battery to panel at night. Did I answer my own question, or am I missing something? If I can go buy a new diode then that is an easy thing to do, and easy to wire in, much easier than what Im about to do.

Anyone have experience with possible culprits? A short? wouldn't that cause a fire or smoke?
There is really nothing in my RV that uses power except the charge controller, everything is on a switch that disconnects the power circuit when in off (as opposed to electronic things that always have power to the power switch). The charge controller is a very small one.

I appreciate any suggestions as I go through the long process of dismantling the electrical system.
It is custom made, so I can't answer make and model, but the circuit breaker came out of a 1970 Winnie, and includes a converter/charger. Circuit breaker is for AC, but Charger is connected to the batt. The DC circuit is 6 fused switches that I keep off. Water pump is a 7th separate switch that is always off. Generator is directly connected (not connected for this project), Frige and solar panel used to be directly connected (fused) to batt, but now on the 6-switch panel. Charge controller still directly connected, but testing showed no current between it and battery.

thanks

notes:
when I say battery goes dead overnight, that is after the initial drain when the RV sat for a few weeks alone. I could charge the batteries back to 12v, but they were in poor shape by then and would lose voltage more quickly than a normal good batter would. Autozone would charge them and swear they were good, and they would hold charge free standing, put them back in coach and they were dead (11.5 volts or less) the next day.

[2oldman]

jhilley wrote:
The design side of EE is a discipline, the application side an art.

It was too much of a discipline for me. I flunked.

[jhilley]

2oldman wrote:

MEXICOWANDERER wrote:
"Electrical engineering is a DISCIPLINE!" he shouted "Anyone of you who thinks it isn't can gather your books and get the hell out of my classroom!"

Perhaps I do not know the precise definition of the word discipline, but I can't imagine what else EE could be thought of as. An art?

The design side of EE is a discipline, the application side an art.