Here is another spin on it. I dont like the fact the voltage went down to 11.8, that means the battery was drained completely. Fully charge the batteries by revving for a little while, and check voltage on both and go from there to eliminate this possible issue. The amp may not be liking the idea of current starvation. Also check the alternator running voltage, or just have it load tested, they do it for free at some places.

 

Yeah my Belle used to go into protect all the time before I sold it. After heavy listening for 45 mins it would go into protect for 10 mins or so then come back on. Thankfully my used Hifonics doesn't do this anymore even though the guy that sold it to me forgot to mention the stripped remote terminal set screw. LOL Although my 4ch Memphis amp has never had issues.
Nick

 

Befor the BIG 3, voltage with car on at front batt was 14V
After BIG 3 its at 14.4V

Battery at the back is 14.1V with the car running.

The 11.8V was with the car's heater on so there was extra strain on the batts as well as the fact we were playing test tones. As of right now, my friend has a battery charger hooked up which I told him to leave on there for around 2 hours or so

 

I used 10awg wiring for my remote wire so I didnt need a screw anyways lol

This whole 'protect' issue seems to be a thing among the older memphis amps

 

Yeah and the weirdest thing with mine was it rarely just shut off. It was 95% of the time only after the car was shut off for a couple of minutes ( stop at the store for smokes etc) start the car again and no noise. Check the amp and red led is on. Shut the system off for 10 minutes and it would come back on. Just got fed up after 6 months of this and finally sold it for what I paid for it. LOL Full disclosure of the problem to the buyer though, we figure he won't be running it at full capacity so less chance of problems like this I hope.

 

These high voltages are coming from the alternator when the car is on. Fully charged battery with car off is not higher than 12.8, and 12.6 is considered fully charged and functional at 100%, but if you think you cannot charge the battery any more and it is showing less, that means the battery no longer holds full charge, and approximately for every 0.2v drop it is around 25% away from full capacity, so if your battery voltage with car off reads 12.4 it means the battery now only charges to 75%, at 12.2 it is 50%, and at 12v it is only working at 25% capacity. From what you're telling me, it seems that the alt may be fine, so switch the engine off and measure the voltage of both batteries and see if they are ok. That's all I got :/

I am confident you know how to put gear together, so I won't ask you to look over all the connections. Impedance is prolly not an issue either. Try another amp and see if it changes anything.

 

Sasha, so are in cases when battery drops into the 10v range, is it at a negative capacity?

those kinds of voltage drops happen all the timein spl applications, 10.8-10v is not unusual. im just wondering.

 

I dont have the answer for that, I'd have to see those drops in person one day. The info I gave will help them resolve bad battery issues if applicable, as fully charged battery at rest should read 12.6-12.8, and if it dosn't there are problems. Recently my friend's battery died and he barely had enough charge to start his truck, and his alt read high voltage so it was fine, but the battery with engine off was reading under 12v even after driving for a while with everything off to charge the battery. I can only speak for normal application, and anyone who is a mechanic/electrician can support me, but SPL use is not my forte. Quite possible that the voltage can drop really low due to battery being drained, but I doubt it can go into negative in terms of capacity, and quite possibly that after the battery is completely drained the voltage will drop and drop till it reaches 0, as there is no more current, and it may just drop lower more quickly when the capacity is being driven to it's lowest points.

 

I am not sure 11.8v is a good sign. I do have an HO alt, but even though, I have never experienced such low voltage drops in my car and I know electrical is good on every level. And believe me, just for fun, during the load test, and had everything going including blinkers and high beams, A/C, the works, all I could think of and I was playing bassy music with long low bass drops on two hoggy 12's with class AB amp of 1800 wrms, and my system barely went into battery assist which starts around 12.8v. BTW, I have only one battery. I've played tones before and also never had such low drops, so it worries me, but Yuli says it may not be an issue, as in spl use it happens all the time, but I know nothing about that. All I know that the more current demand, the lower the voltage drops. In your case, the demand may be higher than your supply(alt+battery), and chances are that if your drop is lower then 12v, there isnt much of juice left in the battery, that is why it is wise to check if the battery your friend is using is even holding the charge properly, cause it may be barely storing anything, thus running out of juice really early and without much demand, causing premature voltage drops. It may be ok for voltage to drop if you have bunch of batteries and the car is off along with amps, but if you have the amps on and start "burping" or something and voltage goes down to like 10v you may be inflicting damage to your amps, which may or not have already happened to this poor Memphis. In this case, heavy tone usage may have enough influence on weak batteries. Bad grounds etc also have a similar impact on the electrical supply. Just a thought.

It is a good idea to check on your friend's electrical system and batteries could be causing problems, cause I am not so quick on blaming the amp, but like I said earlier, try to hook up another amp, and see if that does the same. I dont have any other ideas right now. Time for Yellow Tops or Hawkers/Odysseys? But if all electrical is ok, and you keep getting the same issue from one vehicle to the next, then it looks like that amp may have to go.

p.s. I would like to hear these SSD's one day.

 

guess that's the diff between a bad, good and a really good battery.