Voltage drop

[greg4510]

Hey guys I have an 07 escalade dual alternator set up. Factory alternator powering truck nowhere connected to music. 2nd alternator is an apex 320. Had an alternator shop change it to 1 wire to excite the alternator and put a diode so it charges at 15.2. 1 run each of 2/0 welding cable front to back for power and ground directly to 120ah yinlong back bank. Alternator grounded to frame also and bank has 2 2/0 grounds to frame. I have 2 orion hcca 5000.1d at .5ohm on 4 avatar stu-1546 subs in a flat wall. Deaf bonce 2900.1 and powerbass 600 and 800 for mids and highs. The issue is the alternator post says it is charging 15 volts but is only 14.5 at the bank. Then when I'm playing full tilt I've seen the voltage drop down to 11.2. And even on the drive home no music playing it doesn't seem to charge the bank up. Any help or suggestions in this matter

[CstrokerV]

Never heard of apex … anyways Need a bigger alt and bank

for the power you are running 

[SnowDrifter]

0.5v drop front to rear while idling? As in, under no load? That's a pretty concerning amount tbh

Things I would look at:

1. Inspect all connections. Take then apart, put them back together. Any ring terminals you have on - grab some pliers and pull on them as hard as you can. If they pop loose, they were junk anyway and should be redone.

2. Go through your big 3. Are you grounded to the body or the frame?

3. Do you have access to a clamp meter? I'd want to verify what sort of current the alt is putting out.

4. When you say you drop to the 11s, where is this voltage measured from? bank? amp? Alternator? I'd love to know what the voltage is as both bank and alternator during this time.

5. Your charge voltage is goofy for your bank config. A 6s LTO bank should be charging closer to 16.5-16.8v. You can drop it to 5s and charge at 13.5-14v too.

[greg4510]

6 hours ago, SnowDrifter said:

0.5v drop front to rear while idling? As in, under no load? That's a pretty concerning amount tbh

Things I would look at:

1. Inspect all connections. Take then apart, put them back together. Any ring terminals you have on - grab some pliers and pull on them as hard as you can. If they pop loose, they were junk anyway and should be redone.

2. Go through your big 3. Are you grounded to the body or the frame?

3. Do you have access to a clamp meter? I'd want to verify what sort of current the alt is putting out.

4. When you say you drop to the 11s, where is this voltage measured from? bank? amp? Alternator? I'd love to know what the voltage is as both bank and alternator during this time.

5. Your charge voltage is goofy for your bank config. A 6s LTO bank should be charging closer to 16.5-16.8v. You can drop it to 5s and charge at 13.5-14v too.

1 I'm grounded to the frame from alternator 

2 the voltage was being checked at the bank while playing

3 I actually don't have 6s. I simply put all the cells and equaled them out together and all had the same voltage. 

4 I took every connection power and ground sanded them with sand paper and reconnected. Took frame grounds sanded metal reconnect and sprayed plasti dip on them

[SnowDrifter]

49 minutes ago, greg4510 said:

1 I'm grounded to the frame from alternator 

2 the voltage was being checked at the bank while playing

3 I actually don't have 6s. I simply put all the cells and equaled them out together and all had the same voltage. 

4 I took every connection power and ground sanded them with sand paper and reconnected. Took frame grounds sanded metal reconnect and sprayed plasti dip on them

1. What's your rear bank grounded to?

2. I want to know what it looks like at the alt

3. 6s = 6 in series. LTO cells are 2.8v at full charge. So 6*2.8 = 16.8v at full charge

4. Good deal. Though of note, plasti dip doesn't make great weather proofing. Tar actually works quite well if you can get a hold of some!

[greg4510]

27 minutes ago, SnowDrifter said:

1. What's your rear bank grounded to?

2. I want to know what it looks like at the alt

3. 6s = 6 in series. LTO cells are 2.8v at full charge. So 6*2.8 = 16.8v at full charge

4. Good deal. Though of note, plasti dip doesn't make great weather proofing. Tar actually works quite well if you can get a hold of some!

Bank has 2 2/0 grounds going to frame and 1 2/0 ground from alternator case

[SnowDrifter]

Well

Time to check voltage at the alt while you're hammering on it. And if needed, output. See if we can't narrow down what's going on. I have my guesses.... But I'm a believer in objective evidence

[greg4510]

Took bank apart just to check each cell. Each was sitting between 2.4 and 2.5. Changed fuse holder on positive run. And made sure every connection was right. Only thing I noticed was alternator ground was a lil loose on frame. When I crank the truck and let it get warm it still says 15.2 volts. So I'll test it draw on it tomorrow

[Kyblack76]

On 8/2/2022 at 11:43 PM, SnowDrifter said:

Well

Time to check voltage at the alt while you're hammering on it. And if needed, output. See if we can't narrow down what's going on. I have my guesses.... But I'm a believer in objective evidence

I think my guess, is the same as yours. 

[greg4510]

On 8/4/2022 at 6:07 AM, Kyblack76 said:

I think my guess, is the same 

What would your guess be?