6V vs. 12V Ah equal?

"the systems voltage will cave down below 12.7 volts and the relay will automatically disconnect. The voltage then rises, the relay re-engages: then the voltage drops, the relay disengages and a buzzer-like sound will be heard as the relay quickly switches in and out."

What the hey?

This is so funny it is hysterical...

Anyone with any sense designing an electronic switching circuit knows from basic electronics course that including HYSTERESIS as a quality is mandatory. Turning a power relay into a "buzzer" is a sure recipe for early failure never mind causing schizophrenia.

Let me do one of my infamous parody's....

"Please you notice we at Promiscuous Butterfly television works ltd. make for you special feature. When switch channels, both stay on for 10 seconds make sure you miss nothing..."

I cannot believe such junk as what you have described are on the market. With my LED and piezo annunciator warning systems THIRTY YEARS AGO I had to build meaning add a circuit with hysteresis to avoid exactly what you describe.

Using an inner tube stretched between two trees I wonder how far in hundreds of meters I could hurl your device. Preferably onto a freeway where a dozen 18 wheelers could have their way with it.

Seriously. Get rid of this nightmare - fast. Replace it. Sure power has good battery separators. God I wish Lisle Bruney a fellow engineer (Sure Power) was around to read your post.

This is not your fault. You got stuck with a lemon. Heck even a lemon is useable, what you have should go on display somewhere.

I completed the run down of my batteries to 60% and sure enough, the VSR started flashing and clicking and blocked charging to the camper batteries. So for some reason, low batteries cause the VSR to kick in! I went to the manufacture site and the FAQ section indicates my charging system is too small for the battery bank I am trying to charge. I am going to call the manufacturer and see what they suggest and will report back.

Hi kona,

If it isn't the wire it is the fancy relay. Go to the Kiss principle.

kona12 wrote:

pianotuna wrote:
Hi,

Your wire is too thin and the charging path too long.

I am not convinced this is the problem. Don't get me wrong, I agree long thin wires aren't ideal but in this case, when I was on the road, I was getting zero voltage to the battery and the VSR was clicking. Now that I am home and have manually charged the batteries, when I hook my truck back up via the umbilical, the exact same way as when I was on the road and turn the truck on, my voltage jumps at the battery and there is no clicking at the VSR. Once I have drained the batteries back down to the level they were on the road, I will hook the umbilical up again and see if the low voltage triggers the problem again.

wa8yxm wrote:
There are a few differences.. As you opened your original post you said Group 27's were around 100 AH.. (Just under in my research) but then when you did your comparision suddenly you have 'em at 115 (Closer to a Group 29 rating)

And the GC-2's you rated 203 when they are usually 230.

Did you get your numbers crossed?

Next. The GC2 are DEEP CYCLE designed to be run down as low as 50 percent.

The Group 27 are most likely Marine/Deep cycle.. Lower internal resistance but.. They do not like to be run down so far.. say 75% soc minimum.

My old 12 volt was an interstate marine/rv with no AH listed (or that I could find on their site) so I was speculating on the AH's.

The original GC2's I was looking at were Costco batteries rated at 208 AH's. the GC2's I ended up buying were from SAMs club and were energizers by Johnson controls and are rated at 220AH.

So prior to the swap, my truck would charge the battery. After the swap, with deeply discharged batteries, for some reason the VSR isn't allowing charging.

There are a few differences.. As you opened your original post you said Group 27's were around 100 AH.. (Just under in my research) but then when you did your comparision suddenly you have 'em at 115 (Closer to a Group 29 rating)

And the GC-2's you rated 203 when they are usually 230.

Did you get your numbers crossed?

Next. The GC2 are DEEP CYCLE designed to be run down as low as 50 percent.

The Group 27 are most likely Marine/Deep cycle.. Lower internal resistance but.. They do not like to be run down so far.. say 75% soc minimum.

pianotuna wrote:
Hi,

Your wire is too thin and the charging path too long.

I am not convinced this is the problem. Don't get me wrong, I agree long thin wires aren't ideal but in this case, when I was on the road, I was getting zero voltage to the battery and the VSR was clicking. Now that I am home and have manually charged the batteries, when I hook my truck back up via the umbilical, the exact same way as when I was on the road and turn the truck on, my voltage jumps at the battery and there is no clicking at the VSR. Once I have drained the batteries back down to the level they were on the road, I will hook the umbilical up again and see if the low voltage triggers the problem again.

Hi,

Your wire is too thin and the charging path too long.

This may or may not relate, but in testing the charging when using the 7-pin on my truck to trailer batts, I got no improvement in amps by revving the engine. It seems the engine battery being full is what sets the alternator output (and the temperature factor of course)

Furthermore, when running an inverter clamped to the truck battery, the inverter would run up to a certain watts worth of inverter load at engine idle, then the truck voltage would drop off, while watching the dash voltage gauge. Revving the engine from idle made no difference, voltage still dropped off.

So I am doubting the whole story that revving means more output from the alternator. But others may have different stories with their trucks.

MEXICOWANDERER wrote:

• Double check all your terminals for integrity, crimped correctly
• Double check the connection diagram for which wire on the relay goes where
• Make sure the relay ground wire is connected to a good shiny ground
• Do an in-driveway pre-flight test discharging your house batteries, starting the engine then making sure the house batteries charge

What brand of battery separator are you using?

I have checked all of the above and they look good. I currently have the camper using all possible lights fridge etc to draw the batteries down to test again.

FYI, the VSR is a BEP Marine 100 amp model. The paper work references the clicking I heard but to my novice understanding of the system, I can't make heads or tales,of it:

"The charging system must be correctly sized to the batteries. If the charging system is too small for the batteries the VSR system will not work properly. Once the starting battery has reached the right voltage and the house battery is connected, the systems voltage will cave down below 12.7 volts and the relay will automatically disconnect. The voltage then rises, the relay re-engages: then the voltage drops, the relay disengages and a buzzer-like sound will be heard as the relay quickly switches in and out. This also occurs at idle (low amps out due to slow speed of alternator) if the house battery is at low charge. Increasing the engine rpm will increase the alternator output and hold up the voltage."

My truck has 170 amp alternator so I wouldn't think it is to small. Also, the scenario above seems to replicate my situation exactly but revving the engine(driving) didn't result in any charge.

Pianotuna, if I am understanding you correctly, if my truck battery is fully charged, are you saying the VSR won't allow my camper battery to charge?

Hi kona12,

If the isolator for the "house" battery bank is diode based, then very little in the way of charging will happen, because typically there is about 0.7 volts on the "house" side of the device.

The alternator circuit senses the chassis battery. When that battery is full power output is scaled way back. 13.2 - 0.7 = 12.5 volts = little or no charging.

If there is a continuous duty relay things are a bit better.

Another issue is the length of wire and the thickness from the alternator to the house bank. To get great charging you may need to upgrade to #4 wire, rather than the puny size in the seven pin connector.

It is possible to add a second regulator for the "house" bank. This requires modifying the alternator.