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How to test a VSR

Old 10-03-2014, 03:17 PM
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Default How to test a VSR

I installed a "name brand" VSR last year and is has worked perfect........until today. Went out side and fired up the boat. Both motors each on their own battery fire right up. Go to turn on the electronics and nothing. Some quick testing and I only have 9 volts at that battery. So why didn't the VSR kick over to charge the "house" battery like it is suppose to and did for the past year? Connections are spotless, grounds are clean. Any ideas? How would I go about testing it? Battery is a year old, VSR a year old and all wiring is a year old and all is dry and clean. WTF?
Old 10-03-2014, 03:23 PM
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Look at the specs for the particular model . . . it will be open at certain voltage and closed at other voltages.

There is a lot of possibilities, you could also have a bad battery, or wire(s). I have seen very heavy wall cables that looked perfect but were bad (the meter don't lie).

I have replaced a few bep vsr's, I have not yet replaced one from blue seas. I'm sure they all have some percentage of failures though.

I would bet if it is a blue seas and it is indeed bad they will replace it (they have given me excellent customer service).

PS some of them have a tiny LED on them to show when they close (charge) and you can watch it. It may be opening and closing repeatedly due to some problem upstream, I have seen this as well with some older two stroke outboards (voltage regulator was going out).

Good luck and post back with some more details and we'll get 'er done.

Old 10-03-2014, 09:22 PM
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some have a low battery lock out. the blue sea is 6v though I believe. so if the battery is under 6v it won't combine. so you don't combine a good battery with a bad one. other brands may have different values.

to test. make sure you have ~12v on one side. and 14v on the other side. and they should turn on.

also make sure the ground is still connected.

if you have a good ground have have 14v on one side and 12 on the other and it won't turn on then could be dead.

the blueseas will blink the led for the low voltage cut out. otherwise it's normally off for off and solid for combined.

if it's fused (they should be) and one bank was so low at 9v. when it closed the inrush of current probably blow the fuse. I normally fuse acr's at 200a and run 2awg so I don't have this issue, I have seen 150a fuses blow in acr circuits due to inrush current in a low bank

measure the voltage on both sides of the acr posts to confirm you don't have a blown fuse. best to use acr ground so you know that is good too.
Old 10-04-2014, 08:35 AM
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A clamp-on DC ammeter on the house battery pos. cable should show charging current once the VSR closes when the starter battery is fully charged (with all accessories turned off).
Be aware that many of the cheapest clamp-on meters like most at Harbor Freight will only measure AC amps.

If the house battery is receiving current (should be roughly the same amount of current that the starter battery was getting), you have a bad house battery, otherwise, a bad VSR if it's not sending current to the house battery. A current test is more reliable than a voltage test.

Since it failed suddenly rather progressively, my guess is bad VSR.

You may need to pre-charge the house battery as 9v may be below the voltage threshold the VSR needs to detect, just like most smart-chargers won't charge a dead battery, only a partly depleted one.
Old 10-06-2014, 04:15 PM
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Ok thanks for the start guys. I will begin testing tomorrow..........
Old 10-08-2014, 01:12 PM
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didn't read all the responses so sorry if this is a repeat but...

I see you say that you measured the voltage on the 'house' side of the vsr but I don't see where you measured the voltage on the primary side. that's the first step. most likely causes are the vsr has crapped out or your charging system (probably an alternator) has crapped out. measuring the voltage on the primary side of the vsr will narrow it down by excluding one or the other as the cause...third most likely cause would be bad wiring/connections (including grounds)/fuse but it sounds like you've check those things.
Old 10-08-2014, 08:25 PM
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Just in case, confirm the cables connecting all battery negatives together and to engine grounds are in place , clean and tight otherwise a battery such as a house battery may not be getting charged, only discharge.

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