Over-Voltage

[ctsbillc]

Yes, let us know what happened.

BTW, I'd guess everyone here has blown the fuse in a multimeter by connecting it across two point while set to current (I'm guilty of doing this multiple times). Just a terminology thing, but break the circuit to insert the current meter, and start at the higest current range first. Clamp-on current meters are great, BTW, but make sure the one you buy can measure DC, the cheap ones cannot.

Bill

[Roaring Girl]

OK - quick update so far. Lots of deck work done as first nice day for several!

Front off Victron. No voltage sensor wire at all! (The installation manual does say it's optional.) We will review all settings as well and are now pondering putting in a voltage sense wire. Any thoughts on gauges and whether both (house) batteries need to be connected together or the fact that they're in series already is sufficient.

Thanks for all the help so far and we will definitely do a write up after the imposing job ahead of us.

[ctsbillc]

The sense wire will not help you at all, I would not bother with it (it just removes error associated with the voltage drop on the charge wire). The issue is you appear to be overcharging the batteries. They may be damaged already.

Here's a note from the web:

CHARGING VOLTAGE VALUE IS CRITICAL

AGM and Gelled batteries require a charging voltage that does not exceed 14.00 volts (summer temperatures may require even lower voltages). Unfortunately almost all automotive charging systems have a permanently fixed set point voltage that exceeds 14.00 and this spells trouble. Subjecting the batteries to (commonly found) 14.6 volts for a prolonged period will eventually destroy them

Bill

[Jesse]

A multimeter with a tired battery will give higher readings, sometimes a volt or more. could be worth checking.

[hummingway]

The Victron is very sophisticated. It will handle the AGM batteries very well if set right. The temperature sensor wires would handle any heat issues if connected.

Roaring Girl if I understand what you've written so far, you have two 6v 220AH batteries wired in series to give you 12v 440AH. They're in series because they need to be to give you 12v. If you feel you need to check it yourself rather then having the person who did the install do it read over the installation manual a couple of times. Note that to change some of the settings the batteries must be disconnected from the Victron. You can check them however with it connected but you do have to take the cover off. If you can find the battery manufacturers recommended values for bulk, absorption and float values you can enter those. The system does have some settings suitable as default battery types as well. Turn off the 12v mains and the Victron before disconnecting anything. Once you understand the system of lights and dipswitches for setting the Victron its pretty straight forward. I have lead acid batteries and used one of the defualt battery types, set my charge current ((AH x 0.2) / 2) and then a few other settings relationg to the inverter and it was quite simple and quick. If the settings are all correct you can move on to other tests.

[Roaring Girl]

Hi - can't get the person who installed to do it as in Portugal and we're in Italy!

You're mostly right - we have 2x255AH AGM batteries. They appear, as far as it spossible to tell, in good fettle, subject to all the caveats about accuracy of handheld metters etc - the hand held and the BEP monitor show the same within 0.1V

We have taken the cover off the Victron and contemplated it - which is itself a challenge with failing eyesight. We are researching the absorption and float values through our documentation. And yes we've realised we need to disconnect everything.

I admit to being seriously initimidated by the prospect of moving the switches. Just to help - given the quality of the victron manual! -

Do I turn the DS8 switch on using the pushbuttons (shown as J in appendix A inmy installation manual) - they're marked up and down on the victron itself and I do not understand whether I should push those or not. OR - do I flick the trip switch at DS8 (which is about the size of a pin-head)

I then set a value using those push buttons - and it shows on the LEDs - and the LEDs in question are the ones which normally show through the front cover and indicate the functioning of the charger and inverter. I can't see any other LEDs at all!

I then move the switch on the relevant one of DS3-7. At the moment they are all off (pointing towards my right as I look at it). Do I turn it on and then off again?

If I turn on on, say the charge current (which I think should read 51) will it show me 51 on the LEDs or what?

I know that I could disconnect everything, try all this and then not touch any of the dip switches and nothing would change. But - oooh I would much rather go up the mast (tomorrow's job) any day. Any advice is greatly appreciated.

[hummingway]

Those tiny switches up in the upper right hand corner are the ones that recall, and store the settings. I use a little flat head screwdriver to push them because they are a pain. When you move DS8 it activates the setup. You then move the DS7 through DS3 into the pattern that represents the setting you're interested in. The lights will now be in a pattern you can read using the manual as a guide. If you want to change the setting you use the pushbuttons which allow you to pedal through the possible values for that setting. If you then change one of the DS3 - DS7 dip switches the new setting will be recorded. If you decide not to make the change you return DS8 to the off position without moving one of DS7 - DS3 and the original setting will stay. Once you've done one it doesn't seem so arcane.

[Roaring Girl]

Thanks - that's really great.

So - after checking the rigging tomorrow (it starts raining again on Thursday!) - we aim to disconnect everything and check all the settings on the victron.

Our current thinking is that maybe there is a wrong setting and the over-voltage has damaged the alpenglows. The problem with them is that over time the blubs became dimmer and dimmer. We are talking with alpenglow and tryng out all their tests, including trying the lights directly on the batteries etc, and new bulbs. But it's not helping and so we are wondering if the lights are damaged from too high a voltage to them. Hence we got to the high voltage problem ...

Electrics - hate 'em! (says I typing on a laptop with electric lights on etc ...)

[goboatingnow]

Its quite likely that the Victron is incorrectly programmed. These units can generate upto 16 volts depending on setup. sounds like you need to reprogram it

[senormechanico]

Originally Posted by hummingway

Roaring Girl if I understand what you've written so far, you have two 6v 220AH batteries wired in series to give you 12v 440AH. They're in series because they need to be to give you 12v.

Two 220AH 6 volt batteries in series gives you 220AH @ 12 Volts.

[hummingway]

Of course it does. Thanks Steve.

[seandepagnier]

I thought that if you only charge your AGM to 14.0 and never float to 14.4 it will actually degrade their capacity over time. This is true of all lead acid, if you never fully recharge them, they lose capacity. But please inform me of details on this!

The actual fully charged voltage varies depending on temperature. The trouble is my solar regulator goes to 14.6 for 10 minutes then to 14.4 which is fine for flooded cells, but not so good for AGM. It doesnt seem to happen too often, but I am looking into a dump load to protect them, or a different solar regulator, but it needs a temperature sensor to work correctly, because temperature changes things by .5 volts or more.

Do your AGM batteries make any audible noise when they are higher than 14.4 voltage? You might have to put your head real close to them.

[Roaring Girl]

OK - everything off. Our two 12v 255AH batteries connected in parallel (sorry) now disconnected as are the ones for windlass and start. All generators also unpplugged and off. Lots of learning already and haven't even started the scary bit. Float, charge voltage and charge current all checked.

(Done one mast, but there's a strong windchill and it's b---y cold above 10m up so no more avoidance!)

[Roaring Girl]

Report back time:

1) you do still need to have the mains plugged in to amend the victron. We unplugged and disconnected absolutely everything and then of course, there were no informative LED lights. Duh!
2) Unplugging and disconnecting took far longer than actually reviewing the settings.
3) we focussed on the charge current and the absorption and float voltages. The only one that was correct was the absorption voltage. We checked the maths and our sources of info many times - sources included the labels on the actual batteries, the manuals and the suppliers info, and the sums come from the victron manual
4) then we cautiously reconnected everything. So far - about 1 hour later - so good. When we first plugged back in, in absorption mode it was showing 14.5 to 14.6 on the voltmeter. With fridge running, when I plugged the computer in, it had a brief hissy fit and went up to 15.1 then settled back down again v quickly when the fridge went off. That's as it was, but now it's on float mode it has stayed very constant at 13.4 -13.6 with trials using electric kettle, lights, computer, fridge all at once.

So - we will see if we can replicate the one spike. Also the alpenglow lights are still making a significant voltage draw if more than 1 is on, but we think they may be damaged by the previous problems.

Finally - all the BEP monitor is agreeing with the voltmeter on voltage readings, it needs resetting on the capacity readings. Also - very strangely , when all generators were off (ie solars unplugged, no mains, etc but just the house batteries still connected, the monitor showed us charging at 2.5AH. Gawd knows how. So we intend to try resettting that too - but the manual is a nightmare and this looks like a job for another day.

Thanks to everyone for all your help and encouragement. We've given CF a mention on our blog in writing up this particular challenge.

[hummingway]

Sorry if I didn't make it clear to turn the 12v mains not the shore power :-(