Generator overvoltage

[olley]

Hi Guys my generator/alternator is pumping out a continuous 14.7-8 volts which I am sure is doing my batteries in, anybody confirm that it should be around 13.7

Olley

[DriVer]

Quote:

Originally Posted by olley Hi Guys my generator/alternator is pumping out a continuous 14.7-8 volts which I am sure is doing my batteries in, anybody confirm that it should be around 13.7

olley, I would ask you, how old is your battery? The voltages in of themselves that are being displayed shouldn't give you too much cause for alarm.

If you call the TAC they will tell you that those voltages are most likely at the upper range of "Normal."

If you have a bad or going bad battery which in all too many cases is the root cause of the problem, high charge voltages are not the unusual. I'll take slightly high over too low any day of the week.

PS: Where did you get that avatar photograph. Look how tall it is! You should see if you can insert a thumbnail of a 640x480 picture and not the full blown picture. The graphic that I use in my avatar is formatted 100 x 75 pixels.

[olley]

Hi Driver sorry about the image it displayed ok on the old board, but as you can see I have changed it now.

I replaced all the batteries 2 years ago, 1 85amp engine and 3x180amp house, all the batteries now appear to be u/s and that's without much use.

I am being told it's because the alternator is overcharging them due to a faulty regulator, and am looking at replacing it for £285

Everybody I talk to says that around 13.7volts is the maximum they should be charged at on a continuous basis.

So before I spend some money I wanted to check with you guys in the know, and you reckon its just a bit high but no cause for alarm.

Olley

[DriVer]

Quote:

Originally Posted by olley So before I spend some money I wanted to check with you guys in the know, and you reckon its just a bit high but no cause for alarm.

Olley, I'm always charging in the 14.5 - 14.6 range and I've been alright so far on my automotive battery. 13.7 VDC charge rate is not often seen on a Workhorse instrument panel. I would suspect that something is wrong.

Do the sides of the automotive battery look ballooned out at all? Is it a maintenance free battery or can you open the caps? If you can open the caps have you been adding a lot of water?

Can you smell anything that resembles burnt acid. Believe me you can indeed smell it if the batteries are gassing from being over charged.

Has the new battery ever failed to crank over the engine?

Now if the person that said you are charging too high will back up that statement by taking the new alternator back if it does not change your charge rate then I would say go for it.

I think that those few extra quid would go better in your pocket!

[olley]

Hi Driver thanks for the advice, I have had them on charge since Sunday night and tomorrow I will do a load test and see how long they last.

Olley

[olley]

Just did the load test the battery monitor recorded 43ah at which point the voltage had dropped to 10.9v, thats on a load of around 17amps on a fully charged 540ah battery bank.

They look absolutly fine and after an hour off load they have returned to 12.5v but put the load back on and they go down very quickly.

So its new battery time, local manufacturer is selling 210ah for £137 inc tax, which sounds pretty good.

Thanks for the advice Driver I have cancelled the alternator.

Olley

[hamguy]

Quote:

Originally Posted by olley Hi Guys my generator/alternator is pumping out a continuous 14.7-8 volts which I am sure is doing my batteries in, anybody confirm that it should be around 13.7 Olley

Mine is also putting out 14.7-14.8VDC. I get 2 years out of the batteries (house). I have to add water after every few hundred miles. I cannot see spending $3-400 for a new alternator. All tests show the charing system to be working within limits.

Wish I had an answer for US. I see where some only add water once a year. I have no idea what to do.

[olley]

Hi Hamguy, one idea that occoured to me is to fit a heavy duty change over relay, so when I start the engine the inverter is powered by the engine battery, I could then charge my house batteries via my 4 stage charger.

I would also need to disconnect the battery mode relay feed from the ignition switch. You only need to swop the positive feeds to the inverter so it sounds easy enough to do.

Olley

[TrekPR]

You could also put in a switch to disconnect the alternator from the house batteries. If you are coming from where you have had hook-ups you can disconnect the batteries but leave them connected if you have been dry camping.

Paul

[DriVer]

I would urge "CAUTION" in providing any type of device that would disconnect the alternator from the automotive battery. If the engine is accidentally run without the battery conneted to the alternator, it is my understanding that damage can occur to the alternator.

[olley]

I think your probably right Driver, so I would always leave it connected, one naffed chassis battery every few years is better than 3 house.

olley

[cannon man]

been complaining about this since 2004. workhorse says its ok. here's the deal. batterys start gassing at about 14.2. at 14.8 you are literaly cooking them. i just pulled my alternator. got the numbers and called delco remy international. they say the set point of regulator is indeed 14.8. and temperature compinsated. that is volts should go down to 14.00 as the temp goes up. they say this is the wrong alternator for this aplication. they do make a regulator for it that is set at 14.2 constant. better than 14.8 but i would prefer 14.0. you only need the high voltage to get about the last05% of battery charge . then should go to float. this alternator # DR44G. the regulator # is 02306J283. the 14.2 reg # is 10510232. called several delco remy distributors but they don't have it. they do say it's a good #. these are small frame alternators and the only way to get the high amp output out of a small frame is to push the voltage way up. so for you guys looking at replacing with a new one you will have the same problem. hope this helps some. BTW you should be able to go with an external regulator that is adjustable. check the marine industry. the are expensive but so are 6 batterys. good luck dave

[TrekPR]

I see no mention of disconnecting the chassis battery and fail to see any problem with a switch at the house battery location to disconnect from the charging circuit of the alternator. Correction, if you fail to charge the house batteries by other means you will run out of power.

[Clay L]

If you disconnect a alternator while it is providing a heavy charge current it will cause a "Load dump'. This can cause a fairly long lasting (150 milliseconds as I recall) voltage spike of up to 180 volts or so.

When I designed electronic instrumentation for heavy equipment I made sure my designs would withstand that but not all designers do and damage to some of the vehicle electronics is possible.