Electrical query

[Dorman]

I think l am confusing myself, as usual.

I cannot work out what is wrong or not wrong with my batteries and circuits

 

The alternator on Amazon is driven off the crank via a pulley and is twin output 24 volt 90 amps. One goes (Output 1)to the starter batteries and has a VSR in circuit so it can then charge the Doms (2 sets) when the traction is fully charged. The second (Output 2) goes to bank of 4 batteries 110 ah obviously 24v each pair and a third linked set of two for emergency and soak up any amps left over when all the others are charged.

When the engine is running the Traction battery seems to draw v few amps on output 1 and via the VSR goes over to Doms very quickly.

 

The confusing thing is when the Inverter has been running off the 4 doms (110 amps ea 24volt) to heat the water or run the hoover etc the inverter cuts out within 30 -45 mins--not surprising really and the volts recover a bit when l switch it off. Now when l run up the engine the ampeter only shows about 20-30 amps on the domestics and volt of 25.8-.9 max at 800rpm 25.4 tickover--I would have thought it would be pulling more.

However the fridge etc will all run for days after (without running the engine) but not the inverter so there must be some volts still available.

The cable on the Inverter is the max l could get in the connectors (90mm cs l think?) and l know running at say 1500watts the battery bank of 440ah will not last long. Is it the fact that even pulling off so many amps with the inverter in real terms in not enough to really make the alternator work hard? In other words l need all 8 batteries to be down before it will produce 75 amps.

The batteries keep their charge ok and l have topped up regularly.

 

Can u straighten me out?

 

Thanks

Simon

[capnthommo]

I think l am confusing myself, as usual.

I cannot work out what is wrong or not wrong with my batteries and circuits

 

The alternator on Amazon is driven off the crank via a pulley and is twin output 24 volt 90 amps. One goes (Output 1)to the starter batteries and has a VSR in circuit so it can then charge the Doms (2 sets) when the traction is fully charged. The second (Output 2) goes to bank of 4 batteries 110 ah obviously 24v each pair and a third linked set of two for emergency and soak up any amps left over when all the others are charged.

When the engine is running the Traction battery seems to draw v few amps on output 1 and via the VSR goes over to Doms very quickly.

 

The confusing thing is when the Inverter has been running off the 4 doms (110 amps ea 24volt) to heat the water or run the hoover etc the inverter cuts out within 30 -45 mins--not surprising really and the volts recover a bit when l switch it off. Now when l run up the engine the ampeter only shows about 20-30 amps on the domestics and volt of 25.8-.9 max at 800rpm 25.4 tickover--I would have thought it would be pulling more.

However the fridge etc will all run for days after (without running the engine) but not the inverter so there must be some volts still available.

The cable on the Inverter is the max l could get in the connectors (90mm cs l think?) and l know running at say 1500watts the battery bank of 440ah will not last long. Is it the fact that even pulling off so many amps with the inverter in real terms in not enough to really make the alternator work hard? In other words l need all 8 batteries to be down before it will produce 75 amps.

The batteries keep their charge ok and l have topped up regularly.

 

Can u straighten me out?

 

Thanks

Simon

not an electrician, so nobody shoot me, but a couple of questions occur.

1. is the cable supplying the inverter supplying only the inverter, or is it also supplying the 24v circuits.

2. the items you mention as bringing about the problem are both high amperage, am i right? so are they causing the inverter to heat up and cut out in some way.

all i can think of

cheers

nigel

[blodger]

not an electrician, so nobody shoot me, but a couple of questions occur.

1. is the cable supplying the inverter supplying only the inverter, or is it also supplying the 24v circuits.

2. the items you mention as bringing about the problem are both high amperage, am i right? so are they causing the inverter to heat up and cut out in some way.

all i can think of

cheers

nigel

I am no expert either and have no 24v experience. Just from what you have said I would suspect the VSR, whatever it is. Is it possible to bypass it and common all the batteries to see if the alternator output is greater without, ie the VSR is holding back output.

 

I think the experts will be interested with the voltages at the batteries as well as the charge rate to help diagnose at the start, during and, end of charging

Edited May 19, 2010 by blodger

[Dorman]

I am no expert either and have no 24v experience. Just from what you have said I would suspect the VSR, whatever it is. Is it possible to bypass it and common all the batteries to see if the alternator output is greater without, ie the VSR is holding back output.

 

I think the experts will be interested with the voltages at the batteries as well as the charge rate to help diagnose at the start, during and, end of charging

 

I can take out the VSR as there is a emergency bypass but it makes no difference.

Batteries drop to about 20volt on the Inverter banks (others stay at 24+) When really charged up go up to 29V--espicially on land line mains charger but little less on alternator.

 

not an electrician, so nobody shoot me, but a couple of questions occur.

1. is the cable supplying the inverter supplying only the inverter, or is it also supplying the 24v circuits.

Seperate

2. the items you mention as bringing about the problem are both high amperage, am i right? so are they causing the inverter to heat up and cut out in some way.

No heat build up, Inverter goes out on low volts

all i can think of

cheers

nigel

[capnthommo]

I am no expert either and have no 24v experience. Just from what you have said I would suspect the VSR, whatever it is. Is it possible to bypass it and common all the batteries to see if the alternator output is greater without, ie the VSR is holding back output.

 

I think the experts will be interested with the voltages at the batteries as well as the charge rate to help diagnose at the start, during and, end of charging

to my limited mind i think i agree. the alternator voltages do seem a bit low don't they? it's strange how the inverter won't play nice but the 24v system seems to be fine. i take it that the domestic batteries are deep cycle? stupid question but you never know.

i shall follow this one with interest as i shall soon be wrestling with a 12v system and running a 220v fridge off a 440amp/h bank via a 2kw inverter.

really must chat to an electrician over this.

cheers

nigel

 

edit to add okay, so your answers above have kicked my theories into touch. wish i could help further but that's about done my limited knowledge.

Edited May 19, 2010 by capnthommo

[nb Innisfree]

You say 800 rpm when charging, what ratio is the alternator being driven at?

[Scotty]

Are you powering your immersion heater from your batteries, then charging them with the engine?

Edited May 20, 2010 by Scotty

[Dorman]

Are you powering your immersion heater from your batteries, then charging them with the engine?

 

Yes

 

You say 800 rpm when charging, what ratio is the alternator being driven at?

 

Not sure but when l fitted the ampmeters l got full deflection to 70 amps--but l have recently topped them up regularly with shore power and havent cruised over the winter. 800 ppm is engine revs when travelling on the river at a good lick. Tickover is about 400.

Edited May 20, 2010 by Dorman

[RobinJ]

The alternator on Amazon is driven off the crank via a pulley and is twin output 24 volt 90 amps. One goes (Output 1)to the starter batteries and has a VSR in circuit so it can then charge the Doms (2 sets) when the traction is fully charged. The second (Output 2) goes to bank of 4 batteries 110 ah obviously 24v each pair and a third linked set of two for emergency and soak up any amps left over when all the others are charged.

When the engine is running the Traction battery seems to draw v few amps on output 1 and via the VSR goes over to Doms very quickly.

 

The confusing thing is when the Inverter has been running off the 4 doms (110 amps ea 24volt) to heat the water or run the hoover etc the inverter cuts out within 30 -45 mins--not surprising really and the volts recover a bit when l switch it off. Now when l run up the engine the ampeter only shows about 20-30 amps on the domestics and volt of 25.8-.9 max at 800rpm 25.4 tickover--I would have thought it would be pulling more.

However the fridge etc will all run for days after (without running the engine) but not the inverter so there must be some volts still available.

The cable on the Inverter is the max l could get in the connectors (90mm cs l think?) and l know running at say 1500watts the battery bank of 440ah will not last long. Is it the fact that even pulling off so many amps with the inverter in real terms in not enough to really make the alternator work hard? In other words l need all 8 batteries to be down before it will produce 75 amps.

The batteries keep their charge ok and l have topped up regularly.

The best thing to do when you get a problem like this is to go throught everything systematically!

Bearing in mind I have not worked on 24V for about 10 years, but if a cell were to go with a 24V system it would be less noticable than on 12V and 25.4V doesn't seem a lot, I would expect it to be charging at around 28V.

What I do to start with is to disconnect all the batteries, let them settle and measure the voltage, in your case you will only need to separate each pair. There should be 25V across each pair if they are reasonably charged, anything less and you should select that pair for further charging and testing.

With a well charged pair, use them to test the alternator and see what it is putting out, make sure the charge voiltage is in the 28V range. If you want you can then test charge current by using a less well charged pair.

I suspect you will find either a dodgy battery, dicky connection or a suspect alternator, double check on the straps especially to the engine to make sure there is an adequate common all the way through to the batteries and inverter etc.

The VCR's can be tested with a power supply if you know someone who has a variable one! I would not expect that to affect the charge voltage, but it could affect the current?

[nb Innisfree]

Not sure but when l fitted the ampmeters l got full deflection to 70 amps--but l have recently topped them up regularly with shore power and havent cruised over the winter. 800 ppm is engine revs when travelling on the river at a good lick. Tickover is about 400.

 

You should be getting 90+ amps from a 90 amp alternator when batts are below 80% SoC, I suspect your alternator isn't turning fast enough and therefore your domestics are only being partially charged.

[WotEver]

You should be getting 90+ amps from a 90 amp alternator when batts are below 80% SoC, I suspect your alternator isn't turning fast enough and therefore your domestics are only being partially charged.

Agreed. Furthermore, Mr Peukert says that you'll get more capacity from your domestic bank if you permanently connect the 2nd pair with the 1st two pairs, giving you three pairs for 24V usage (although this will be of less impact if you drag them all down in one go by using them to heat* something).

 

Tony

 

* Heating (anything) with batteries is a really bad idea.

[Dorman]

Agreed. Furthermore, Mr Peukert says that you'll get more capacity from your domestic bank if you permanently connect the 2nd pair with the 1st two pairs, giving you three pairs for 24V usage (although this will be of less impact if you drag them all down in one go by using them to heat* something).

 

Tony

 

* Heating (anything) with batteries is a really bad idea.

 

I only use the immersion occasionally why is it such a bad idea? I will probably link up the batteries when l can affford the cable!

 

You should be getting 90+ amps from a 90 amp alternator when batts are below 80% SoC, I suspect your alternator isn't turning fast enough and therefore your domestics are only being partially charged.

 

The pulley on the crank is about 12" in dia and the alternator tiny--lve revved the engine out but no more than 26volts--is it worth having the alternator checked out or could it still be dud cells? The ampmeter used to go to 90amps before. How can i check the ampeters out or is that not possible? The alternator is exMOD and huge!!

Edited May 20, 2010 by Dorman

[WotEver]

I only use the immersion occasionally why is it such a bad idea?

Because it's so totally, incredibly, maddeningly inefficient. If you have no other means of getting hot water then you have no choice, but you really should be looking at acquiring any other means (gas, solid fuel, diesel) of generating heat.

 

 

I will probably link up the batteries when l can affford the cable!

It's cheaper than another pair of batteries

 

Tony

 

The pulley on the crank is about 12" in dia and the alternator tiny--lve revved the engine out but no more than 26volts--is it worth having the alternator checked out or could it still be dud cells? The ampmeter used to go to 90amps before. How can i check the ampeters out or is that not possible? The alternator is exMOD and huge!!

I'll let an alternator expert answer this one.

[Tony Brooks]

Because it's so totally, incredibly, maddeningly inefficient. If you have no other means of getting hot water then you have no choice, but you really should be looking at acquiring any other means (gas, solid fuel, diesel) of generating heat.

 

 

 

It's cheaper than another pair of batteries

 

Tony

 

 

I'll let an alternator expert answer this one.

 

 

First of all I am in no way an expert when compared with others on here.

 

Now the comment about 90 amps and two outputs starts to make sense. I think its the huge thing fitted to FFR military Landrovers and my circuits show a mechanical regulator. It also shows a a high low link in the regulator giving 28.5 to 29 volts n high and 26.5 to 27 volts when set to low.

 

From the readings I suspect the link is set to low - that is assuming it uses the same regulator as my diagram.

 

The regulator (from memory) was contained in a large metal box that also contained a battery a complicated battery relay that not only acted like a split charge relay but also refuse to energise if one battery set was reverse connected. It totally isolated the alternator when it was not charging.

 

The ignition warning lamp is put out by the output from the MAIN alternator output (B+ in our terms but A linked to Z on my diagram) via a diode and parallel resistor. Now, if the military box has been removed or "bodged about" so the engine battery remains connected to the alternator with no output that parallel resistor would supply a low current back feed through the instruments all the time the engine is not running. A shorted diode would be worse.

 

The accompanying notes also say that the warning lamp IS NOT a charge indicator, the ammeters are.

 

There are in-line chokes and also pass through capacitors for radio suppression inside that box on the main charging leads and as my notes date from 1980 and if you have such a box then there is the possibility you also have leaking capacitors.

 

Still best check for that link. If you take the lid off the box and look at it with a large horizontal relay thing situated at top right the link is at bottom left to the left of the mechanical regulator and filter chokes (big thick coils of copper "wire").

[nb Innisfree]

First of all I am in no way an expert when compared with others on here.

 

Not far off though

[Dorman]

First of all I am in no way an expert when compared with others on here.

 

Now the comment about 90 amps and two outputs starts to make sense. I think its the huge thing fitted to FFR military Landrovers and my circuits show a mechanical regulator. It also shows a a high low link in the regulator giving 28.5 to 29 volts n high and 26.5 to 27 volts when set to low.

 

From the readings I suspect the link is set to low - that is assuming it uses the same regulator as my diagram.

 

The regulator (from memory) was contained in a large metal box that also contained a battery a complicated battery relay that not only acted like a split charge relay but also refuse to energise if one battery set was reverse connected. It totally isolated the alternator when it was not charging.

 

The ignition warning lamp is put out by the output from the MAIN alternator output (B+ in our terms but A linked to Z on my diagram) via a diode and parallel resistor. Now, if the military box has been removed or "bodged about" so the engine battery remains connected to the alternator with no output that parallel resistor would supply a low current back feed through the instruments all the time the engine is not running. A shorted diode would be worse.

 

The accompanying notes also say that the warning lamp IS NOT a charge indicator, the ammeters are.

 

There are in-line chokes and also pass through capacitors for radio suppression inside that box on the main charging leads and as my notes date from 1980 and if you have such a box then there is the possibility you also have leaking capacitors.

 

Still best check for that link. If you take the lid off the box and look at it with a large horizontal relay thing situated at top right the link is at bottom left to the left of the mechanical regulator and filter chokes (big thick coils of copper "wire").

 

As always very imformative Tony--can you attach diagram pls?

Edited May 20, 2010 by Dorman

[Tony Brooks]

As always very imformative Tony--can you attach diagram pls?

 

 

Please will you PM with your email address. I am not sure I should put it on a public forum.

 

Cheers

[Dorman]

Please will you PM with your email address. I am not sure I should put it on a public forum.

 

Cheers

I think l found it on a landrover website. Will PM you though.

[WotEver]

I think l found it on a landrover website.

For anyone else who's interested the info is available here: http://www.winwaed.com/landy/mil/military.shtml

 

Tony

[Gibbo]

I only use the immersion occasionally why is it such a bad idea?

 

Prices have changed a bit since I wrote this in 2007 but the message remains the same.

 

A standard 25kg bag of coal, or an 18 litre can of diesel contains

roughly the same energy as 140 fully recharged lead acid batteries

weighing just over 4 tonnes.

 

To get a 25kg bag of coal onto your boat will take about 5 minutes and

cost 7 quid. To get 18 litres of diesel onto your boat will take 15

minutes and cost about a tenner.

 

140 batteries will cost about £8,000 and last about 200

discharge/recharge cycles. Thus £40 per cycle.

 

To recharge 140 lead acid batteries from flat with a 70 amp alternator

will take just under 2 weeks using about 500 litres of diesel and cost

around 300 quid. Plus the £40 battery costs............

 

Same energy.........

 

That's one reason why it's a bad idea tyo heat anything using electricity from batteries.

[nb Innisfree]

Agree totally with the above, but we do occasionally use our immersion heater(s) when running the engine, this sometime arises when our domestics are nearly full and we need to load the engine a bit to warm it up faster when we are moving a shortish distance, inefficient yes but better for the engine? + in the process we are getting water heated faster.

Edited May 21, 2010 by nb Innisfree

[Dorman]

Agree totally with the above, but we do occasionally use our immersion heater(s) when running the engine, this sometime arises when our domestics are nearly full and we need to load the engine a bit to warm it up faster when we are moving a shortish distance, inefficient yes but better for the engine? + in the process we are getting water heated faster.

 

Thats how we tend to use it to--penalty of vintage engines l'm afraid take a while to heat up and thermostat 70oC

 

For anyone else who's interested the info is available here: http://www.winwaed.com/landy/mil/military.shtml

 

Tony

 

Thats the one

[Dorman]

Can anybody recommend an electrical engineer that could test the FFR alternator and repair in West Mids??

Edited May 21, 2010 by Dorman

[GUMPY]

Can anybody recommend an electrical engineer that could test the FFR alternator and repair in West Mids??

 

I have a 24v one sitting on the shelf in my workshop

No external regulator just the alternator

Just checked its still there

Its been there for 8 years, if its of any use make me an offer.

[paulcatchpole]

Can anybody recommend an electrical engineer that could test the FFR alternator and repair in West Mids??

 

This and the two other docs in the same series (use google) will help you with it:

 

http://ferret-afv.org/manuals/allchargedup1.pdf

 

Let me know if you get properly stuck and I could come and have a look. Where, roughly, are you in the west mids?

 

PC