Battery Monitor.

This is one of my favourite modifications. Very simple but oh, so useful.

I chanced across this unit during one of my drunken eBay escapades one evening, took a punt on it and this is the third vehicle I have fitted one to!

It allows you to read the voltage of 2 batteries (usually the coach & chassis) and monitor the current in & out of the coach batteries.

It can also tell you how many amp hours have gone in or out and tell you how long, at the current rate of charge (or discharge), until you are completely flat (or charged).

Awesome stuff.

Here is how the shunt is wired in the basement.

Top left is the negative to the battery that was previously connected to the WC chassis.

Top right is a new cable (comes as part of the kit) which is connected to the WC chassis. I used the same mounting point as the original cable.. so in effect the battery is earthed in the same way as before but via the shunt.

Bottom left is the untouched positive going to the battery. You can see I have run in a voltage sense wire with an in-line fuse from the positive battery terminal.

The brown wire loop you can see is unused. I left it there just in case I find a use for it in the future... I left the same loop at the other end. You can use any multi-core cable.... I used 7 core trailer light cable .



Here is a close up of the shunt. It is rated at 100 Amps. That repair washer is the only one I had in my bits bin! It does the job!



So here we have a fully charged battery sitting at 13.7v with zero current flowing... i.e. Fully charged and ready to go.



Here we have all the lights in the 5er turned on and the converter turned off. You can see the battery voltage has dropped to 12.1V and the discharge current is 41 Amps. Not bad for the standard Mickey Mouse battery they give us.



So you calibrate the battery monitor with ambient battery temperature & amp hour rating... then you leave it for a couple of days and do a few charge / discharge cycles and eventually it can figure out that: at the current rate of discharge (pun intended) you x.x hours to go. In my case leaving all the lights on would flatten the battery in 1.7 hours!!!



This unit is actually designed for a boat so comes with a cover and is water proof.

It has a second voltage sense that is designed for the chassis / engine battery (St = start). I decided to connect it directly to the converter (battery charger) output.. or in other words, this is the voltage at the 12 Volt fuse board above the converter. Here you can see the voltage at the converter is 11.4 Volts.

That's a 0.7 volt drop at 41 Amps... not too bad in the scheme of things but why in holy heck do they put the battery so far away from the converter? In my case at absolute opposite ends of the 5er. Ridiculous!!!

It seems like the WC design team come up with some pretty strange ideas!!! They should ask me where to put stuff!!! Sometimes I would say "where the sun don't shine"... but that's just me.



Here we have the converter turned back on again showing a decent enough 15.5 Amps of charge with a battery voltage of 13.2 Volts. Charge current starts off high and drops off very quickly. I saw 20 Amps or so but by the time I had the camera out it had already dropped to 15.5 Amps.

Currently sitting here writing this it is telling me 6.8 hours to 100% charge and she's dropped to 2.7 Amps charge. In reality it usually takes about 24 hours or so to re-charge completely.



My last vehicle was a Winnebago motor home. The coach batteries were knackered and always took 1 or 2 Amps regardless of how long they have been on charge. I was for ever topping up the water as a result... Interesting I thought.

This makes my inner geek go all moist. I love these battery monitors.

Thanks. Nice info to store someplace. Good photos.

Tater

Nasa makes them... No, not that Nasa!!

I didn't realise it but after thumbing through the manual it is (and I quote) "Designed and Manufactured in England"... well this must be a first. I thought we only produced dangerous financial instruments these days.

Here is a link to where you can buy one.

http://www.nasamarine.com/proddetail.php?prod=BMN-1_Battery

And here is a link to the manual.... I think it is corrupted... at least it doesn't read right on my laptop. Perhaps you'll have better luck with it.

http://www.nasamarine.com/pdfs/BM1.pdf

The link above seems to be for an earlier version... they only looked after one battery. When I installed this last one I discovered that they had been upgraded to 2 battery versions as per above!!

Perhaps we should start a "group buy" forum!!

31TS_in_England wrote:Nasa makes them... No, not that Nasa!!

I didn't realise it but after thumbing through the manual it is (and I quote) "Designed and Manufactured in England"... well this must be a first. I thought we only produced dangerous financial instruments these days.

Here is a link to where you can buy one.

http://www.nasamarine.com/proddetail.php?prod=BMN-1_Battery




And here is a link to the manual.... I think it is corrupted... at least it doesn't read right on my laptop. Perhaps you'll have better luck with it.

http://www.nasamarine.com/pdfs/BM1.pdf

The link above seems to be for an earlier version... they only looked after one battery. When I installed this last one I discovered that they had been upgraded to 2 battery versions as per above!!

How much is 87.50 pounds in "US Funny Money"??

1 pound = $1.63

$142.63

Yeah, it's kind of pricey but it looks well built.

There are plenty of variations on a theme out there but none that I have found that you'd be happy looking at in the living room.

It also has a large display that you can read from the other end of the 5er... I find myself unconsciously checking it all the time. Every now and again I catch it going into battery conditioning mode where the voltage goes up to 14.xx I can't remember exactly what the conditioning voltage is. I thought I had a problem the first time I saw that happen.. then I read the manual for the converter.

Oh, and it illuminates!

Incidentally, if anyone knows of any alternatives pipe up. Lets check them all out!

I also installed an "energy monitor" for the AC input... I'll post another thread soon.

31TS_in_England wrote:This is one of my favourite modifications. Very simple but oh, so useful.

I chanced across this unit during one of my drunken eBay escapades one evening, took a punt on it and this is the third vehicle I have fitted one to!

It allows you to read the voltage of 2 batteries (usually the coach & chassis) and monitor the current in & out of the coach batteries.

It can also tell you how many amp hours have gone in or out and tell you how long, at the current rate of charge (or discharge), until you are completely flat (or charged).

Awesome stuff.

Here is how the shunt is wired in the basement.

Top left is the negative to the battery that was previously connected to the WC chassis.

Top right is a new cable (comes as part of the kit) which is connected to the WC chassis. I used the same mounting point as the original cable.. so in effect the battery is earthed in the same way as before but via the shunt.

Bottom left is the untouched positive going to the battery. You can see I have run in a voltage sense wire with an in-line fuse from the positive battery terminal.

The brown wire loop you can see is unused. I left it there just in case I find a use for it in the future... I left the same loop at the other end. You can use any multi-core cable.... I used 7 core trailer light cable .



Here is a close up of the shunt. It is rated at 100 Amps. That repair washer is the only one I had in my bits bin! It does the job!



So here we have a fully charged battery sitting at 13.7v with zero current flowing... i.e. Fully charged and ready to go.



Here we have all the lights in the 5er turned on and the converter turned off. You can see the battery voltage has dropped to 12.1V and the discharge current is 41 Amps. Not bad for the standard Mickey Mouse battery they give us.



So you calibrate the battery monitor with ambient battery temperature & amp hour rating... then you leave it for a couple of days and do a few charge / discharge cycles and eventually it can figure out that: at the current rate of discharge (pun intended) you x.x hours to go. In my case leaving all the lights on would flatten the battery in 1.7 hours!!!



This unit is actually designed for a boat so comes with a cover and is water proof.

It has a second voltage sense that is designed for the chassis / engine battery (St = start). I decided to connect it directly to the converter (battery charger) output.. or in other words, this is the voltage at the 12 Volt fuse board above the converter. Here you can see the voltage at the converter is 11.4 Volts.

That's a 0.7 volt drop at 41 Amps... not too bad in the scheme of things but why in holy heck do they put the battery so far away from the converter? In my case at absolute opposite ends of the 5er. Ridiculous!!!

It seems like the WC design team come up with some pretty strange ideas!!! They should ask me where to put stuff!!! Sometimes I would say "where the sun don't shine"... but that's just me.



Here we have the converter turned back on again showing a decent enough 15.5 Amps of charge with a battery voltage of 13.2 Volts. Charge current starts off high and drops off very quickly. I saw 20 Amps or so but by the time I had the camera out it had already dropped to 15.5 Amps.

Currently sitting here writing this it is telling me 6.8 hours to 100% charge and she's dropped to 2.7 Amps charge. In reality it usually takes about 24 hours or so to re-charge completely.



My last vehicle was a Winnebago motor home. The coach batteries were knackered and always took 1 or 2 Amps regardless of how long they have been on charge. I was for ever topping up the water as a result... Interesting I thought.

This makes my inner geek go all moist. I love these battery monitors.

What is the model of your trailer.

So you had to run wires from the front or the back to where ever you mounted the gauge.

This is what i will use.
http://voltminder.com/

2010 31TS.

Yes the shunt needs to go close to the battery then you need 4 or 5 small gauge wires to where ever you place the gauge.

Not to hard to do on mine but still to costly.