NASA BM-1 Battery Monitor (1 Viewer)

pablomc

LIFE MEMBER
Apr 20, 2010
772
237
Durham
Funster No
11,161
MH
A Class
Exp
Since 2009
Need to buy a BM-2 (as I now have a 2.5KW inverter :Eeek:), so selling the BM-1 I have (never installed or used). Offering here before I put on ebay. ::bigsmile:


For anyone who does not know the difference, the BM-1 is rated up to 100 ams and the BM-2 to 200amps.
 

G8WVW

Free Member
Jan 15, 2013
92
67
Cumbria
Funster No
24,296
MH
C class
Exp
Since 1990 on/off
BM1 excellent. Have one myself.

2.5KVA inverter; crikey!
 

Wildman

Free Member
May 30, 2008
0
8,470
Ilfracombe, Devon
Funster No
2,913
MH
Amazon Ambassador
Exp
since 1967
my existing Solar regulator shows charge rate, discharge rate and battery Voltage or % charge what is the differance please.
 

MicknPat

Free Member
Dec 16, 2007
614
3,606
Touring UK
Funster No
1,030
MH
39ft American A class RV
Exp
Since Oct 2007
Simply, what does the BM-2 do that the BM-1 doesn't?

I have a BM-1 still in its box waiting for good weather and someone ( one of my sons) to crawl under the RV to route and secure the wiring between the batteries and the BM-1 monitor. :Smile:

Subscribers  do not see these advertisements

 

Terry

LIFE MEMBER
Dec 27, 2007
11,904
8,969
Lincolnshire
Funster No
1,075
MH
A class
Exp
Can't remember ;)
my existing Solar regulator shows charge rate, discharge rate and battery Voltage or % charge what is the differance please.
£100 ish ::bigsmile:

Need to buy a BM-2 (as I now have a 2.5KW inverter :Eeek:), so selling the BM-1 I have (never installed or used). Offering here before I put on ebay. ::bigsmile:


For anyone who does not know the difference, the BM-1 is rated up to 100 ams and the BM-2 to 200amps.
But the blurb says it can handle from 5 to 650 amps :Smile:What on earth are you running to want 2.5kw--must be overkill :Eeek:::bigsmile:
terry
 

MicknPat

Free Member
Dec 16, 2007
614
3,606
Touring UK
Funster No
1,030
MH
39ft American A class RV
Exp
Since Oct 2007
Sorry about that Pablomc, I'm no electrician nor do I fully read the postings. :Sad:

So have I goofed in buying a BM-1 to connect to the 4x 6 volt 232 Amp hour house batteries that are connected in series so giving (if I understand it correctly) 12 volt 464 AH?

Thanks :thumb:

Subscribers  do not see these advertisements

 
OP
OP
pablomc

pablomc

LIFE MEMBER
Apr 20, 2010
772
237
Durham
Funster No
11,161
MH
A Class
Exp
Since 2009
Sorry about that Pablomc, I'm no electrician nor do I fully read the postings. :Sad:

So have I goofed in buying a BM-1 to connect to the 4x 6 volt 232 Amp hour house batteries that are connected in series so giving (if I understand it correctly) 12 volt 464 AH?

Thanks :thumb:

Nope overall rating does not matter, it's if you intend to pull a high current in excess of 100 Amps from them.

So if you only ever pull say 20 amps max then no biggy, but if you have an inverter then there is potential to draw a lot more depending on the inverter size. E.g. when I tested mine with the wife's hair dryer it was pulling 165amps :Eeek:.

If you don't have an inverter, then don't worry the BM-1 will be more than adequate. ::bigsmile:
 
OP
OP
pablomc

pablomc

LIFE MEMBER
Apr 20, 2010
772
237
Durham
Funster No
11,161
MH
A Class
Exp
Since 2009
Sorry about that Pablomc, I'm no electrician nor do I fully read the postings. :Sad:

So have I goofed in buying a BM-1 to connect to the 4x 6 volt 232 Amp hour house batteries that are connected in series so giving (if I understand it correctly) 12 volt 464 AH?

Thanks :thumb:

BTW if you have 4 X 6 volt batteries then they should be wired as pairs in series then those two pairs in parallel for 12 volts. If you wire them all in series you will have 24 volts and if all in parallel 6 volts. If in doubt ask. :thumb:
 
Last edited:
OP
OP
pablomc

pablomc

LIFE MEMBER
Apr 20, 2010
772
237
Durham
Funster No
11,161
MH
A Class
Exp
Since 2009
£100 ish ::bigsmile:


But the blurb says it can handle from 5 to 650 amps :Smile:What on earth are you running to want 2.5kw--must be overkill :Eeek:::bigsmile:
terry

See the previous post re the rating. :thumb:

Re the 2.5 better to have too much than too little. :Tongue1: :roflmto:

Subscribers  do not see these advertisements

 

pappajohn

LIFE MEMBER
Aug 26, 2007
43,207
48,814
Dark side of the moon
Funster No
172
Exp
Since 2005
See the previous post re the rating. :thumb:

Re the 2.5 better to have too much than too little. :Tongue1: :roflmto:
only drawback with a large inverter, it will use more power when idle...ie: on standby with nowt plugged in... than a litte 'un so really needs turning off completely when not in use.
 

MicknPat

Free Member
Dec 16, 2007
614
3,606
Touring UK
Funster No
1,030
MH
39ft American A class RV
Exp
Since Oct 2007
BTW if you have 4 X 6 volt batteries then they should be wired as pairs in series then those two pairs in parallel for 12 volts. If you wire them all in series you will have 24 volts and if all in parallel 6 volts. If in doubt ask. :thumb:

Looking at the pdf schematic from Fleetwood for our RV the connections go like this.

Battery 1. + to battery 3 + inverter etc
- to battery 2 +

Battery 2. + to battery 1 -
- to battery 4 -

Battery 3. + to battery 1+
- to battery 4+

Battery 4. + to battery 3-
- to battery 2- and ground

Doesn't those connections make is part serial part parallel ? All Greek to me :Smile:

thanks :thumb:
 

Techno

LIFE MEMBER
Deceased RIP
Jul 28, 2010
15,475
20,752
Leeds the one up North
Funster No
12,905
MH
Rapido 7090F 3 litre 160
Exp
May 2010
only drawback with a large inverter, it will use more power when idle...ie: on standby with nowt plugged in... than a litte 'un so really needs turning off completely when not in use.

The bigger Sterlings come with remote switch to place where convenient.My inverter is in the garage
Inverter%20remote-M.jpg

Subscribers  do not see these advertisements

 
OP
OP
pablomc

pablomc

LIFE MEMBER
Apr 20, 2010
772
237
Durham
Funster No
11,161
MH
A Class
Exp
Since 2009
only drawback with a large inverter, it will use more power when idle...ie: on standby with nowt plugged in... than a litte 'un so really needs turning off completely when not in use.

0.4A in power save mode and 1.8 A in on mode, or as described by Techno100 can be switched off at the remote panel. :Smile:
 

jb0371old

Free Member
Jul 8, 2011
465
408
Norfolk
Funster No
17,259
MH
Autotrail
Exp
1 year
If its still for sale can I have first dibs on it, away in the van till tomorrow so internet a bit touch and go at the minute
 
OP
OP
pablomc

pablomc

LIFE MEMBER
Apr 20, 2010
772
237
Durham
Funster No
11,161
MH
A Class
Exp
Since 2009
If its still for sale can I have first dibs on it, away in the van till tomorrow so internet a bit touch and go at the minute

Was going to put it on ebay at the weekend if there were no takers, but will hold off until you are back on line, so you can certainly have first shout. :thumb:

Subscribers  do not see these advertisements

 

pappajohn

LIFE MEMBER
Aug 26, 2007
43,207
48,814
Dark side of the moon
Funster No
172
Exp
Since 2005
0.4A in power save mode and 1.8 A in on mode, or as described by Techno100 can be switched off at the remote panel. :Smile:
thats what i mean.....doesnt sound a lot but added up it is a lot.

0.4amp over 24hrs = 9.6amps

1.8amp over 24hrs = 43.2amps

turned off completely, either remotely or manually = 0.0 amps
 

hilldweller

LIFE MEMBER
Dec 5, 2008
605
36,108
Macclesfield
Funster No
5,089
MH
Zilch Mk1
Exp
From Aug 2007
1.8amp over 24hrs = 43.2amps

That's your average MH battery flattened in 24hrs and the inverter has done sweet FA work.

Mind you, same average battery wouldn't last 10 mins with that thing really working. Lifespan of battery wouldn't be long I would think.

Subscribers  do not see these advertisements

 
OP
OP
pablomc

pablomc

LIFE MEMBER
Apr 20, 2010
772
237
Durham
Funster No
11,161
MH
A Class
Exp
Since 2009
That's your average MH battery flattened in 24hrs and the inverter has done sweet FA work.

Mind you, same average battery wouldn't last 10 mins with that thing really working. Lifespan of battery wouldn't be long I would think.

I don't have "average" motorhome batteries and the inverter is off when not required. :winky:
 
Last edited:

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Log in

Already a member? Log in here.

Latest journal entries

Funsters who are viewing this thread

Back
Top