Best battery monitors? And low voltage cutoff?

A forum for discussing boat or trailer repairs or modifications that you have made or are considering.

Moderators: Catigale, Paul S, Heath_Mod, beene, Hamin' X, kmclemore, tangentair

Flightfollowing
Chief Steward
Posts: 91
Joined: Sun Aug 10, 2014 7:37 am
Sailboat: MacGregor 26X

Best battery monitors? And low voltage cutoff?

Post by Flightfollowing » Tue Jan 26, 2016 9:39 am

I am considering adding a battery state of charge monitor and wondered what others recommend? I am leaning towards being cheap and installing one of these:
http://www.amazon.com/gp/product/B013PK ... ge_o03_s00
A bayite $18 model, but might also consider a nice one called a balmer smart gauge which is highly recommended on phase and avoids most of the programming that can make them inaccurate:
http://www.pbase.com/mainecruising/smart_gauge

I also have one of these in the system, which so far has never been tripped:
http://www.amazon.com/gp/product/B00BEA ... ge_o03_s00
An energy core products lvd

Any recommendations?

User avatar
Seapup
Captain
Posts: 923
Joined: Tue Nov 16, 2010 10:05 am
Location: 2002 26x - Virgina Beach, Va

Re: Best battery monitors? And low voltage cutoff?

Post by Seapup » Tue Jan 26, 2016 11:01 am

The $300 Balmar is certainly the techiest option. The victrons seem pretty nice too for about half that amount, but not "smart".

There is an abundance of the Chinese import options for under $50. I like buying them from china then having a surprise when forget about it and they show up a month later :D I saw the one you linked on amazon and have been considering it to play with. They look to be the best budget model currently. One thing to look for on the cheaper ones is that they count both amp hour or watt hours in & out. Many are one or the other depending on how you wire it, but not both.

I like the basic generic doc wattsons for under $20, They have been around a long time so there is a lot of info online about them and ways to mod them. I wired one to a 55lb thrust (50A continuous draw) trolling motor figuring it would heat up but after 15 minutes it was still cool. I found it useful when equalizing batteries at 15.5 V too.

Image

I picked up another under $20 model with remote shunt to be a little safer. The display cable had to be extended to make it usable away from the shunt, but otherwise it worked fine. I was a cool tool to watch my battery bank acceptance rate and outboard alternator output. According to it my DF 90 put 30A just above idle and a little over 40A into the batteries at 1800rpm. The DF 20 put out 12A at 2000 rpm, but soon as I went much over 2000rpm it would drop down to 3A and stay there, letting me know there was an issue and to not count on it charging my batteries. You can also see the voltage stay at 14.8 and watch the battery Amps quickly drop down as they reach their acceptance and end of bulk charge. You can program them to run a relay to shutoff the battery if you want, but they also flash when you reach your set values which was good enough for me.

Image

Then I went big and spent $35 on a remote one :D Its a little nicer looking but the nicest thing is its wireless between the shunt and display. So all you need to do is put the shunt on the battery and then put the display anywhere you want, like next to your switch panel. I have only used this in in the house so far, but seems to work just like the others.


Image

I am still waiting for someone to make a cheap wireless meter/shunt to display on a tablet app and do the logging :wink: Unless its already out there...

C Buchs
First Officer
Posts: 334
Joined: Thu Apr 23, 2015 8:49 pm
Sailboat: MacGregor 26X
Location: Camas, WA; 2001 26X w/ 2000 Honda 50

Re: Best battery monitors? And low voltage cutoff?

Post by C Buchs » Tue Jan 26, 2016 11:26 am

I'm very interested in what everyone is using. Right now I have no way of knowing what condition my batteries are in without using my volt meter (I do have one on board). My brother-in-law recommended a Xantrex Link Pro like this one http://www.amazon.com/gp/product/B001E4 ... PDKIKX0DER. However, he has a 40 foot Nauticat that he sailed solo to Hawaii. He’s got a bank of eight gel batteries. I’m willing to pay for it if it’s worth it. Is this one overkill for a boat with two batteries that is mostly used for overnighters on the weekend and will hopefully take us for a week long cruise this year?

Jeff

User avatar
Sumner
Admiral
Posts: 2374
Joined: Sun Jan 04, 2009 6:20 pm
Sailboat: MacGregor 26S
Location: SE Utah
Contact:

Re: Best battery monitors? And low voltage cutoff?

Post by Sumner » Tue Jan 26, 2016 12:13 pm

Seapup wrote:....I like the basic generic doc wattsons for under $20,....with remote shunt....Then I went big and spent $35 on a remote one :D ....
Any links for some you like. I"m interested in remote shunt models and also the wireless one...

Image

http://purplesagetradingpost.com/sumner ... de-25.html

... I use the volt and amp meters shown above in both boats but they are now hard to find and don't give any other info. I did buy a cheaper Chinese volt meter for under $15 to read the two batteries that can be switched between a 24 volt series bank (trolling motor) or a 12 volt parallel bank (house loads) and it worked on the Bahama trip fine but now sometimes seems to about double the indicated voltage at times and one segment doesn't work :( .

Thanks,

Sumner

============================
1300 miles to the Bahamas and back -- 2015

The MacGregor 26-S

The Endeavour 37

Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

Flightfollowing
Chief Steward
Posts: 91
Joined: Sun Aug 10, 2014 7:37 am
Sailboat: MacGregor 26X

Re: Best battery monitors? And low voltage cutoff?

Post by Flightfollowing » Tue Jan 26, 2016 12:26 pm

Great info Seapup! I agree with Sumner do you have a link to your $35 wireless shunt and remote meter?
Looks like their are a few options for app based remote meters with wired shunt, but I didn't see one cheap. The link I provided to the cheap one is only one way.
I have an 'add a battery' kit with a switch that separates the house and start batteries, so as long as I don't switch to "both" my meter wired to the house battery should work properly for load monitoring the house battery. These units are cheap enough I may put one on the solar and engine input side to see how recharge is going as you demonstrate.

User avatar
grady
Captain
Posts: 946
Joined: Tue Jan 19, 2010 11:38 am
Sailboat: MacGregor 26S
Location: Dallas

Re: Best battery monitors? And low voltage cutoff?

Post by grady » Tue Jan 26, 2016 12:45 pm

Had a Davtron volt meter left over from a Avionics upgrade. Put a DPDT with center off switch on it so it could read both batteries independently.

Image

User avatar
BOAT
Admiral
Posts: 4243
Joined: Fri Oct 19, 2012 7:12 pm
Sailboat: MacGregor 26M
Location: Oceanside, CA MACMJ213 2013 ETEC60

Re: Best battery monitors? And low voltage cutoff?

Post by BOAT » Tue Jan 26, 2016 1:49 pm

Sumner, I have no idea what you are saying - but I am trying to figure out how to monitor my batteries with some sort of display. I have been trying to figure out how to do it for over two years! Then you come along and say you have been doing it forever with Chinese "stuff" and when you talk about it all I hear is words I don't understand.

What should I do? I would like to put up a display that tells me how my batteries are doing.

(what the heck is a shunt?) :cry:

User avatar
Wind Chime
Captain
Posts: 868
Joined: Sun Jan 21, 2007 7:30 pm
Sailboat: MacGregor 26X
Location: Vancouver, B.C. Canada. 2000-26X, Suzuki-50hp, 8' Walker-Bay tender (with sailkit)
Contact:

Re: Best battery monitors? And low voltage cutoff?

Post by Wind Chime » Tue Jan 26, 2016 1:58 pm

Question?

When wiring two separate 12v batteries into an A/B-toggle switch and then to a meter - do you need to run BOTH pos and neg wires from BOTH batteries? ... or can you just use one neg wire.

User avatar
Sumner
Admiral
Posts: 2374
Joined: Sun Jan 04, 2009 6:20 pm
Sailboat: MacGregor 26S
Location: SE Utah
Contact:

Re: Best battery monitors? And low voltage cutoff?

Post by Sumner » Tue Jan 26, 2016 2:08 pm

BOAT wrote:Sumner, I have no idea what you are saying - but I am trying to figure out how to monitor my batteries with some sort of display. I have been trying to figure out how to do it for over two years! Then you come along and say you have been doing it forever with Chinese "stuff" and when you talk about it all I hear is words I don't understand.

What should I do? I would like to put up a display that tells me how my batteries are doing.

(what the heck is a shunt?) :cry:
Hey sent you a PM about your traveling.

As far as the info above you need that wasn't me with the long, very good post above, I'm just looking for more info like you are :) .

In the 'old' days when you had an amp meter all the current for everything you wanted to read went through it. If it went bad it could burn your car up so they quit using that time and went to just a voltmeter for info in the car and a volt meter will tell you battery charge level but won't tell you how much elect. is flowing in or out of the battery (current--in amps).

Since we might still want that info they have a different type of amp meter that uses a shunt....

[img]javascript:void(0)[/img]

... the current you want to read can flow through the shunt which is place on the negative cable going to the battery if you want to read all loads and is very safe. It in turn sends a signal, that is actually the voltage drop across the shunt to the amp meter (which is actually a volt meter with an amp scale on it). Since we are sending a voltage to the meter and not running all the amps through it we only need a small wire. The meter interprets the voltage signal and gives you the amps that are flowing at that time.

A meter can also do more if it is more sophisticated. It can keep track of those amps over a time period going into the battery (charging) or out to the loads and tell you how much your battery is charged and totals for the amps in and out depending on the meter.

Image

Above (bottom left arrow) is the shunt in my wiring on the Mac and it sends the signal to the amp meter in the other picture. If you want to measure amps please get a meter that uses a shunt and don't install one where all the amps flow through the meter,

Sumner

============================
1300 miles to the Bahamas and back -- 2015

The MacGregor 26-S

The Endeavour 37

Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

User avatar
Sumner
Admiral
Posts: 2374
Joined: Sun Jan 04, 2009 6:20 pm
Sailboat: MacGregor 26S
Location: SE Utah
Contact:

Re: Best battery monitors? And low voltage cutoff?

Post by Sumner » Tue Jan 26, 2016 2:09 pm

Wind Chime wrote:Question?

When wiring two separate 12v batteries into an A/B-toggle switch and then to a meter - do you need to run BOTH pos and neg wires from BOTH batteries? ... or can you just use one neg wire.
Only one negative as the negatives on the batteries should be tied together. Also if you run the volt meter to the common terminal on the A/B switch you will see the combined voltage or the voltage of whichever battery has been selected by the switch,

Sumner

============================
1300 miles to the Bahamas and back -- 2015

The MacGregor 26-S

The Endeavour 37

Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

Stevenhigbee
Engineer
Posts: 100
Joined: Tue Aug 26, 2014 10:15 am
Sailboat: MacGregor 26S

Re: Best battery monitors? And low voltage cutoff?

Post by Stevenhigbee » Tue Jan 26, 2016 2:18 pm

A shunt is a parallel pathway for the current to cross, with high resistance compared to the low resistance of the main conductor. It is needed to measure amperage flowing in a high current circuit, so that only a small current goes through the meter. It seems like you would want one on each battery, unless both batteries are always on together.

User avatar
BOAT
Admiral
Posts: 4243
Joined: Fri Oct 19, 2012 7:12 pm
Sailboat: MacGregor 26M
Location: Oceanside, CA MACMJ213 2013 ETEC60

Re: Best battery monitors? And low voltage cutoff?

Post by BOAT » Tue Jan 26, 2016 2:20 pm

Okay, thanks Sumner - I will get a "shunt" - (might take me a while to figure out how or what kind but I will defiantly do that).

I'm sort of an 'off the shelf' kind a guy when it comes to electric stuff so it takes me a little longer.

User avatar
jimmy alonso
Engineer
Posts: 132
Joined: Mon May 02, 2005 11:27 am
Sailboat: MacGregor 26M
Location: Puerto Rico, 2004 26M,Yamaha 50

Re: Best battery monitors? And low voltage cutoff?

Post by jimmy alonso » Tue Jan 26, 2016 4:50 pm

I like the Blue Sea Systems State of Charge meter. Model 1830
It's on the top of the long MODs list.
I so far have installed the electrical system with Blue Sea's products so far, 2 Fuse Blocks, a 360 Switch Panel, and MRBF Terminal Fuse Blocks on each battery.

https://www.bluesea.com/products/1830/M2_DC_SoC_Monitor

User avatar
BOAT
Admiral
Posts: 4243
Joined: Fri Oct 19, 2012 7:12 pm
Sailboat: MacGregor 26M
Location: Oceanside, CA MACMJ213 2013 ETEC60

Re: Best battery monitors? And low voltage cutoff?

Post by BOAT » Tue Jan 26, 2016 5:19 pm

So I need to buy this, right?

Image

User avatar
grady
Captain
Posts: 946
Joined: Tue Jan 19, 2010 11:38 am
Sailboat: MacGregor 26S
Location: Dallas

Re: Best battery monitors? And low voltage cutoff?

Post by grady » Tue Jan 26, 2016 7:00 pm

BOAT wrote:So I need to buy this, right?

Image
That looks good!!!

Post Reply