Reply
 
Thread Tools Display Modes
Old 03-03-2020, 03:08 PM   #1
Member
 
Join Date: Jul 2018
Location: Seward NE
Posts: 76
Battery Capacity Monitor

I just finished installing the battery monitor to keep track of the exterior 12v battery. Install included extending the shielded wire and mounting the shunt in a box mounted to the side of the battery case. I just completed testing and everything works as it should. This is the relatively inexpensive unit made in China. Overall I think it is a good value for the $. Now as far as durability, only time will tell.
__________________
RDW
RogerWo is offline   Reply With Quote
Old 03-03-2020, 06:01 PM   #2
Senior Member
 
Join Date: Jul 2017
Location: North of Seattle, WA
Posts: 8,997
Quote:
Originally Posted by RogerWo View Post
I just finished installing the battery monitor to keep track of the exterior 12v battery. Install included extending the shielded wire and mounting the shunt in a box mounted to the side of the battery case. I just completed testing and everything works as it should. This is the relatively inexpensive unit made in China. Overall I think it is a good value for the $. Now as far as durability, only time will tell.
These inexpensive monitors that just measure voltage and current in/out of the battery are pretty durable. Super simple so not much to go wrong.

Where they come up short is in the accuracy of their CAPACITY or State Of Charge calculations. Lead Acid batteries have inefficiencies that require the use of a more complex meter to accurately measure SOC.

The inexpensive units are better than just the LED units but nowhere near that of the Victron type units. If you "work off the top" of your battery charge they may be good enough. However if you need more of your battery the indication from the cheaper meters may leave you thinking you have more battery left than you do. That can make for some cold mornings when the furnace is out of power
__________________
"A wise man can change his mind. A fool never will."

"Sometimes you're the dog, sometimes you're the tree"

2018 Flagstaff Micro Lite 25BDS
2004 Nissan Titan
TitanMike is online now   Reply With Quote
Old 03-03-2020, 06:05 PM   #3
Trailer Park Supervisor
 
NJKris's Avatar
 
Join Date: Sep 2018
Location: Northern NJ
Posts: 3,283
I was looking at some of the China special monitors on Amazon, pretty good for 30 bucks, but I noticed from comments that current in and current out are totaled, no way to see either by themselves. In that case, a simple voltmeter/percentage is about the same. I think it's worth a few extra bucks to see current in, current out.
__________________
2019 Rockwood Geo Pro G19FD w/off road package
2015 Ford F150 XLT Super Cab 4x4 V8
NJKris is offline   Reply With Quote
Old 03-03-2020, 06:20 PM   #4
Senior Member
 
Join Date: Jul 2017
Location: North of Seattle, WA
Posts: 8,997
Quote:
Originally Posted by NJKris View Post
I was looking at some of the China special monitors on Amazon, pretty good for 30 bucks, but I noticed from comments that current in and current out are totaled, no way to see either by themselves. In that case, a simple voltmeter/percentage is about the same. I think it's worth a few extra bucks to see current in, current out.
The issue with these meters is that it's not as simple as current in, current out, with a lead acid battery. The faster you draw current out or put current in (charge) the more inaccurate they become for determining the actual SOC of the battery. It's all due to the "Lag" in the chemical reaction in the battery and thus the need for a monitor that can utilize the Peukert Factor in it's calculations. THAT is what adds to the cost.

Also, Lead Acid batteries are slaves to temperature. Temperature correction becomes a factor as well and ideally the monitor has a temperature sensor as well.

If one wants to do all the calculations in their head (good luck) or on paper (I'd rather do a crossword puzzle) then a simple meter is probably OK. That said, if it's essential that one know how much power they are using and how long it will last, then spring for the better meter. You only have to buy it once and it may even allow your battery bank to last a few years longer.
__________________
"A wise man can change his mind. A fool never will."

"Sometimes you're the dog, sometimes you're the tree"

2018 Flagstaff Micro Lite 25BDS
2004 Nissan Titan
TitanMike is online now   Reply With Quote
Old 03-03-2020, 10:02 PM   #5
Senior Member
 
Join Date: Jul 2017
Location: California
Posts: 7,451
Had a guy send me some videos of his cheap chinese amazon monitor to try and troubleshoot. Went through all the trouble of wiring up his shunt and found that the thing would oscillate between a bunch of current readings that didn't make any sense. He is now waiting for the Victron Smart shunt to come out.


The one he bought was this piece of junk
https://www.amazon.com/Voltmeter-Amm...b_b_asin_title
__________________
2017 Coachmen 233RBS
2018 Ford F150 Lariat 3.5 Eco
"Common sense is not very common"
babock is offline   Reply With Quote
Reply

Tags
battery

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.



All times are GMT -5. The time now is 11:31 AM.