Community Forums

jbreault · 01-10-2023, 09:19 AM

I recently (finally) installed a BMK battery monitor after replacing all 8 coach batteries. The question I have is around terminal protection. For those who have one, did you coat the terminals of the shunt with terminal spray? I don’t know if heat dissipation is necessary with the shunt and I don’t want to risk any damage either with corrosion without protection or heat issues if it’s coated.

What have you done?

Bobby Dowdle · 01-10-2023, 10:11 AM

You can coat all terminals with the protectant as needed. Don't saturate the entire shunt but you can address the terminals. Maybe tape off the area to keep it looking good.

voltdoc · 01-10-2023, 06:45 PM

Mine is installed in the relatively dry battery compartment amidships on my 2017 so no, I didn't feel the need.

I assume yours is installed on a pre-2017 so the battery compartment is exposed to the weather, so some terminal protection would be in order. As Bobby said it probably isn't a great idea to put anything that could possibly be conductive on the shunt blades.

A 500A 50mV shunt (0.0001 ohms) could potentially be required to dissipate 25 watts (.05V x 500A) if the full 500 Amps were being pulled thru it. That isn't much heat, think of a 25W incandescent light bulb, plus that should never happen anyway, at least not for any length of time. If you were to run your microwave off the inverter (not recommended!) that would draw about 150 Amps from your batteries and generate only 2.25 watts across the shunt so heating should be minimal to insignificant under normal use.

I would suggest checking it every so often and removing any dirt with a rag or compressed air. You could also consider adding an enclosure of some sort, and/or moving the shunt into the adjacent cargo bay area.

RescueRamsey · 01-10-2023, 09:26 PM

Depending on where the shunt is mounted, it may not need any protection. I mounted mine in the converter/inverter bay. It's away from the batteries, and out of the elements. Been there for a while, with no signs of corrosion.

rorr1821 · 01-11-2023, 10:44 AM

Quote:

Originally Posted by jbreault

I recently (finally) installed a BMK battery monitor after replacing all 8 coach batteries. The question I have is around terminal protection. For those who have one, did you coat the terminals of the shunt with terminal spray? I don’t know if heat dissipation is necessary with the shunt and I don’t want to risk any damage either with corrosion without protection or heat issues if it’s coated.

What have you done?

I installed the BMK on my coach shortly after purchase in 2017. Works great and helps prolong life of the batteries by allowing you to monitor the State of Charge (SOC) so it does not go below 75%. They say 50% is maximum but 75% is better when you look at battery life chart. My 4 L-16’s are approximately 6 years old this month and still seem to be strong. My shunt is completely protected inside back bay.

What year and model coach?

twinboat · 01-11-2023, 12:42 PM

Quote:

Originally Posted by rorr1821

I installed the BMK on my coach shortly after purchase in 2017. Works great and helps prolong life of the batteries by allowing you to monitor the State of Charge (SOC) so it does not go below 75%. They say 50% is maximum but 75% is better when you look at battery life chart. My 4 L-16’s are approximately 6 years old this month and still seem to be strong. My shunt is completely protected inside back bay.

What year and model coach?

You can double the life of your batteries by drawing down to 75% rather then 50% OR you could only install 2- L16 batteries and draw them down to 50%, cutting their life in half and cutting your cost in half.

Either way, your buying the same amount of batteries over time.

Sent from my SM-A025V using iRV2 - RV Forum mobile app

voltdoc · 01-11-2023, 06:13 PM

Quote:

Originally Posted by twinboat

You can double the life of your batteries by drawing down to 75% rather then 50% OR you could only install 2- L16 batteries and draw them down to 50%, cutting their life in half and cutting your cost in half.

Either way, your buying the same amount of batteries over time.

Sent from my SM-A025V using iRV2 - RV Forum mobile app

That's one way to look at it

But I have found with these power hungry coaches, when dry camping, which almost all of us do occasionally, even if you can somehow achieve a full charge beforehand, 390 AH (2 L16's) is not enuf to get thru 8 or 10 hours of quiet time and not go below 50% SOC. So if you do that type of camping regularly having more capacity up front will increase longevity.

jbreault · 01-12-2023, 04:19 PM

Quote:

Originally Posted by rorr1821

I installed the BMK on my coach shortly after purchase in 2017. Works great and helps prolong life of the batteries by allowing you to monitor the State of Charge (SOC) so it does not go below 75%. They say 50% is maximum but 75% is better when you look at battery life chart. My 4 L-16’s are approximately 6 years old this month and still seem to be strong. My shunt is completely protected inside back bay.

What year and model coach?

Its a 2012 Anthem. Batteries are not in the standard compartments and the Shunt was installed on the back wall, just below the ground stud.