Blue Sea Add A Battery query

ESGWheel

Petty Officer 1st Class
Joined
Aug 29, 2015
Messages
247
I plan on setting up a dual battery system in my 2005 Larson 228 LXi with a VP 5.0 GXi-E. Its more for a peace of mind vs. significant house loads. There is no trolling motor or bow thruster. The most going on the ‘house side’ is the stereo and the chart plotter and its not one of those high amp stereos. But after about an hour run, we do sit at anchor for most of the day with the stereo going and we keep the chart plotter on to monitor anchor drag. Plus, I like to tinker and have some cool battery cable making tools and want to use them.

The batteries would both be the lead acid / flooded type and I will buy two of the exact same batteries for this set up.

My web research so far has turned up the Blue Sea brand “Add-A-Battery Dual Circuit System” that combines both the needed switch and an automatic charging relay (ACR), link that should do the trick.

Here is what I have read / learned so far on this site:
  • Blue Sea brand is solid.
  • Simple to use: On or Off and generally will not need Combine unless you do.
  • Charging via the ACR is fully automatic, hands off, no worry solution.
  • Installing a relay to open the ACR Gnd wire may be the way to go for extended downtime at the dock to preclude parasitic drain by the ACR (so do not have to remember to flip another switch).
  • I’ll set it up to charge the start bat first because the house is not used that much and reliable starting is the goal.
  • And based on that I’ll wire up the automatic side of the bilge pump to the start battery.
  • It may or may not need fuses fm batteries to ACR, but I will follow the OEM’s recommendations.
Any other helpful tips and comments are appreciated.
 

ESGWheel

Petty Officer 1st Class
Joined
Aug 29, 2015
Messages
247
The leaning continues:
Blue Sea tech support confirmed there is a small current draw by the ACR itself. So even with the switch to OFF the ACR will draw “~ 15mA as it is constantly looking at the voltage of each bank.” Further “The ACR draws from each bank since it is a dual sensing unit.”

I also found an excellent article regarding ACRs that provide clarity not only about their operation but also has a ton of good info, like mixed battery chemistries and such: link.
 

JASinIL2006

Vice Admiral
Joined
Feb 10, 2012
Messages
5,609
One thing to consider when wiring your bilge pump to the starting battery: if your bilge pump is the sensor type, which senses the presences of water electronically, it can put a major drain on your start battery (which is not good, of course). If your pump has a float valve, there is less concern.

When I installed my Add-A-Battery kit, I put my primary bilge pump on the house battery and the backup pump on the starting battery. The backup pump doesn't kick in unless the primary fails (or can't keep up).

I've been really happy with the Blue Sea kit. It really is well made and I've never notice any problem from the sensing function, even though my boat sits for weeks at a time.
 

cyclops222

Chief Petty Officer
Joined
Mar 21, 2024
Messages
597
NEVER put anything. Including a Bilge Pump on the starting battery !!!!!!!!!!!!!
You are supposed to learn how much rain will cause the house battery to run down after pumping out a big rain storm.
Someone can simply go down while the house battery is almost DEAD. Start the main engine and IT IT will supply power to the house battery to pump faster AND AND safely recharge the battery also. A fast idle is all that is required. No danger to battery or the engine alternator.
 

airshot

Rear Admiral
Joined
Jul 22, 2008
Messages
4,634
If it were my boat, I would take whatever steps were needed to keep the water out, so there would be no strain on the battery to start with. That is where a good cover comes into play....
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,762
Blue Sea tech support confirmed there is a small current draw by the ACR itself. So even with the switch to OFF the ACR will draw “~ 15mA as it is constantly looking at the voltage of each bank.”
Been running a ACR since 2015.
Has never cause any issues

Not all too concerned with 0.015 Ah drain.
Comes out to 10 Ah per month
Have 14 times that in capacity in each battery.
Further “The ACR draws from each bank since it is a dual sensing unit.”
Confirmed or speculative?
Easy enough to alternate monitoring of sense lines with a common sensor
 

ESGWheel

Petty Officer 1st Class
Joined
Aug 29, 2015
Messages
247
If your bilge pump is the sensor type, which senses the presences of water electronically, it can put a major drain on your start battery...

When I installed my Add-A-Battery kit, I put my primary bilge pump on the house battery and the backup pump on the starting battery. The backup pump doesn't kick in unless the primary fails (or can't keep up).
Current pump is the senor type that does have a minor draw. I like the idea of a backup on the other battery that will only activate if above the current one. Great suggestion! I will do that!

NEVER put anything. Including a Bilge Pump on the starting battery !!!!!!!!!!!!!
Someone can simply go down while the house battery is almost DEAD. Start the main engine and IT IT will supply power to the house battery to pump faster AND AND safely recharge the battery also.

Strong recommendation and I appreciate the logic. Also, no option where I dock for others to go down and help out. And I am 3 hrs away from the boat with no ability to monitor (no shore power really bad cell service).

That is where a good cover comes into play....
While a 2005 boat it’s a fairly new mooring cover that is working well. Even in the most severe storms the area has seen in a while, never any issues. However I am always concerned about someone accidently (or purposely) unsnapping a portion creating a funnel into the boat. Keeping my fingers crossed!

I've been really happy with the Blue Sea kit. It really is well made and I've never notice any problem from the sensing function, even though my boat sits for weeks at a time.
Been running a ACR since 2015.
Has never cause any issues
Good to get the strong support for the Blue Sea. That is what I was looking for. Thank you!
 
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