Multiple Batteries, with Multiple Bilge Pumps

[stupidav]

Currently I have 3 batteries and 3 bilge pumps. I have each bilge pump on a separate battery. Two of the batteries are for each motor, and the third is for the generator.

Recently one of the batteries died. Which also ment that one of the bilge pumps wouldn't work along with one of the VHF radios.

Is there a device or a setup that all batteries could be connected to that gives a single point of connection for the bilge pumps and or the rest of the boat? Something along the lines of leaving each motor connected to one battery, yet the "house DC" connected to all 3. It seems like there should be a device already available to do this, but if there is I don't know where to start, any ideas are greatly appreciated!

 

[alldodge]

Howdy

While there are many ideas of putting in backup bilge pumps, I don't know of anything currently to do what your wanting. It could be done but it would be specialized circuitry. If your only worried about the bilge pump, you could install a second pump which runs off another bat, but if your wanting everything to work, that needs a manual switch.

 

[sam am I]

I run something similar to this and have my three batts OR'd to my bilge pumps so as to prevent what you experienced. I simply beefed up the OR'ing diode array and added a house path as you requested.......




m50-diode-series-power-modules.pdf

Realize there will be a max current load on the house path (like any) in the case of 100A (I'd heat sink it and fuse it with say a 50A breaker switch). Also, the house supply voltage will always be slightly less than the highest batt voltage of the three batts, somewhere's around Vbatt -1.2V max at 100A, Vbatt - 0.8 V at 50A, Vbatt - 0.5V @ 20A, etc.

Also, the house (and bilge) paths are not isolated battery paths, i.e., if something (bilge pump/s, light, amp etc) is left one long enough, all three batts will discharge totally...........D4, D5, D6 aren't required but, prevent the floats switched from turning each others pumps on. The schottky diodes (D4, D5 and D6) only drop an appox 0.2/0.3V but, only on manual override.

 

[stupidav]

I am terribly sorry I didn't get back to this sooner, had a few other issues to get straightened out so this got put to the side. Sam, your concept was much along the lines of what I was thinking if I couldn't find anything. I actually was thinking that instead of your D4-6, I was going to have 3 individual switches for manual control rather than the single switch, which would also eliminate the need for the D4-6.

​At the rate that I am going I will have to get this setup this winter. I will try to take some pictures of what I come up with.