Replacement Battery Monitor et al.

[farkle48]

Hi - These are two related questions:

1. My electrical set-up includes a smart alternator regulator (model SAR V3) from Ample Power. The Ample Power brand battery monitor (called a BatMon) that was installed in the boat when I bought her finally bit the dust. The shunt assembly is still wired in (including the little ckt bd with its rj12 6-cond exiting wire). The othe end of that rj-12 cable is still in place at my nav station but not connected to anything. Since Ample Power recently closed its doors and disconnected its phones I am trying to find a pinout diag so that I can choose an appropriate new monitor and still use the existing, in-place shunt and cable. Any ideas or knowledge or suggestions would be greatly appreciated.
2. Also dealing with the SAR V3. The battery(+) mounted temperature sensor going to the SAR was recently shorted accidently to the extent that a lot of the wire leading into the SAR had its insulation melted a bunch. About 2" of the two wires coming out of the epoxy(?)-potted battery terminal and the terminal itself were saved. I replaced all the wiring and checked R with the terminal in ice water, at RT, and in boiling water. R varied inversely as the temperature over about 2K ohm range. It seems to me this variation would indicate an operable battery temp sensor. I haven't powered that whole system up yet but it's all wired. I'd like some feedback before the juice flows from the alternator. Again, thnx for the advice and help.

[djmarchand]

OK, starting with question #2 first, I think you will be all right. I suspect that the battery sensor only affects the float voltage of the regulator/alternator. You could measure the float voltage (once the alternator fully charges the battery and switches to float) and see if it in the mid 13s. Then heat up the temp sensor to see if it drops the float voltage a bit. If so, it is working ok.


For question #2, most battery monitors need to measure both sides of the shunt as well as the voltage at the battery terminal, plus a ground, so four wires. Look at the shunt end of the circuit and note the color of the wires to the neg terminal of the battery, to the ground bus and the positive rerminal of the battery and the negative terminal of the battery. Then use those colors to hook up your new battery monitor.


David

[farkle48]

Hi David, and thnx. In your reply you said 4 connections, but you only listed 3 different ones because you mention the negative terminal of the battery twice in your specific list. Am I missing something?

[djmarchand]

Well yes and no.


The battery monitors I am familiar with have separate connections for the battery terminal negative and the battery terminal side of the shunt. Yes they are the same, usually separated with a foot or two of heavy wire so the voltage should be very, very close to the same. You can combine the two but use the battery side of the shunt as the one to use. The voltage drop across the shunt is critical and even a few feet of heavy cable (and maybe more importantly the voltage drop in the connection) will make a big difference in measured current.


I hope that makes sense.


David

[farkle48]

Yes it does. I'll be sure to note whether there are 3 connections or 4 when I get the cover off that little ckt. I'm technically competent enough to make sure there's a wire from each end of the 1/0 cable now going from house bank negative to shunt reaching my new yet-to-be-chosen battery monitor.


Thank you SO much for helping shed light on this. Now that I have this added clarity I can get it done.


Fair wind and calm seas.
Mark, s/v Sparkle Plenty
CAL 39 MKII, Titusville FL

[mitiempo]

Originally Posted by farkle48

Yes it does. I'll be sure to note whether there are 3 connections or 4 when I get the cover off that little ckt. I'm technically competent enough to make sure there's a wire from each end of the 1/0 cable now going from house bank negative to shunt reaching my new yet-to-be-chosen battery monitor.


Thank you SO much for helping shed light on this. Now that I have this added clarity I can get it done.


Fair wind and calm seas.
Mark, s/v Sparkle Plenty
CAL 39 MKII, Titusville FL

Any battery monitor I sell or have seen comes with its own shunt. Why not use the one that comes with the new monitor?

[smac999]

I would use the new shunt, and then try to use the old cable with it.

the victron ones use a phone jack cable. but I can't recall if it's a 4 or 6 pin. it may plug straight into your old cable on both ends.