N150 Lead Calcium Charging

[Meck]

Hello,

I have some questions about charging the 3 bank N150 batteries on our boat.

I have a Xantrex 60 amp charger and they call for an absorption charge rate of 15.5 volts. My Xantrex inverter will only handle up to 15 volts before it shuts down. Can I put a regulator of some sort on the line into the Inverter so that I can run it with the Battery Charger?

Also, can I expect more efficient charging if I connect a separate output from the battery charger to each of the 3 batteries? Versus just one output to each side of the bank..

Thanks again for any information, this site has kept me afloat!!!

Meck
S/V Ocean Mandalay

[noelex 77]

A diode would drop the voltage by the required amount. You could leave it in place permanently but it will use a little bit of power. To overcome the power loss the diode could be engaged, or bypassed, manually with a battery switch, or even automatically with a relay or VSR

[Meck]

Thanks Noelex77,

I guess I'll go shopping for a diode.

Can you estimate if charging a 15+ volts with damage other 12v components on the boat, like my adler/barbour compressors?

Thanks again,
Meck

[noelex 77]

Originally Posted by Meck

Thanks Noelex77,

I guess I'll go shopping for a diode.

Can you estimate if charging a 15+ volts with damage other 12v components on the boat, like my adler/barbour compressors?

Thanks again,
Meck

It is a risky voltage. Lots of equipment used on a boat is only slightly modified car equipment and car regulators are set at much lower voltages. The 14.7V or so that most boat batteries are charged at is often pushing the limits for equipment voltage tolerance.
Many things will be fine, however, and motors often like running at a high voltage.

You could put the diode in your switchboard feed line so all the equipment gets the voltage drop.

You need to find diode can tolerate the maximum current. Diodes with ratings above 150A are hard to find. I think you could parallel them although unless closely matched they would not share the current completely evenly.

[CharlieJ]

Can I put a regulator of some sort on the line into the Inverter so that I can run it with the Battery Charger?

I am mighty confused!

I think you have 3 Ca batteries that require 15.5 VDC absorption voltage. Correct?
You have a Xantrex three bank battery charger that will or will not achieve the desired 15.5 VDC?
You have a separate Xantrex inverter (not an inverter/charger) that will not achieve the desired 15.5 VDC. Correct?

I think that you want to draw power from the Ca battery bank to provide DC to the inverter which will make AC to run the battery charger to charge the Ca battery bank. If this is correct, you will lose the battle as every time you go through an energy conversion process (DC > AC > DC) the system inefficiencies multiply together and doom you. Battery charger about 90% efficient. A good inverter, maybe 95% efficient. System efficiency = .9 x.95 = .855 So for every amp-hour removed from the bank, 0.86 amp-hr will be put into the bank by the system.

Unless I am missing something in your description which is certainly possible.

Regarding operating your nominal 12 VDC equipment at 15.5 VDC...not recommended. That is why, when we equalize a FLA bank, nominally to 15.5 to 16 VDC, one of the preliminary steps is to isolate the battery bank being isolated from the normal 12 VDC loads.

Hope this helps.
Charlie