Solar + alternator = faster charge?

[haywoodphotomaccom]

Just talking out loud here....

Also could be the batteries not holding a charge or one of them not being good and pulling the other one down.

I check mine by fully charging them and then let it sit overnight. Put a load on the battery in the morning and then check the voltage.

I had a new battery once that was bad and it pulled the others down when they were connected....

[boywonder]

Janliness: Have your batteries load tested.......

[janliness]

OK, will get them load tested...

4D is one year old. Starting is...uh...previous owner! I'll start there.

Thanks, guys!
jan

[Scalf77]

What separator do you have, the old Surepower unit is notorious for getting dirty internal contacts.

-greg

[daveb]

Yep I've found even solar can mask that problem Greg is talking about. Just because the voltmeter reads a higher value when the sun is up, you still might not reach heavy charge amount or bulk charge required. You'd still really need to do a load check. If it falls off quickly it's possible the batteries never reached a full charge. You need to reach a real float level.

[janliness]

OK, load tested the starting battery and it's fine.

My separator is a Sure Power Model 1602. Should I be suspicious??? Is this something I can "clean" or is there a reasonable replacement?

Thanks!
jan

[boywonder]

Originally Posted by janliness

OK, load tested the starting battery and it's fine.

My separator is a Sure Power Model 1602. Should I be suspicious??? Is this something I can "clean" or is there a reasonable replacement?

Thanks!
jan

You have a battery "isolator"......you should consider a battery "separator". Sure Power makes separators as well.

Isolators use diodes (the electrical equivalent of a check valve) and diodes typically have a forward voltage drop of .7V. .7 volts may not sound like much, but it is significant if you have 13.5 volts or so to work with and are trying to fully charge a 12V battery.

The Sure Power separators are relays which burn a small amount of power when the batteries are connected, and since the relays are mechanical they have contacts that can wear.

Blue Sea sell separators that burn much less power when actuated, although this is mostly a concern when incorporating a solar panel.

[Scalf77]

Here is the surepower data on checking a isolater, I would also generally check the connections to make sure there is no built up contact resistance. Also check for any fuses or circuit breakers in line to your house battery.


Instructions for testing a isolator,
INSTRUCTIONS FOR TESTING A SURE POWER ISOLATOR WITH OHMMETER*:
1. Remove all wires from the isolator.
2. Using a needle movement ohmmeter RX-1 scale or a digital ohmmeter diode scale, hold the Red* probe on the terminal "A" and with
the Black* probe touch terminal #1 and #2, and the "E" terminal for 3A isolators (group 2), and the "R" terminal for (group 3) isolators.
A good isolator will show a current flow from "A" to #1, #2 and "R", and no current flow to "E".
3. Next, hold the Black* probe on the "A" and with the Red* probe touch terminal #1 and #2 (terminal "E" and "R", if used). A good
isolator will allow no current flow from "A" to #1, #2 or "R" and will show current flow from "E" to "A".
4. Hold one probe on the aluminum heat sink, being sure there is contact by scratching through the protective coating. Then touch
with the other probe, terminals "A", #1, #2 (the "E" terminal for 3A isolators [group 2] , the "R" terminal for group 3 isolators). A
good isolator will show no current flow.
5. Colored terminal indicates "E" post on group 2 isolators and "R" terminal on most group 3 isolators.
*On some import ohmmeters, the red and black probes are reversed for these tests.
**If using a digital ohmmeter, a diode scale MUST be used.

-greg

[janliness]

Thanks for the test instructions. I'm electronically literate, so that makes sense to me...just checking the diodes out.

I think it's more likely that a fuse has gone in the house charging circuit. I'll try and track that down as well.

BoyWonder...nice explanation, but... The alternator is running 14.4 volts (via scan gauge), so dropping 0.7 vdc shouldn't be a problem. I'll have to check if "A" is getting 14.4 and "B" is getting 0.7 less, out of curiosity. Also, why would one use a separator for solar applications?

later,
jan

[boywonder]

Originally Posted by janliness

Also, why would one use a separator for solar applications?

later,
jan

The same reason that you would use one without solar, so that you don't accidentally discharge your starting battery.

The issue with the Sure Power mechanical relay type with solar, is that the relay burns about .75A when the batteries are connected, and many times the solar panel may only be outputting an amp or less.......so unless the sun is high in the sky, a good portion of the solar charge is burned up in powering the relay. This assumes a bi-directional type separator which charges the starting battery with solar power; this requires the separator to be connected when the solar is connected to the house batteries.

The Sure Power Separators also come uni-directional, only connecting when the alternator is charging, these only charge the house batts.