charging batteries

Wayne,

You need to check the voltage at the batteries, throughout the charge, with a handheld. Never trust the readout on any portable charger. Yes, it does appear your vector does not continue to raise its volts while amps taper, but that's according to its own readout. As BFL noted, voltage does indeed continue to rise... as seen when yours suddenly "adds" another .1-.2v near the end.

In all likelihood, voltage is rising slowly the entire time, but the vector's digital readout is staying put at 14.7v, either at a rounded up or rounded down value. My pm4b-45 does the exact same profile since I modded it, and voltage rises very slowly near the end; slowly enough that a single decimal place readout would hold steady, even though voltage is changing.

X5 on needing to know the charge rate.

What I can tell you is a 40a charger will do a 50-85% on those batts in under 2 hours; provided the voltage is kept at 14.4v or above, at the terminals. The final 15% will take over twice as long.

Again it depends on what you have. Might just need a $25 Wizard or IQ controller. Get into the panel and list a model number. If you go above 45 amps you may need to pull new wire.

smarty wrote:
Thanks to all for your responses.
It would appear that my next question is what type/size converter should I acquire?

What do you have now? The usual 45-60a converter would be fine for a 200AH bank. Ugly graph shows diminishing returns in time to do a 50-90 with increasing charger amps. You can figure what would be "worth it" in generator time minutes saved vs dollars more for a bigger amp charger.

With the solar you also need to factor in how often you will need the converter anyway. Depends on amount of expected sunshine where and when you camp.

Thanks to all for your responses.
It would appear that my next question is what type/size converter should I acquire?

Onan just powers the converter or inverter/charger.
You need to list the model of the charging equipment for best answers.

Although generally when camping off grid most shoot for about 90% charge because the last 10% will always take an extended period. Once the battery hits 14.2 volts, run the generator one more hour. If your voltage does not go above 13.8 volts you need a new charging system.

The voltage read-out on the 1093DBD can be different at times from battery voltage. I have a 1093DBD too. Yes it does temperature compensation which affects the voltages.

It is normal for battery voltage to keep rising during the Absorption Stage. It is hard to measure what the charger's "own" voltage is when they are connected. They are at either end of the same wires, so the voltage difference seen is affected by voltage drop

With an adjustable voltage charger you can "set" the Vabs voltage, and battery voltage will rise to that. When they are the same voltages, no current, and you are done. But long before that, amps will taper from the constant amps stage.

Just what the SOC is when amps start to taper depends on the charging rate (charger amps wrt battery capacity in AH.) Vectors are a little different by having that "trip" occur at 13.9v.

BFL13 wrote:

waynefi wrote:
BFL13 - I'm curious about the label on your graph "Fixed Battery Acceptance Curve 14 - 14.5 Volts". Is the battery acceptance really the same at 14 vs 14.5? My VEC1093 uses 14.7, so I'm trying to figure out how it compares to your graph.

I did the graphs with two 35 amp 1092As (older Vectors) that go to 14.6v while the 1093Ds go to 14.8. I did a 35 and a 35+20 and two 35s

But the thing is both kinds of Vector do the same charging profile where it stays at constant amps until battery voltage reaches 13.9v and then it "trips" and amps start to taper. But this is not the classic Vabs where voltage is held constant so amps taper.

There may be confusion between charger's own voltage here, and battery voltage. The curve is battery acceptance voltage. Also there is voltage drop between them which gets less as amps taper.

The Vectors appear to let the voltage continue to rise as amps taper so by the time you get to 90%, battery voltage is about 14.5. It reaches max voltage at the end just before shutting off and says FUL. (which is actually about 97% SOC)

Most automatic chargers (which shut off when done) stop at about 97% Also RV converters that are so-called 3 stage do too. 97% is about where a PD drops to 13.6 so you get the rest of the recharge done at that, if you ever get higher what with running things in the rig. (You need to be not camping to get to full when it will be 13.2 by then)

Interesting, what I see with my VEC1093DBD is a little different. Current will be 40 amps with rising voltage until the voltage gets to 14.7. Then voltage stays at 14,7 with tapering amps until the amps gets down to about 5. Then in adds another 0,1 or 0.2 volts, and holds that until amps drop to about 1, when it say FUL.

That is the chargers voltage, I haven't tried measuring directly on the battery. The 14.7 number is at normal temperatures, at 0F it will go above 15.

waynefi wrote:
BFL13 - I'm curious about the label on your graph "Fixed Battery Acceptance Curve 14 - 14.5 Volts". Is the battery acceptance really the same at 14 vs 14.5? My VEC1093 uses 14.7, so I'm trying to figure out how it compares to your graph.

I did the graphs with two 35 amp 1092As (older Vectors) that go to 14.6v while the 1093Ds go to 14.8. I did a 35 and a 35+20 and two 35s

But the thing is both kinds of Vector do the same charging profile where it stays at constant amps until battery voltage reaches 13.9v and then it "trips" and amps start to taper. But this is not the classic Vabs where voltage is held constant so amps taper.

There may be confusion between charger's own voltage here, and battery voltage. The curve is battery acceptance voltage. Also there is voltage drop between them which gets less as amps taper.

The Vectors appear to let the voltage continue to rise as amps taper so by the time you get to 90%, battery voltage is about 14.5. It reaches max voltage at the end just before shutting off and says FUL. (which is actually about 97% SOC)

Most automatic chargers (which shut off when done) stop at about 97% Also RV converters that are so-called 3 stage do too. 97% is about where a PD drops to 13.6 so you get the rest of the recharge done at that, if you ever get higher what with running things in the rig. (You need to be not camping to get to full when it will be 13.2 by then)

BFL13 - I'm curious about the label on your graph "Fixed Battery Acceptance Curve 14 - 14.5 Volts". Is the battery acceptance really the same at 14 vs 14.5? My VEC1093 uses 14.7, so I'm trying to figure out how it compares to your graph.