Battle Born Performance & Charging

[Hans627]

I've read through most of this thread and find it interesting, although there is much I don't understand.

But I have a specific question relative to BB and charging. I have a (just one) BB 100ah battery in my 2018 Globetrotter. I had it transferred from my 2009 AS when I traded it in for the GT.

The charger/converter is the standard one that comes with the GT. After charging for several days the battery reading 13.28 after unplugging. Is that satisfactory?

Thanks!

[ROBERT CROSS]

Originally Posted by Hans627

I've read through most of this thread and find it interesting, although there is much I don't understand.

But I have a specific question relative to BB and charging. I have a (just one) BB 100ah battery in my 2018 Globetrotter. I had it transferred from my 2009 AS when I traded it in for the GT.

The charger/converter is the standard one that comes with the GT. After charging for several days the battery reading 13.28 after unplugging. Is that satisfactory?

Thanks!

Yes...but you should equalize @ 14.4 min.

Our 2 BB's also rest @ 13.28



I got a Boondocker set to 14.4 fixed.
You might consider an up-grade...not all that $$$.
You can safely use what you have but you won't be getting all the the BB's have to offer.

Bob
🇺🇸

[Hans627]

Thanks Bob.

One thing about the Victron is you can see what percentage of the battery charge remains. Without is there a SOC chart to provides the same information? Like the other day, before I plugged in the shore power, the batter voltage was 12.4. How much battery is left at that reading?

[ROBERT CROSS]

Yes...you can scroll thru it on the Monitor itself.👍
What I posted was WiFi screenshots.
When you see 12.4 you can scroll to get the %.

This it the monitor I have in the AS.
You can scroll and see all the info that you see on Mac screenshot.

Bob
🇺🇸

[waninae39]

my monitor area

[ROBERT CROSS]

When are the 👽 expected to land? 😂

I didn't realize electrons have so many problems.

Bob
🇺🇸

[uncle_bob]

Originally Posted by Hans627

I've read through most of this thread and find it interesting, although there is much I don't understand.

But I have a specific question relative to BB and charging. I have a (just one) BB 100ah battery in my 2018 Globetrotter. I had it transferred from my 2009 AS when I traded it in for the GT.

The charger/converter is the standard one that comes with the GT. After charging for several days the battery reading 13.28 after unplugging. Is that satisfactory?

Thanks!

Hi

Maybe yes, maybe no. There really is no way to tell from a voltage just how "full" a lithium is. You might be at 97%, you also could be at 70%. The voltage vs charge state curve is *very* flat.

A "typical" lead acid charger will try to drop back to float mode if it can. It does this by looking at the current going out of the converter / charger. If just a battery was involved that would be easy. In an RV with current also going into various loads, it's not so easy.

If the charger drops back to 13.2V, then it's not supplying any of the loads until the battery also gets down to 13.2. As you do this and that in the RV (run lights, power the propane detector ...) it all comes out of the battery. Once the voltage on the battery drops low enough, current begins to be sourced by the converter / charger.

Once *enough* current (how much that is depends a lot on the exact charger and often is not well documented) the charger goes out of float mode and moves into another mode. When it does, the voltage on the converter goes up and current flows into the battery. (= the battery is recharged).

Net result of all this is that you really don't know just how well charged your BB actually is if it's on a conventional lead acid charger that goes into float mode. Toss in manufacturing tolerances on various voltages and who knows what you will get ....

Bob

[SCOTTinNJ]

BB shared this with me a while back when I purchased mine.

[Hans627]

That chart seems like it might be helpful if I understood it.

Can anyone offer an explanation?

Thanks!

[uncle_bob]

Originally Posted by Hans627

That chart seems like it might be helpful if I understood it.

Can anyone offer an explanation?

Thanks!

Hi

If you know the number of load amps being pulled on the battery, you can guess the capacity. Between 13.4 and 13V you go from 100% down to 20% at no load.

Since most trailer metering is only good to +/- 0.1V (at best), that error can mean a 50% error in your capacity estimate. I certainly have devices in my trailer that are off by 0.4V in some cases. (so 100% would read as 20%).

The next gotcha with the chart is that it is rounded off. The real voltages are more like 13.356 for 100% and 13.021 for 20%. (yes those are just random guesses). Even there, you would need to know the temperature to get to a 5 digit level of precision.

Bob

[SCOTTinNJ]

One thing it shows is that once you hit 13v with nominal loads you should think about finding a charge.

[ROBERT CROSS]

I'm thinking that the number I'll use most often in relation to when to charge is AH consumed. 124 looks good for us.

Bob
🇺🇸

[uncle_bob]

Hi

The "tail" of the chart is steep enough that 12V isn't all that bad a stopping point. The BMS actually will shut the battery down before anything is damaged. Yes, there is a bit of wiggle room on this end due to drops in the wiring .....

Bob

[68 Overlander]

Originally Posted by ROBERT CROSS

Yes...but you should equalize @ 14.4 min.

Our 2 BB's also rest @ 13.28



I got a Boondocker set to 14.4 fixed.
You might consider an up-grade...not all that $$$.
You can safely use what you have but you won't be getting all the the BB's have to offer.

Bob
🇺🇸

Hi Bob, curious why you have it set to 14.4?

[uncle_bob]

Originally Posted by 68 Overlander

Hi Bob, curious why you have it set to 14.4?

Hi

*Some* Bob's set them to a lower voltage

Bob