Battle Born Charging

Thanks BFL , finally makes sense

Mobilesport wrote:
@BFL
How are you coming up with the Ah numbers?
123.6ah ??
10 more at the end??

I wasn't aware I put that many amp hours into the battery, still learning.

My recorded soc% numbers came from the monitor.

Yes there is a ah counter but I didn't think about it.

AH is amps and time. 53 amps for the first two hours is 106AH then 20 minutes worth of 53 is 17.6AH so now at 123.6. About 10 more after that.

EDIT--I missed the 10 minute time out at 2:00 for 9AH, so total is 125AH all 25 in the first hour.

A normal allowance for heat loss is 6% or whatever with Wets and most of that starts after 80% SOC with "gassing". Li batts supposedly don't have so much of that.

You have 33% overage in AH assuming the batt is at 100AH rated capacity. You found where some or all of that was going, but most of it was after you fixed the problem early on. Still more to find!

You can't take the % SOC from a monitor unless you know for sure what the battery capacity is before you even start.

EDIT--this is where the Li blurbs drive me crazy--they seem to say that you can equate cell voltage with SOC and capacity. Cart before the horse.

New thought!--the BMS kicks in at 14v. How much of the recharging energy goes into running that thing instead of to the cells? That would reduce your charging efficiency a little, but you only get to 14v near the end so no big deal probably.

Just use the AH counter adjusted for heat loss for that type of battery. ISTR Trimetric says to use 1.5% for Li? But in this case, you have 33%!!!! (if the batt is 100AH)

It must be very frustrating for you with all this, but the good thing is that this is how you find out something isn't right--when the numbers don't come out right. BTDT.

@BFL
How are you coming up with the Ah numbers?
123.6ah ??
10 more at the end??

I wasn't aware I put that many amp hours into the battery, still learning.
My meter told me i put about 100ah into the battery.

My recorded soc% numbers came from the monitor.

Yes there is a ah counter but I didn't think about it.

Great info! Still not clear why not 60 amps constant, but at least this time you did get constant amps as though the charger is a 53 amper. (Too bad no way to see if that is indeed a 55 amper)

Good thing you noted the rising temp too because: Your charger put out 123.6 AH from 1 till 3:20 and about 10 more to the end.

Total approx AH 133.6 AH into a 100AH battery. So where did the extra 33.6 AH go? Usually that would be to heat. Your temps rose by 10 degrees F during the recharge. Some heat was noted going to wiring /connections.

Looks like the data table matches the charging spec. Bring the battery to 14.4 volts for a few minutes and call it done.

@Landyacht318
4 foot long 4 guage

I did a resistance check on this part in the picture, it has no continuity.
Thanks for the advice , sanding block wet 400 grit

I see thats a 100 amp fuse.... What size wire is it protecting?

I have an aversion to underfusing, and don't believe it is any safer 99% of the time, and just adds more resistance/heat than is needed in order to protect the wiring.

Try flattening the mating surfaces of that Blue seas fuse and make that aluminum appear like silver. A file is too aggressive. some 400 grit or finer sandpaper on a flat sanding block works best, especially when wet.

Trying to achieve perfectly flat with Folded sandpaper is the defintion of insanity

Just got done testing .
I started out by draining the battery until the low voltage shutdown was activated.
That was supposed to be 10 volts.
My meter read 9.3 volts when the battery shut off and the lights went out.

I immediately went out side and fired up my portable Honda 2000i generator. I used the same 60 amp charger as previous tests .
My other chargers are out of commission.

Right when the battery charger powered on the battery immediately started working again and I started documenting readings.
The red line in my chart represents when I briefly stopped charging because the amps did'nt look like they were constant, I tested my electrical connections for excessive heat and found my
Blueseas fuse terminal to be getting hot , it ranged in a temp of 134 degrees Fahrenheit all the way up to 153 degrees Fahrenheit.

All my other connections were on average of 79 degrees Fahrenheit.
I removed the fuse and holder and reconnected without that fuse assembly,, afterwords that area was around 85 degrees Fahrenheit.
Still bad but way way better.

deleted--too confused.

"If using IC I'll set incoming ac from generator so 100a will charge steady almost all the way to 100%, once it gets to 96-98% it will start dropin some current but not a lot"

It would be the same constant amps with a 100a PowerMax or any other converter or charger that does constant max rated amps. What you didn't report there is what charging rate that 100 amp is. To do that you need the capacity of your battery bank in AH.

With the charging rate you can then compare when Bulk ends in SOC with where it ought to, like that 1C gets you to 65% (or 60 in the other link)

What confuses me is the notion that you can pick your capacity by choosing your absorption voltage. A lower Vabs gives you a lower capacity they say. That seems bizarre to me. To me the capacity is what it is and is not adjustable by changing your settings.

You can get higher amp acceptance rates by increasing Vabs, but that will then make your Bulk end at a lower SOC by increasing the charging rate.

With Li they like a lower Vabs to reduce stress, but that is not the issue here.

If you are getting to 99% SOC at constant 100a, then to me that says you are using a low charging rate. The battery bank must be big in AH as its capacity