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Old 09-16-2021, 09:51 AM   #21
ShaneGreen
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Join Date: Jul 2018
Location: Gassville
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M.O.C. #22218
EDIT ---- ignore this. As bcrvman has pointed out, something isn't right with my settings. The math doesn't work out.


Just as a point of reference...


300AH Battle Born with Victron Multiplus 12/3000/120-50 and all of the old inverter/convert stuff disconnected. No solar...yet


We usually run the batteries down to around 15%. HF Predator 3500W generator takes about 75 minutes to reach "100%". It will keep taking a charge for a little while after that, but they are essentially topped off in that time. If we are running the TV, coffee pot, hot water heater, residential fridge and microwave during that time it may take another 15 minutes to fully charge.


On a couple of occasions we have woke up to no power. I believe BB set up the Victron profile to cut off at 5% and said fully draining them would not be a problem. Even at 5% and running all the stuff mentioned above, it's never taken more than an hour and 35 minutes to completely recharge.
 
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Old 09-16-2021, 10:13 AM   #22
bcrvman
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Quote:
Originally Posted by ShaneGreen View Post
Just as a point of reference...


300AH Battle Born with Victron Multiplus 12/3000/120-50 and all of the old inverter/convert stuff disconnected. No solar...yet


We usually run the batteries down to around 15%. HF Predator 3500W generator takes about 75 minutes to reach "100%". It will keep taking a charge for a little while after that, but they are essentially topped off in that time. If we are running the TV, coffee pot, hot water heater, residential fridge and microwave during that time it may take another 15 minutes to fully charge.


On a couple of occasions we have woke up to no power. I believe BB set up the Victron profile to cut off at 5% and said fully draining them would not be a problem. Even at 5% and running all the stuff mentioned above, it's never taken more than an hour and 35 minutes to completely recharge.
Sorry, but I can't get your math to work.
You have a 120A charger as I do. You run 300AH of BB down to 15% which means 300x.85 required to fill back to 100%. That is 255AH. At the full 120A charge rate that gives us 255/120 or 2hrs 7.5 mins. In fact it will be more like 2.5 hrs. Can you show us your VRM charts for the most recent charge period? I assume you have a Victron shunt, which model? The shunt has ONLY 1 4/0 cable from shunt to battery negative less than 3 ft long. NO other wires attached to the neg bat post other than inverter temp sense.
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Old 09-16-2021, 10:37 AM   #23
bcrvman
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Let's just parse your last sentence. 1hr 35min to go from 5% to 100%. You have a 12V 3000W inverter, 120A charger, 50A pass thru. in 1 hr you put in 120A of the 285 you are down, in the remaining 35 mins you put in another 70. You are still short by 95AH.
The math is 300AH - (300AH*5%) is the amount you need to get back to 100% which is 285AH. Your charger puts out 120A. 285AH / 120A is 2.375H It will take a little longer. I will give you access to my VRM account (via DM) so you can see my system and if you share yours with me maybe I can see something you are missing.
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Old 09-16-2021, 11:26 AM   #24
ShaneGreen
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bcrvman - You're right, the math doesn't add up. I double checked with the wife and we've never had to run the generator longer than that to recharge.



I pulled up the Victron phone app and it says "Deepest Discharge: -258Ah." So something isn't set right somewhere since the Victron has shut us down more than once. Even at 258 it should be taking longer to charge.



Was a little busy at the time and I never set up a VRM account. Will it be able to pull old data?
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Old 09-16-2021, 12:02 PM   #25
bcrvman
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Quote:
Originally Posted by ShaneGreen View Post
bcrvman - You're right, the math doesn't add up. I double checked with the wife and we've never had to run the generator longer than that to recharge.



I pulled up the Victron phone app and it says "Deepest Discharge: -258Ah." So something isn't set right somewhere since the Victron has shut us down more than once. Even at 258 it should be taking longer to charge.



Was a little busy at the time and I never set up a VRM account. Will it be able to pull old data?
Either your shunt is reporting incorrectly or a setting is incorrect. Can you post the BMV settings page on your phone? I am posting mine for reference. I will be changing mine a bit, I don't like my absorb at 14.2 since I learned that is the min value to trigger cell balancing. I will go to 14.4 (the Charged voltage will need to be set to 14.2 as it is defined as Absorb - 2)

Your deepest discharge of 258AH IS 86%. That's what you said earlier.

As far as old data, it depends on a few things. Get it going ASAP and hope the CF/TF card you are using is big enough to hold a lot of your history. Are you using a CCGX or some other GX device?

I will try to DM you with my personal email as doing this back and forth via the forum is slow and inefficient.
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Old 10-05-2021, 02:32 PM   #26
hemiallen
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I finally got back to the charging problem. After working with Dennis at PD, he made a good suggestion.
My converter has 2 each connections for output wires, max 3 AWG, and of course all I could find was 2 AWG. I made 2 short jumpers 24" long, and had to remove 4 strands of wire for them to fit into the chargers ports. Bought a block to connect 3 wires, about 1 AWG size, and fed them to a 1/0 welding cable currently routed out the door and to the positive of the battery that currently has the + feeding the coach ( the far corner battery has the - feeding the shunt, ala recommendations to cross a bank of several batteries for best performance.

Dropped the bank top 75% and connected the rv to shore power. I did add a 80A fused block so I can turn it off. What the heck! I am getting 63 Amps charging with the larger wire. This should be a shorter run when I pull the main power-converter so I can feed the bigger wire to the panel, and will run above the storage area across to where the wires feed the inverter from the batteries.

Hoping the main panel comes out easy, lol. The factory sure does have a lot of recharging loss due to the route they take the 4awg wire through, mainly so the master switch is in the convenience bay, I believe.

I sure was surprised how much faster the recharging went, and this will maximize my Honda 2000I for recharging while dry camping.

Thanks for all the suggestions, hope someone else learns from this, besides me!

Allen
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