Update recharging 400Ah BB Lifepo4 attempt / test

[hemiallen]

Sorry for all the questions, but I don't have other resources for asking this, so far.

I did another draw down test, dropping my now 400Ah BB lithiums down to 75% -13.43v.

PD 4575A charger, factory Montana 4 gauge wire. Stared using my generator and finished with shore power, no difference seen in charging rate.

Started Charging at 51.59Amps as measured on Victron smart shunt and tapered down as batteries recharged.

I have 400Ah of Battleborn Lifepo4 that I need to recharge using my Honda 2000I generator. The trailer has a PD4575A converter, and I ran my battery bank down to 75 percent / 13.43V. Recharging the bank started with 51.59A at 13.43v ( total loss was -102.6 Ah) and gradually reduced Amps while increasing volts using my victron smart shunt measuring battery status. After 2 hours it was 13.62V and 39.38A ( -12.7Ah) and after 2 hours 45 minutes it was fully recharged at 14.55V, 0.76A and 0.0Ah loss.

This seems longer to top off than the advantage of Li batteries should take, all I want is to maximize recharging times when boondocking. It seems AC recharging isn't a readily found component for a decent price , and my 300W solar isn't as useful as my generator for where we camp.



Is there any way to get a faster recharge out of my 2000I generator, which running puts out an advertised 1800w? I wish to maximize my recharge time with this generator, but am willing to get a higher output generator if I can find an AC-DC charging system for times when I want a fast recharge, knowing this reduces the life of the batteries. BB states a suggested 50A / per battery so I could go as high as 200A, but realize that probably needs more AC watts than I care to take with me when boondocking. The largest I have found is a Victron 120A inverter-charger, but I only need the charging system.


My current thoughts are: plan to drop my batteries to a lower state of charge than I did in this test, and just run the generator a few hours a day to recharge some of the loss, and when I get the bank low enough either recharge longer, go find shore power for a day to recharge to 100%, then continue boondocking.

I am used to boondocking with L-A batteries, so maybe I just need to learn it's ok to drop to ~20% capacity before recharging them some? It is hard for an old dog to learn new ways , maybe the above is the route I should take....?


Thank you very much



Allen

[PNW Fireguy]

Since it appears that you are basing quite a bit on the data from the smart shunt are you certain it is synchronized? I suppose a better way to ask the question would be has it recently been synchronized at a known 100% SOC. If your measurements are all based upon the pack being in bulk charge without the pack ever making it through the absorption phase then the accuracy of the shunt is in question the more time the pack is in this state.

[hemiallen]

Well

I placed the rig on shore power for 2 days after installing the 4th battery and reconfiguring them with the shortest 1/0 wires I could make, all equalized as much as possible, and the charge showed 14.66 for those 2 days. My belief is, that allowed them to synchronize, but am not 100% sure if that is correct.

All are BB-GC2 w/o heaters. 2 side by side, and the other 2 face to face for the shortest wiring lengths.

Thank you very much

Allen

[PNW Fireguy]

After the 2 days did you sync the shunt to 100%?

[hemiallen]

Sorry, yes I did syn them to 100% on the app.

When the recharge test got to 14.01v , 20.43A, and -2.3Ah readings it said 100%, and I allowed the rechaqrging to go another 20 minutes until the readings were 14.55v , 0.76A ( charging) , 0.0Ah used.

Allen

[PNW Fireguy]

Ok so your shunt drift appears to have been accounted for. So is the expectation that your factory converter powered with a 30A gen should provide a higher charge rate possibly aligned with the .5C you noted for the 4 BB’s? I may be missing something but I think that initial 60A is in line with the 4575 converters. 60 A continuous output rating.

[Daryles]

For those short boondocking times I don’t want to carry a generator, I installed a 60A DC-DC charger.
Here the write up and test results.

https://www.montanaowners.com/forums...hlight=charger

[66 Galaxie]

You can add a secondary charger that only works when on shore or add truck charging fairly easily. The victron multiplus will be great but you'll need to make sure your current charger isn't on the inverted leg. I'd personally disconnect the converter and let the Victron do all the work.

[carlrx7]

Hey Hemi,

Are you tracking how many watts are left over while charging? You could easily add another charger and directly plug it into the generator. Something like this:

https://www.amazon.com/Progressive-D...1313502&sr=8-5

Ray from Love Your Rv does something similar here:

https://www.youtube.com/watch?v=6kgF...nel=LoveYourRV

[hemiallen]

Thanks Carl.

Yes, great idea. I'll see if my Generator will support a second charger like that.

I was hoping to locate a single, larger Amp unit, but this will work also and his video is where I planned to add the larger single unit.

It seems the price of a charger isn't a linear $ / A, it isn't much more on a 90A unit vs a 60A unit, hence my hope to find a single large charger and just eliminate the factory one with the long 4 gauge wire.

Thanks for the idea and video.

Looking back over my spreadsheet at the 2 hr mark my system got the bank to about 95% / 13.6v, maybe I should just accept that as ok to top out at until I get to shore power to top them off.

Thanks again for all of your help, my friends

Allen

[Chasw98]

Originally Posted by hemiallen

Thanks Carl.

Yes, great idea. I'll see if my Generator will support a second charger like that.

I was hoping to locate a single, larger Amp unit, but this will work also and his video is where I planned to add the larger single unit.

It seems the price of a charger isn't a linear $ / A, it isn't much more on a 90A unit vs a 60A unit, hence my hope to find a single large charger and just eliminate the factory one with the long 4 gauge wire.

Thanks for the idea and video.

Looking back over my spreadsheet at the 2 hr mark my system got the bank to about 95% / 13.6v, maybe I should just accept that as ok to top out at until I get to shore power to top them off.

Thanks again for all of your help, my friends

Allen

Before you go out and spend a bunch of money on chargers... You might want to call a company named 'Iota'. They make a variety of various electronic devices and are mostly known for their chargers and power supplies. They are very friendly and I recommend that you call their engineering department and tell them what you want to achieve. I have 2 Iota DLS 55 amp chargers with Lithium firmware for my LiFEP04 batteries. I was told that when using multiple chargers you can run into a problem where the 1st charger affects the 2nd charger and neither charger is sure of the battery capacity or SOC. You can end up damaging things. Give them a call and speak to engineering before you spend. My 1400 watts of solar can charge my 400AH bank from 20% to 100% in 3 hours with good sun.

[bcrvman]

Originally Posted by hemiallen

Sorry for all the questions, but I don't have other resources for asking this, so far.

I did another draw down test, dropping my now 400Ah BB lithiums down to 75% -13.43v.

PD 4575A charger, factory Montana 4 gauge wire. Stared using my generator and finished with shore power, no difference seen in charging rate.

Started Charging at 51.59Amps as measured on Victron smart shunt and tapered down as batteries recharged.

I have 400Ah of Battleborn Lifepo4 that I need to recharge using my Honda 2000I generator. The trailer has a PD4575A converter, and I ran my battery bank down to 75 percent / 13.43V. Recharging the bank started with 51.59A at 13.43v ( total loss was -102.6 Ah) and gradually reduced Amps while increasing volts using my victron smart shunt measuring battery status. After 2 hours it was 13.62V and 39.38A ( -12.7Ah) and after 2 hours 45 minutes it was fully recharged at 14.55V, 0.76A and 0.0Ah loss.

This seems longer to top off than the advantage of Li batteries should take, all I want is to maximize recharging times when boondocking. It seems AC recharging isn't a readily found component for a decent price , and my 300W solar isn't as useful as my generator for where we camp.



Is there any way to get a faster recharge out of my 2000I generator, which running puts out an advertised 1800w? I wish to maximize my recharge time with this generator, but am willing to get a higher output generator if I can find an AC-DC charging system for times when I want a fast recharge, knowing this reduces the life of the batteries. BB states a suggested 50A / per battery so I could go as high as 200A, but realize that probably needs more AC watts than I care to take with me when boondocking. The largest I have found is a Victron 120A inverter-charger, but I only need the charging system.


My current thoughts are: plan to drop my batteries to a lower state of charge than I did in this test, and just run the generator a few hours a day to recharge some of the loss, and when I get the bank low enough either recharge longer, go find shore power for a day to recharge to 100%, then continue boondocking.

I am used to boondocking with L-A batteries, so maybe I just need to learn it's ok to drop to ~20% capacity before recharging them some? It is hard for an old dog to learn new ways , maybe the above is the route I should take....?


Thank you very much



Allen

I have 600AH of BB LiFePO4 and 6x180W solar panels. I also carry a pair of Honda EU2000I's hooked up in parallel with the factory cable. This gives me close to a 30A service. My inverter charger is a 3,000W 120A charger. The gennys have no problem charging at full power since 120A at 12V is roughly 12A at 120V. One genny would work but just in case I want to run 2 AC units I bought the pair. One of the things I did different from you is remove/disconnect the built in converter. It is a POS. You say you don't need an inverter, so just buy a Victron charger. I don't see any that come close to 120A but maybe I missed something. I don't understand why you need 400AH of Lithium if you don't use an inverter.
I have my Victron 3,000W inverter charger set to charge at 180A (120 shore/genny plus 60 from solar) I have never let the batteries get that low, but in theory I could recharge from almost 0 to 100% on genny alone in 5 hours, 3.5 hrs with full sun at a high angle.

[hemiallen]

Thanks for your reply with your system. Sorry, I didn't mean to imply I don't USE an inverter, I have the 2000 factory, so I am looking for a 120A charger without an inverter. I suspect yours is a Victron multiplus like I am looking at, I hate to pay over $1k for just the charger as I don't need an additional inverter.

Thanks

Allen

[bcrvman]

Originally Posted by hemiallen

Thanks for your reply with your system. Sorry, I didn't mean to imply I don't USE an inverter, I have the 2000 factory, so I am looking for a 120A charger without an inverter. I suspect yours is a Victron multiplus like I am looking at, I hate to pay over $1k for just the charger as I don't need an additional inverter.

Thanks

Allen

I understand, but you may not be aware of the capabilities of the Multiplus. It can do more than the factory 2,000. The new model of Multiplus is even more capable. Sell the factory 2,000 and get the Victron, you will never regret it. BTW, if you do not boondock a lot none of this is cost effective but if you do it's a game changer. My plan is to boondock 5 out of 7 days then 2 days at Harvest Hosts and Boondockers Welcome with a monthly stay at a KOA or similar. Do your research.

[bcrvman]

Originally Posted by hemiallen

Sorry for all the questions, but I don't have other resources for asking this, so far.

I did another draw down test, dropping my now 400Ah BB lithiums down to 75% -13.43v.

PD 4575A charger, factory Montana 4 gauge wire. Stared using my generator and finished with shore power, no difference seen in charging rate.

Started Charging at 51.59Amps as measured on Victron smart shunt and tapered down as batteries recharged.

I have 400Ah of Battleborn Lifepo4 that I need to recharge using my Honda 2000I generator. The trailer has a PD4575A converter, and I ran my battery bank down to 75 percent / 13.43V. Recharging the bank started with 51.59A at 13.43v ( total loss was -102.6 Ah) and gradually reduced Amps while increasing volts using my victron smart shunt measuring battery status. After 2 hours it was 13.62V and 39.38A ( -12.7Ah) and after 2 hours 45 minutes it was fully recharged at 14.55V, 0.76A and 0.0Ah loss.

This seems longer to top off than the advantage of Li batteries should take, all I want is to maximize recharging times when boondocking. It seems AC recharging isn't a readily found component for a decent price , and my 300W solar isn't as useful as my generator for where we camp.



Is there any way to get a faster recharge out of my 2000I generator, which running puts out an advertised 1800w? I wish to maximize my recharge time with this generator, but am willing to get a higher output generator if I can find an AC-DC charging system for times when I want a fast recharge, knowing this reduces the life of the batteries. BB states a suggested 50A / per battery so I could go as high as 200A, but realize that probably needs more AC watts than I care to take with me when boondocking. The largest I have found is a Victron 120A inverter-charger, but I only need the charging system.


My current thoughts are: plan to drop my batteries to a lower state of charge than I did in this test, and just run the generator a few hours a day to recharge some of the loss, and when I get the bank low enough either recharge longer, go find shore power for a day to recharge to 100%, then continue boondocking.

I am used to boondocking with L-A batteries, so maybe I just need to learn it's ok to drop to ~20% capacity before recharging them some? It is hard for an old dog to learn new ways , maybe the above is the route I should take....?


Thank you very much



Allen

It doesn't matter what generator you are using, the converter is never going to put out more than it's designed to and probably not even that much. Use Watts when doing these calcs as it eliminates the need to convert and avoids the risk of a conversion error. Here are some salient measurements.
The gennie c an put out 1,600W steady
The Converter puts out 75A if I remember the model number code correctly but I think the max you saw was about 52. That maybe caused by converter inefficiencies or wiring. I use 4/0 wires for the battery interconnects and from my inverter/charger to the batteries. My converter is totally disconnected freeing up a breaker!
At roughly 60A you should have no problem re-charging 102.6AH in under 2 hours but the last little bit does take a little longer by design. How is your Battery Monitor set up, that might make a difference. My batteries just reached full charge about an hour ago, here is the chart. You can see there is still some charging happening after it reaches 100%. I also included a calculation for 4AWG wire, I use 4/0 and the result for 10 ft is 0.5% but my run is less than 3ft so it's 0.15%

[ShaneGreen]

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.

[bcrvman]

Originally Posted by ShaneGreen

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.

[bcrvman]

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.

[ShaneGreen]

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?

[bcrvman]

Originally Posted by ShaneGreen

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.