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Old 11-02-2017, 10:36 PM   #181
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Originally Posted by SilverHouseDreams View Post
So I installed the new PD4655 unit and a Victron BMS-712 (the new one with built in Bluetooth) today. So far in lithium mode my voltage hasn’t ever hit 14.6V, it plateaus at ~14.44V. Which isn’t necessarily a problem, if it is a true CC/CV it may actually limit there which is about ideal as it flat lines at just over 3.6V per cell which is exactly the target. Perhaps in CC mode it attempts to run 14.6V but it bleeds down due to the battery acting as a load. I also haven’t seen 55 amps, only ~27amps.

Currently running s load to draw the battery down to 10% or so and will see how it goes.
What voltage do your batteries sit at when not charging? Or I guess to say when your charger is floating?
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Old 11-15-2017, 11:10 AM   #182
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Another good thread

If you're researching the BB batteries like I am, you might find the thread at Expedition Portal to be worth reading.

Post #29 in this thread concerns the PD4655LV unit and raises very similar questions to the ones that have arisen here. In particular, is the "lithium" aspect of this unit simply a constant 14.6V? If so, won't some individuals (maybe me!) accidentally leave the battery in the "Use" position while hooked to shore power and keep kicking 14.6V at a full battery?

My basic knowledge is not high in this field, but I am seeing a lot of agreement that overcharging LFP batteries reduces total cycles. In fact, stopping a little short of 100% charge is generally recommended.

-Adam
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Old 11-15-2017, 01:01 PM   #183
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If you're researching the BB batteries like I am, you might find the thread at Expedition Portal to be worth reading.

Post #29 in this thread concerns the PD4655LV unit and raises very similar questions to the ones that have arisen here. In particular, is the "lithium" aspect of this unit simply a constant 14.6V? If so, won't some individuals (maybe me!) accidentally leave the battery in the "Use" position while hooked to shore power and keep kicking 14.6V at a full battery?

My basic knowledge is not high in this field, but I am seeing a lot of agreement that overcharging LFP batteries reduces total cycles. In fact, stopping a little short of 100% charge is generally recommended.

-Adam
Who is saying that 14.6V is "over charged" and what spec sheets is that based on? 3.65V charge voltage is the charge voltage spec for almost every brand of LFP cell that I've used or seen, which is 14.6V for these packs. Now charging to 4.2V (LiPo voltage) per cell will absolutely decrease longevity as the extra energy generates heat...but some LFP cells are actually specified to charge up to 3.95V cell voltage.

Now, for long term storage it would be best if we had way of maintaining the packs at 40-60% SOC...but then we would need more intelligent charging systems and they would require user intervention to specify when your are truly going to store the battery, and then switch back to "use" mode where it would bring it back to 100% SOC. In the case of the PD4655LV you could switch it back to "normal" mode and let it maintain 13.2V storage mode (~70%), but then with no load on the system the equalization could overtime increase the SOC to ~100% anyhow.

BattleBorn weighs in the thread you posted and states that

Quote:
Hi everyone!

Here is some info that is not in the marketing materials. The BMS is not bucking or doing any voltage regulation. It is simply monitoring the voltages, current and temperatures and acting as a high current switch, when things are out of whack. Charging and discharging circuits may be opened independently. For each, we have a bunch of high-current MOSFETs (along with some snubber circuitry) doing the switching. Basically, the charging switches will open if one of the following is detected: one cell exceeds a prescribed high voltage, the cell temperatures exceed 140F, the MOSFET temperatures exceed 170F, the charging current exceeds 200A for 0.5s, or 100A for 30 seconds. The discharging switches open if one cell falls below a low voltage threshold, the cell temperatures exceed 140F, the MOSFET temperatures exceed 170F, the cell temperatures fall below 25F (deadband at 30F), the discharging current exceeds 200A for 0.5s, or 100A for 30 seconds. High current disconnects are automatically reconnected after 5 seconds. Note that discharging is still allowed under low temp and high voltage, and charging is still allowed under low voltage. The 0.5s high current allows for initial cranking currents which typically last a couple hundred milliseconds. It’s our happy medium between allowing cranking and protecting against short circuit. The BMS also has a standard passive balancing mechanism, whereby cells that are charged faster than the rest bleed current through a resistor. The batteries can be connected in parallel (provided you use appropriate cables and fittings to handle the current), and in series up to 48V.

Operationally, the batteries should be bulk charged up to 14.3-14.6V, and absorb ideally at 14.4V. The person who suggested that Li-ion batteries should not float is correct. However, some chargers require a float, and we recommend setting it at 13.6V or below, since that is below the natural float of the charged cells. The cells leak charge at a rate of only 2-3% per month, so they can be stored for long periods of time without a trickle charge.
In general it isn't that they are saying a float is required, they are saying that if your charger supports floating that it is compatible with that and they give guidance on the ideal float voltage. The issues with "over charging" are reduced by the use of a CC/CV profile.
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Old 11-15-2017, 01:35 PM   #184
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Overcharging lithium

I'm not disagreeing that 14.6 isn't a good charge for the batteries (though it is at the upper edge), I'm simply wondering what happens when the battery is at 100% SOC and the trailer is plugged into shore power and no draw exists on the 12V system. I don't think the Battle Born battery's BMS will get in the middle of this since all it could do is fault the battery and take it offline. That wouldn't be good.

It is my understanding that the controller's 14.6V output will overcharge the battery when this exact condition exists. This overcharging will hurt the battery and impact the total available cycles. The diligent user can find ways to keep this from happening, but I think we all want systems that require as little attention as possible.

As for BB's statement about float, I think it underscores my point. You want to have the controller drop below the charging threshold when the battery is fully charged. Ideally it would float at 0.0 but in the PD4655LV case, I think it goes full throttle until shore power is disconnected.

If I am misunderstanding something here, it'll be a relief. So chime in if I am.

-Adam
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Old 11-15-2017, 03:07 PM   #185
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It is my understanding that the controller's 14.6V output will overcharge the battery when this exact condition exists. This overcharging will hurt the battery and impact the total available cycles. The diligent user can find ways to keep this from happening, but I think we all want systems that require as little attention as possible.

As for BB's statement about float, I think it underscores my point. You want to have the controller drop below the charging threshold when the battery is fully charged. Ideally it would float at 0.0 but in the PD4655LV case, I think it goes full throttle until shore power is disconnected.
My understanding is that 14.6V with a CC/CV charger will not harm the batteries, in my case my PD4655LV actually cuts off at ~14.37V which is 3.59V/cell. CC/CV is a key aspect of this, and is the standard used for all lithium chemistry batteries and avoids this "full throttle" piece, as it is operating in CV mode at that point.

The only way to get a "better" system would be to have a truly fully integrated DC power management/monitor/converter. The issue with the way this all works in a TT is that you have 2 power sources that are independent (converter & battery). The converter has no knowledge of where the "load" it sees is, that could be the battery absorbing energy or it could be a DC powered device...it cannot differentiate in the current design. You would need the charger/converter to actually know where the energy is going, if it is generating 10A but the battery is only seeing 0.04A going "in" to it, then the converter could know that the battery SOC is 100% and it is safe to reduce voltage. However, unlike lead acid, it is impossible to truly judge SOC purely by voltage and this could result in negative outcome if implemented improperly. Victron has all of the pieces to make this work, but I am not aware of them actually having the charger be informed by the battery monitor...instead it is just another CC/CV power supply, and their battery management system is there to protect against over/under voltage, temperature, and cell voltage balancing (just like that within the BattleBorn). Someone could definitely step up and make a fully integrated power management solution for TT, but who knows when that will happen as the market is likely too small.

One option would be a relay that disconnects the battery automatically when at 100% SOC for a given period of time *and* connected to shore power, it would actually be relatively easy to wire something like that up. You would just want to make sure that it defaults to being "closed" when shore power is removed. I will warn that you might get annoyed by the PD4655LV's noise when in "disconnected" state, YMMV but mine makes a rather annoying noise when the shore power is connected and the battery is disconnected with no other load in the system. It is likely because of the frequency the switching power supply operates at when in CV mode with no load and there is nothing to dissipate any of the energy so it is operating very "fast" to maintain the voltage.

At some point in the future we will all just be buying "recycled" batteries out of EVs, just like the "power wall" products. When we are flooded with EV batteries seeking a second life and we can buy 10kWh of capacity for a reasonable cost this will all change for sure...and all of those devices include their own full battery management systems. So basically you could just remove your battery and let your trailer see a "power wall" as the energy source and accept the efficiency losses in the AC/DC/AC/DC conversion, or maybe someone will make one focused on TT use case and have 12VDC and 120VAC output and we can just remove the converter and battery in our RV/TTs entirely. The power wall itself becomes your transfer switch, you plug in when you can but your trailer always operates as if it is on shore power.
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Old 11-16-2017, 01:32 AM   #186
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So some of this is over my head, but I’m grateful the conversation is happening amongst so many who seem very knowledgeable. I’m learning despite myself lol. As I read it, at the moment (and likely foreseeable future) the best available charging option is the 4655LV. Ok. I’ll order one up. While I suspect my install isn’t correct 100%, my recently added BMV712 is telling me I’m at 13.77volts and 99%SOC. It won’t seem to exceed that in my 26U utilizing the stock Parallax 5355. I do have the BMV712 set up according to BB’s recommendations on their video. If someone could clue me in on the best way to post a pic I’d be glad to offer screenshots of my history and live data if it were to prove helpful.
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Old 11-16-2017, 05:50 AM   #187
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So some of this is over my head, but I’m grateful the conversation is happening amongst so many who seem very knowledgeable. I’m learning despite myself lol. As I read it, at the moment (and likely foreseeable future) the best available charging option is the 4655LV. Ok. I’ll order one up. While I suspect my install isn’t correct 100%, my recently added BMV712 is telling me I’m at 13.77volts and 99%SOC. It won’t seem to exceed that in my 26U utilizing the stock Parallax 5355. I do have the BMV712 set up according to BB’s recommendations on their video. If someone could clue me in on the best way to post a pic I’d be glad to offer screenshots of my history and live data if it were to prove helpful.

http://www.airforums.com/forums/f138...tml#post612569
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Old 11-16-2017, 06:04 AM   #188
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Picture or diagram of your wiring of the shunt and such would be very helpful.
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Old 11-16-2017, 09:40 AM   #189
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Haha!! Thank you again Trout!
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Old 11-16-2017, 02:00 PM   #190
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So some of this is over my head, but I’m grateful the conversation is happening amongst so many who seem very knowledgeable. I’m learning despite myself lol. As I read it, at the moment (and likely foreseeable future) the best available charging option is the 4655LV. Ok. I’ll order one up. While I suspect my install isn’t correct 100%, my recently added BMV712 is telling me I’m at 13.77volts and 99%SOC. It won’t seem to exceed that in my 26U utilizing the stock Parallax 5355. I do have the BMV712 set up according to BB’s recommendations on their video. If someone could clue me in on the best way to post a pic I’d be glad to offer screenshots of my history and live data if it were to prove helpful.
The reason the BMV712 says it is 99% SOC has to do with the settings for detecting SOC, it has to do with voltage and amperage. Given enough time, 13.77V could be viewed as 100% SOC...or at least very close. It "auto-detects" 100% SOC based on voltage and charge amps over a defined time period, or you can manually set it to 100% within the app. I don't have access to my AS normally, or I would show the settings I collected from various sites and am using. I will be back at my AS to check on it over the weekend and will take some screen shots of the configuration though.

This may have the info: https://battlebornbatteries.com/conf...etooth-dongle/ Not sure why everyone is so obsessed with giving information in videos rather than also including a text format of the settings...I hate this new obsession that a "video is worth a million words", because it isn't. Skip to the 3:56 part to actually get the area with the Bluetooth connected app. This video wasn't out when I set mine up.

Since you can't force your converter to operate in bulk mode you may not actually ever achieve true 100% SOC, as that really requires closer to 14.2V or greater.

Also, to get "time remaining" to be accurate you need to adjust the settings for the cutoff relay. I don't remember the exact details, but the references I had found online didn't actually cover those settings so i figured them out in trial and error. The video above does include configuring that.
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Old 11-16-2017, 02:50 PM   #191
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Amen - video maybe worth a million words but only 10,000 are worth anything.
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Old 11-16-2017, 03:57 PM   #192
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That’s the video I used to set up my BMV712. I totally agree. I miss the old days of people writing stuff down. This YouTube craze is a painful way to get to the point. Regardless though, beggars can’t be choosers. I’m eternally greatful that people are kind enough to share their time and provide their videos for feee. As much as I’m grateful for you guys helping me out on this forum:-).
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Old 11-16-2017, 05:01 PM   #193
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So some of this is over my head, but I’m grateful the conversation is happening amongst so many who seem very knowledgeable. I’m learning despite myself lol. As I read it, at the moment (and likely foreseeable future) the best available charging option is the 4655LV. Ok. I’ll order one up. While I suspect my install isn’t correct 100%, my recently added BMV712 is telling me I’m at 13.77volts and 99%SOC. It won’t seem to exceed that in my 26U utilizing the stock Parallax 5355. I do have the BMV712 set up according to BB’s recommendations on their video. If someone could clue me in on the best way to post a pic I’d be glad to offer screenshots of my history and live data if it were to prove helpful.


DannyClark, a number of folks have the 4655 installed long before installing Lithium batteries and the discussion is really that the 4655 is adequate and not going to damage the Li battery. There are more suitable, Lithium specific chargers to consider and a call to Bestconverter.com or Battleborn may be worthwhile for a specific charger recommendation that will be optimal rather simply adequate.
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Old 11-16-2017, 05:40 PM   #194
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Thanks BBANDEDIE. I sent an email to Bestconverter today and haven’t heard back yet.
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Old 11-16-2017, 06:04 PM   #195
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PD4655 and Lithium

bbandeddie said it well. The PD4655LV is only one option and it appeals to people who might have one already (like me) and those who want to do lithium but want to do it in stages rather than in a big bang (like me). There are many fantastic designs to be found here - each working within their own constraints. I've spent many many hours reading old threads and now I know just enough to be dangerous.

Lithium is trying to become plug and play but there is still a long ways to go. Outside of retaining pros like AM Solar or Lewster, I think a DIYer is a hobbyist first.

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Old 11-26-2017, 01:12 PM   #196
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Just wanted to share that you can get a 10% discount on the Battleborn batteries if you buy from solar-electric.com before the end of Monday. They have been on sale all weekend. Wasn't sure if I really wanted them, but jumped on the opportunity and picked up two since this deal saved me nearly $200.

You need to use the 10FOR10 promo code at checkout. The code actually applies a 10% discount for anything on their site.

https://www.solar-electric.com/battl...m-battery.html
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Old 12-07-2017, 09:48 AM   #197
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Below Freezing

I know the Battleborn lithium-ion batteries have built in protection and they will not charge below freezing.

Are there any precautions/actions that must be taken when experiencing freezing temperatures? Can the "Use" button remain on with unit plugged into shore power below freezing?

Thanks!
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Old 12-08-2017, 09:13 AM   #198
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I know the Battleborn lithium-ion batteries have built in protection and they will not charge below freezing.

Are there any precautions/actions that must be taken when experiencing freezing temperatures? Can the "Use" button remain on with unit plugged into shore power below freezing?

Thanks!

Leave everything connected as you would normally. if the internal temperature of the battery gets below 25F then the battery itself will not accept a charge But as soon as the temp comes back up charge can recommence.
If you have any other questions please let us know.
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Old 01-21-2018, 12:15 PM   #199
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Just an FYI - I have a Magnum MSH3012M Hybrid inverter/charger. I have been extensively been researching to replace my Lifeline batteries that are at end of life. I looked at LiFeBlue batteries which I liked but I found out their batteries are NOT compatible with my inverter and apparently any Magnum HYBRID inverters due to the start up current spike they have which shuts down the batteries. I confirmed this non-compatibility with Magnum techs and LiFeBlue techs.

I have since ordered six Battle Born 100AH batteries which are due to arrive at my RV park on Thursday. The BB techs checked and confirmed to me that their batteries are compatible with my inverter.

Just to be clear, NON HYBRID Magnum inverters are compatible.

I don't have an Airstream but I thought this info may be useful to this thread.
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Old 01-21-2018, 12:58 PM   #200
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6 batteries? Wow.
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