LiFePO4 and auto alternator concerns...

[mapguy525]

For trailers I run a separate power and ground line and try to use Victron products. Anderson powerpole connectors are very nice for this application. The Victron products have adjustable turn on/off voltage set-points. This avoids running a separate ignition wire to turn on/off the DC-DC charger or installing an automatic charging relay.

I typically only use the Renogy products in vans and motorhomes because the ignition wire signal is easily accessible.

Also, consider a set of heavy duty lift gate electrical connectors like made by Phillips and others. Usually a bit cheaper than Anderson Connectors but still capable of the needed amps/volts.
http://phillipsind.com/main/electrical-connectors/plugs/liftgate-charging-plugs.html

Anderson connectors in several sizes -both genuine and copy available here:
https://www.helmarparts.com/searchresults.asp?Submit=Go&Search=anderson

 

[sunrise]

Can the 'Charge' connector of the 7-way plug be disconnected from trailer, so the trailer battery will be charged by either shore power or solar? I can't think of any reason why I would need towing vehicle to charge my trailer's battery. I prefer they stay isolated even without the alternator concern. would this cause issues for rest 6 connector to function properly?

 

[HRTKD]

Can the 'Charge' connector of the 7-way plug be disconnected from trailer, so the trailer battery will be charged by either shore power or solar? I can't think of any reason why I would need towing vehicle to charge my trailer's battery. I prefer they stay isolated even without the alternator concern. would this cause issues for rest 6 connector to function properly?

Yes, that is possible. It's one of the options I'm looking into for my trailer. However, you'll still need a battery to power the breakaway system. If you have an on-board generator - like I do - then you'll need a starter battery for that.

 

[sunrise]

However, you'll still need a battery to power the breakaway system.

That's my main/house battery. is it illegal not to have the charge connector connected and no 'secondary/backup' battery?
Breakaway is not a common event, and I just need to make sure I don't drain the main battery before start towing. The solar will top it off right?

Wait, dang - I see the problem now, if I am at 10% battery SOC and the electric fridge is drawing 2.2 ah constantly. driving long distance at night/cloudy/rainy day would put me at risk should breakaway happens. guess I will have to keep this in mind when camping so the battery would still have power left for an emergency brake.

 

[Motorpro]

Your alternator is not battleborn's concern.

it should be their concern when they advertise it as a direct drop in replacement

 

[John Frum]

it should be their concern when they advertise it as a direct drop in replacement

Perhaps the whole market segment should stop saying "drop in replacement"?
Or maybe they should find a way to make the internal resistance of their batteries comparable to lead acid?
What do you suggest?

 

[Motorpro]

Perhaps the whole market segment should stop saying "drop in replacement"?
Or maybe they should find a way to make the internal resistance of their batteries comparable to lead acid?
What do you suggest?

Maybe everyone should try truth in advertising. ..........that’s never going to happen

 

[HRTKD]

If the BMS is working and configured properly, then it should cut off the charge from the alternator when the batteries reach the high voltage mark.

 

[Motorpro]

If the BMS is working and configured properly, then it should cut off the charge from the alternator when the batteries reach the high voltage mark.

that’s not the problem... the problem is they will draw so much power so fast the alternator will burn out

 

[HRTKD]

that’s not the problem... the problem is they will draw so much power so fast the alternator will burn out

I hear what you're saying, but I'm not convinced. My truck will only ever provide a maximum of 30 amps to the trailer charge circuit. I haven't seen any posts on the RV forums where an alternator died and the trailer battery was the culprit.

 

[Jims94vmx]

Plus, even with DC to DC, wouldn't the alternator/battery still send power through the 7 pin connector as well?

 

[sunrise]

I hear what you're saying, but I'm not convinced. My truck will only ever provide a maximum of 30 amps to the trailer charge circuit. I haven't seen any posts on the RV forums where an alternator died and the trailer battery was the culprit.

Victron has a video showing this (alternator smoked), but that's in a lab setting, the alternator was installed with a motor (not an engine) so that only applies to that model of alternator I think.

BTW how do you know your truck only supply 30A to trailer?

 

[HRTKD]

The fuse and relay for that circuit is 30 amps.

 

[DonPhillipe]

This alternator melt-down video is the most lucrative youtube video every produced. Has made bundles for Victron and has convinced me because of this video to never buy another one of their products. By the time you count the belt gear up ratio, most alternators run at 2400 RPM at idle and on up from that, and not 500 RPM as the fine print that pops up briefly during their bench smoke and mirrors section of the video. Otherwise OP, the answer is hard to find. Depends on the alternator as they say. I've read about every story line on this B2B business and I'm about to check it for myself, but Victron can go "CENSORED" after that video.

Rule of thumb here is google the phrase "burned out alternator from charging lithium" and the first page of results returned is from a world of blogs where that Victron video has been posted. It's been this way with every new technology from the beginning of high tech. A couple of engineers get together in the same room with marketers and they get asked to turn out some new products and what we're being told now is the only logical solution is more devices and more $$$. They deliver something so complicated and so expensive (especially if you goof it up) and most are not willing to experiment to find alternative solutions. The public then falls under your spell. So I have yet to set up the 280A with Daly BMS-250A but going to try everything I can before forking over money for a B2B.

Otherwise I don't pull a trailer but if I did, while assuming that I had a converter/charger in the camper that would adequately charge my bank of lithium batteries, if there was room near the chassis battery of my truck I would mount a conventional 12VDC-120VAC inverter on my chassis battery, run a 120VAC wire to the trailer and use that existing120VAC to utilize my existing charger in the trailer/camper pull-behind. In this case I (personally) would not buy some B2B for this particular setup (a lithium battery needing charging in my camper) and that would be a) it is assumed you would already have a good 120VAC lithium charger in the camper regardless which would allow b) a conventional inverter to be added because you already have half of a make-shift B2B which is the stock or improved lithium charger in the camper and with that you only need a 120VAC source which can be an inverter. When I suggest this many say "it's so inefficient" but the loss is negligible when compared to the highly inefficient diesel/gasoline engine anyway.

 

[John Frum]

Otherwise I don't pull a trailer but if I did, while assuming that I had a converter/charger in the camper that would adequately charge my bank of lithium batteries, if there was room near the chassis battery of my truck I would mount a conventional 12VDC-120VAC inverter on my chassis battery, run a 120VAC wire to the trailer and use that existing120VAC to utilize my existing charger in the trailer/camper pull-behind.

Great idea!
More utility and less voltage drop for approximately the same cost.

Samlex PST-600-12 600W, 12V Pure Sine Inverter | DonRowe.com

The Samlex PST-600-12, 12 Volt, 600 Watt Pure Sine Wave Power Inverter features a commercial grade design for extreme reliability and is designed to accommodate tools and appliances in vehicles, RVs, boats, solar systems and more.

www.donrowe.com

 

[John Frum]

Put the shore power inlet on the tongue side of the trailer.
For bonus points use a locking connector or a strain relief on the extension cord.

 

[ianganderton]

Vehicle based inverter to shore power for charging while driving is a really clever solution. ??

 

[Pierre]

This alternator melt-down video is the most lucrative youtube video every produced. Has made bundles for Victron and has convinced me because of this video to never buy another one of their products. By the time you count the belt gear up ratio, most alternators run at 2400 RPM at idle and on up from that, and not 500 RPM as the fine print that pops up briefly during their bench smoke and mirrors section of the video. Otherwise OP, the answer is hard to find. Depends on the alternator as they say. I've read about every story line on this B2B business and I'm about to check it for myself, but Victron can go "CENSORED" after that video.

Rule of thumb here is google the phrase "burned out alternator from charging lithium" and the first page of results returned is from a world of blogs where that Victron video has been posted. It's been this way with every new technology from the beginning of high tech. A couple of engineers get together in the same room with marketers and they get asked to turn out some new products and what we're being told now is the only logical solution is more devices and more $$$. They deliver something so complicated and so expensive (especially if you goof it up) and most are not willing to experiment to find alternative solutions. The public then falls under your spell. So I have yet to set up the 280A with Daly BMS-250A but going to try everything I can before forking over money for a B2B.

Otherwise I don't pull a trailer but if I did, while assuming that I had a converter/charger in the camper that would adequately charge my bank of lithium batteries, if there was room near the chassis battery of my truck I would mount a conventional 12VDC-120VAC inverter on my chassis battery, run a 120VAC wire to the trailer and use that existing120VAC to utilize my existing charger in the trailer/camper pull-behind. In this case I (personally) would not buy some B2B for this particular setup (a lithium battery needing charging in my camper) and that would be a) it is assumed you would already have a good 120VAC lithium charger in the camper regardless which would allow b) a conventional inverter to be added because you already have half of a make-shift B2B which is the stock or improved lithium charger in the camper and with that you only need a 120VAC source which can be an inverter. When I suggest this many say "it's so inefficient" but the loss is negligible when compared to the highly inefficient diesel/gasoline engine anyway.

Bad idea. I am sure you are writing this ?. Surely this is not legal and you will soon electrocute the next mechanic who services your vehicle and possibly yourself.

 

[DonPhillipe]

Bad idea. I am sure you are writing this ?. Surely this is not legal and you will soon electrocute the next mechanic who services your vehicle and possibly yourself.

No comprende monsieur ....

 

[Rrrracer]

Short time lurker, first time poster... glad I found this thread

We've got a 2010 Class C on Ford E450 chassis. From what I've been able to determine, alternator is rated at 120-140A and internally regulated by the ECU.

Our "beginner" solar infrastructure is in place; 2x100W panels, 40A MPPT charge controller, 1500W sine wave inverter. It's been working flawlessly for a couple months now, but the flooded house batteries are definitely the weak link. I'm looking a replacing the two 100Ah "deep cycle" Wal Mart batteries with a DIY setup using four 304Ah EVE lithium cells, and want to make sure I have all our bases covered.

As it stands, we can charge the house batteries through shore power, generator, chassis via alternator, and solar although we are mostly using the latter two. We're looking to extend our boondocking capability. I try to use solar as much as possible, and give 'er a bump charge by firing up the rig every now and then when the clouds are out. I prefer to not run the genny, it's more of a nuisance, especially if we have neighbors. Don't wanna be "that guy" lol.

Our power needs are low; the most draw we have at any given time is about 15-20Ah. I've noticed the chassis/alternator regulates the charge it provides to the FLA; as house battery charge rises, alternator output diminishes. The microwave has been ditched for more cabinet space, the fridge runs off propane, and if I need to run the AC we can always fire up the generator. Mostly we chase 70 degrees though.

I *suspect* we'll be OK with the setup as-is and not need a DC to DC. However, I'm not well-versed when it comes to the house/chassis relationship, so reaching out for input from those who know more. Thoughts? Pitfalls? Am I full of it? LOL...

Edit: It's a 12V system and no plans or need to change at the moment.