Axis/Vegas Lithium Swap, Who has done it?

[Lysergeon]

Hi David, good point, I could just unplug from shore power and let them drain down as needed, or leave them disconnected at 50% or something like that...

As far as your winter question, I live in the pacific north west (on the Canadian coast, in BC) winter here rarely gets below zero so shouldnt be an issue. Will have to be careful on the rare possibility we get below zero and some snow but, generally its quite rare here. Otherwise I likely would not attempt to live in this over the winter.

[DavidEM]

Yes that is a good plan for best Li life.

I didn't realize that southern, coastal BC, Vancouver specifically has such moderate winter temps. I suppose I was thinking about the inland ski areas. Looking at Weatherspark, Vancouver gets down to -4 C or below only 10% of the time in January. You should be ok with that.

Where I am thinking about going in Maine, it gets down to -15-20 C routinely.

[Lysergeon]

Originally Posted by DavidEM

Yes that is a good plan for best Li life.

I didn't realize that southern, coastal BC, Vancouver specifically has such moderate winter temps. I suppose I was thinking about the inland ski areas. Looking at Weatherspark, Vancouver gets down to -4 C or below only 10% of the time in January. You should be ok with that.

Where I am thinking about going in Maine, it gets down to -15-20 C routinely.

Yes definitely seems a bit warmer here than Maine lol.. im actually on the sunshine coast in Powell River, probably even less than 10% here...

I have seen some of your other posts with the weird backward a b on alternator charger, do you think this could be why mine is not charging from alternator? Should I have a look at that wiring?

Also from researching last few days my converter should be charging the batteries just not to 100%.. but I am getting absolutely no charge even with the batteries at 28% now... im guessing its because they are still reading 13.1v..

[DavidEM]

Don't know how Lis will react, but I saw a dramatic improvement in chassis alternator charging when I fixed Thor's miswiring of the BIM 160. See the attached files for the BIM 160 and L 225. The chassis alternator should be wired to terminal A.

And the same can be said about the WFCO converter. If it isn't charging while the Li batteries are down to 28% then it isn't working right. I replaced it with a Precision Dynamics charger with an AGM setting for my battery, but you should use their 9180 ALV version for faster and more complete charging.


David

[Chance]

So how exactly does alternator charge the chassis lead battery and the coach lithium batteries at same time efficiently, given that they require different voltages and the BIM appears to be a smart ON-OFF switch?


RV manufacturers often add a dedicated house charging system with a second alternator, or on lower capacity systems add a DC-DC converter/charger that can boost alternator voltage to higher lithium requirements.

I’ll be curious to see how much alternator current these BIM can actually charge into lithium batteries, especially as the state of charge goes up.

[DavidEM]

I have only seen one post on this question, which I agree is largely unanswered. The post said that on a Sprinter based RV which has a 200+ amp alternator, the charging rate to his lithium batteries was 30 or so amps. This was into a 200 Ah bank as I remember and I don't remember if the SOC of the lithium battery was mentioned.

Chassis alternators have a fixed voltage output, usually about 14 volts. This voltage should supply lots of current to a Li battery until it gets mostly charged.

I do agree that a better, safer solution is a DC to DC charger which is set up to charge Li batteries at about 14.5 volts but leave the alternator putting out 14 volts. How it works with or without a BIM to also provide aux starting is still a question in my mind as a DC to DC charger is like a big diode- one way.

David

[Lysergeon]

Originally Posted by DavidEM

Don't know how Lis will react, but I saw a dramatic improvement in chassis alternator charging when I fixed Thor's miswiring of the BIM 160. See the attached files for the BIM 160 and L 225. The chassis alternator should be wired to terminal A.

And the same can be said about the WFCO converter. If it isn't charging while the Li batteries are down to 28% then it isn't working right. I replaced it with a Precision Dynamics charger with an AGM setting for my battery, but you should use their 9180 ALV version for faster and more complete charging.


David

wait so you are saying it will only start charging them if they are below 28%? is that because the voltage drops at that point? What % do you think it would charge them up to? I haven't let them fall that low yet so maybe it will charge at that point... but its been very sunny so the solar been generally keeping them above 50%.

[DavidEM]

Originally Posted by Lysergeon

wait so you are saying it will only start charging them if they are below 28%? is that because the voltage drops at that point? What % do you think it would charge them up to? I haven't let them fall that low yet so maybe it will charge at that point... but its been very sunny so the solar been generally keeping them above 50%.

I am not saying that at all, just repeating what you said. No charge at 28% means something is wrong is what I am saying.

David

[Lysergeon]

Originally Posted by DavidEM

I am not saying that at all, just repeating what you said. No charge at 28% means something is wrong is what I am saying.

David

Oh haha sorry, I was re reading some older posts and I guess I read that out of context.. duh..

[Lysergeon]

Originally Posted by DavidEM

Don't know how Lis will react, but I saw a dramatic improvement in chassis alternator charging when I fixed Thor's miswiring of the BIM 160. See the attached files for the BIM 160 and L 225. The chassis alternator should be wired to terminal A.

And the same can be said about the WFCO converter. If it isn't charging while the Li batteries are down to 28% then it isn't working right. I replaced it with a Precision Dynamics charger with an AGM setting for my battery, but you should use their 9180 ALV version for faster and more complete charging.


David

Hi again David, I did order the 9180, should have next week, now just debating whether to try and install it myself... I am wondering though... if the onan GQ4000 only outputs 40A, is there any real benefit in getting this converter that charges at 80A?

[DavidEM]

Originally Posted by Lysergeon

Hi again David, I did order the 9180, should have next week, now just debating whether to try and install it myself... I am wondering though... if the onan GQ4000 only outputs 40A, is there any real benefit in getting this converter that charges at 80A?

I think you are confusing AC amps from the Onan generator with DC amps from the converter. Converters aren't very efficient, but it will only take maybe 12 amps AC to produce 80 amps DC.

It isn't that difficult to install the 9180 ALV but maybe you should get a mobile RV tech to do it for you.

David

[Lysergeon]

Originally Posted by DavidEM

I think you are confusing AC amps from the Onan generator with DC amps from the converter. Converters aren't very efficient, but it will only take maybe 12 amps AC to produce 80 amps DC.

It isn't that difficult to install the 9180 ALV but maybe you should get a mobile RV tech to do it for you.

David

Haha yes you are totally right.. as I said I know very little about this stuff, I do want to learn it but..probably best I have it installed professionally (although the dealer here is... less than professional ot seems, just over confident) but at least if he messed it up its on him lol.. thanks again David

[DavidEM]

The problem is that most dealers only do what they know how to do and rarely listen to the customer. I mentioned mobile RV techs because they have to listen to the customer and are often much better technicians since they have to make it on their own wits.

David

[Lysergeon]

Right, well I'm pretty limited on who I can take it to as I live on the gulf islands in bc.. this place specializes in rv solar installs but I don't think deals with lithium much.. if I take to q real rv dealer I would have to spend a couple days and take 2 ferries each way at $80 each one top :-/

[DavidEM]

Anyone who does solar installation has by now figured out lithium batteries to go with the solar and all of the accessories like chargers required. Sounds like a good solution.

David

[Lysergeon]

Ok so, update, I got the PD9180ALV installed, another interesting thing... my generator+converter finally started charging the batteries (of course) when I brought it to the shop lol... but only at about 15a so very slow.

Also, on the way there, the alternator finally started working for charging(seriously? wtf!) and it was charging at about 60a, so that's great (Although I don't have the aftermarket BIM so.. not sure if I am going to burn up the alternator or if that only happens on super long drives? You can only drive around 20mins at a time here MAX, small island)

I had the PD9180ALV installed, with 2G wire, but I only seem to get about 40A charge rate at max... do you think this is due to the wire gauge from the Genny maybe? not sure why it wouldn't get the full 80A, it has a short run with low gauge wire to batteries... thoughts?

[DavidEM]

Drive it for 10-15 minutes charging at the 60A rate and measure the alternator case temp with an IR gun. Should be 220 F or less. Not sure if the Li BIM is going to help much with only 20 minutes of driving room.

#2 gauge should be fine if it is a reasonably short run to the batteries. With a 10' run you only get a 1/4 volt drop at 80 amps.

Also I doubt that the AC wire from the generator is a problem. That generator is good for 33 amp AC. The breaker feeding the converter is usually 15 amps and you should never get close to that while putting out 80 amps DC even with the lousy efficiency of these converters.

What is the voltage at the battery terminals while charging at 40A. Your batteries may be nearly full and even lithiums drop off at 90+% charged.

All in all it sounds like it may be operating as it should without more data.

David

[Lysergeon]

Originally Posted by DavidEM

Drive it for 10-15 minutes charging at the 60A rate and measure the alternator case temp with an IR gun. Should be 220 F or less. Not sure if the Li BIM is going to help much with only 20 minutes of driving room.

#2 gauge should be fine if it is a reasonably short run to the batteries. With a 10' run you only get a 1/4 volt drop at 80 amps.

Also I doubt that the AC wire from the generator is a problem. That generator is good for 33 amp AC. The breaker feeding the converter is usually 15 amps and you should never get close to that while putting out 80 amps DC even with the lousy efficiency of these converters.

What is the voltage at the battery terminals while charging at 40A. Your batteries may be nearly full and even lithiums drop off at 90+% charged.

All in all it sounds like it may be operating as it should without more data.

David

Hi David, thanks again for the reply. I will check the alternator next time I drive, but I imagine with the short distances probably shouldnt be an issue.

The batteries charge at 35-40A even when the battery was at 60% this morning.. I haven't tried it from a lower state yet but, you would think should still get higher than that...

Right now voltage at terminals is 13.5 while charging at 33.5A (this is based on the built in bluetooth monitor showing about 16.7A on each battery.)

[DavidEM]

Originally Posted by Lysergeon

Right now voltage at terminals is 13.5 while charging at 33.5A (this is based on the built in bluetooth monitor showing about 16.7A on each battery.)

I would give Progressive Dynamics a call. An 80A rated lithium charger should raise its voltage up to as high as 14.5 volts to push its full 80A. It is not, it is only at 13.5 volts and is only pushing 33.5 amps.

Was the state of charge at 60% when the above data was taken?

Thanks for providing this data. Most MH owners don't and I suspect that they are not getting optimum results from their DC system.

David

[Lysergeon]

Originally Posted by DavidEM

I would give Progressive Dynamics a call. An 80A rated lithium charger should raise its voltage up to as high as 14.5 volts to push its full 80A. It is not, it is only at 13.5 volts and is only pushing 33.5 amps.

Was the state of charge at 60% when the above data was taken?

Thanks for providing this data. Most MH owners don't and I suspect that they are not getting optimum results from their DC system.

David

Hi David, thanks again, I have supplied the same data to PD to see what they say.

The batteries were at about 80%SOC when I took that measurement, however the amps going to batteries from converter has not changed since I turned on the generator at about 65% SOC... it could just be the way the converter works, doesn't make a lot of sense but...I will let it drain down to like 20% next time and see what happens, if it gets up to 80A then, I will know it is simply the design of the converter.