Upgrading House Batteries to Lithium

[DavidM]

Some answers in bold below:

Originally Posted by tim myers

1. My existing converter should be able tol charge a pair of Lithium batteries but probably not up to 100%, maybe only 90% or so. True or false? True. If you have the Progressive Dynamics converter with the dongle, you can push that and extend the charging time once it reaches 90% and get the last 10%.

2. I will need to install a BIM or dc to dc charger to keep from cooking my 160Amp alternator. Question how is the dc to dc charger or the BIM sized? There is little published on this question. For a DC to DC charger, 40 amps is probably safe for your alternator. The PC Li-BIM 225 only has one setting: on and off every 15 minutes.

3. If I want to know how much power I have left in a pair of Lithium Batteries I need to have something like a Victron Battery Monitor, as my existing battery monitor will only show remaining voltage not amperage or % of power left? True. Everyone who dry camps a lot should have a shunt based battery monitor. Renogy also makes a good one and Qworks, makes an inexpensive one which is what I have.

[tim myers]

1. I have the original Magnadyne from 2007
2. 15 minutes is plenty of time to fry an alternator, so based on that the dc to dc sounds better, so does a 40A limit the charging amperage load on the alternator to 40 amps. is that how it works?
3. I do not at this time camp off grid that much. Since my Journey has a simple battery voltage device, if I know the voltage at which a Lithium battery is safely discharged then the Victron Monitor, while convenient may not be needed yet.



Good stuff, thanks for the reply.

[DavidM]

Answers in bold:

Originally Posted by tim myers

1. I have the original Magnadyne from 2007. I think that is a dumb, fixed voltage charger. Replace it with a lithium specific charger like the PD 91xxL.

2. 15 minutes is plenty of time to fry an alternator, so based on that the dc to dc sounds better, so does a 40A limit the charging amperage load on the alternator to 40 amps. is that how it works? Yes the DC to DC charger will charge at 40A, no more.

3. I do not at this time camp off grid that much. Since my Journey has a simple battery voltage device, if I know the voltage at which a Lithium battery is safely discharged then the Victron Monitor, while convenient may not be needed yet. If you don't dry camp much, then why are you changing to lithium batteries?

Good stuff, thanks for the reply.

[creativepart]

Originally Posted by tim myers

1. My existing converter should be able tol charge a pair of Lithium batteries but probably not up to 100%, maybe only 90% or so. True or false?

This one, I don't know. Your existing converter is 14 years old. It will depend on what charger is in your converter and what it's capabilities are. You'd have to look for the info on the model and check it's charging profiles. Many would simply pull the charger and replace it with one that has lithium charging profiles... or at least provide custom charging so you can set the profile the way your batteries require.

Originally Posted by tim myers

2. I will need to install a BIM or dc to dc charger to keep from cooking my 160Amp alternator. Question how is the dc to dc charger or the BIM sized?

You do need to do something for this. The BIM isn't sized as far as I'm aware. It's just an on/off switch that automatically charges for 15 mins and then is off for 15 mins. The DC to DC charger is a lithium specific charger that is a better option. You select how many charging amps and I would suggest that it depends on the size of the battery bank. With a 200ah bank you may be fine with a 30-amp charger. With 400ah you may want a 60amp charger. OR be like goldielocks and find that 40amp is just right.

Originally Posted by tim myers

3. If I want to know how much power I have left in a pair of Lithium Batteries I need to have something like a Victron Battery Monitor, as my existing battery monitor will only show remaining voltage not amperage or % of power left?

Even if you never install LiPo4 batteries you'll be much better served with a shunt-based battery monitor. They "count" all amps in and out of your battery bank and give you a SOC (state of charge) in percentages. The Victron bluetooth models are super convenient and work great.

[tim myers]

David,


I am just looking down the road, while we do not boondock now, we do plan to give Harvest Home a try next year and those do not always have electric available. Also, in another thread I am looking to convert my Norcold fridge to a 12 VDC compressor, which will be fine when driving or parked with shore power, but my current LA AGM batteries will not give me a lot of cooling.


With all this in mind I might find myself needing to take the plunge and wanted to know what I needed to do and the proper steps in which to make the change. I like to plan ahead as much as I can.



In concert with creativepart's reply, I will research which converter I have, it should be listed in my build sheet from Winnebago.

[AJMike]

Originally Posted by creativepart

Well, the not charging to 100% all of the time is pretty much recommended

Hard for me to see how to do that if your rig has solar and it is in storage. Unless you physically disconnect the batteries by removing the cable connection they are going to charge even from the ambient sunlight in covered storage.

Our RV is in covered storage when we are not using it and the batteries are always at 100% when we go to do something at the RV. We use the battery disconnect and that shuts the power off to the RV but it does not shut down the connection from the solar panels.

[tim myers]

Originally Posted by tim myers

1. I have the original Magnadyne from 2007
2. 15 minutes is plenty of time to fry an alternator, so based on that the dc to dc sounds better, so does a 40A limit the charging amperage load on the alternator to 40 amps. is that how it works?
3. I do not at this time camp off grid that much. Since my Journey has a simple battery voltage device, if I know the voltage at which a Lithium battery is safely discharged then the Victron Monitor, while convenient may not be needed yet.



Good stuff, thanks for the reply.

I checked the paperwork and according to the Operation Manual Supplement I have a Parallax Power Supply, 7400 Series Converter Battery Charger. I have an e-mail into Customer Care so see if they can tell me which model I have. They came in a T (timer) option and a non T option. The T option charges at 14.1 V for 13 hours then drops to 13.5 V for float charge. and came in 30, 45, 55, and 65 amp.

[lonekazoo]

Originally Posted by AJMike

Hard for me to see how to do that if your rig has solar and it is in storage. Unless you physically disconnect the batteries by removing the cable connection they are going to charge even from the ambient sunlight in covered storage.

Our RV is in covered storage when we are not using it and the batteries are always at 100% when we go to do something at the RV. We use the battery disconnect and that shuts the power off to the RV but it does not shut down the connection from the solar panels.

When I store my Adventurer (with an SOK 206ah LiFeP04 battery and 400W of solar), I temporarily set my solar charge controller settings to 13.5V for both Absorption and Float, and and leave my Winegard TOGO LTE router on, along with a couple of wifi cameras, a wifi thermostat, and my VictronConnect gear running so that I can monitor from 300 miles away).

I figure that the daily charge never goes above about 90%, extending the life of the Lithium battery, yet with power remaining on and with the remote capabilities, I'm able to keep an eye on things and pretend I'm vacationing in my motorhome in a warm climate while I sit at my desk with snow outside.

[Marine359]

Originally Posted by tim myers

David,


I am just looking down the road, while we do not boondock now, we do plan to give Harvest Home a try next year and those do not always have electric available. Also, in another thread I am looking to convert my Norcold fridge to a 12 VDC compressor, which will be fine when driving or parked with shore power, but my current LA AGM batteries will not give me a lot of cooling.


With all this in mind I might find myself needing to take the plunge and wanted to know what I needed to do and the proper steps in which to make the change. I like to plan ahead as much as I can.



In concert with creativepart's reply, I will research which converter I have, it should be listed in my build sheet from Winnebago.

If by “taking the plunge” you mean 12v compressor fridge and LiFePo4 batteries, you won’t be happy keeping your old charger (been there, hated it) and won’t be fully taking advantage of what you paid the extra money for. Most LiFePo4 batteries can gobble up to 80amps charging current. Providing them as much charge current as they’re rated for means the batteries will charge fully and much much faster. You should plan for at least 50amp hrs/day consumption for the fridge alone. So, size your batteries for this plus what your normal load daily consumption is. At 80amp charge current, I like watching my smart shunt while charging from my small generator and seeing the “fill gauge” go up so fast. 2 hrs from 20% and it’s done (100%). A new charging setup with LiFePo4 profile and 80-100amp output is not a lot to pay compared to the other gear you’ll be installing.

[creativepart]

Originally Posted by tim myers

we do plan to give Harvest Home a try next year and those do not always have electric available.

Tim, I meant to respond to this when you posted it the other day.

We love staying at Harvest Host but, be aware we've never encountered a Harvest Host location that offered electric or any other service like water or sewer. So, actually you should plan on those stays always being a dry camping stay.

I haven't used Boondockers Welcome, but I have heard that a number of those do have electric and sometimes other services too.

[tim myers]

That is good counsel, Jim, thanks for the information.

[tim myers]

Originally Posted by creativepart

Tim, I meant to respond to this when you posted it the other day.

We love staying at Harvest Host but, be aware we've never encountered a Harvest Host location that offered electric or any other service like water or sewer. So, actually you should plan on those stays always being a dry camping stay.

I haven't used Boondockers Welcome, but I have heard that a number of those do have electric and sometimes other services too.

We will look into it this spring and will plan on having no AC for the overnight stays.

[Oakprk]

Did you leave the charging line to the house batteries from the alternator alone?