Converting my RV to LiFePO4

[pearcedl]

I have installed the battery and am wiring in a WFCO AD-9855-AD converter/charger. That should take care of the RV, but I've been told that the truck battery is at risk because the alternator is not designed to handle the higher lithium voltage. Do I need to install a DC-to-DC charger between the alternator and the 7-pin plug or what? If I need something, what Victron product should I buy?

Other thoughts/suggestions?

Thanks!

 

[John Frum]

I have installed the battery and am wiring in a WFCO AD-9855-AD converter/charger.

One or more of the "AD"s in the model number stand for auto detect.
Which is something that the converter just utterly fails at doing.

Do you have or intend to purchase an inverter?

Since you mention a 7-pin plug I'm guessing this is a trailer, confirm?
How much excess alternator capacity do you have?
What is the amp hour capacity of your battery?
I'm assuming is a 12 volt LFP battery, confirm?
How much charge current would you like to charge with?

 

[pearcedl]

One or more of the "AD"s in the model number stand for auto detect.
Which is something that the converter just utterly fails at doing.

Do you have or intend to purchase an inverter?

Since you mention a 7-pin plug I'm guessing this is a trailer, confirm?
How much excess alternator capacity do you have?
What is the amp hour capacity of your battery?
I'm assuming is a 12 volt LFP battery, confirm?
How much charge current would you like to charge with?

Unfortunately, I've heard they have problems with that, but I didn't know what else to use...

No inverter - just DC when boondocking (unless I buy a generator).

Sorry - yes, a trailer. The truck is a 2007 Tundra - standard battery/alternator. I can find out the capacity tomorrow if needed.

The RV battery is a 304AH battery (12V). I guess it would be nice to charge the RV, but my main concern is to protect the truck. I'm assuming a 4-6 hour tow wouldn't add too much to the battery charge - am I wrong?

Thanks for the response...

 

[John Frum]

Sorry - yes, a trailer. The truck is a 2007 Tundra - standard battery/alternator. I can find out the capacity tomorrow if needed.

The RV battery is a 304AH battery (12V). I guess it would be nice to charge the RV, but my main concern is to protect the truck. I'm assuming a 4-6 hour tow wouldn't add too much to the battery charge - am I wrong?

The 7 pin tow cable is probably 10 awg max.
Likely very little charge current will flow into the house battery because of the distance induced voltage drop.
My wild ass guess is <10 amps even if the LFP battery is deeply discharged.
You should have at least one proper charge source to maintain the top balance of your LFP battery.
IMO neither the 7 pin tow cable or the wfco converter is up to the task.

 

[John Frum]

To charge optimally you should charge at no less than .2c.
In your case that is 60.8 amps.
That would either require a solar charge controller or an inverter/charger

Here is a line of dc2dc isolated chargers that might work "ok" for you depending on how much excess alternator capacity you have.

Orion-Tr Smart DC-DC Charger Isolated - Victron Energy

The Orion-Tr Smart DC-DC charger is a professional DC to DC adaptive 3-stage charger with built-in Bluetooth. For use in dual battery systems in...

www.victronenergy.com

Here is a line of ac2dc chargers that might work "ok" for you, an inverter generator is preferred to an old constant speed generator.

Blue Smart IP22 Charger - Victron Energy

The Blue Smart IP22 Charger is the new professional battery charger with built-in bluetooth. Find a Victron Energy dealer near you.

www.victronenergy.com

 

[pearcedl]

To charge optimally you should charge at no less than .2c.
In your case that is 60.8 amps.
That would either require a solar charge controller or an inverter/charger

Here is a line of dc2dc isolated chargers that might work "ok" for you depending on how much excess alternator capacity you have.

Orion-Tr Smart DC-DC Charger Isolated - Victron Energy

The Orion-Tr Smart DC-DC charger is a professional DC to DC adaptive 3-stage charger with built-in Bluetooth. For use in dual battery systems in...

www.victronenergy.com

Here is a line of ac2dc chargers that might work "ok" for you, an inverter generator is preferred to an old constant speed generator.

Blue Smart IP22 Charger - Victron Energy

The Blue Smart IP22 Charger is the new professional battery charger with built-in bluetooth. Find a Victron Energy dealer near you.

www.victronenergy.com

The WFCO is the inverter/charger (assuming I can get it to work) and I have a Victron SmartSolar MPPT 100/50 Charge Controller for solar.

So I DO need a dc2dc charger? Do you think the alternator is "smart" so I need a smart Orion - given that it is a 2007 truck, so should I just get that because it is better?

I'll check out the alternator tomorrow since it seems the choice depends on the excess capacity.

I have the ac2dc charger you mentioned, but that doesn't have anything to do with the truck battery (does it?)

 

[John Frum]

The WFCO is the inverter/charger (assuming I can get it to work) <snip>

No its a converter/charger.

So I DO need a dc2dc charger?

No, but as I said you do need some way to properly charge your LFP battery in order to maintain the top balance.

Do you think the alternator is "smart" so I need a smart Orion - given that it is a 2007 truck, so should I just get that because it is better?

I don't know what alternator you have.
Suggest you research that.

I have the ac2dc charger you mentioned, but that doesn't have anything to do with the truck battery (does it?)

Nothing to do with the truck battery.
You mean the Victron?
If yes I suggest you install that and get rid of the WFCO.

 

[pearcedl]

No its a converter/charger.

No, but as I said you do need some way to properly charge your LFP battery in order to maintain the top balance.

I don't know what alternator you have.
Suggest you research that.

Nothing to do with the truck battery.
You mean the Victron?
If yes I suggest you install that and get rid of the WFCO.

My bad - yes, converter/charger. (I was thinking invertor because of your invertor question...)

Won't the WFCO converter/charger properly charge the LFP battery? (Assuming I can get it to recognize the Lithium). If not, is the Blue Smart IP22 Charger the best choice to replace the AD-9855-AD?

So, am I understanding you correctly that the truck battery/alternator doesn't need protection from the RV lithium? No harm will be done by running the truck current through the 7-pin plug?

 

[John Frum]

My bad - yes, converter/charger. (I was thinking invertor because of your invertor question...)

Won't the WFCO converter/charger properly charge the LFP battery? (Assuming I can get it to recognize the Lithium).

First of all I would not assume that the WFCO will recognize the battery and even if it does I believe it will only bulk for 4 hours max.
And it will bulk to high.
None of the "LFP" converters have a charge profile that I would consider optimal.

If not, is the Blue Smart IP22 Charger the best choice to replace the AD-9855-AD?

Well, best costs money.
An inverter/charger by Victron or Samlex would be better charge sources but they are quite a bit more expensive.
The Blue Smart is the best bang for buck charge source.

So, am I understanding you correctly that the truck battery/alternator doesn't need protection from the RV lithium?

That is correct.
Because the wire is quite thin the voltage drop will be quite high so the current flow won't be high enough to hurt the alternator.

No harm will be done by running the truck current through the 7-pin plug?

I think it will be fine.
Assuming the 7-pin charge circuit is 10 awg it will be fused to no higher than 30 amps and I expect you will see ~5 amps flow.

 

[pearcedl]

First of all I would not assume that the WFCO will recognize the battery and even if it does I believe it will only bulk for 4 hours max.
And it will bulk to high.
None of the "LFP" converters have a charge profile that I would consider optimal.

Well, best costs money.
An inverter/charger by Victron or Samlex would be better charge sources but they are quite a bit more expensive.
The Blue Smart is the best bang for buck charge source.

That is correct.
Because the wire is quite thin the voltage drop will be quite high so the current flow won't be high enough to hurt the alternator.

I think it will be fine.
Assuming the 7-pin charge circuit is 10 awg it will be fused to no higher than 30 amps and I expect you will see ~5 amps flow.

Thank you so much for the help!

"Well, best costs money. An inverter/charger by Victron or Samlex would be better charge sources" - I'm willing to pay for the best to minimize the risk of problems later that always seem to end up costing more. What Victron inverter/charger would you recommend?

 

[time2roll]

I have installed the battery and am wiring in a WFCO AD-9855-AD converter/charger. That should take care of the RV, but I've been told that the truck battery is at risk because the alternator is not designed to handle the higher lithium voltage. Do I need to install a DC-to-DC charger between the alternator and the 7-pin plug or what? If I need something, what Victron product should I buy?

Other thoughts/suggestions?

Thanks!

I doubt the DC-DC charger is needed. The existing wire will be self regulating to limit voltage and amps due to the resistance. Besides there is a fuse to limit the current and save the alternator.

More likely the charge rate could be a bit slow and some improvement could be made to increase the charging.

Post the actual results of success or disappointments after a few trips but the alternator will be fine.

 

[John Frum]

Thank you so much for the help!

"Well, best costs money. An inverter/charger by Victron or Samlex would be better charge sources" - I'm willing to pay for the best to minimize the risk of problems later that always seem to end up costing more. What Victron inverter/charger would you recommend?

Samlex EVO-1212F-HW, 1200 Watt, 12 Volt, Pure Sine Wave Inverter/Charger - Hardwire | DonRowe.com

The Samlex America EVO-1212F-HW, 1200 Watt, 12 Volt Pure Sine Wave Inverter/Charger (Hardwire) is a rugged inverter/charger designed for mobile and off-grid applications

www.donrowe.com

and this to configure it

Samlex EVO-RC-PLUS Remote Control | DonRowe.com

The Samlex EVO-RC-PLUS Remote Switch provides convenient remote power control, operational status monitoring and data logging for the EVO inverter/charger series.

www.donrowe.com

 

[ianganderton]

To charge optimally you should charge at no less than .2c.

Is that the case with lithium?

I thought it was just Lead acid to prevent sulphation?

 

[pearcedl]

Samlex EVO-1212F-HW, 1200 Watt, 12 Volt, Pure Sine Wave Inverter/Charger - Hardwire | DonRowe.com

The Samlex America EVO-1212F-HW, 1200 Watt, 12 Volt Pure Sine Wave Inverter/Charger (Hardwire) is a rugged inverter/charger designed for mobile and off-grid applications

www.donrowe.com

and this to configure it

Samlex EVO-RC-PLUS Remote Control | DonRowe.com

The Samlex EVO-RC-PLUS Remote Switch provides convenient remote power control, operational status monitoring and data logging for the EVO inverter/charger series.

www.donrowe.com

John:

The alternator seems to be 150A. I have no idea how to determine the excess alternator capacity...

That Samlex EVO sounds interesting - although a grand is a BIG chunk of money. Hadn't planned on an inverter (yes, I screwed up again and said inverter/charger), but maybe I'll go that way. If not, what Victron converter/charger would you recommend?

 

[kbeefy]

Without seriously upgrading the wiring between your alternator and house battery you won't get much out of it.
As mentioned above, 10 amps is pretty optimistic.

You probably have an additional 50 amps of charge capacity from your alternator during regular driving, but would need a DC-DC charger and 4ga+ wire all the way to get it to your battery.

 

[John Frum]

John:

If not, what Victron converter/charger would you recommend?

Its not a converter/charger(which is a good thing).
the single output 30 amp version of this

https://www.victronenergy.com/upload/documents/Datasheet-Blue-Smart-IP22-Charger-120-VAC-EN.pdf

Use the Victron connect app on your phone to program a custom charge profile.
bulk/absorb = 14.2 volts
absorption timer = 30 minutes(adjust to needs of your battery)
float = 13.4 volts

 

[pearcedl]

Its not a converter/charger(which is a good thing).
the single output 30 amp version of this

https://www.victronenergy.com/upload/documents/Datasheet-Blue-Smart-IP22-Charger-120-VAC-EN.pdf

Use the Victron connect app on your phone to program a custom charge profile.
bulk/absorb = 14.2 volts
absorption timer = 30 minutes(adjust to needs of your battery)
float = 13.4 volts

So - it would get its power through a 120V CB in the power box and the output would power the 12V side of the power box? The RV items that run on 12V wouldn't mind the changing voltage from 14.2V to 13.4V?

 

[pearcedl]

Without seriously upgrading the wiring between your alternator and house battery you won't get much out of it.
As mentioned above, 10 amps is pretty optimistic.

You probably have an additional 50 amps of charge capacity from your alternator during regular driving, but would need a DC-DC charger and 4ga+ wire all the way to get it to your battery.

Thanks! At least for my needs right now, that would be too much work.

 

[pearcedl]

I doubt the DC-DC charger is needed. The existing wire will be self regulating to limit voltage and amps due to the resistance. Besides there is a fuse to limit the current and save the alternator.

More likely the charge rate could be a bit slow and some improvement could be made to increase the charging.

Post the actual results of success or disappointments after a few trips but the alternator will be fine.

Thanks! Protection of my truck was my primary concern, so thanks for settling that.

 

[John Frum]

So - it would get its power through a 120V CB in the power box and the output would power the 12V side of the power box?

Correct.

The RV items that run on 12V wouldn't mind the changing voltage from 14.2V to 13.4V?

They will be fine.