diy solar

diy solar

Converting my RV to LiFePO4

The legacy converter probably had a dedicated breaker.
I suggest to use remove the old converter and use that breaker for the victron charger.
 
I believe the rule of thumb is not to draw more amps than 65% of the rated capacity of the alternator, so as to avoid over heating the alternator. My 2018 Chevy pick up truck OEM alternator is rated at 150 amps. Consequently, I only have about 97 useable amps.

I bought a $60 clamp on meter that measures DC current, clamped it around the wire feeding my starter battery, and recorded a 21 amp draw, at idle, with no accessories on.

Thereafter, I progressively turned on each accessory, such as radio on high volume, turn signals, head lights, wipers, heater fan on high, air conditioner on high, etc., until I recorded a cumulative draw of 70 amps. Consequently, on an ultra conservative basis, I had approximately 27 spare amps of capacity, at idle.

I decided to buy the Victron Orion TR Smart 12v DC-DC 18 amp isolated charger, rather than the 30 amp charger. I did not want to do the "big three" wire upgrade needed to handle 30 amps.

In addition, I bought and carry a spare OEM alternator with me in case I burn the first one up. I figure it is cheap insurance.

My nightmare scenario is to be on a dark rainy night, in the mountains, on a narrow two lane highway, pulling my 16 ft trailer and having my alternator fail.
 
I had my alternator fail and the truck immediately pulled power from the trailer for a few hours 'til I found an O'Rileys in Gillette WY. Now have a 'lifetime' warranty.
DC-DC charger would have had to be bypassed.
 
featherlite said:
I bought a $60 clamp on meter that measures DC current, clamped it around the wire feeding my starter battery, and recorded a 21 amp draw, at idle, with no accessories on.

Thereafter, I progressively turned on each accessory, such as radio on high volume, turn signals, head lights, wipers, heater fan on high, air conditioner on high, etc., until I recorded a cumulative draw of 70 amps. Consequently, on an ultra conservative basis, I had approximately 27 spare amps of capacity, at idle.
Click to expand...
Thats a good Idea, I already have a clamp ampmeter, I'm going to do that.


featherlite said:
My nightmare scenario is to be on a dark rainy night, in the mountains, on a narrow two lane highway, pulling my 16 ft trailer and having my alternator fail.
Click to expand...

Fortunately, most people on this board have a spare 100aH+ on their trailer that could power the tow vehicle for a while if necessary.
 
WFCO Charger/converter's are crap. I know this is a bit late, but I'd go with a Lithium Progressive brand upgrade to that POS. They are well known for never getting into higher voltage levels the Lithium prefers.
 
RoadTurtle said:
Lithium Progressive brand upgrade to that POS. They are well known for never getting into higher voltage levels the Lithium prefers.
Click to expand...
Yeah but PD floats lithium at 14.4V and that is a LOT higher than i ever want my battery, let alone float.
If they offered a configurable model, i would upgrade from my PD4645.

And agree, the WFCO i replaced was nothing but trouble with deep cycle lead acid.
 
MisterSandals said:
Yeah but PD floats lithium at 14.4V and that is a LOT higher than i ever want my battery, let alone float.
If they offered a configurable model, i would upgrade from my PD4645.

And agree, the WFCO i replaced was nothing but trouble with deep cycle lead acid.
Click to expand...
did you check with best converter? I know they had a "modified" Progressive version they sold?
 
RoadTurtle said:
IRC, one of their units had a switch for Lithium.
Click to expand...
Yes, i have seen that. Its either a lead acid profile (which my PD4645 has) or you switch it to lithium and it floats at 14.4V which i have absolutely no interest in (nor should anybody else in my opinion).
 
RoadTurtle said:
why not?
Click to expand...
LiFePO4 should not be floated or held at that high of a voltage. At that voltage, i would expect to have runaway cells and unfortunate BMS disconnects. I see no reason to charge right up to the theoretical limits before they are damaged.

Heck, i only ever charge any of my LiFePO4 batteries to 13.8V (3.45Vpc) to get to 99% charge. Hoping these last many many years too.
 
MisterSandals said:
LiFePO4 should not be floated or held at that high of a voltage. At that voltage, i would expect to have runaway cells and unfortunate BMS disconnects. I see no reason to charge right up to the theoretical limits before they are damaged.

Heck, i only ever charge any of my LiFePO4 batteries to 13.8V (3.45Vpc) to get to 99% charge. Hoping these last many many years too.
Click to expand...
Zamp solar charger sits at 13.4v and never seems to stop feeding electrons to the battery. I just turned my 120v charger on as we have gone a couple of days with very little sunlight, and it's expected to continue. Currently at 13.6v and 250W (smart shunt), which is interesting as it's a 60a charger.
.
I may learn to hate the shunt... Because now I'm wondering if there's another unseen wiring issue. Only getting 10a off the 30a solar and 20a off 120v charger. I had found one battery wire terminal that was loose on the wire from the factory. Most if not all of that system will get replaced as I upgrade in the next several weeks.
 
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