BLITZEN goes Lithium

[Trail Talk]

After much consideration, including playing around with cardboard mock-ups, we had to face the fact that installing a 3000w inverter/charger would cost us a cabinet. We weren’t ready to accept the loss of valuable storage space for something only “nice to have”. Instead, we asked OEV to upgrade our solar panels. The newer bifacial designs offered a 30% gain within virtually the same footprint!


Heading out in a couple of days for some off-grid adventures and looking forward to seeing the results. We have room for at least a couple panels more but I’m not yet ready to give up the carrying space.

 

[calameda]

we asked OEV to upgrade our solar panels. The newer bifacial designs offered a 30% gain within virtually the same footprint!

been considering this myself. What panels did you opt for?

 

[DiploStrat]

Aside from all the well-known advantages of converting to Lithium batteries, we did lose a bit of functionality :-(

Due to the incompatibility of our LiFePO4 house batteries and the lead-acid truck batteries (the same reason we needed a DC to DC charger) our Samlex dual-sensing voltage relay became redundant.

The Samlex would allow shore power to first charge the house batteries, then the truck batteries. It further prevented either from draining the other side. Now our dual truck batteries are removed from the charging mix.

Not sure yet if that will prove a disadvantage during freezing weather, but "experts" say that a fully charged battery is the best protection vs battery warmers.

Has anyone found a means of retaining the truck battery charging from shore power while using lithium in their house?

Yes, the "Twisted Sister™" set up with two B2B. (Given to me by REDARC.)

Basically:
-- One B2B charges from the starter battery to the camper battery, with an added relay to assure that it only does this with the ignition on. In our case, this takes from 24v lead acid and outputs 12v with a lithium iron profile.

-- A second B2B (can be smaller) charges from the camper battery to the starter battery, with a relay that assures that this B2B is disconnected when the engine is running. (Easy to do with a "crossover" relay - basically, when the ignition is on, the relay is on, but this disconnects the power.) In our case, this takes from 12v lithium iron and outputs 24 lead acid.

Worked like a charm for over five years. Never bothered to add any kind of cut out. You could, as this second B2B is really only needed when the truck is in storage.

 

[Trail Talk]

been considering this myself. What panels did you opt for?

Lumera, made in BC. Our 170w panels were replaced with 220w, requiring new mounting brackets but nothing else.

 

[Trail Talk]

Yes, the "Twisted Sister™" set up with two B2B. (Given to me by REDARC.)

Basically:
-- One B2B charges from the starter battery to the camper battery, with an added relay to assure that it only does this with the ignition on. In our case, this takes from 24v lead acid and out puts 12v lithium iron profile.

-- A second B2B (can be smaller) charges from the camper batter to the starter battery, with a relay that assures that this B2B is disconnected when the engine is running. (Easy to do with a "crossover" relay - basically, when the ignition is on, the relay is on, but this disconnects the power.) In our case, this takes from 12v lithium iron and outputs 24 lead acid.

Worked like a charm for over five years. Never bothered to add any kind of cut out. You could, as this second B2B is really only needed when the truck is in storage.

Thanks for confirming this. We left the Samlex cable in place in anticipation of doing just that but I have to get on with it

 

[DiploStrat]

Thanks for confirming this. We left the Samlex cable in place in anticipation of doing just that but I have to get on with it

There used to be a really neat product, designed especially for this purpose, the AMP-L-Start, but they appear to have gone out of business. Pity as it was small, neat, and even had a lithium to lead acid setting.

Adding a second B2B is pricy, but you may be able to find a small one.

 

[Trail Talk]

Adding a second B2B is pricy, but you may be able to find a small one.

I discussed a second charger more in-depth with the good folks at OEV while there for the solar panel upgrade. We came to the conclusion that the best way forward was to repurpose our existing Orion 12/12-30 DC to DC for the camper to truck circuit and install the newer Orion XS 12/12-50 for the truck to camper circuit. Lot of advantages with that new Orion XS, will be on our to-do list for 2025.

 

[Trail Talk]

Looking to update this thread with new developments. 1) Although covered in another thread, last winter we installed heated battery trays under our two coach batteries. They draw 1A directly from each battery and are thermostatically activated so not on all the time. This allowed us to discontinue using a space heater while in storage; warming the entire cabin just to keep the batteries online.



On this last picture you can see battery 0114, our problem child :-( Since delivery its been acting up, I detailed some of the issues in post #16. Last week the BMS shut it down for Over Voltage protection...again. The app revealed one cell was 400mV higher than the others - it wasn't coming back to life. Sent the details off to Discover Battery tech support and received a reply within hours that it needed to be replaced and would be covered under warranty. Today, three days later, I've swapped in the new battery and all looks good (fingers & toes crossed).

Huge credit to the company and our local dealer for not p*ssing around like so many do. OTOH, we just purchased new kitchen appliances and, after reading the dismal industry-wide reviews on appliance warranties, I'm dreading the day we might have to file a claim.

 

[Trail Talk]

I discussed a second charger more in-depth with the good folks at OEV while there for the solar panel upgrade. We came to the conclusion that the best way forward was to repurpose our existing Orion 12/12-30 DC to DC for the camper to truck circuit and install the newer Orion XS 12/12-50 for the truck to camper circuit. Lot of advantages with that new Orion XS, will be on our to-do list for 2025.

Make that a 2026 project…just ordered the 50 amp Orion DC to DC from CDN Solar at a great price so we’re inching closer to getting it done.

 

[simple]

I'm not an electronics wiz and have a general curiosity. Regarding your previous design considerations for switching to the larger inverter and trying to find space for it. Could you have added an additional smaller inverter or two and run an additional AC circuit or two?

 

[Ninelitetrip]

I discussed a second charger more in-depth with the good folks at OEV while there for the solar panel upgrade. We came to the conclusion that the best way forward was to repurpose our existing Orion 12/12-30 DC to DC for the camper to truck circuit and install the newer Orion XS 12/12-50 for the truck to camper circuit. Lot of advantages with that new Orion XS, will be on our to-do list for 2025.

So as OEV outlined to you, is the Camper to Truck DC - DC circuit to use the Lithium Camper batteries to trickle charge the Truck batteries when stationary?


@Trail Talk

 

[Trail Talk]

Could you have added an additional smaller inverter or two and run an additional AC circuit or two?

I suppose so…what advantages do you see with that?

 

[Trail Talk]

So as OEV outlined to you, is the Camper to Truck DC - DC circuit to use the Lithium Camper batteries to trickle charge the Truck batteries when stationary?


@Trail Talk

Yes, that’s the plan.

 

[simple]

I suppose so…what advantages do you see with that?

Was mostly thinking about the space tradeoff and how you might be able to fit them into various crannies.

Wouldn't work as Well for an AC unit but offers redundancy.

Maybe more efficient if you're running a smaller single load. You could leave the additional inverter(s) turned off.

 

[Trail Talk]

Was mostly thinking about the space tradeoff and how you might be able to fit them into various crannies.

Wouldn't work as Well for an AC unit but offers redundancy.

Maybe more efficient if you're running a smaller single load. You could leave the additional inverter(s) turned off.

OK, I see where you're going.