Lithium, again...

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Originally Posted by W&KO

Thanks for the explanation drivesafe.

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Quote:

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Originally Posted by W&KO

I’m not convinced converting to lithium is complex given the OP has a 300tdi so not a modern/late model car.

Costs aside the way I read your explanation is if the OP converted to lithium than it would be best change both the vehicle AUX-AGM and the camper AGM to lithium to maximize the function of the DC-DC rather than keep the vehicle aux-AGM and camper lithium.

Austatar seems to getting good performance from his setup with just a starter and lithium in the camper.

I’m considering the switch, space and weight is becoming an issue for planned overland trip.

I have a TD5 > basic redarc isolator > 110amp/hr AGM. I’m not interested in using the capacity in my starter hence why I didn’t consider a traxide isolator when I started the build and acknowledge that cost per amp it’s way I front of lithium.

To me this is a simple switch to gain more capacity. I also in a position not having to use a drop in replacement, I need to start researching sizes.

TD5 Starter > Enerdrive DC-DC > either a Revolution (or similar) drop in or a EV Powerpac all backed up with 2 x 125w panels on the roof and a 125w portable blanket.

How does that sound??

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Hi W&KO and your choice to leave your cranking battery alone is your business.


But it’s a waste of at least 40Ah of usable capacity that could be put to good use and at the same time be a considerable cost saving.


Note, if you did have one of my isolators, you would not only have that extra 40Ah available, but you would need a much shorter drive time to replace used battery capacity as compared most likely extend the operating lifespan of your cranking battery.


Next, if you have a lithium in your tow vehicle and lithiums in your camper trailer, you are going to need two separate DC/DC devices. Thats a huge setup cost.


You would be far better off leaving the tow vehicle setup as is and just concentrate on your camper battery setup.

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Originally Posted by DiscoMick

As I understand it, if the alternator generates one level of output, then it's okay, but if the alternator varies it's output depending on the state of the battery, then lithium is a problem unless a DC-DC is used.
So a 300 Tdi and our Defender both have standard output alternators but a D4 is variable.
Is that right?

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Hi Mick and pretty well on the money.

Pumas have a variable voltage alternator operation but not a full on SMART operation like the D4s.

A word of caution. There are some videos on YouTube, ranting on about fitting dual battery systems to D5s. If you follow the instructions, you will most likely destroy your cranking battery in short time.

Just be careful of the "EXPERT" advice out there.

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Originally Posted by drivesafe

Hi W&KO and your choice to leave your cranking battery alone is your business.


But it’s a waste of at least 40Ah of usable capacity that could be put to good use and at the same time be a considerable cost saving.


Note, if you did have one of my isolators, you would not only have that extra 40Ah available, but you would need a much shorter drive time to replace used battery capacity as compared most likely extend the operating lifespan of your cranking battery.


Next, if you have a lithium in your tow vehicle and lithiums in your camper trailer, you are going to need two separate DC/DC devices. Thats a huge setup cost.


You would be far better off leaving the tow vehicle setup as is and just concentrate on your camper battery setup.

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I’m not towing,just have the one starter and AUX for the house as stated above.

You say it’s my choice leaving my starter, I stated my position so we wouldn’t get bogged down about your products. Yes I used your isolator on my previous car. Apologies for referring to your product in this instance.

I don’t get too caught up in the time to charge, given when touring there is a good chance I/most drive many hours each day. To date on a 10 day and a 16 day trip I haven’t seen my aux below 12.2 and in the days I’m parked up or travel a shortish distance my solar get me to float each day. I’m increasing power usage therefore this thread is handy.

I did say costs aside in a hope to discuss setups/technology.

For me I’m struggling to find room for a second AGM as I choose not to use an isolator that uses starter capacity and/or fit a second battery under the passenger seat therefore my next option for increasing capacity with the same real estate is lithium..

Thanks for answering my question about two lithium’s in separate spots that there would a need for two DC-DC’s. Not that it’s applicable in my setup but if it did I’d first try parallel before a second DC-DC.

My apologies W&KO, I see you were talking about the OP's setup, not yours.

While it does not apply to your setup, but you can not use one DC/DC device to charge two batteries in separate location. Lithium or otherwise.

Doing so will either cause the closest to be continually over charged, or the furthest to be continually undercharged.

Undercharging a lithium is not a major problem but the slightest overcharge situation can be a problem, particularly with a lithium fitted with a poor quality BMS.

Hi again folks, and there is a need to cover both the potential use and advantages of converting to a lithium battery based DBS, and if there is actually a REAL benefit for converting.


Since I started selling Lithium batteries I have had quite a few enquiries from existing customers, about “upgrading” to a lithium setup.


In most cases, once the benefits and drawbacks were explained, the majority of those enquiring decided what they already had, was better, for their needs, than what a lithium “upgrade” would give them.


Because of the grossly misleading advertising used to sell many of the different brands of lithium batteries, most people do not fully understand the implications, pros and cons, of changing to a lithium battery setup.


To this end, over the next few days, time permitting, I will add a section on this subject, to the On-Line auto electrical info thread in the VERANDAH section.


As soon as I post up the info, I will post up a link here.