Prado 150 2015 limited space for aux battery

[krypto Avid PP Poster! Find all posts View Profile Close krypto]

I purchase the Bluetti EB70. Runs my Waeco fridge for 2 days

[DeeBee Junior Member Find all posts View Profile Close DeeBee]

Thanks krypto. The prado has an inverter built in but I know little about its specs. I should read the book !!! Suffice to say, a 12v rechargeable system with a dcdc controller is my plan at this time.

[DeeBee Junior Member Find all posts View Profile Close DeeBee]

Just took a look at pradopoint discussion on rear 240v output. Looks like pathetic attempt and almost useless. Emergency use only I'd say .

[krypto Avid PP Poster! Find all posts View Profile Close krypto]

There are a lot of strong opinions on the use of DCDC on this forum. With Lithium depending on the BMS that you may need one. I have been using the diode/fuse successfully for many years

[snewby Junior Member Find all posts View Profile Close snewby]

There are a lot of strong opinions on the use of DCDC on this forum. With Lithium depending on the BMS that you may need one. I have been using the diode/fuse successfully for many years

A silicon diode drops the voltage (on the voltage sensing line) by 0.7volts. So the regulator is tricked into boosting the alternator voltage to the battery by 0.7v
It will not effect the current.
The bms in a lifepo4 battery will limit volts and current if it detects anything beyond the design limits of the battery. Or just shuts it down in a worst case. (To restart after a suitable time). It should protect the battery. Voltage regulators are designed for lead acid batteries, that is why a charger with a Lithium profile is desirable for a Lithium battery. (On top of that you often get a nice solar input )

[gunda Member Find all posts View Profile Close gunda]

When I had the under-bonnet DCS lithium fitted to my Prado, my sparkie just fitted a Victron isolator. He ran a similar system in his new Hilux, and found that the alternator wasn't outputting a high enough voltage to charge the lithium as quickly as should have been possible. I found the same in the Prado. I had a Redarc DC2DC fitted in place of the isolator. Apparently this is not an issue with a 200 series. My sparky is experimenting with alternator mods to remove the need for a DC2DC. I'll probably just stick with the 40A Redarc, as that is plenty fast enough and I don't have the appetite for any more auto electrical work.

[Leethal Advanced Member Find all posts View Profile Close Leethal]

IMO a lot of the discussion about the merits of a DCDC charger versus some form of VSR revolve around either;

A/ the available charge rate of the alternators 50+ amps versus the DCDC's design rate e.g. Redarc BCDC1225D at 25amps etc.
or
B/ the actual alternator output voltage versus the DCDC specific voltage profile (usually higher than alternator voltage) to suit different battery types.

Depending on your usage a high charge current to boost battery state of charge quickly may be more important than the charging profile to fully charge a AGM or Lithium battery.
For some being able to fully charge the second battery may be the better option although it will often take longer to achieve a 100% SOC.

Installation location of a DCDC charger can dictate what size unit can be installed, that is an engine bay install will need to be a waterproof unit and often top out at 45 -50 amps well below the potential charge rate available from the alternator.

For instance if setting up camp and minimal driving till leaving a high charge rate with solar backup would probably be best. If after setting up camp you do a fair bit of driving like say on Fraser Island exploring the island, then the longer drives will allow a DCDC's lower charge rate to fully charge the battery.

Sorry for the long post but my point is there is no definitive answer as to what second battery system is best as imo the best option will change depending on how you use your Prado.

Lee

[DeeBee Junior Member Find all posts View Profile Close DeeBee]

Thanks for those comments. I think I'd like to use a cTek D250SE with an IP65 water resistant rating..It has some reasonable/good specs on various aspects of compatibility with a selectable mode for a lithium battery or AGM, solar charging with mppt, and .smart alternator compatible plus more

[catherder Junior Member Find all posts View Profile Close catherder]

Any ideas would be welcome.

Have a look at Vonnies battery tray. It lifts the battery above the AC piping. The specs say it's 308mm long.
https://www.4wddepot.com.au/vonnies-...r-toyota-prado

[Leethal Advanced Member Find all posts View Profile Close Leethal]

DeeBee,

I would go with the DCDC charger with the highest charge rate that will fit in your chosen location so as to maximize battery charging from short drives.
I use an Enerdrive DC2DC+ which is user selectable up to 50 amp output, it cannot be mounted in the engine bay though.

Lee