Hybrid - Dual Batteries?

[X4T8ee$]

I'm posting this under hybrid because the question is specific to hybrids. In my previous ICE ownership years, I routinely installed a dual battery setup to allow me to use a deep cycle battery for powering random things (propane heater, USB outlets, etc). Now, as an hybrid owner, I'm curious if anyone has done anything similar. In particular, I have a couple of DC-to-DC chargers the laying around (Redarc BCDC 1225's) and would be interested in installing a second battery to power outlets in the bed (rather than drawing down the starter battery).

Just starting this project, so not sure if connecting the BCDC directly to the starter battery is OK because it stays topped off by the hybrid battery (rather than a traditional alternator)? Or if not recommended for whatever variety of reasons may exist?

I appreciate any thoughts on the topic.

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[Nesser]

Not exactly what you're asking about but I'll leave this post here which could be useful for an upgrade. The solar trickle charger is pretty slick until you need additional power at night.

https://www.mavericktruckclub.com/forum/threads/hybrid-12v-battery-replacement.28921/post-854405

 

[inline_five]

Why not just run off an inverter, turn truck on and let it recharge using the engine as needed? It will keep the hybrid battery topped off as it runs down.

 

[MakinDoForNow]

I'm posting this under hybrid because the question is specific to hybrids. In my previous ICE ownership years, I routinely installed a dual battery setup to allow me to use a deep cycle battery for powering random things (propane heater, USB outlets, etc). Now, as an hybrid owner, I'm curious if anyone has done anything similar. In particular, I have a couple of DC-to-DC chargers the laying around (Redarc BCDC 1225's) and would be interested in installing a second battery to power outlets in the bed (rather than drawing down the starter battery).

Just starting this project, so not sure if connecting the BCDC directly to the starter battery is OK because it stays topped off by the hybrid battery (rather than a traditional alternator)? Or if not recommended for whatever variety of reasons may exist?

I appreciate any thoughts on the topic.

Do not connect directly to 12v battery particularly the negative post since that's location of stock BMS. The truck DCDC converter can supply up to 265 amps continuous through a 300 amp fuze at up to 15.6 (not sure but maybe a little more ?). The stock 12v is on a 200 amp fuse. I would think it would be prudent to have separate dcdc charger that can accept input voltage range and output what your separate BMS ( could be internal to your second battery) wants. I would think that a delay on might be considered to let truck 12v buss stabilize even if for just a few seconds. Someone replaced his 12v with a custom built LiFePo4 battery and reported 100amp charging but toasted his battery in a few months.
Note: Some battery power supplies like you are considering may have voltage protection at or near 15 volts so they will not accept recharge while truck buss exceeds that voltage. Also some allow dual DC inputs for faster charging (each input may be 8-10 amps) so check that out. Depending on your usage solar might also be of some limited help. Good luck....

Why not just run off an inverter, turn truck on and let it recharge using the engine as needed? It will keep the hybrid battery topped off as it runs down.

No need to waste conversion loss inverting dc-ac-dc. While truck is in ready state and ice is not running dcdc converter is furnishing current using the HVB and ice is started if HVB is low or current flow is restricted.

 

[X4T8ee$]

The truck DCDC converter can supply up to 265 amps continuous through a 300 amp fuze at up to 15.6 (not sure but maybe a little more ?).

Sounds similar to my Ford Transit where there is a separate bus that you can tap into? Where might this bus bar be located? And am I correct in thinking that to the extent you draw down the HVB through the 'DC-to-DC charging of the secondary battery' that the ICE will turn on to charge the HVB back up?

I would think it would be prudent to have separate dcdc charger that can accept input voltage range and output what your separate BMS ( could be internal to your second battery) wants.

Yes, the Redarc can take a standard range of voltage inputs and charge the battery at the correct voltage based on type (AGM, Lithium, lead acid, etc).

Depending on your usage solar might also be of some limited help.

Yes, the Redarc has a solar input and prioritizes solar over DC to the extent there's overlap.

 

[Darnon]

Sounds similar to my Ford Transit where there is a separate bus that you can tap into? Where might this bus bar be located? And am I correct in thinking that to the extent you draw down the HVB through the 'DC-to-DC charging of the secondary battery' that the ICE will turn on to charge the HVB back up?

As long as the truck is in its fully started state then, yes, it should automatically start the engine to recharge the HVB as needed.

There isn't a dedicated bus for supplemental loads. The DC-DC converter is connected via a short cable to the lower part of the underhood High Power Junction Box. The terminal that it connects to has the integrated 300 amp fuse. That in turn connects to a bus bar you can see with the junction box flipped up:

The upper connection and nearby copper cable lug in that picture are for the 12V battery cable (that screencap is from one replacing the 12V batt cable end). At the 12V under seat battery there's a 200A mega fuse bridging the connection between the cable and terminal.

Your BCDC charger presumably isn't going to draw more than 200A so you're probably safer attaching on the battery terminal side of the 200A fuse. In the event something goes catastrophically wrong then your 12V cable is still protected by the fuse and you can probably just jump the vehicle under the hood. Whereas blowing the 300A DC-DC converter fuse disables the whole charging system.

 

[bgn]

You may want to pick up a portable battery. I have a Delta 2 from Ecoflow (1kwh, 1800 watt inverter) and they can be had for around $500 these days.

 

[CurtisB]

I'm posting this under hybrid because the question is specific to hybrids. In my previous ICE ownership years, I routinely installed a dual battery setup to allow me to use a deep cycle battery for powering random things (propane heater, USB outlets, etc). Now, as an hybrid owner, I'm curious if anyone has done anything similar. In particular, I have a couple of DC-to-DC chargers the laying around (Redarc BCDC 1225's) and would be interested in installing a second battery to power outlets in the bed (rather than drawing down the starter battery).

Just starting this project, so not sure if connecting the BCDC directly to the starter battery is OK because it stays topped off by the hybrid battery (rather than a traditional alternator)? Or if not recommended for whatever variety of reasons may exist?

I appreciate any thoughts on the topic.

I'm guessing you had a Prius? Many Prius owners installed in the back of their cars an additional battery. I almost did it with mine, but changed my mind. I would say it is probably easier to do this with a Prius than with a Maverick. The computer on the Maverick can tell when you install anything extra within the system. It can tell me when I have to take a leak. The Maverick likes to go into a deep sleep if I am vacuuming the truck. My guess is trying to do a two 12v battery thing with the Maverick is going to create a cluster F#$%! that the dealer will default to you if any electrical issues arise after your install/upgrade. But hey, you could be the first to do this and then we can all copy you!

 

[MakinDoForNow]

Sounds similar to my Ford Transit where there is a separate bus that you can tap into? Where might this bus bar be located? And am I correct in thinking that to the extent you draw down the HVB through the 'DC-to-DC charging of the secondary battery' that the ICE will turn on to charge the HVB back up?
Yes similar. The transit is PHEV with larger battery. The SOC of the HVB (a flow battery meant for temporary storage) Is monitored, the ice is started and stopped to maintain 30% to 40%. SOC between 40%-72% is for Regen usage. From 72% is reserved for emergency braking if needed and to provide battery aging buffer, etc. I would suspect %'s can be adjusted over battery life. (I have read where on other HVB's the "installed" battery date has been changed to "restore" charge capacity, which of course, could increase the possibility of fire if overcharged).

Yes, the Redarc can take a standard range of voltage inputs and charge the battery at the correct voltage based on type (AGM, Lithium, lead acid, etc).
Just be sure it's standard range of input is larger than 15.6volts.

Yes, the Redarc has a solar input and prioritizes solar over DC to the extent there's overlap.
Might be worth looking into a glue on rooftop solar panel.

As far as the so called additional buss bar. Perhaps the 12v between battery and dcdc. I would have to research to see what the 200 and 300 amps are protecting. Adding 60-100amp draw location needs thought. There are 140 amp heater fuses most of which could come on probably seldom. The safest most likely unnecessary thing would be to not charge your battery above 40 amps while stock battery is in absorption charge status.

 

[Master Blaster]

If all you want this battery for is to isolate camping loads or something similar, just jumper a deep discharge marine battery through a diode and about a 10 ohm resistor, so that it can charge slowly without overloading the existing charging circuit, and discharge without affecting your main 12V supply.

 

[Cleek]

The Maverick 12v BMS is currently such a cluster, I would hesitate to try anything until Ford gets first principles figured out.

As an aside, The F150 hybrid (albeit different hybrid architecture than the Mav) has two 12V batteries wired in parallel.

 

[X4T8ee$]

I appreciate all the feedback; quite the variety of viewpoints. Generally, it sounds like this isn't a common upgrade. I'll be reaching out to RedArc tomorrow to discuss whether they have experience or recommendations with their product in the hybrid space. I'll report back for the benefit of the thread. Thanks again!

 

[Darnon]

The Maverick 12v BMS is currently such a cluster, I would hesitate to try anything until Ford gets first principles figured out.

It's not really a problem with the BMS. The batteries are just bad.

 

[MakinDoForNow]

It's not really a problem with the BMS. The batteries are just bad.

Depending on other things the BMS AND/OR it programming can destroy a battery. Yes there are be better batteries and they may last longer than the oem one but still be done in a lesser time than their design life. Hard to understand without knowing exactly what the system is actually doing.

 

[peyo]

I appreciate all the feedback; quite the variety of viewpoints. Generally, it sounds like this isn't a common upgrade. I'll be reaching out to RedArc tomorrow to discuss whether they have experience or recommendations with their product in the hybrid space. I'll report back for the benefit of the thread. Thanks again!

I was wondering if you decided to go in this direction?

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