On board this and that... What about a battery charger

Anyone done an onboard battery charger? We talked about an aux battery a while back. I plan on doing an on board inverter and have been pondering the merrits of an onboard charger for some time.

Not like a 5 amp tender, but a legit charger ranging between 25-100 amps, like on an RV effectively giving you "shore" power. They make outdoor/onboard units that are relatively small you could slap onto a fender wall, they can also be used to jump a vehicle. Larger units (30+amps) you may want to get creative and mount in a battery box. One of the great things about a bullnose especially the 300-6 is a lot of room under the hood.

This works well for those of us that like to truck camp, for recreation or even travel. Pull up plug it in. Power pole > battery charger > Main and aux battery > trucke stereo etc or > power inverter> accessories/lights/heaters etc.

If you do add a charger then don't implement a Cole-Hersee smart battery isolator in its normal wiring plan.  Because if you do you'll raise the battery voltage to 13.2 volts and the CH isolator will parallel the batteries.  Been there, done that.

The solution is to run the ground for the CH isolator through a relay that is triggered by the ignition switch.  That way the isolator won't come in unless the vehicle is running.

TheScatch wrote

.... Pull up plug it in. Power pole > battery charger > Main and aux battery > trucke stereo etc or > power inverter> accessories/lights/heaters etc.

Why would you use a transformer to get to 12V and then step it up with an inverter to get 120AC???
or maybe I'm reading this wrong?

At that point I'd just get a whisper quiet Honda or Onan generator and be done with it.

ArdWrknTrk wrote

TheScatch wrote

.... Pull up plug it in. Power pole > battery charger > Main and aux battery > trucke stereo etc or > power inverter> accessories/lights/heaters etc.

Why would you use a transformer to get to 12V and then step it up with an inverter to get 120AC???
or maybe I'm reading this wrong?

At that point I'd just get a whisper quiet Honda or Onan generator and be done with it.

     I think my late night brain did not communicate this properly to begin with, because the generator at that point wouldn't make much sense either if you were at a KOA with a power pole lol. In either case just grab a 30amp to standard plug rv adapter and call it a day.

     There are two instances I have seen this done and the reason is simply because the need is built into the vehicle. One gentleman had a pick up he used for over landing/camping, with accessory/outlets built into the bed. He then had a canvas tent that affixed to the bed. If over landing he could run power in his "tent" off of battery/engine power. If at a KOA he could plug his truck in, run his stero system, on board CB etc while keeping the batteries fresh and then also running other accessories in the back(heater, truck fridge etc). It was a "newer" truck so he had everything built into a tool box in the bed. The second time I have seen this was in a cargo van -> camper conversion. In an RV the power I believe comes into a PDC from either a generator or shore power and then splits powering the RV and charging the batteries, seems that would take up a lot more real estate.

     While not quite similar, when I was in Texas I purchased a old field found Willy's MB for $500 to do something similar. I had a friend group that ran old CJ jeeps with small diesel conversions (like the VW 1.6). They had on board inverters and either tiny trailers or hitch mounted carriers for gear. They would go out (sometimes for multi-day hog hunts), set up a wall tent and idle those tiny diesels to generate power for lights and a little window AC unit, charge radios and cell phones. A 5.5k Onan might have been more efficient but space was a premium especially if you were hauling a canvas tent and little AC unit to combat Texas heat. For fuel sharing they would have needed a more expensive diesel version too adding several thousand bucks vs idling a 1.6l diesel sipping fuel and running an $500 inverter. That build never happened, ended up emptying my storage unit with the parts and jeep selling it off so I could move from San Antonio to Charleston for work.

Gary Lewis wrote

If you do add a charger then don't implement a Cole-Hersee smart battery isolator in its normal wiring plan.  Because if you do you'll raise the battery voltage to 13.2 volts and the CH isolator will parallel the batteries.  Been there, done that.

Can you explain why this is a problem if the charger is big enough to overcome the isolator draw? As you know, I'll have this situation and also want to use an onboard maintainer.

kramttocs wrote

Can you explain why this is a problem if the charger is big enough to overcome the isolator draw? As you know, I'll have this situation and also want to use an onboard maintainer.

Good question.  If the charger can overcome the draw of the pull-in current of the isolator then there's no harm no foul.  In my case the little HF charger couldn't and the relay would pull in and the voltage would head south.  Then the relay would drop out and the cycle would start again.

But in this case the charger is going to be adequate to not only overcome the current of the relay/isolator but also that of the inverter, so there's no problem at all.  I wasn't thinking.  

In your case, check the capability of the charger you are going to use. But also note that the relay will parallel the batteries so the charger will see both of them instead of just one.

It's definitely something to be considered when using dual batteries and a smart isolator so I am glad you brought it up.

Amps aside, I looked at tech sheets for three chargers and they had min values of:
#1. 13.4
#2. 12.6
#3. 12.7

Isolator joins at 13.2

Which would be better?

1:
Would keep the batteries constantly connected and thus both charged
Would also keep the solenoid engaged continuously
More prone to short cycling as the solenoid would be a parasitic draw?

2/3:
Would primarily be floating the main battery.
Only triggering the solenoid and charging the secondary battery if the main battery needs topped off as that would go over 13.2.
Chance of the aux battery draining and not being charged


Correct me if my logic isn't right on this.

This is really easy depending on what you want to do with your tender. 1) To keep both batteries topped off (tended) or topped during low power continuous use. or 2) Plug the truck in to keep the batteries charged while you are running equipment say like a big freaking stereo system for and extended time or other truck equipment.

For item 1 its simple. Get a two bank onboard charger and leave your set up as you planned it. The on board tender connects to each battery separately but only charges typically with 8-12 amps.

For item 2, if you want to keep it topped off with heavier draw you need something more sufficient that more mirrors your alternator so a on board charger putting out 25-100 amps depending on your use would be required.

My plan has always been to use a good isolator/solenoid/relay pick your choice of nomenclature. That is actuated in start/run to connect the batteries.

I know I posted on another thread about this but my mindset is to keep the main battery isolated for cranking/running the engine so with the key off there is no chance for any parasitic drain etc from any other system. Everything else, lights radio etc to the aux battery. When the key is in run/start the batteries are linked so the aux can also add to cranking if needed, and both batteries then share load when the engine is running and both are being charged by the alternator in this state.

Hooking up a 25-100amp charger to the aux battery in this set up does not do anything but supply power to the truck/accessories and keep the battery charged. If you are just running LED lights, a few small items, charging some tool batteries, 25 amps should be more than sufficient. If camping out in the back with your kid and you add a space heater, radio, laptop for some reason(kids or angry wife has you living in your truck bed), or got silly and wanted to run a winch with the engine off (I know doesn't make sense, just a high load example) you probably want something more sufficient in the 75-100 amp ranges.

A few years ago I converted most of my yard equipment to 80v battery driven units. After Hurricane Matthew hit us I also converted my chainsaw. Post hurricane ethanol free pre mix was hard to get a hold of, mixing gas and oil was an option ethanol makes micro carbs run like poop. I and several others ran into some issues that required some in field tear downs. No one dropped $800 on a really nice Husqvarna mind you. My 80V has never let me down, I actually just felled, limbed, and bucked a maple and a red oak in the back yard last week with ease, and no ear plugs. What I did during the emergency times was run an inverter off my vehicle with two chargers. I have several batteries due to multiple tools. Two batteries on the charger, one in the tool kept my 80v chainsaw running none stop during storm clean up. Only thing I needed to do was lube the bar, make sure the oil was good and sharpen the chain from time to time. Long story short, my truck will have two battery chargers in it as part of its payload and one for my porter cable 20v lithium set.

Scott - Sorry, I missed this.

On the chargers, most battery maintainers, which I think is what you want, will take a 12v battery to something around 14v to get it fully charged, and then go into "maintenance" mode and keep the batttery at around 13.0v.

Battery Tender has a good, but quite lengthy, discussion of the battery charging "algorithm" on the Battery Charging Algorithm Fundamentals" tab here: http://www.batterytender.com/Battery-Basics.

If you want the battery(s) maintained at full charge w/o boiling them dry I'd recommend that you get something like a Battery Tender, or the HF equivalent, to do the job.  If I remember correctly, Battery Tenders come in dual versions so you could have one of those permanently mounted and just plug the truck in when the time comes.

TheScatch - While for the most part I agree with what you've said, I do have a concern with this plan: "When the key is in run/start the batteries are linked so the aux can also add to cranking if needed, and both batteries then share load when the engine is running and both are being charged by the alternator in this state."

The way Ford's auxiliary battery setup works, as shown below, is that the aux battery only comes in during Run, not Start.  I believe that is so you can run that battery completely down and still start the vehicle.  Otherwise the Start battery would be trying to charge the Aux battery at the same time as starting the vehicle.

And this is one reason I like the Cole Hersee Smart Isolator.  It won't parallel the batteries automatically until one is up to 13.2v, meaning the vehicle is running.  But, there's a manual feature where you can force-parallel the batteries by pushing a button.  So if you know the Aux battery is charged and want a boost you can do that.

The push button to force parallel is a nice feature. I think I originally read how Ford had it run was so you could just run parking lights with the key in off from the Aux battery to reserve the main, then in Run/ACCY off the aux battery and main. Had to do a quick double take here (granted I don't have this set up to begin with so we can deviate a bit) to look and make sure.

But my mindset was linking both batteries in ACCY is a potential failure point. If you have your truck in ACCY running the radio and say the blower for an extended period of time you drain both batteries and could end up leaving yourself stranded. I can see how using Start and Run would also leave you with a battery trying to charge the other rather than start the truck. If I understand you right, this would not be an issue with a smart isolator.

Take this with a grain of salt, because I haven't sat down and really run through the schematics to check all odds and ends, but we talked about a plug and play fusible link PDC the other day, or even one that uses studs. Take all your non-ignition fuse links, put them in the box powered by the aux battery as hot all the time. Between the hot post and S102 put your isolator keyed hot when the ignition is in RUN. I would personally do it between S101 and Connector C610 so it could be unplugged. This would give you everything in the truck power from the aux battery and keep the main battery isolated until the vehicle is started and engine running at which time the alternator is now charging both and supplying power to whole gambit. Nothing is left on to drain the aux battery, normal function is retained because lights are all switched, and the radio/clock/power window circuits need to have the ignition in ACCY just like before. Sounds like you can do the same with your smart isolator.

Aux fuse link box would contain:
-Fuse link C - Body Marker Lamps
-Fuse link B - Trailer
-Fuse link L - Main lights (parking, headlamps, courtesy dome etc)
-Fuse link F - Trailer
-Fuse link M - Ignition Switch (Required to run radio/power windows in ACCY off only the AUX battery, but may need to be on the main batts line in case you killed your aux battery so you could crank, push button to force parallel solves this easily)
-Fuse link P - Trailer Lamps

Main Battery fuse link box would contain:
-Fuse link S - elec. fuel pump
-Fuse link M - Ignition Switch (possibly, see above)
-Fuse link N - Start/Ignition (EEC)
-Fuse link AX - Carburetor circuit


For those add on that are going to run off the aux battery, right next to the PDC for the fusible links put a PDC for fuses for your toys on the driver side. For the fusible links for the main battery/start/ignition you could mount it next to the starter solenoid keeping the two PDC's seperate if you wanted to.

I agree with you that Ford's implementation of the aux batter left a lot to be desired.  As you said, running the radio, like at a car show, could easily drain both batteries if you have an upgraded sound system.  And, you are right that the Cole Hersee smart isolator wouldn't do that.

As for the fuse links, I'm hoping to make this fairly straightforward.  The '96 harness has, as I remember it, a large feed that crosses the radiator support and goes to the PDC.  So I'm planning to pull the feeds you listed and take them to that PDC, using maxifuse positions stuffed with slow-blow fuses to provide the power.

However, there will have to be something on the passenger's fender to hold the megafuse that takes the alternator's output.  And, I'm thinking that having a heavy-duty relay on that fender to be the starter relay would be good to keep the wiring from having to run over to the other side.  So, maybe a small PDC there to hold both the megafuse and starter relay.  Also, I'm hoping to use a relay in the heater circuit to take the load off the switch.  Plus, I want headlight relays.  And since all of those things are on the passenger's side it would be easiest to do that if the relays are on that side.

Concerning the fuse links, they feed either the fuse box under the dash or go to things on the firewall on the driver's side.  So it should be easy to pull those wires out of the harness and take them to the PDC.

Having said all that, it will be interesting as I start laying out the wiring harnesses and see how they match up.  And, thanks for the suggestions.

I like the NW Power Products dual battery system that I first had on my '95 F-150 and now have on my motorhome (I took it off the F-150 when I traded it in).  It has a relay and an on-off-on switch with a 2-color indicator lamp.  In one "on" position it uses power from the main battery to power the relay, but it's switched power (on the motorhome I use an oil pressure switch so it only gets power if the engine is making oil pressure, meaning it's running).  In that position the indicator lamp is green (if the oil pressure switch is on).  So I leave it in this position most of the time.  The batteries are separate when the engine is off, so the aux battery can be drawn down without risking being able to start the truck.  And they remain isolated while I crank the engine on only the main battery.  But they are connected once the engine is running so the alternator can charge both batteries.

In the other "on" position the relay is powered directly from the aux battery and the indicator lamp is red.  This position is labeled "emergency" or something to that effect and can be used to jump start the truck when the main battery is dead but the aux is still charged.

But on the motorhome I also use the "emergency" position when the motorhome is plugged into shore power so the power supply can recharge the main battery as well.  I also do this when I start the on-board generator once a month or so.  This then has the dual purpose of keeping the generator carb from getting plugged up and keeping the batteries charged.


On the topic of an on-board battery charger, it depends on the intended use.  In my motorhome it is almost essential.  When I'm camping I'm not going to be running the truck engine, but I'm going to be using a number of 12V items (lights and the furnace blower mostly) but if possible I'm going to want 110 AC for the water heater and fridge (so I don't need to use up my propane) and for the microwave and occasionally the AC or TV.  So if I'm plugged in anyway it might as well be charging the battery.  And even if I'm not using the 110, I still don't want to run my aux battery down if I don't need to.  So this power supply needs to be a little better than just a battery charger, and it really needs to be on-board.  So any vehicle that's used for camping (or something) near where it maty be plugged in could certainly benefit from something like this.

On my Bronco I could see the benefit of an on-board battery tender.  It sits all winter and every so often I try to remember to hook the battery charger up for a few hours.  Having an on-board tender and leaving it plugged in all the time would make it simpler.  I'm not choosing to do that because it's not that hard to put a charger on it and I don't particularly want to clutter up the Bronco worse than it already is.  But I can see the benefit for a vehicle that's stored for longer periods.

On my truck I don't see as much reason for an on-board charger.  It never seems to sit for more than a day or two in the winter and a week or two in the summer, so it doesn't need a tender.  And the only times I camp out of it are when I'm going somewhere the motorhome won't go, so there probably isn't power anyway.  But living in Minnesota I have thought about having a block heater and a battery heater wired into one plug so I can make sure it will crank over easily on a -35 morning.  If I did that I suppose I could add a battery charger, but it wouldn't really be needed at that point either.

So if you have a use for it, great!  I certainly do on the motorhome (which has one).  But not quite so much on anything else.

It's interesting you bring this up.

I'm considering a rewire of my little PDC so that the PMGR goes to the now spare 'bosch' relay and the big relay wakes the rest of the box up only in start, run or accy.

Ordering that stud mount and fuse at NAPA tomorrow!

https://www.amazon.com/Bay-Marine-Single-Terminal-included/dp/B07LC6PH1L

Odd thing is, the double fused marine version kit (mount and fuses) is a dollar less than single stud kit on Amazon.

The set up I am talking about basically has the truck take place of a motorhome without having a bed slide in. I have seen a lot of the overland guys bring portable 200+watt solar panels to plug in to top off Batts when off grid.  Back when I had a class a rv I was close to buying a set I saw on another guy's class a where he had a solar panel on the roof that was pretty much a rolled out mat that was then attached to the roof.

Perevoskite solar films are finally taking hold in the building industry.
Nothing comes close for ease of installation and damage protection that metal panel roofs with film already applied.

They are also more efficient in diffuse light and off axis orientation than silicon wafers.

ArdWrknTrk wrote

Perevoskite solar films are finally taking hold in the building industry.
Nothing comes close for ease of installation and damage protection that metal panel roofs with film already applied.

They are also more efficient in diffuse light and off axis orientation than silicon wafers.

It's pretty awesome stuff. one of the cool things about the panels on my house (and I believe LG has a line of these) is the light that passes through or gets behind the panel is reflected back up to the underside of the cells and is able to increase the output of the panel by 10-15%. Ill see if I can find the brochure from when I did my roof.

I lied, I actually forgot I opted for the panels made by Canadian Solar and controller by solar edge. 17.8% efficiency rating is in the top tier of current panels. I think the most efficient panel is only around 20%.

Help me understand those charts?  Are we looking at days?

1-12, I would assume months.

There are cells now that are layered and each layer is 'tuned' for a different slice of the spectrum.
So you're gaining from many instead of trying to transform a broad spectrum at reduced efficiency