Ideas for charging batteries while on long road trip?

[PdxSteve]

They charge at 16.8V, not 120V. The current draw is a lot higher the lower the packs charge is. If your pack is around 20% full and you put it on the stock charger, it will draw closer to 3.3A@16.8V.

They start at a high charging current and slowly trickle off to 200mA as the battery voltage increases until fully charged. The initial charging current is determined by how full/empty the pack is, which is determined by the batteries voltage.

Since you were reading .9A, I'd assume your pack was already over 80% charged to start with.

The max the stock charger will do is 16.8V * 3.3A = ~55W. But again, it will only draw that much if your battery is pretty low. You should be able to safely simultaneously charge 3 totally depleted batteries using the stock chargers with a 200W inverter.

 

[Contestedmilk]

I installed a 1000W Pure Sine inverter in my SUV. Ran 0 gauge wire from the battery to the back. I charge all of my batteries (6), laptop, iPad mini, and galaxy tablet at the same time.

Works great.

wow! ok, I would love more information. Do you have 6 battery charger cables? How do you charge all 6 at once? Also, does this drain the battery so much that it would bring other problems?

 

[Contestedmilk]

I went overboard with my inverter. It is a 2000 watt, and I have 6 Solo batteries and 2 OEM chargers. I can throw my pellet grill in my truck and enjoy lunch while charging my batteries while listening to my satellite radio on my boombox. It makes for a more enjoyable day. Good luck, Contestedmilk, and welcome to the forum. By the way, me and my inverter are available to accompany you Iceland...

thanks for the info

 

[Contestedmilk]

For a road trip in Australia I bought a solar panel, put in a second battery and a converter which was excellent set up. I have 3 batteries and managed to work around that. The sun sets pretty early in Australia, even in summer. Not like (I assume) summer in Iceland. That would be amazing.

Thank you for responding. Which solar panel did you buy? How long did it take to charge a 3dr solo battery? Did you just keep the second car battery inside the vehicle?

 

[Contestedmilk]

The cool thing about the Wagan is that it's just so handy for just about everything, Solo or no Solo. And at around 120-130 bucks, a good deal too.
It has two outlets, too.

View attachment 3050

this looks perfect! (for in country trips) I'm going to fly internationally however. Sill want one for home use! thx!

 

[ajdelange]

They charge at 16.8V, not 120V. The current draw is a lot higher the lower the packs charge is. If your pack is around 20% full and you put it on the stock charger, it will draw closer to 3.3A@16.8V.

That's on the DC side. These things are not 100% efficient.

They start at a high charging current and slowly trickle off to 200mA as the battery voltage increases until fully charged. The initial charging current is determined by how full/empty the pack is, which is determined by the batteries voltage.

Since you were reading .9A, I'd assume your pack was already over 80% charged to start with.

No, about half charged.

The max the stock charger will do is 16.8V * 3.3A = ~55W.

That's on the DC side. From the mains the charger is drawing about 108 watts at mid charge level.

But again, it will only draw that much if your battery is pretty low. You should be able to safely simultaneously charge 3 totally depleted batteries using the stock chargers with a 200W inverter.

That would be ill advised. I don't know what the draw is for a fully depleted battery but for a half way depleted one it is 108 -110 watts. Three chargers would draw 330 W when their batteries are half charged which is an overage of 50% which I'm guessing most inverters would not be able to withstand for very long. Now if you have a copilot willing to monitor things you might be able to charge more than one simultaneously as the charger's draw does decrease to 24 W by the time only 1 light is flashing. You could top off two at the ends of their charge cycles and start one completely discharged one (assuming th charger doesn't draw much more than 0.92 amps when the battery is close to being completely discharged.

 

[ajdelange]

Did a measurement on a nearly completely discharged battery. Charger drew 0.86 amps at startup so it appears that the current draw is 0.86 - 0.92 amps (corresponding to 103 - 110 W) over most of the charge cycle with a taper in the last 20% (?) down to 20 W or so.

 

[Contestedmilk]

Guys forgive me but I am new to understanding how batteries/power flow works. I am learning but not solid on the terminology so a layman explination of these terms and concepts would be appreciated greatly! How exactly do I know if I will be pushing my inverter further than it is capable. I have an "Aukey 300W Power Inverter" Input DC 12V Output AC:110V +-10% , I also have two solo charging cables, 4batteries. I will be driving a camper van or a rented car. I s it possible to run a wired connection from the battery under the hood into the car/van so I can charge directly off of the battery and still drive at the same time?...just a thought...

 

[ajdelange]

Under normal circumstances you plug the charger into a wall outlet from which it takes AC current and converts that to DC current which it supplies to the battery over time at a level appropriate to the charge status of the battery - a fairly hefty current at first and then at a tapering rate as the battery nears full charge. The charger consumes at most 110 Watts (that's a unit of power). In the auto there is no AC and so you must take DC from the auto's battery and convert it to AC 110 volts with the inverter. The battery charger(s) are then plugged into the inverter. As the chargers draw at most 110 watts AC the maximum load on the inverter will be 220W, well below its capacity of 300 W and all should be well. Keep in mind that the inverter will be drawing about 20 amperes from the battery to supply the 220 watts the chargers consume. That's a pretty hefty load and it will drain a 60 Ampere Hour battery in about 3 hours with the engine off. If you do your charging while driving there should be no problem with this.

Is it possible to connect directly to the automobile battery? No. The inverter changes the auto electric system's 12 V to 120 VAC which the charger then converts back to DC for the battery. There are very probably chargers which accept 12 VDC that will charge these batteries. They are called DC/DC converters but here's a big secret. They have inverters in them.

 

[PdxSteve]

You could also just use a DC-DC CC/CV step up converter. Set CV to 16.8V, CC to 5A and plug directly to the car battery. You don't need the 3dr charger or an inverter to charge in a car. Going from 12vdc (battery) to an inverter to convert it back to 120VAC, so you can plug your 3dr charger to convert it back to DC is just a long round trip with a lot of unnecessary parts and very inefficient.

They cost about $13 bucks. No $50 3dr charger needed. No expensive DC-AC inverter.

Edit: the only advantage the inverter has is being able to power other 120vac devices. The boost converter will only charge the batteries.

 

[ajdelange]

The big advantage the inverter has is that he's already got it.

 

[PdxSteve]

Not everybody reading this thread does though. Just providing info for others...

 

[Contestedmilk]

Under normal circumstances you plug the charger into a wall outlet from which it takes AC current and converts that to DC current which it supplies to the battery over time at a level appropriate to the charge status of the battery - a fairly hefty current at first and then at a tapering rate as the battery nears full charge. The charger consumes at most 110 Watts (that's a unit of power). In the auto there is no AC and so you must take DC from the auto's battery and convert it to AC 110 volts with the inverter. The battery charger(s) are then plugged into the inverter. As the chargers draw at most 110 watts AC the maximum load on the inverter will be 220W, well below its capacity of 300 W and all should be well. Keep in mind that the inverter will be drawing about 20 amperes from the battery to supply the 220 watts the chargers consume. That's a pretty hefty load and it will drain a 60 Ampere Hour battery in about 3 hours with the engine off. If you do your charging while driving there should be no problem with this.

Is it possible to connect directly to the automobile battery? No. The inverter changes the auto electric system's 12 V to 120 VAC which the charger then converts back to DC for the battery. There are very probably chargers which accept 12 VDC that will charge these batteries. They are called DC/DC converters but here's a big secret. They have inverters in them.

thurough. thank you.

 

[Contestedmilk]

You could also just use a DC-DC CC/CV step up converter. Set CV to 16.8V, CC to 5A and plug directly to the car battery. You don't need the 3dr charger or an inverter to charge in a car. Going from 12vdc (battery) to an inverter to convert it back to 120VAC, so you can plug your 3dr charger to convert it back to DC is just a long round trip with a lot of unnecessary parts and very inefficient.

They cost about $13 bucks. No $50 3dr charger needed. No expensive DC-AC inverter.

Edit: the only advantage the inverter has is being able to power other 120vac devices. The boost converter will only charge the batteries.

I did not understand this.

 

[pete]

when using inverter to charge the Solo batteries, would it have some long term negative effect on them ?

my camper is equipped with Dual 120AH deep cycle batteries that are charged while I'm driving or alternatively by solar panels. I have Sinergex Pure sine wave 700w inverter, when charging Solo batteries I noticed they get fully charged much quicker than when charging them at home, I think it takes less than 1 hour per battery (I'll use my stop watch next time I'm charging) and I'm not sure if such a quick charge would affect the batteries somehow.

 

[PdxSteve]

In general it wouldn't have an effect. It might be possible it could if you have a crappy inverter putting out a lot of noise.

I'm not sure how they could charge faster using a DC to AC inverter. Solos charging brick won't output more or less based on small variances in the supply AC since it's a voltage regulator and meant to smooth such things out. The output should be pretty much constant.

 

[Pedals2Paddles]

I your 3DR solo charger is recharging the battery in "less than an hour", your battery was only half empty, or it wasn't fully charged, or your charger is lying, or your clock is lying. It is mathematically impossible for a 3.3 amp charger to put 5 amps into a battery in less than an hour.

 

[SPP]

If this is the inverter, Sinergex 700 Watt PureSine II 12 Volt Pure Sine Wave Inverter SIPS700/12 - 12 Volt Technology
I doubt at US$700ish price tag its a modified sine wave inverter, it must be as what it claimed as PURE sine wave.
I think Pete's battery was at 50% discharge as P2P mentioned.

 

[pete]

I your 3DR solo charger is recharging the battery in "less than an hour", your battery was only half empty, or it wasn't fully charged, or your charger is lying, or your clock is lying. It is mathematically impossible for a 3.3 amp charger to put 5 amps into a battery in less than an hour.

that "under 1 hour" was my guestimate, I didn't actually time it that time, I just know I put the battery on charge and it was full in no time, then I did 2nd battery and same thing happened, I was little bit busy around the camp fire, next time I went to check it was fully charged. but I think you are right, probably I just had too many beers that day.
yesterday I was timing it with stop watch and it took 2:20.
(usually I land with 10-15% battery left)

 

[faroutmatt]

That's on the DC side. These things are not 100% efficient.

No, about half charged.

That's on the DC side. From the mains the charger is drawing about 108 watts at mid charge level.

That would be ill advised. I don't know what the draw is for a fully depleted battery but for a half way depleted one it is 108 -110 watts. Three chargers would draw 330 W when their batteries are half charged which is an overage of 50% which I'm guessing most inverters would not be able to withstand for very long. Now if you have a copilot willing to monitor things you might be able to charge more than one simultaneously as the charger's draw does decrease to 24 W by the time only 1 light is flashing. You could top off two at the ends of their charge cycles and start one completely discharged one (assuming th charger doesn't draw much more than 0.92 amps when the battery is close to being completely discharged.

Any one actually set up a dc to dc charge system? What converter? Fused? No pure sinewave direct from battery?