Converters, Batteries, Solar Controllers and BUYERS BEWARE

[gypsydad]

Originally Posted by CarterKraft

So you only charged once for 4 hours with 80w solar the whole 5 days?
I am still learning so I really can't comment right or wrong but something does seem odd with your usage and voltages. Were you at 12.7v when you started?

I don't worry about getting to 11.9 with flooded lead acid batteries but you might. I have no problem going to 80% If I will be recharging same day but I might on a 5 day trip if I hit 80% early and didn't have the charging watts to recoup to 100% in a day.

More accurate data: My wife reminded me, we did stay in Placid lake first couple days, then we moved to Hungry Horse Reservoir the last 3 days, so my statement was not accurate; There was a 2 hour drive plugged in provided charge from the TV on way from Placid to Hungry Horse....(guess that would have been pretty good if I had used them for 5 days with heater each morning!).

These are the wet cell, 6V, T105's, now 1 year old. I typically monitor just the inside meter and will use the solar or my DualFuel generator when they drop below 12.1V usually. I guess getting that additional monitor with the shunt is a good idea after reading all your recommendations. Any more suggestions/ comments about installation of the monitor and running the wires is appreciated...

[Fair_Enough]

Originally Posted by gypsydad

More accurate data: My wife reminded me, we did stay in Placid lake first couple days, then we moved to Hungry Horse Reservoir the last 3 days, so my statement was not accurate; There was a 2 hour drive plugged in provided charge from the TV on way from Placid to Hungry Horse....(guess that would have been pretty good if I had used them for 5 days with heater each morning!).

These are the wet cell, 6V, T105's, now 1 year old. I typically monitor just the inside meter and will use the solar or my DualFuel generator when they drop below 12.1V usually. I guess getting that additional monitor with the shunt is a good idea after reading all your recommendations. Any more suggestions/ comments about installation of the monitor and running the wires is appreciated...

Trimetric installation guide is a class of study in itself. Too much information to type on here. But, download from the link and read it. I am not a Victron guy, but my guess is they have good info as well.

In a nutshell, you add a device called a shunt, which is a precision 1 ohm resistor that is rated at 100A or typically 500A. The smaller is more accurate, but actual amps that can pass are far below 100A or 500A. I recommend going with the 500A/50mv variety. It might require minor wiring redo. The battery negative side is connect to one side and ALL loads and charging sources the other. Then there is low voltage wires to the monitor, including 12vdc to power it. It reads the voltage between battery and source/load and converts into amps or watts used or gained.

Victron (get the right one) sends data to a smartphone, thus possibly eliminating the need for a physical monitor and wires ran.

http://www.bogartengineering.com/wp-...2=false&r=wide

WW

[leedav]

You still need the physical monitor. It houses the Bluetooth radio. You just don't have to mount it somewhere prominent.

[leedav]

And the microprocessor that integrates the current flow over time. It checks the current continuously and adds up the time slices to get ampere hours. That's what makes an ammeter into a useful battery meter.

Originally Posted by leedav

You still need the physical monitor. It houses the Bluetooth radio. You just don't have to mount it somewhere prominent.

[CarterKraft]

Originally Posted by gypsydad

More accurate data: My wife reminded me, we did stay in Placid lake first couple days, then we moved to Hungry Horse Reservoir the last 3 days, so my statement was not accurate; There was a 2 hour drive plugged in provided charge from the TV on way from Placid to Hungry Horse....(guess that would have been pretty good if I had used them for 5 days with heater each morning!).

These are the wet cell, 6V, T105's, now 1 year old. I typically monitor just the inside meter and will use the solar or my DualFuel generator when they drop below 12.1V usually. I guess getting that additional monitor with the shunt is a good idea after reading all your recommendations. Any more suggestions/ comments about installation of the monitor and running the wires is appreciated...

Opinions vary but I don't think a shunt meter will be a necessity for you, handy yes but not mandatory. With lithium batteries its of more importance due to the very narrow voltage range but with lead acid you are moving from 12.77-11.6v making counting amps less important.

For me I like to geek out on the various amp consumption of each device in the trailer and how they effect my overall usage/capacity. When I lay down at night I can see if there is an usual amp draw that doesn't need to be there and can prevent it from prematurely running my batteries down when I don't expect it.
I used this Bayite 100amp shunt meter first but I didn't like how I couldn't power the 1500w inverter through it so I have swapped it for this Juntek VAT-1300 that has a wireless display and a 300 amp shunt. The 100A shunt meter will get moved to the bass boat for monitoring the trolling motor batteries.

I have no doubts that the quality compared to Bogart or Victron is not there but they have some features the others don't, like wireless display and economical price tags.

[Fair_Enough]

Originally Posted by gypsydad

More accurate data....There was a 2 hour drive plugged in provided charge from the TV on way from Placid to Hungry Horse....

Hi again g,

That 2 hour drive did very little to charge your batteries. The major culprit is the TV system is "concerned" about the TV battery and secondarily the voltage drop due to small wire gauge is another big factor, the third and most obvious is the 2 hour run time.

If you had driven all day, it would help.

If you ever had to use the TV... turn it around and use jumper cables. But, the hours idling would be a definite CON, IMO. Here's something interesting. Your car idling could possibly use slightly less gasoline than a 1000W Honda.

The "key" to voltage drop for a charging source, is that the loss at the voltage and current should be no greater than 3%... less is better.

Clint

[rickst29]

Originally Posted by gypsydad

More accurate data: My wife reminded me, we did stay in Placid lake first couple days, then we moved to Hungry Horse Reservoir the last 3 days, so my statement was not accurate; There was a 2 hour drive plugged in provided charge from the TV on way from Placid to Hungry Horse....(guess that would have been pretty good if I had used them for 5 days with heater each morning!).

slightly OT, and well-covered in Threads such as this one: http://www.airforums.com/forums/f37/...ml#post2269160. After testing that the "Starter" Battery under the hood has been pretty fully charged, most modern Tow Vehicles will drop the on-board Voltage down to a "Float" Value (13.4-13.8V). The control module (ECM) under the hood, which manages alternator output, sees the Starter Battery Voltage, but cannot "see" the Trailer Battery Voltage through the long and thin "Trailer battery charge" wire path.

In camp, you can overcome that problem by connecting the Trailer batteries to the TV battery with a jumper cable (or other high-amperage cable). With a jumper cable, all of the the batteries are basically interconnected - and the low charge state of Trailer batteries drags down the Voltage of the TV Battery, causing the ECM to raise voltage (so that the "low" TV battery gets charged.) This works well, but doesn't work on the road. It also requires long idle times, which might not be healthy for the TV.

On the road, you can use a Voltage "Boost" Converter and Charge Controller, built into a single box and installed in the Trailer on a permanent basis. The cheapest one is pretty good: https://www.renogy.com/renogy-12v-dc...ttery-charger/. When the Tow Vehicle is running at 13.5V, The Renogy will pull power through the Bargeman "Battery Charge" wiring path. The high current causes voltage drop in the thin wires, but the initial "Boost Converter" stage raises the Voltage from the TV. Then, it goes into a simple PWM "Solar Battery Charge" section, which converts the boosted Voltage back down to the Voltage your batteries want to take at that moment - based on State of Charge. The Renogy can provide a maximum battery charge of about 250 watts (roughly 17A at 14.2V).

But from the TV, high current causes Voltage Drop on the "Trailer Battery Charge" wires and connectors - so it is typically pulling up to 25A through the Bargman, and using the "Boost Converter" section to raise the Voltage above the battery charging requirement.

Without such a device, the 13.5V "under the hood" of the Tow Vehicle, when trying to charge batteries, isn't enough to do more than a nominal float.

[gypsydad]

Originally Posted by Wolfwhistle

Hi again g,

That 2 hour drive did very little to charge your batteries. The major culprit is the TV system is "concerned" about the TV battery and secondarily the voltage drop due to small wire gauge is another big factor, the third and most obvious is the 2 hour run time.

If you had driven all day, it would help.

If you ever had to use the TV... turn it around and use jumper cables. But, the hours idling would be a definite CON, IMO. Here's something interesting. Your car idling could possibly use slightly less gasoline than a 1000W Honda.

The "key" to voltage drop for a charging source, is that the loss at the voltage and current should be no greater than 3%... less is better.

Clint

Thanks for that suggestion, but I didn't mean to suggest I didn't have alternative source..I have a generator (Dual Fuel Champion) if/when needed. I don't carry jumper cables either; I have a small portable Li battery I use if needed for emergency use.

I am happy with the T105's vs the OEM Interstate 12V that came with my AS...for our use model these 6V batteries are doing a great job. I am also still very interested in the Goal Zero suggestions in another thread currently on the Forum. The option of a GZ 1000 or GZ 1400 is very attractive! (just need to find the right discount)

http://www.airforums.com/forums/f37/...um-196422.html

[Ponobill]

Wow, I've been told I'm wrong about the complexity of maintaining LA batteries a whole bunch of people who go on to detail far more complex maintenance issues than I've even contemplated. I will build a BMS for lead acid, just for fun, which is all I do any of this stuff for.

[batman]

Good info. Thanks memph.

[uncle_bob]

Originally Posted by Ponobill

Wow, I've been told I'm wrong about the complexity of maintaining LA batteries a whole bunch of people who go on to detail far more complex maintenance issues than I've even contemplated. I will build a BMS for lead acid, just for fun, which is all I do any of this stuff for.

Hi

Indeed for a couple thousand dollars you could build up a proper BMS for a bunch of individual lead acid cells. You would have to start with 2V cells to do it right ( = you need to get at each cell). The gotcha is that you can buy a Lithium battery *with* the BMS for a lot less than what a proper one off would cost you. Unless you just have a bunch of money to throw around - why bother?

Bob

[Ponobill]

Originally Posted by uncle_bob

Hi

Indeed for a couple thousand dollars you could build up a proper BMS for a bunch of individual lead acid cells. You would have to start with 2V cells to do it right ( = you need to get at each cell). The gotcha is that you can buy a Lithium battery *with* the BMS for a lot less than what a proper one off would cost you. Unless you just have a bunch of money to throw around - why bother?

Bob

A couple thousand? What? I'd modify the code for a SimpBMS and run it on an ESP32. Might cost me ten bucks and an hour or two. Plus 35 bucks if I wanted to add a Raspberry pi and touchscreen to monitor it. What I don't have is time to add yet another project.

[kpm]

Originally Posted by Ponobill

A couple thousand? What? I'd modify the code for a SimpBMS and run it on an ESP32. Might cost me ten bucks and an hour or two. Plus 35 bucks if I wanted to add a Raspberry pi and touchscreen to monitor it. What I don't have is time to add yet another project.

I don't see how this helps anyone.