The 150 series Dual Battery Guide

[drivesafe]

I currently have a d34 optima yellow top sitting in a ARB battery tray is there anything out there that is new on the market that would be an upgrade from the d34.

thanks.

Hi Shonky, I am a big, BIG fan of Optima Yellowtop batteries, and have been using them for many years with great success, but late last year, I was given some info about the new Lead Crystal batteries.

I looked into them and the data being supplied sounded just way to good to be true. But I bought a small number of them in different sizes and started testing them.

I am never interested in the advertising claims made about products intended for RV use, I just want to see if they stand up to the many claims made, when these products are used, and abused, in real world RV situations.

Well I have caned the crap out of all these Lead Crystal batteries and have not managed to damage one of them, and believe me, I have been deliberately abusing them.

Lead Crystal batteries have a number of benefits that makes them ideally suited for the RV market. One of their primary advantages is that they can be left in any state of charge, for very long periods and not have any detrimental effects, other than requiring a couple of charge cycles to get them back to full capacity. This makes them ideally suited for use as house batteries in camper trailers and caravans, that are left unused for long periods between trips.

The batteries are actually delivered with a sticker on them indicating when the battery was last charged, and some of the batteries I bought were last charged nearly 12 months earlier.

This one feature alone makes Lead Crystal batteries ideal for RV use, particularly for use as house batteries in caravans and camper trailers, that are left unused for long periods of time, between trips.

They are also “UNDER-RATED”, meaning they are actually rated at a lower Ah than they can provide.

Lead Acid deep cycle batteries have their Ah rated by testing at C20 loads, where as a Lead Crystal battery's marked Ah is rated using C10 loads. When tested using C20 loads, they are much better than equivalent lead acid batteries.

Another big advantage is that they can be CONTINUALLY discharge to 0% SoC ( 10.5v ) many hundreds of times.

I have been cycling a number of these batteries down to 0% SoC and then charging them with different recharge voltages and they can be easily fully recharged with voltages as low as 13.6v. I have not bothered charging them with lower voltages as yet.

I have had quite a few conversations with the owner of Betta Batteries and he has supplied me with a lot more info about these batteries than is found on the site.

Lead Crystal batteries can be charged with up to 800% of their marked Ah rate, for example a 100Ah Lead Crystal battery can be charged with 800 amps. I am not sure how you would achieve that in RV applications, but they can still be charge with an alternator at high currents and no problems of overcharging or over heating.

Again for example, I have been carrying out bench testing of these batteries, charging FLAT ( 0% SoC or 10.5v ) batteries using different voltages to see how well they can be charged in different vehicles, with varying alternator voltages and here are some of the results.

55Ah battery, charged at 14.0v, had a starting current draw of 47.4 amps and after 1 hour, was still drawing 20.8 amps.

70Ah battery, charged at 13.6v, had a starting current draw of 53.2 amp and was still drawing 31.4 amps.

NOTE if you need faster charging, then an Optima Yellowtop is the way to go, but if you need larger battery capacity, Lead Crystal batteries are a much better choice over AGMs and they have near the same cycle rates as lithium batteries, but at a fraction of the cost of lithium batteries.

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[carco]

I went through this dilemma too, buy an overpriced relatively low output pure sine wave invertor or a direct 12V CPAP power supply.
The CPAP power supply was the same price as the overpriced invertor, a complete rip off from Resmed.
Could have bought a massive output dirty output invertor for less but there was the risk of cooking the CPAP's electronics.
I went the invertor route and it's been very handy. We run 240v fans on hot days, fans that cost $10 from Woolies, can't buy a reasonable output 12V fan for that sort of $$.
A previous poster got the numbers pretty well spot on. You need around 200ah and that will easily give a couple of nights running the CPAP, humidifier and all.
12v fridge is what eats the power.

[shonky 150]

I currently have a d34 optima yellow top sitting in a ARB battery tray is there anything out there that is new on the market that would be an upgrade from the d34.

thanks.

[carco]

I have two GSM batteries in the camper, giving me 250ah capacity. (DC-DC charger) They run my 400w invertor which does the CPAP machine no worries as well as charging the laptop and other small stuff. Same batteries are also running LED lights and the 12V fridge which I set at around -8 Deg C. The next day they'll get a top up via solar panels or half a day's driving will have them fully charged. Car has a new alternator, nothing massive just the standard size and two lead acid cranking batteries. Wiring down to the Anderson plug is nice and generous and I replaced the Toyota starter and earth cables with decent sized stuff. The factory grounds on the 90 were puny, not anymore. It's all about voltage drop.

[drivesafe]

If your CPAP runs on 12V DC from a power supply, than I would suggest running it on battery power instead of through an inverter and a power supply. That will decrease total power use as there are losses in both the inverter and the power supply. Every bit counts!

Hi All In and spot on the money.

This is why I quoted 10 amps per hour, to allow for worst case inefficiency loses in his setup.

Motortrans, as requested earlier in this thread, if you can post up the make and model of your CPAP machine, we can give you a far more accurate idea of what you need.

[All in]

"Sorry for the late reply - The in line power supply that runs to the back of the machine says :
Input - 100 - 240 V 50 - 60 Hz
Output 12v - 6.67 amps.. "

"I'm not sure what you mean by "where are you measuring the current" i thought you relied on current draw by the device..??"

Your earlier post:

"The CPAP machine only runs for 8 hours a night and peaks at an exadgerated 5amp on startup before settling back between 1 - 3 amp depending on how hard its working, humidifier setting etc.."

The question about where you are measuring current I think was refured to before or after an inverter.

With you stating input/output, I assume this is on a power supply. If your CPAP runs on 12V DC from a power supply, than I would suggest running it on battery power instead of through an inverter and a power supply. That will decrease total power use as there are losses in both the inverter and the power supply. Every bit counts!

[drivesafe]

Hi again M, from the info posted, you are probably looking at up to a 10 amp draw for 8 hours.

If this is the case, you would really need to have two 100Ha batteries to get two nights power, and this is just to run your CPAP machine.

You then need to drive for at least 4 hours to get the bulk of the used battery capacity replaced.

Again, can you post up your likely drive times between stops.

[Mototrans]

Where are you measuring the current? You say it's a 240v machine so if you're measuring 1-3A at 240V then your maths isn't correct and I suspect you'll need a much bigger battery.

AB

Sorry for the late reply - The in line power supply that runs to the back of the machine says :
Input - 100 - 240 V 50 - 60 Hz
Output 12v - 6.67 amps..

I would generally camp in the one spot for a two night maximum.

The Fridge is a 65l Waeco that draws .8 amp while running according to their specs...

In terms of camping lights, i will be running LED light strips mainly around the rack.. and that's about it...

I'm not sure what you mean by "where are you measuring the current" i thought you relied on current draw by the device..??

[LeighW]

It indicates the charger has a temperature compensation function to protect the battery and should be installed in the same ambient conditions as the battery.

"It is recommended that you contact the battery manufacturer and see if they recommend having a derating charging source due to temperature

The above statement makes no sense, they have indicate like other chargers it has inbuilt temperature compensation to protect the battery, they then suggest you ask the battery manufacturer if it is needed, they know it is!

"Just for your information it has been noted that a lot of installers have found in front of the radiator to be a good location to mount a BCDC charger but also need to be conscious of which profile has been selected."

What they are alluding to with that statement is if you don't have the charger in the same ambient environment to the battery then you may need to lower or increase the charge voltage profile to what would normally used, ie an AGM might have a charge profile of 14.6V@24C but as the charger is in a cooler environment you may need to derate to 14.4V if possible for example. In my opinion that is a poor solution, the temperature compensation is a dynamic function, as the temperature drops the charger increases the voltage by around 3mv per cell per 1C fall, as it rises it decreases the voltage. The charge rate will will never be what the designer intended if the charger is in a different environment to that of battery, they should have provided a remote temperature sensor for when the charger must be located away from the battery.

[2016VX]

Thanks for all of your input. I did send an inquiry off the Redarc and here is what they had to say. A fairly general response if you ask me, but they did respond within 2 hrs of the inquiry.

"Thank you for your email
For the most possible protection of your battery, having the BCDC charger right next to it is the most suitable situation. Unfortunately with a lot of modern vehicles having the BCDC charger right next to the battery is just not possible due to spacing restrictions. The requirement to move the BCDC charger closer to the battery will be dependent on the auxiliary battery that has been fitted. It is recommended that you contact the battery manufacturer and see if they recommend having a derating charging source due to temperature fitted closer to the battery for extra protection, and also note to them the charging profiles available from the BCDC charger. Just for your information it has been noted that a lot of installers have found in front of the radiator to be a good location to mount a BCDC charger but also need to be conscious of which profile has been selected.

I trust this clarifies the question for you. If you have further queries, I recommend you call REDARC Technical Support on (08)83224848."


Doesn't really tell us anything we don't already know.

[drivesafe]

There is a Catch22 in situations like this.

All DC/DC devices must be mounted as close as possible to the battery they are intended to charge.

Failure to do so can cure enough voltage drop, be it very small, but this can result in the battery being continually undercharged, but because of the temperatures being imposed on the DC/DC device if it is close to the battery, can again cause undercharging.

The alternative is, if the DC/DC device has a temperature monitoring probe, then the DC/DC device could be mounted in a cooler location and then fit extremely thick cables between the DC/DC device and the battery being charged by it.

[rpn]

The bottom line is does the charger modify its output voltage as the temperature rises or falls
as it should for correct charging of the battery, ie see temperature compensation of charging voltage
for lead acid batteries? If it doesn't have inbuilt temperature compensation then this is not good for the
battery and I would be looking at a charger that does. If it does then mounting the charger in a cooler
environment to the battery will cause the battery to be overcharged and reduce its life.

Advising to fit the unit in front of the radiator is to overcome poor design of their charger as it
it can't cope with the heat, that is cool itself and it overheats and derates its output, this is a know
issue can result in little or no charging in hot environments ie heading up north. If the charger
needs to be mounted in a cool environment they should have an external temperature sensor
for battery temperature monitoring.

If it doesn't have inbuilt temperature compensation then this is not good for the battery and I would
be looking at a charger that does.

The Projecta IDC25 I just installed does have a temperature probe that should be attached to the battery case.

I mounted the unit behind the aircleaner, so in the corner between the right hand guard and firewall and even after the 40km commute to work the case is barely warm to touch. I guess slow low-range 4WD work may increase under bonnet temps due to lack of air flow. I'll see how it goes and consider moving it if required.

[LeighW]

The bottom line is does the charger modify its output voltage as the temperature rises or falls
as it should for correct charging of the battery, ie see temperature compensation of charging voltage for lead acid batteries? If it doesn't have inbuilt temperature compensation then this is not good for the battery and I would be looking at a charger that does. If it does then mounting the charger in a cooler environment to the battery will cause the battery to be overcharged and reduce its life.

Advising to fit the unit in front of the radiator is to overcome poor design of their charger as it
it can't cope with the heat, that is cool itself and it overheats and derates its output, this is a known issue can result in little or no charging in hot environments ie heading up north. If the charger needs to be mounted in a cool environment they should have an external temperature sensor for battery temperature monitoring.

If it doesn't have inbuilt temperature compensation then this is not good for the battery and I would be looking at a charger that does.

[2016VX]

It was actually the NSW RedArc rep who pointed me to the supplier for this bracket.

I don't think there is anything wrong with mounting in the engine bay, afterall people have been doing it for years, but the problem is, Redarc recommend that the charger be installed as close as possible to the Aux battery, and as we know on a D4D Prado, the Aux battery is right next to the hot turbo charger. Redarc state "The unit will operate optimally below 55°C with good airflow. At higher temperatures the unit will de-rate output current up to 80°C where the unit will turn OFF ".

I have never measured it, but on a hot day in summer, I would bet the engine bay gets close to or above 80degC. There were a few days last summer that reached 45degC in Sydney and I bet my BCDC would have given up if I had it installed back then. Might be an experiment I do over the weekend. I have a digital thermometer with Max/Min readings (I use in my wine fridge). I'll find a way to mount it under the bonnet so I can see how hot it gets.

[LeighW]

It seems to be the flavor of the month to mount the charger in front of the radiator to
keep it cool and stop it throttling back due to high temperatures etc.

Most chargers are temperature compensated, ie they reduce their output voltage as
the ambient temperature increases, as the battery gets hotter it needs less voltage to
fully charge it. As such most charger manufactures recommend the charger be located as
close as possible to the battery being charged, ie in the same ambient temperature as the
battery being charged so that the charger can compensate as the temperature changes.

Some chargers have an external temperature probe that can be fitted to the battery being
charged should the charger be located in a different environment.

Reading the current literature for the Redarc chargers they no longer mention temperature
compensation but I would imagine their chargers are still doing it if they are providing the best
charging regime for the battery. It may therefore not be a good idea to locate the charger in a
cool air stream when the battery is located in a different location especially under the bonnet.
I note they do state charger should be located as close to the battery being charged as possible.
I would be asking Redarc if it is a good idea to mount as above.