DEEP CYCLE BATTERIES and BUSH POWER

Not sure if this has been covered under this thread so having never owned an AGM battery I have now purchased a 120AH AGM and about to use it for the first time in my camp situation to run a 60L portable fridge and a LED light.

However I have read this : " Most batteries (AGM) when purchased are not at 100%, when manufactured the plates are coated with crap to slow the charge rate/burn rate from manufacture to delivery. When you buy the battery and install it for intended use you need to burn the coating off the plates to do this you need to work it hard and recharge it hard for the first several cycles eg use it down to on 100 amp battery bring it down to 65 to 70 amps and recharge back to 100% the same day do this for several days to get the battery fully operational."

Therefore if true what DOD should I do on my 120AH AGM for its first several cycles?

Thanks in advance.

I've not heard of that one, however, the biggest single problem with an AGM is operator error.

The key points of maximising AGM battery life are;

• Limiting Depth of Discharge[/*]
• Correct charging [/*]
• Temperature[/*]
• Being aware of condition.[/*]

I have a 120AH in my caravan, I limit DOD to 25% and on occasion will suffer 30%, so 30AH to 36AH, which should get me about 8 years of battery life. If you constantly draw 50% between charges, you will reduce battery life to about 3 years. (The life expectancy is variable so use these figures as a guide)

Charging - Do not use a workshop battery charger or the 12VDC output of a generator to charge an AGM, they need a "smart charger" as noted earlier in this thread.

Be careful to avoid getting the battery overly hot i.e. under some bonnets, their output drops off and life expectancy is reduced.

Awareness - If you don't have some kind of monitor on a deep cycle battery (AGM, GEL or Wet Cell) how can you know what you are using (DOD) or when to charge.

If you are concerned about "burning the plates off" it's not so much about DOD as it is about the load applied. To explain - pulling 2 amps for 30 hours = 60AH and does not "work" the plates. Pulling 10 amps for 6 hours, will. However I'd still be limiting DOD to between 30 and 40AH on a 120AH AGM. Running your fridge should be enough load to work your battery.

You haven't stated how you charge it, what the load of the fridge is, other devices powered, if you monitor or any thing else, but the above will apply regardless.......

condor22 said:

You haven't stated how you charge it, what the load of the fridge is, other devices powered, if you monitor or any thing else, but the above will apply regardless.......

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Thanks Condor22,

Btw Solar Charging is out of the question due to the camp being under plenty of tree foliage.

Therefore I will be charging the 120AH AGM using a generator to supply 240v to operate a Power Train 20 Amp 8 Stage Smart Battery Charger With LED Display Panel.

This particular charger while it is charging displays the Charging Voltage, Battery Capacity % as well as Charging Current in Amps.
Also below these figures Bar Lines appear that refer to what stage the charger is up to during its 8 Stage of operation.

My 60L portable fridge according to its specs says when running in Fridge Mode with the operating temp at -2 to +2 degrees it draws 1.49 amps per hour (Average over 24 Hours)

My LED light draws 0.6 amp per hour.

I am hoping to limit my DOD too as you say 25% or 30 amps with the figures Ive stated although would be struggle over a 24 hour period and so limit my generator use time?

Maybe I could limit my charging only up to the Absorption Mode which says the battery is at 92 to 94% charged then do a full 100% charge when back home on normal 240 v supply since I will be out at the camp up to 4 days at a time?

However what % DOD from 90% Battery Capacity would be required and if doing it this way would it harm its overall life?

Or just accept the fact of having to run the generator every 12 hours and hopefully for not too long?

Rush, sounds like you have an ok setup for charging/monitoring. If charging, you should charge back to full, otherwise you are not conditioning the battery properly.

Your fridge average of 1.49 A is subjective, at that the fridge will pull 36AH in 24 hours. You need to find out what it's really doing in 24 hours in various conditions.

As I stated, my Engel uses 25AH/day on a 20deg ambient day (cooler at night), it uses 25AH in 8 hours on a 40 deg day, so probably more like 50AH for the day. On a recent trip to Loveday it went to -2 overnight. I stopped driving at about 3.30pm, so fully charged and in the morning about 8 am I had only used a very small amount of battery. I can't remember exactly how much, but it was something like 5AH for the 16 hours.

With my setup, I'm charging my 4x4 Auxiliary when driving, as well as the van battery. But when camped, I'm not charging the van battery unless I either put solar on or crank up the genny. On that recent trip running the TV until 2am watching cricket, a couple of LED lights and running the diesel heater I used about 36AH out of my 120AH AGM, it took about 3 hours to charge it off the genny.

On my next trip I will be taking a folding 120W panel and although I may have shade on the van, I can move the panel into the sun. It will still be spring and I'll be on camps in the GT. So, I'll take a battery reading in the morning, then see what the panel puts back in by the time I return to camp from prospecting and on sunny and overcast days to see the difference. The way I look at it is, the more the panel puts in, the less genny gets used.

BTW my smart charger is only 15A, but I'm not running a fridge in the van, it's on LPG.

You should only need to run the genny once per day, however, if like me you are around camp in the morning for an hour or more, turn the genny on whilst you have brekky, then when back at camp in the arvo, charge until full. A genny on economode will only be idling using the charger anyway. A partial charge in the morning is better than no charge, so long as you fully charge at night.

As I also previously said, I also run the genny to heat water for dishes and a shower as well as cook in the microwave to save the LPG for the fridge.

Having the right gear is only half of it, the process of how long, when and with what is the other half.......i.e. management.

Excellent advice Condor22.

Just in regards to the ECO Throttle mode on my Honda genny,which I am yet to use, it says in the operator manual that the engine is kept at idle automatically when the electrical appliance is disconnected and it returns to the proper speed by the electrical load when the electrical appliance is connected.

Therefore will the genny be idling when the charger is charging the battery as it appears to me as NOT from how I interrupt the above?

Thanks again.

I only go with what my Honda does. My charger pulls 408W max to charge, which is < 1/4 of what my 2kVA will provide. It is a demand throttle, so only increases as the load demands. It barely increases in speed when charging and slightly reduces as the chargers load reduces the nearer the battery gets to fully charged.

I can't quote other gensets apart from Yamaha, I know these work the same way. If yours is an el cheapo it could do anything.

condor22 said:

If yours is an el cheapo it could do anything.

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My genny is a 1kva Honda EU Invertor EU10i

Not sure what my charger pulls?

Oki, well your charger will pull more than mine on a genny half the size, not hard to figure it will rev more, lol.

An update on my above posts re: Solar Panel mal-function on my Troopy High-top BushMaster.....

Thanks to Condor/others : yep, the panel was u/s .... as you commented.

Original panel on the Troopy High-top was 190 watts, has now been replaced by a 200 watt unit which is currently
out-putting 20.3V to my AGM [house] battery, functioning perfectly with no load @ 14.3V ...................

Unit was approx. $200 only, delivered free from Melbourne to the Sunshine Coast - and very prompt.

In the process of hooking up my 55 litre fridge freezer to it - anticipate no further problems !!

Have also mounted an LED 120W Light Bar to the leading edge of the panel , also operating from this battery'
But remotely switched only and not connected to my vehicle high beam lights.
Gives me the option of 'boosting' my high beam, at my discretion, great for crawling through the bush at night-time.
Don't do this often though, but very handy to have.

Great advice from all - am once again a happy camper/prospector .....................

Is there any chance your panel mounted light bar might damage the panel due to the vibration ?

Can you mount the light bar independently ?

Pedro the Gold said:

An update on my above posts re: Solar Panel mal-function on my Troopy High-top BushMaster.....

Thanks to Condor/others : yep, the panel was u/s .... as you commented.

Original panel on the Troopy High-top was 190 watts, has now been replaced by a 200 watt unit which is currently
out-putting 20.3V to my AGM [house] battery, functioning perfectly with no load @ 14.3V ...................

Unit was approx. $200 only, delivered free from Melbourne to the Sunshine Coast - and very prompt.

In the process of hooking up my 55 litre fridge freezer to it - anticipate no further problems !!

Have also mounted an LED 120W Light Bar to the leading edge of the panel , also operating from this battery'
But remotely switched only and not connected to my vehicle high beam lights.
Gives me the option of 'boosting' my high beam, at my discretion, great for crawling through the bush at night-time.
Don't do this often though, but very handy to have.

Great advice from all - am once again a happy camper/prospector .....................

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Great news Pedro...

NOTE - I'm out prospecting, so may not be online much for the next month or so.

Heads-Up :
Good point there, will activate appropriate countermeasures to prevent that !!

quick question.
On the back of the panel in the junction box, Have you checked both sides of the diode. ?
Some have a diode to stop the battery discharging at night through the panel.
They crack up and don't conduct turning into either a resistor or open circuit.

Pedro , how much current does your angelina jolie blow up doll draw in standby mode ?

Mine pulls about o.3 amps in standby and 40 amps in party mode which seems like a lot but you got to admit she is pretty hot.

Pedro the Gold said:

Thanks for the very prompt responses .

I'm pretty sure you have 'pegged' it correctly ...... as a faulty Panel or wiring problem.
I will thusly bite the mullet and remove the panel, either way.

The isolator between Bat 1 & Bat 2 Yep, understand that.
BUT : I have a cunning plan in place

Can also power up my Air Pumperer-upper for tyres, airbeds, my Angelina Jolie Blow-up Doll, swimming tubes, lights, 12v soldering iron
and anything else I can find !!

These posts are a great learning experience for me, as a member of the OFFAL Group - like Manuel says " I learn, I learn ! "

Your reputation on here is well deserved, Condor and am grateful for your time.

Click to expand...

http://www.getohm.com
Seen these?

Back from my prospecting trip.....

On one night it was near zero C, plus I watched the cricket till near 2am. Of the 120AH I have in the van battery, I used 41AH, which is a little more than 33% and a bit more than I would normally use. This was checked first thing the morning after, the 120W solar panel was connected, the weather was partly cloudy that day. When I returned at 4.30pm, I again checked the battery and it was at 99% charged. I completed the charge with the genny as previously described.

Most other days, I had TV on for about 5 hours and the diesel heater for 12-13 hours and used between 18 and 26AH, most if not all was replaced by solar.

I'm going to look at mounting flat panel solar on the roof of the van, possibly another 120AH AGM and a larger inverter, with a view to not having to take the genny.
This means altering my cooking (microwave) and hot water to LPG rather than 240V. So the trade off will be a 3rd 4.5kg gas bottle which is still lighter than the genny and takes less space.

The deciding factor will be cost, plus approval from SWMBO.........

I was happy with the performance of the electrics, but leaving the van in a campground with a solar panel on the ground, even though padlock and chained, was still concerning re theft. At least on the roof, a panel is far more secure.

Got the van booked in next week for a panel install. Going with 2 x 100W panels. I'm told they will put in about 78AH on a good day, which is about 2 1/2 times my normal maximum usage.

Still it's not the good days that one needs to work with, it's the cooler, cloudier days when less power is produced and more might be used......

The panels are U.S. cells and unlike most panels that work on visible light, these work using visible, infra red and ultra violet light from 1st light to dusk.

The cells are assembled to a 2 to 3mm thick poly base (very thin), the leading edge of both panels are screwed in each front corner using a captive nut to the van roof (as a wind safety fixing when travelling) then glued to the van roof. Wiring is double insulated, UV stable and also glued.

Normally the wiring is joined in parallel on the roof so that only 2 wires go through the roof. However, mine will have the negative wire from each panel joined on the roof and one wire goes through the roof for negative. Then each panels positive will go through independently, i.e. 3 wires. There will be 3 holes @ 5.5mm dia 20mm apart, which gives a better seal than clumping 3 wires together through one big hole.

The negative wire will go direct to the solar controller. Each positive wire will go to a 10A "noarc" circuit breaker then be joined in parallel to the controller. The reason being is, that if there is a future problem with one of the panels, I can isolate it and still get power from the other and if needed can isolate both panels from the system.

The controller has no LCD display as I already have a monitoring system, only a couple of LEDs. It is also made in Holland and has a reputation for efficiency. There will then be a small run directly to the battery.

A day or 2 before I'll run the battery down 30% to check charging from the panels. The guy doing it, will do the outside fixings (panels and wiring, holes through the roof and supply the controller and circuit breakers. I'll pre wash the van roof for the gluing and fix all the internals, to keep cost down. The panels are $495 ea, Controller $145 and about $17 ea for the breakers. Labour about $250, so a bit over $1,400.

Not the cheapest, but definitely the best.....

http://www.getohm.com/
Thanks Sw1fty, had a read about the batts and it really sounds good. Great way to reduce weight in the camper trailer as well.
Jaros

condor22 said:

Got the van booked in next week for a panel install. Going with 2 x 100W panels. I'm told they will put in about 78AH on a good day, which is about 2 1/2 times my normal maximum usage.

The panels are $495 ea, Controller $145 and about $17 ea for the breakers. Labour about $250, so a bit over $1,400.

Not the cheapest, but definitely the best.....

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Sorry Condor22 but that is crazy money to be spending on a solar setup for a caravan.
Why not just use a 250 watt grid connect type solar panel on your van? You could pick one of them up for $200 or less. That alone would save you $800..