How much interior space can I squeeze in for batteries?

[John Pissey]

Hi all

I'm not yet ready for the electrics but am concerned about the amount of interior space in the tank. I'm planning to put in a set of fan clusters and the duck work behind them and either a full HL230 or the half version engine which would take up less interior space. It will be a fully loaded tank with every extra feature Armortek has available. This is why I'm concerned about space. I have put the power packs in just to consider their placement and with the smoker and speakers in as well there isn't much space left. I'm planning to put the smoker just behind the engine compartment and how long will the smoker work with the size of the reservoir it has? Can I put some of the power packs between the electric drive motors to conserve space? Is there smaller speakers that can give the same performance and where do most of you put them? I was planning to install them behind the fan clusters duck work. What Ah batteries do you use and what physical size are they? How long can you play with your tank with that size batteries you use? The reason for all these questions is that I want to run the tank for as long as I can, so I want to get the biggest batteries I can squeeze in. I think I will put them just under the turret area. What do you advise?

Thanks
John

[Stephen White]

John

One factor for you to consider is choice of battery type. Look here for discussion.

http://www.armortek.co.uk/Forum3b/viewt ... cid#p42921

I've used LiFePO4 now for a year and couldn't be more satisfied. (And no, they're not at all the same as LiPo, which are susceptible to mistreatment). LiFePo4 will halve the space (and weight).

Stephen

[Adrian Harris]

If you scan through the Tiger section, quite a few people have posted pictures of their Tiger's internal layout.

A popular layout is to have the Armortek modules sitting on the sponsons, the smoker centrally against the hull rear plate, with the speakers either side of it.

I also use a LiFePO4 battery, and have found it very reliable. Mine is probably 3/4 the size of the equivalent pair of AGM batteries, but less than half the weight.

Battery life depends a lot on the surface on which you are running, and the way you are driving the tank. On grass, you may only get an hour or so between charges, whereas on a smooth surface such as indoors or on tarmac, you may find the tank runs all day.

One thing to note is that, when running, you don't get any 'feel' for how much capacity is left, as LiFePO4 has a much flatter voltage curve than AGM types. With AGM batteries, you can tell when the tank starts to get sluggish as the battery drains. With LiFePO4, the battery monitoring PCB will disconnect the battery when it has reached its minimum charge level, which means the tank just switches itself off.

This means you need a 'Plan B' in place in order to continue running, loading the tank back into the car etc. I now carry a second battery, which can be attached in place of the internal one. With the size of the pack which Stephen uses in his Panzer III, it would be quite easy to fit at least two into a Tiger. I believe Denny Patterson has fitted two pairs of standard AGM batteries into most of his models, and has toggle switches to swap between pairs, and to isolate them for charging.

Make sure the Power Supply Module is accessible, as you need to remove the cover to change fuses, so it's no good having it buried under the motors, or the false engine or whatever

I don't know that anyone will have figures for how long the smoker runs on one filling. As they don't work when over filled, most people seem to have worked out how much theirs takes for a reasonable effect, then just refill it when it has stopped smoking. Running empty will cause the wadding inside to deteriorate quicker but over filling means the element can be sitting in the oil, causing it to boil the oil rather than make smoke, which can leads to a very greasy tank interior.

The Tannoy speakers which Armortek supply with the sound option pack are extremely efficient, so produce a lot of sound for their size. Once you get things built up, you could try running just one speaker, possibly hidden under the false engine block. You'll need to run one harder than running two but these Tannoy ones seem to be pretty robust, especially given the volumes at which some people run their tanks

Adrian.

[John Fitzsimons]

I am thinking of adding a removeable engine bay for running which can be installed for static display. I need the open space under the turret as I plan to fit a turret floor and sponson amo bins.

It is worth adding a full length floor to help with layout.







Interior is quite spacious. My electronics are older type and not as compact as the new version. Speakers are my main issue with space but I think they would fit behind radiator fans.

[Kevin Hunter]

Apologies - I know there has been much discussion on batteries elsewhere. However, with reference to Adrian's last post (and comments about flat discharge / sudden stoppage of LiFePo4) I use a Spektrum radio set up which includes battery voltage telemetry. Would this warn of impending failure or is the battery more or less on or off??
Regards
Kevin

[Adrian Harris]

From what I understand, the voltage discharge graph for LiFePO4 is almost too flat to be able to spot the cliff coming.

Spektrum are bringing out a battery capacity add-on for their telemetry system, so that should show how much capacity has been used, rather than just the raw voltage or current.

Presumably you must be able to reset it whenever the battery is charged.

Adrian.

[dennypatterson]

just to add to this 4 out of my 5 panzer.s have 4 , 12 volt batteries,no problem!!!!! denny.belt and braces.

[John Pissey]

Thanks for all your input on batteries. I would not even consider LiFePo4 batteries before. However I have a large backyard that empties into a forest so I have lots of room to play and I am a little nervous about my power suddenly running out. You just can't pick one of these tanks up and bring it back home. Adrian mentioned getting about an hour on grass compared to all day on concrete however did not mention the size of his battery. I will be in a field with lots of hills and ditches so I would really like to know what ampere/hour your batteries are so that I can judge how big I should go, even if I go LiFePo4. Give me a clue so that I can plan wisely. I do like that the size of the LiFePo4 batteries are a little smaller so that I can accommodate more amperage though, but around here they are 2 ½ to 3 times the price of an AGM battery. That’s a lot! I can buy 4 AMG batteries at the same amperage for the cost of one 24 volt LiFePo4. I think I can squeeze in with two AGM beep cells between 35 to 45 Amps and between 45 to 55 Amps with LiFePo4.

I also think I am going with a ½ engine and putting the smoker underneath and not getting the duck work behind the fan clusters so I can put the speakers where they would have gone. Is there a lot of maintenance with the smokers? Do I need to get at it often?

Thanks
John

[Stephen White]

John, if you read the thread I mentioned, you'll see answers to some of your points.

Cost - in short, LiFePO4 have the same whole-life cost as lead acid: their acquisition cost is higher but their useful life is significantly longer in cycles.

Size and weight - see the tables provided. About half the comparable lead acid, if you buy on of the latest packaged arrays.

Endurance - I've run my Centurion around on the grass at Tank Fest all day and used about a quarter of the capacity. I have a single 24v, 22 ah LiFePO4. For better data, the rc aircraft guys have a number of logging devices. I've installed one of these:

http://www.modelhelicopters.co.uk/safet ... lyser.html

That should give you sufficient awareness of battery capacity remaining if you build up usage data in your first few runs.

Stephen

[Tim Page]

hi, can someone please reccomend a place in the UK that I could get a 24v 22ah LifePo4 pack as I am struggling to locate any.

I have a pair of 12v SLA packs but they take up so much space although May do for now. I don't know how good they are a am looking at a viable alternative.

cheers
Tim

[Adrian Harris]

Hi Tim.

I'm using this pack:

http://www.eclipsebikes.com/eclipse-com ... -1059.html

It's only 15Ah, but seems to be equivalent to the previous pair of 22Ah AGM batteries I had as the voltage drop curve is much flatter, so you get nearly all the juice from the battery before it switches off.

I'm going to get a second pack, plus some spare battery supports, as the pack is made up of 8 cells, somewhat similar to AA batteries, so you can change the layout of the pack. You could have them all in a line, like the old receiver packs, which means they would sit on the floor of the tank and only take up 30mm or so of height.

Adrian.

[John Heath]

Not exactly cheap but..........

http://www.tracerpower.com/24v-20ah-battery-slab.html

John

[Tim Page]

Thanks guys, I had seen that Tracer pack but discounted it on cost!

I like the look of that 15mah pack and although bulky should be a lot smaller than my pair of sealed lead acids which I think are 20 or 22mah.
Cheers
Tim

[John Heath]

The Tracer would be my first choice if it wasn't for the extortionate price.

Might go for one of these.
http://www.ebay.co.uk/itm/24v-20ah-LiFe ... 280262244e

John

[Stephen White]

LiFe PO4 has roughly the same whole life cost as lead acid. Yes, the acquisition cost is higher but their working life is significantly longer. I provided some data in my post. You could think of it as twice the cost for twice the life. That rule of thumb is actually worst case. The precise figures give LiFePO4 a significant whole life cost advantage. There is one more operational consideration. With lead acid in our tanks, the useable capacity of lead acid is nothing like the nominal capacity because the discharge curve is not flat. With LiFePO4, pretty much the whole capacity is useable, which either allows greater endurance or a lower aH.

There are pros and cons for each type of course but in performance terms, the newer technology has advantages.

Stephen