I recently set up a Trimble R12i base/rover with an external battery. I'm using a Bioenno Power 12v 20Ah LiFePo4 battery. (I believe someone on here suggested this battery and I have to say, this thing rocks! All the benefits and none of the drawbacks...? It's lightweight, relatively cheap, doesn't build up memory, lasts a long time on a single charge. We've used it for an entire week everyday without charging.... until adding the external radio)
Then last week we added an external radio, TDL-450, to increase our radio range. We are using factory Trimble cables with a splitter to power both the radio and receiver off the one battery. We are connecting it with factory alligator clips to our LiFePo4 battery. The problem is that it drained the battery in literally 15-20 minutes. The radio power consumption is labeled at 15A. I don't know the consumption of the receiver though. And our radio is currently set to 20w (as a lot of you know, it can be set to multiple wattages. 25w being the max).?ÿ
Does anyone have an idea why we are losing power so quickly? To me, it seems we are overloading the power rating of the battery at 20Ah. That would imply the receiver is pulling more than 5Ah. Or is it the connection?? Either I'm overloading the battery or there's a short, or something...?
Simple answer. Based on what I read. Battery architecture. Some of these modern batteries are designed for long slow drain. Others for short and fast. You have gotten outside of the parameters for that battery.?ÿ
Suggest you go read up on the kind of modern battery needed, and that you stay above a 40 ah battery
?ÿNot because you have to. But because you need a bigger than needed margin of extra power at the base. Because a dead base battery can shut you down, 10 minutes too soon.
Just from what I read.
I really hate dead batteries. Everywhere they are found. Except in my mother-in-laws "go make trouble" chariot.
Nate
You'll need at least 100ah to run most of the day at 20 watts. If you plan to run above 20 watts, a conventional deep-cycle battery is probably best. The lifepo4 price-to-weight ratio advantage drops drastically above 100ah.
I really liked the Optima yellow tops for external radio batteries. Heavy as sin but would last even through the 12-14 hour days I used to do during summertime.
It also helps to start by boosting that whip antenna up high, rather than crank up the power. It's pretty rare for us to operate at 20W or higher. Depending on terrain, obstructions and the distance between base & rover, increased power will degrade rather than improve the signal.
CAT batteries and I've only put them on the battery tender maybe couple times a year but they're used daily for GPS and lasers when necessary. If somebody steals them you'll be furious but they WORK
A 35AH minimum battery is recommended for the TDL-450.
Buying a 35AH lithium battery is expensive but it will do the job.?ÿ
There is a LiFePo4 54AH available, it's overkill and it costs $500, but will handle the TDL easily.?ÿ
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@michigan-left I believe your numbers are skewed to the high side because you've used the published draw for when the radio is transmitting and neglected that the TDL450H only draws 1.7W @ 12V when not transmitting. I know that the ratio of tx/rx is influenced by the link protocol and baud rate but I don't have a handle on what that ratio is.?ÿ
On page 17 of the TDL450H user manual under Battery Care, Trimble states that the TDL450H battery/charger kit includes a 12V, 35AH battery and that it will provide "all day" operation of the radio.
I've recently bought a TDL450H and a 50AH LiFePo4 battery with the plan of running a R10-2 base + the TDL450H.?ÿ We'll see how much it has left after a long day.
My numbers were based only from the datasheets of each product as supplied by Trimble. I was not able to find the watts for the 12i @ no internal radio, @ 0.5W internal radio, or @ 2W internal radio other than "4.2W for RTK Internal Radio".
And I know that the Tx/Rx ratio means not 100% @ Tx power, etc.
R10v1, R10v2, & R12's all have different efficiencies, so that's a thing too.
My analysis for these scenarios is always for "worst case" and I think you may find that for 10+ hours of use at 16W or more broadcast power will drain all but the larger deep-cycle batteries.
Everyone keeps mentioning "weird" numbers for the power of their TDL450H, but ours are 2W, 8W, 16W, 35W.
The size of the battery (35Ah or 50Ah) are completely dependent upon how hard you plan on running the TDL450H.
My understanding of Lithium is that they will supply 100% of the nominal voltage until they can't, and then they are "dead". Which is very different than the deep cycle style batteries.
I'm not an electrical engineer, but us surveyors need to wear a lot of different hats.?ÿ
Your EE hat may fit better than mine...
Everyone keeps mentioning "weird" numbers for the power of their TDL450H, but ours are 2W, 8W, 16W, 35W.
Those numbers are usually set by the dealer (technically they are "user-defined") and depend upon the output power and ERP that the end user is licensed for. The dealer is supposed to make sure that the max output power is no higher than what your license allows.
IIRC (definitely not an EE) the 5dB whip antenna (long skinny yellow bag) will give an ERP of ~100W with a 35W power output at the source, which is what we are licensed for.
The problem is that it drained the battery in literally 15-20 minutes.
That's a bad battery issue.?ÿ ?ÿPeriod.
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Inrush current and output wattage are two biggest variables in this scenario.?ÿ
The pulse of the radio broadcast is being run through a circuit,?ÿ and not a direct 35 or other wattage constant stream of data from the radio.?ÿ
With a small AGM 10AH BATTERY I broadcast for several days using the internal R12i radio selected to 2w and at day 4 decided to charge the battery just in case..
Lion batteries have their own issues like a minimum operating voltage 'shelf' but that is variable by vendor or equipment manufacturer.?ÿ
As far as license goes to output wattage, I sat with our radio shop and talked with the FCC gal, and we weren't restricted by any output amplitudes,?ÿ only the range of frequency and the length of license subscription.?ÿ
IANAEE OR A L
The problem is that it drained the battery in literally 15-20 minutes.
That's a bad battery issue.?ÿ ?ÿPeriod.
?ÿ
Inrush current and output wattage are two biggest variables in this scenario.?ÿ
The pulse of the radio broadcast is being run through a circuit,?ÿ and not a direct 35 or other wattage constant stream of data from the radio.?ÿ
With a small AGM 10AH BATTERY I broadcast for several days using the internal R12i radio selected to 2w and at day 4 decided to charge the battery just in case..
Lion batteries have their own issues like a minimum operating voltage 'shelf' but that is variable by vendor or equipment manufacturer.?ÿ
As far as license goes to output wattage, I sat with our radio shop and talked with the FCC gal, and we weren't restricted by any output amplitudes,?ÿ only the range of frequency and the length of license subscription.?ÿ
IANAEE OR A L
I'm not so sure it's a bad battery. The OP is running both the base and the 35W repeater using the same 20AH battery, I would expect it to last some time but not all day. The 20 AH battery we purchased for the repeater is not adequate to run it all day, it lasts longer than 1/2 hour but not nearly 8 hours, adding the 2 watt base might overwhelm it.
@stephen-ward I'd love to hear about your results with that battery/receiver combo! And could you tell me what output wattage you choose or test with? My TDL 450 is set to include 16w, 20w, and 25w (lower ratings as well, but the higher range is why we bought the thing). And if you could share a link to where you bought it? Thanks!
I know the tried and true battery would be a deep cycle option. But why not investigate the other newer options out there so we're not dragging a boat anchor everywhere??!!
BTW, the 20Ah LiFePo4 (brand - Bioenno Power) battery we have runs the R12i (with internal radio) amazingly!! If anyone out there doesn't need an external radio, you NEED to get this battery! As I stated in my original post, the battery lasts for an entire week and then some. And it weighs maybe a few pounds.
I use a 100 ah sla (sealed lead acid) battery. Present cost around 180$ eBay. They last a couple of years, and work well.
Nate
Are you really needing to reach 10 miles??ÿ Maybe you could turn it down to 8w and still get the job done??ÿ Or run the receiver on an internal battery and set the radio as a repeater closer to where you're actually working to lessen the load?
